~~~~H~'i'~~~ 
: THE UNIVERSITY OF TEXAS MINERAL SURVEY ~ 
BULLETIN NO. 4, OCTOBER, 1902. 
! ~ 
I

THE TERLINGUA 
~ 
QUICKSILVER DEPOSITS, ~ BREWSTER COUNTY. 
BULLETIN OF THE ·UNIVERSITY OF TEXAS, NO. 15. 
ISSUED SEMI-MONTHLY. 

LOOKING ACROSS CROEBVS CAiON TOWARDS MARFA• MARIPOSA FURNACE. 
THE UNIVERSITY OF· TEXAS MINERAL SURVEY 

BULLETIN NO. 4, OCTOBER, 1902. 
NOTICE. 
Owing to an unavoidable delay in the preparation of the topographic map to accompany this Bulletin we are unable to send it out at this time. It will be mailed separately as soon as possible, but may not be ready before December 1, 1902. 
BULLETIN OF THE UNIVERSITY OF TEXAS, NO. 15. ISSUED SEMI-MONTHLY. 
ENTEltED IN THE POSTOFFIOE AT AUSTIN AS MAIL MATTER vF TEE 
SECOND CLASS. 



THE UNIVERSITY OF TEXAS MINERAL SURVEY 

BULLETIN NO. 4, OCTOBER, 1902. 
THE TERLINGUA 
QUICKSILVER DEPOSITS, 
BREWSTER COUNTY. 

BULLETIN OF THE UNIVERSITY OF TEXAS, NO. 15. 
ISSUED SEMI-MONTHLY. 

ENTEKED IN THE POSTOFFICE AT AUSTIN AS MAIL MATTER vF T!!E 
SEOOND OLASS. 

LET'l1ER OF TRANSMITTAL. 
Hon. Wm. L. Prather, President, The University of Texas. 
SIR: I beg herewith to transmit a Report on the Terlingua Quick­silver Deposits, Brewster County, as Bulletin No. 4: of The University of Texas Mineral Survey. 
The special report on this district has been prepared-by Mr. B. F. Rill, Assistant Geologist, and to it has been added some additional matter by way of correllation of these with other deposits now producing quick­silver. The t-0pographic map was prepared by the United States Geolog­ical Survey, the party being in charge of Mr. Arthur Stiles, topographer, under a plan of co-operation which enabled us to avail oursEJve.s of the excellent facilities offered by that Survey. 
Very respectfully, 
WM. B. PHILLIPS, 
Professor of Field and Economic Geology and Director of the Survey. 
Austin, Texas, October, 1902. 


ANNOUNCEMENT. 
The University of Texas Mineral Survey has a well-equipped labora­tory at its disposal and is prepared to undertake all kinds of investiga­tions of ores, clays, cements, building materials, water, etc. Prices will be quoted on application. Address all communications to the Director of The University of Texas Mineral Survey, Austin, Texas. 
CON'rENTS. 
CHAPTER I. 
Location of district.-Sections constituting the mineral belt.-General conditions.­History. 
CHAPTER II. 
Geology and Topography of the district.-Fredericksburg Division of the Lower Cretaceous.-Washita Division.-Upper Cretaceous.-Teritary.-Structural Geology.-Igneous Rocks.-Petrography.-Phonolite. -Basalt. -Rhyolite. ­Andesite.-Relation of Volcanic Rocks to the Cinnabar Deposits. 
CHAPTER III. 
Mercury Minerals.-Associated Minerals.-Vein Material.-Ore Deposits.-Forms of Deposits.-Fissure Veins.-Shear Veins.-Bedded Veins.-Fanlt Veins.­Irregular Deposits.-Chalcedony Veins.-Aragonite Veins.-Deposits of the Upper Cretaceous.-Deposits in Rhyolite. 
CHAPTER IV. 
Methods of Mining.-Treatment of the Ore.-Furnaces.-Condensers. 
CHAPTER V. 
Mode of Occurrence of Ores.-Future Possibilities of the Field. 
CHAPTER VI. 
Companies and Production. 
CHAPTER VII. 
Quicksilver Ores.-Geological Formations in other Countries.-Associated Minerals. -List of Minerals Containing Quicksilver.-Production and Value of Quick­silver in the United States, 1880 to 1900.-Imports and Exports.-Average Prices, 1850 to 1900.-Production of the World.-Quicksilver in Austria, Canada, Italy, Mexico, Rm1sia, Spain and United States.-General Conditions of railroad facilities, transportation, etc., in the Terlingua District, Brewster County, Texas. 
THE TERLINGUA QUICKSILVER DEPOSITS, BREWSTER COUNTY, TEXAS. 
BY 
BENJ. F. HILL, 
ASSISTANT GEOLOGIST. 
INTRODUCTION. 
'l'he field work upon which the preparation of this report is based occu­pied the writer for three months-March, April, and May, 1902. All the workings and prospects in the district were examined carefully, and the general geology studied in some detail, with especial reference to the structure. This structure is, as a whole, quite simple, the sedimentary rocks involved belonging to the Cretaceous and 'rertiary. Though the country has been badly broken and faulted, and has been subject to intru­sions of later eruptives, their relations to each other are plain. 
H has not been considered necessary to go into any detail concerning the paleontology of the sediments involved. Many fossils are pregent. They are being collected and will be described and classified elsewhere than in this report. The divisions of the Cretaceous have been recognized in most cases by type fossils, and in other cases by their association in the geological scale with known divisions. 
n must be borne in mind that in the treatment of the metliods of deposition of the ore, the criteria used were practically surface indica­tions. The development in the district has not been varied or extensive. Considerable ore has been taken out and considerable quicksilver has been produced; but exploration and prospecting, except with pick and shovel on the surface, has not been resorted to extensively. A few shafts, all less than 100 feet deep, have been sunk, with varying results. In some instances the veins seem to continue in depth. More often what has been assumed to be a vein, pinches out or disappears. Only the future can furnish positive evidence of the character and permanency of the deposits. 
The writer is greatly indebted to the property owners and -to the offi­cers of the various companies for facilities for investigation extended to him, especially to Messrs. I. A. and R. A. Dewees, of the Terlingua Min­
INTRODUCTION. 
ing Co. (:formerly Lindheim and Dewee.c;) ; Mr. Montroyd Sharpe, of the Marfa and Mariposa Mining Co.; and to Mr. Wm. L. Study, who owns the property east o:f Terlingua creek; and to Mr. L. E. Tigner, of the Col­quitt-Tigner Mining Co. Thanks are due to all the companies and many of the prospectors for handsome specimens of ore and associated minerals. 
The literature on the district has been very meager, short articles hav­ing appeared in the Engineering and Mining Journal, and The Transac­tions of the American Institute of Mining Engineers, by Mr. Spaulding and Prof. Blake, respectively. The government publications on mineral resources have had short articles on the deposits. 
The analyse.s used in the report have been made in the laboratory of the United States Geological Survey, at Washington, or in the laboratory of the Mineral Survey, in Austin. A great many thin sections of the various rocks of the district have been made and were studied by the writer in the office of the Survey. The micro-photographs were made in the Geological Laboratory of Columbia University, New York City. 
The topographical map of the district, called the "'l'erlingua Special," was made by the United States Geological Survey topographic corps, under the direction of Mr. Arthur Stiles. The expenses of the field work were borne bv the University Mineral Survey. 
~ 
Dr. Geo. F. Becker's report on the "Geology of the Quicksilver Depos­its of the Pacific Slope," Monograph XIII., U. S. G. S., is the most com­plete and comprehensive treatise on quicksilver extant. In this volume he has entered into great detail concerning the theoretical and practical considerations governing the chemistry o:f the deposition of quicksilver. These considerations are just as true for Texas as for California. The writer of this paper will not attempt to go into the philosophical side of the questions, but will refer those interested in this very important i-ide of the subject to Dr. Becker's monograph. 
The writer is greatly indebted to Dr. Wm. B. Phillips, Director of the University of Texas Mineral Survey, for valuable suggestions and mate­rial assistance in the preparation of this paper. 
MARFA & MARIPOSA MINING COMPANY'S NO. 1 FURNACE (10 TONS.) 
FAULT IN VOL.A. LIMESTONE, SOUTH END OF SECTION 39, BLOOK G4. 
CHAPTER I. 
Location, General Conditions and History. 
Although many metals or metallic minerals are known to exist in Texa.s, the value of the output of the State has been romparatively quite small. The Shafter· Mine, of Presidio county, has been a heavy producer of silver for the last fourteen years, and the Hazel Mine, in El Paso county, produced considerable silver and copper during the period in which it was worked. Although localities are known to exist where gold, silver, copper and "tin are in apparently paying quantities, little develop­ment along these lines has been undertaken. . In the last :live years, however, a new industry has sprung up which has added very materially to the value of the output of metals from Texas, and which bids fair to increase until it becomes one of the most productive of Texas mining industries. Reference is made to the quick­silver mines of the Big Bend of the Rio Grande, in the southwestern part of Brewster county. 
LOCATION. 
The belt that may be designated as mineral bearing, as :far as at pres­ent prospected, occupies a rectangular strip, approximafoly fifteen miles long and :four miles wide, the greatest length being east and west. The longitude is about 104° West, and latitude 29° 30' North. The Fresno caiion is the western boundary o:f the district, this waterway representing the we.stern limit of the geological formation in which the quicksilver has been found to occur. The eastern end of the rectangle would be several miles ea.st of the Terlingua creek. 
While it is not at all sure, or even probable, that all the paying mines will be found within this area, still it may be stated that it will be within this district that nearly all the development of the near future will take place. 
The district is about twelve miles :from the Rio Grande, on an average; and, roughly speaking, lie,.s parallel to the course of the river. The belt outlined above lies in blocks of the public lands which were .surveyed by the railroads, on the alternate section arrangement. The blocks involved are Block G 12, Gulf, Colorado & Santa Fe Railroad; Block 341, and Block G4, Texas Central Railroad, and Block G5. Of these Block · G 12 is the westernmost a.nd Block G4 the easternmost. Most of the sections of these various blocks do not, so far as has . been discO'Vered up to the present time, contain quicksilver in paying quantities. Block G 12 has been developed most, the discoveries and explorations there being the ·first in the district. It is only within the last few months that ore has been found east o:f Terlingua creek in Block G4. Block 341 lies between the two above-mentioned blocks. It must be borne in mind that one-half of the sections are patented land and have not been prospected to any con­
THE TERLINGUA QumKSILVER DEPOSITS. 
siderable exfamt, but are being held by the owners to await the develop­ment on the State sections which are subject to mineral locations. The Terlingua postoffice, which may be considered as the center of the district so far developed, is in Section 58, Block G 12. 
The following sections, of 640 aqres each, have had mineral claims located upon them, or are contiguous to such sections, and may be con­sidered as constituting the most promising belt of the district: In Block G12, Sections 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 15, 46, 47, 48, 49, 55, 56, 57, 58, 59, 60, 69, 70; in Block G5, Sections 98, 99 and 100; in Block 341, Sections 69 arid 70; in Block G4, Sections 295, 286, 298, 297, 216, 248. The individual sections (odd-numbered ones) are not, of course, subject to location by prospectors; but in all instances cite'd, the sections have been reported as actually showing the mineral, and in a number of instances are the most productive in the field. 
GENERAL CONDITIONS. 
The location of the district is one of the drawbacks encountered by the developers. The remoteness from railroad facilities, and the inhospit­able aspect of the country, are deterring influences in the opening up of the district. Terlingua postoffice is 105 miles from Marfa by wagon road, from Alpine 95, and from Marathon 90, all these being stations on the Southern Pacific Railway, from 200 to 250 miles south of east of El Paso. The wagon roads are fairly good, but lack of water on the Mara­thon and Alpine roads in the dry season is a source of great inconven­ience to freighters. The elevation of the mines above the sea level is about 3200 feet, while the points of shipping on the railroad vary from 4000 to 4689 feet. This is an advantage in the haulage of freight, such as heavy machinery and supplies, to the mines. The grades are for the most part very gentle. 
Except in the rainy season, which lasts theoretically from June until October, the water· used at the main camps is hauled for distances vary­ing from six to twelve miles, the sources of supply being Cigar springs, Terlingua creek and the Rio Grande. The method of transportation is by wagons carrying metallic tanks of from 350 to 500 gallons capac­ity. The prices of water per tank vary from $2.50 to $3.50. It is most fortunate for the operators that no water is required in the reduction of the quicksilver from its ores, all the water being used for domestic pur­poses. 
Reservoirs have been constructed in numerous canons and draws for 
the storage of storm water. In some instancci> great difficulty has been 
encountered in getting them to retain the w~ter, owing to the fractured 
condition of the limestone, in which they are built. However, the three 
larger companies now have . tankage of considerable capacity available 
for use. 
In addition to these artificial reservoirs, there are numerous natural 
tanks, or "tinajas," which hold considerable quantities of water, some 
lasting through the entire year. The open workings along the veins, too, 
hold considerable water, which is utilized by freighters for stock water, 
while it lasts. 
A few attempts have been made to get water by sinking wells. So far 
only very shallow wells have been dug in arroyos. A little water has 
been found, but it is badly impregnated with mineral matter, chiefly 
THE TERLINGUA QUICKSILVER DEPOSITS. 
gypsum. The possibility of getting deep artesian water has been consi~­ered, but no experiments have been made up to this time. However, the badly faulted condition of the country is a drawback in this respect. 
Altogether, the water problem is somewhat serious, and as the district develops will be more serious. The most feasible plan of obtaining water will be to construct more and larger reservoirs. 
'l'he vegetation in the district is very sparse, and consists entirely of the desert types. The most common plant encountered is the sotol (Das­ylirion heteracantha), which is used by the miners for making huts and fol'. thatching roof of temporary structures. It has been claimed that it is possible to use the sotol as a fuel, and in all probability the experiment will be made when the Rcarcity of wood causes the fuel problem to be serious. Other abundant types are the lechuguilla (Agave heteracantha), the okatilla ( Fonguiera splendeus), palma and palmilla, and nopal. In the immediate vicinity of the mines there are a few stunted mesquite bushes and in the draws the mesquite and catsclaw (Acacia weightii) grow to be sufficiently large to be used for fuel for the furnaces. How­ever, a very large proportion of the wood is hauled from the valley of the Rio Grande, from twelve to twenty-five miles from the mines. 
The climate is mild in winter, but the summer months are very warm. 
The flats, especially, are almost uninhabitable on account of the high 
temperature. However, the nights are always pleasant enough to allow 
comfortable rest, which iR a great necessity after the exhausting temper­
ature of the day. 
HISTORY. 
At Comanche spring, a small "seep," seven miles north of the Rio 
Grande, the gray limestone bluffs have been covered in 'a number of 
places with rude paintings of characteristic Indian designs. The artists 
were without doubt the Comanche Indians, and the vermillion pigm®t 
used by these aboriginal artists was prepared from cinnabar. This cin­
nabar must have been obtained from the outcrops of the veins and pock­
ets in the neighborhood of California Hill, the locality that has yielded 
several thousand flasks in the last few years. 
The Indians disappeared from the country and nothing was heard con­
cerning the presence of quicksilver until about the year 1887, when 
rumors reached the stations along the Southern Pacific Railroad that ore 
was plentiful in the country west of Boquillas and east of Presidio. No 
record has been kept of any authentic find or locations. The Geological 
Survey of 'l'exas had reconnaissance parties in the regions west of the 
Pecos, in the years 1889-90, and Mr. von Streeruwitz, who was in 
charge, mentions that the presence of cinnabar had been reported to· him, 
but that he had been unable to find traces of it. (Geol. Survey of 
Texas, 1889, page 225.) Mr. E. T. Dumble, also, states in his gen­
eral report, that no confirmations had been made of reported localitiP::. 
Dr. Becker, in his monograph on the "Quicksilver Deposits of the Pacific 
Slope," gives a very complete account of the then known quicksilver 
localities, not only of the United States, but of the world; but no men­
tion is made of the Texas deposits. 
The Mexican miners on their trips between the Shafter mines and 
Boquillas would in all probability pass near the localities that have since 
been found to be quicksilver producing. Some of these miners were 
familiar with cinnabar, or "azogue," as the Mexicans call it, but its pres­
THJ<J TERLINGUA QumKSILVER DEPOSITS. 
ence so far as can be learned was not reported to the Americam at 
Shafter or Boquillas. According to accounts, early in the year 1894, 
some Mexicans residing on a small irrigated farm at the mouth of Ter­
lingua creek, obtained some pieces of rich cinnabar fl.oat, and took them 
to the village of San Carlos on the Mexican side of the river. From San 
Carlos they were carried to Chihuahua. 
Mr. Geo. W. Wanless, of Jimenez, Mexico, who was agent at that point 
for the Rio Grande Smelting Works, learned of the :finds and obtained 
directions from the Mexicans how to reach the locality. He, together 
with Mr. Chas. Allen, of Socorro, N. M., went to Marfa and from 
thence down to the locality indicated by the Mexicans. They found the 
veins and located claims. Shortly after this time Prof. Wm. P. Blake 
and Mr. Jos. P. Chase, of New Mexico, visited the locality, and Prof. 
Blake's description of the deposits, published under the title of "Cinnabar 
in Texas,'' in the Transactions of the American Institute of Mining 
Engineers, Vol. XV, page 68, is the first notice of importance that we 
have of the region. 
Messrs. Chase and Allen acquired Sections 41 and 59. After doing a 
small amount of work they left the country and subbequently sold their 
holdings to Messrs. Turney, Wright, Chase, Woods and Combs, an<l. it 
became known as the California property . 
. In the winter of 1896 and the spring of 1897, a considerable amount 
of prospecting was carried on in the district. About this time Messrs. 
Thomas Goldby and G. H. Normand made a prospecting trip to the dis­
trict and obtained samples, which were assayed and found to contain 
quicksilver. The land situation was in a chaotic state and no claims 
were filed by them at this time. 
Meanwhile Mr. I. A. Dewees had become interested in the :field, and, 
in company with Mr. Hess, of Marathon, and Mr. Reid, spent consider­
able time prospecting over the entire district, which resulted in his loeat­
ing valuable claims for J;indheim and Dewees in various parts of Block ·G12. Other prospectors to locate claims at the time were Messrs. Gaughran, McGuirk and McKinney and Parker. 
In December, 1898, Messrs. Normand, Sharpe and Goldby took up 
claims on Sections 38, 40 and 58, and in August, 1900, began to treat ore 
in a. ten-ton furnace that had been erected by Mr. Robt. Scott, of Cali­
forma, after models of the furnaces in use at New Almaden. The ore 
treated was principally from Sections 38 and 58, the ore from Section 
38 being hauled two miles over very rough roads. 
Mr. W. E. Bell had meanwhile secured an option on the California 
property, and had done considerable prospecting and development work, 
and had erected retorts and produced some quicksilver. 
Mr. Dewees also retorted ore successfully. His retorts were locatea. on 
'l'erlingua creek, nine miles south of the mines. 
Hess and Gaughran put up a retort on their property, known as 
Excelsior, on Section 38, and produced some quicksilver· and later 
McKinney and Parker and Dr. Coltrin retorted ore, producing some 
quicksilver. 
In February, 1901, Messrs. Normand, Sharpe and Goldby purchased the 
California property from W. E. Bell, and their holdings are. at present 
worked by the company composed of these gentlemen, and is known as 
the :Marfa and Mariposa Mining Company. In the Spring of the present 
THE TERLINGUA QUICKSILVER DEPOSITS. 
year an additional ten-ton furnace was added to their plant. This com­pany has produced a large proportion of the output of the field, and is at present in successful operation. 
In the early part of the present year the Terlingua Minin,g Co. (Lind· heim and Dewees) had built for them a forty-ton Scott furnace of the most improved type, and produced considerable quicksilver. This com• pany is said to have had several thousand tons of ore on the dumps when operations were commenced. 
Messrs. Hess and Gaughran, owners of the Excelsior claims on Section 38, have disposed of their property to the Colquitt-Tigner Mining Com­pany. A furnace is now being erected for this company and mining is being carried on in anticipation of an early completion of it. 
The latest discoveries of any importance were made in January, 1902, when quicksilver was found on Section 216, Block G4, and later on Sec­tion 248, Block G4. Mr. W. L. Study, of the Marfa and Mariposa Com­pany, has located claims and will develop the property on Section 216. 
The country, as a whole, has been fairly well prospected. Many claims have -been 1-0cated whose value is at be.st uncertain. The individual sec­tions, in some in.stances, promise good values, but the owners are in no hurry to develop or dispose of them, preferring to wait and profit by the experiences of others. 
Allusion has been made to the remoteness of the country, the lack of water, etc., as being deterrent influences in the rapid development of the district. 
CHAPTER II. 
The Geology and Topography of the District. 
The study of the geology of the Terlingua di.strict involves the study of a considerable scope of country, if its general relations are to be under­stood. By the Terlingua district here is meant the area between the Fresno canon on the west and the foot hills of the Chisos mountaim, on the east, the Grand Caiion mountains on the south, and the Alamo de Cresario and Terlingua creek on the north. Within this district are encountered extensive series of sedimentary and volcanic rocks, whose mutual relations will be described hereafter. 
North of the district the country is a high plateau of volcanic mate­rial. This plateau extends from north of Marfa to the Fresno canon, sloping gradually from Alamito southwards. The plateau is not level, but has many mesa-like hill..~ of lava and volcanic tuft's, no sediment~ except of volcanic origin being visible until the conglomerates and thin­bedded marls and limestones of the Fresno are encountered. 
East of this plateau the underlying sediments are exposed on the Mara­thon and Alpine road in the neighborhood of Santiago Peak, a single mountain of granitic acidic eruptive rock, quite distinct from the flows making up the plateau. The sediments are of two distinct series, the lower of which is upper Cretaceous, the higher members immediately underneath the volcanic complex being in all probability divisions of the Tertiary. The strata exposed on the east are practically the same that 
THE TERUNGUA QUICKSILVER DEPOSITS. 
are exposed above the Cretaceous in the section along the Fresno caiion, The eruptions furnishing the enormous masses of volcanic rock were probably in the latter part of the Tertiary period. 
East of the Fresno and south of Alamo de Cresario the country changes its character entirely. Instead of the volcanic tu:ffs and lavas with the associated Tertiary sediments, there are present massive thick-bedded limestones of the Lower Cretaceous, overlaid by the thinner bedded series of the Upper Cretaceous. These Cretaceous sediments dip sharply to the west and northwest at a high angle, and furnish evidence of a great fault having a northwest southeast trend that can be traced from Alamo to beyond the Rio Grande. The Tertiary sediments and tuffs are laid down horizontally on the steeply inclined strata of the Cretaceous. West of the Fresno canon, and north of Polvo on the river, these vol­canic flows and Cretaceous sediments are seen in great development, and extend into Mexico west of the fault line that forms the western scarp of the Grand Caiion mountain. The valley between this mountain-block and the plateau upon which the mines are situated represents a dMo­cated block, three to five miles wide and of indefinite length. On the north side of the valley the heavy Lower Cretaceous strata dip to the south and southwest at a high angle, being almost perpendicular in ~ome localities. The south line of the block fault which is the north scarp of the Grand Caiion mountain plateau shows vertical bluffs that reach the height of 1200 feet. The strata dip gently towards the south­west at an angle of ten degrees to fifteen degrees. The Grand Canon de Santa Helena, which traverses the fault block, is an enormous shut-in with perpendicular walls varying in height from less than 100 to more than 1800 feet in height. It is in the neighb9rhood of this canon that the most complete section of the heavy sediments of the Lower Creta<:E:9us may be obtained. 
The eastern limits of the heavy limestone in the Terlingua district is a caiion that represents a north and south fault line. This caiion shows the Lower Cretaceous sediments on the west side with the thin-bedded Upper Cretaceous members on the east side. It is near this <'a:iion that the mines of McKinney and Parker are located. The down throw is to the east and the displacement probably seven hundred feet. This fault can be traced northward in the direction of Agua Fria for several miles, the displacement becoming constantly less towards the north. 
The heavy sediments that form the body of the plateau dip to the north and to the west, under the volcanics and Tertiary sediments mentioned before. It will be seen that there has thus been produced a large area of the heavy limestones dipping in three directions. The flanks of the area are covered by the sediments referable to the Upper Cretaceous and to the Tertiary, and all are cut in various places by dikes and bosses of late igneous rocks. These eruptions are most common and the flows most extensive along the fault lines. 
TOPOGRAPHY. 
The to.pography of the district is v~ry distinctive, being due to the deformat10n beds that are of such physical construction as in !>Orne cases to resist, while in others to yield quite easily to erosion. The structure. ~ue to extensive faulting, is als~ quite an important factor in the shap­mg of the topography. The highest part of the district is along the 
THE TERLINGUA QUICKSILVER DEPOSITS. 
northern scarp of the uplift that lies to the eastward of the Fresno canon. Here the highest beds of the Lower Cretaceous form a serrated ridge somewhat less than 4000 feet above the sea level. The Lower Cretaceous sediments have been eroded from the s.ummits, but are seen along the flanks, as mentioned before. From this highest part of the district the general dip is southerly and southwesterly, although there are many rnb­ordinate valleys and ridges within the various limits of the' uplift. At no place on the uplift are the remains of the Tertiary to be seen, although in one of the valleys, caused by a subordinate block fault, Cretaceous strata are exposed immediately underlying the Tertiary. 
One of the most conspicuous topographic features of the district is Block Mesa, which consists of a dome of Lower Cretaceous limestone, having a general elliptical shape, its longest axis being northeast and southwest. This mesa. dips in all directions from the summit, forming a particularly fine example of the qua-qua-versal type of fold structure. Erosion shows the cause of the uplift to be a mass of igneous material near the center. This mass never reached the surface and was laccolitic in nature, the erosion of the limestone allowing it to be exposed. The dips on the slopes of the hill are .quite uniform, having a general average of forty degrees. The dip, however, :flattens out towards the base of the hill and :faults occur on four sicl.es, making the mesa a detached _block. The displacement, however, is not great. 
The character of the limestone arid the thickness of the beds in the Lower Creta~eous series is favorable for the formation of numerous deep and vertical walled canons. These canons, all of which are dry except in the rainy season, traverse the country in every direction and make it very difficult to build roads, or even trails. 
Probably the most distinct and characteristic feature of the topography of the district are the clay hills with their cappings of white limestone. The hard limestone has protected the softer clay and shales from com­plete erosion, and in many places the mesa-like structure due to these two strata is still prominent. These beds occur in the geological section as the uppermost members of the heavy limestone series. Owing to the fault system of the district these beds are found at various elevations. In studying the structure of the country they are most useful, as they furni.sh a distinct horizon· in the section whose rocks in many places are not of so varied a character as to be readily distinguishable. In addi­
'tion to being prominent in the fault valley, and on the summits of the mesas; these beds are in a number of cases, notably at California Hill and Olay mountain, intimately associated with the igneous intrusions, in which .cases the contrast between the pure white limestone and the dark colored clays and lavas make prominent landmarks. Along the ff!ult line on the south and west side of the Terlingua plateau these beds are prominently exposed and mark the boundary between the upper and lower strata of the series. 
Off the flanks of the plateau or uplift the surface has been more easily eroded, and the soft beds have been worn away, leaving the hills much lower and less abrupt, except where they have been cut by igneous flows aDd intrusions. East of the fault line marking the erosion limit of the massive limestones, the most conspicuous features of the topography are the volcanic neck and bosses that rise from the comparatively level ]Jlain formed by the thin beds of the Upper Cretaceous and the Tertiary. In some instances these masses attain the height of more than a thou,;and 
Tm·~ T1mLINGUA QuICKSILV:ER DEPOSITS. 
fret. The sediments arC' often capped by thin flows of lam, and rn a number of instances dikes radiating from Yolcanie uecks mav be traced acro:3s the country for miles. 
GEOLOGY. 
The rocks of the area, as before stated, may be divided into two claHses, those of sedimentary origin, and those of igneous origin. The rocks of the igneous class may be subdivided into those which came into their pres­ent positions in the molten state, and those which, though of igneous material.. have been laid down in beds, as volcanic ash and tuft's. These latter are important only on the outskirts of the district proper, as along the Fresno cal'ion, for instance. 
Except for minor unconsolidated deposits of recent origin, all the sedi­ments present in the district are marine, although they indi cate that the conditions under which they were deposited varied to a considerable extent, as there are present deep sea and shallow water deposits, with many intermediate varieties. 
The sediments belong to two periods, the Cretaceous and Tertiary. The Cretaceous section is quite extensive, and ha.s representatives of both the Lower and Upper divisions. The total thickness of the Creta­ceous is in the neighborhood of 2000 feet, while the Tertiary, with the volcanic tuffs and ashes, represent several hundred feet more. There has been no attempt to subdivide the Tertiary, and the Cretaceous has been studied in a general way with the view of obtaining an understand­ing of the structure. . 
Mention should be made of the extensive gravel and "adobe" depof'its that occur in the district. These are in some cases more than 50 feel in thickness and are the results of deposition from the drainage ways However, most of the surface is uncovered and the country rock is nearly always in evidence. 
THE LOWER CRETACEOUS (FREDERICKSBURG DIVISION). 
The oldest sediments exposed in the area studied are those of the Fredericksburg division of the Lower Cretaceous or Comanche series. The bottom of this series is not exposed in the region. so far as has bee~ ascertained. The lowest member found exposed in the high bluff along the north side of the Grand Canon mountain is the Comanche Peak limestone. This formation is exposed along the fault scarp about five miles northeast of Terlingua. In the Grand Canon mountain section the Comanche Peak beds are at the base of the cliffs on both sides of the Rio Grande. Over 100 feet of these beds are exposed in each of the localities mentioned. The limestone is rather thick bedded, massive, and is of a bluish gray· color. It hns quite characteristic nodular weath­ering. The m-0st common fossil recognized is the oyster "Exogyra tcxana." 
.Above the Comanche Peak formation is the Ed,rnrds limestone. This formation 011tc-rops in many places over the whole area and i' the most exposed of the whole Comanche series. It is seen outcroppina in the ran'.tC of hills ra't of the Fresno fault, in the hills south of the Alamo de (';psario. ;rnd it-ontcrop forms, for the most part, the escarpment of lwaYy limestone runnin~ northwest and southeast. that forms the eastern 
IGNEOUS ROCK, ELEPHANT HEAD. BL.A.CK MES.A. FROM MARIPOSA. STORE. 


General View of the Geology of the Terlingua District.. 
THE TERLINGUA QUICKSIINER DEPOSITS. 
limit of the Lower Cretaceous in the Terlingua district. It is present in the Crcesus ca:iion, and in Black Mesa, and is the material underlying the formations that are the most productive of quicksilver. 
There is no breach between the Comanche Peak and the Edward.ti limestones. They can be easily distinguished, however, by their differ­ent physical characteristics. It is thick bedded for the most part, but carries in some horizons thin-bedded marly streaks, whose softness con­trast strongly with the hard, indurated surfaces of the greater part of the form ati on. 
Fresh pieces of the limestone from various portions of the section show . the color to vary from pure white to blue, cream and yellow, but the weathered surfaces always present a dull gray color, whatever the original color may have been. . 
A very characteristic feature of the Edwards limesrone is the oceur­rence in it of beds carrying large numbers of flint nodules. The flint horizorni, of which there are several, vary in thickness from 30 to 80 feet. 'l'he flints differ in size, shape and color, though kidney-shaped masses of a dark red, about two inches in length, are the most common. In some of the beds of the Edwards limestone the siUceous material is not all segregated, but is disseminated through the beds, causing cherty patches. 
The total thickness of the Edwards limestone in the Terling.ua dis­trict is about 750 feet. It is probable that the complete section is pres­ent in the Grand Canon mountain exposures, but no attempt was made bv the writer to subdivide it into its various horizons. The Edward£; limestone carries quicksilver ore in several loc11lities north and west of Terlingua postoffice, but orily in, its upper divisions. 
The upper part of the formation is characterized by numerous caves, .some of which are of considerable extent. 
The most common and characteristic fossils present in the Edwards limestone dre those of the "Monopleura," "Requienia" and "Nerineidae" genera. 
WASHITA DIVISION. 
Above the Fredericksburg division of the Lower Cretaceous are the members of the Washita division. No structural break has taken place, · and in its lower members no great physical difference in the character of the beds is to be noted. Near the top of the series, however, a series of clays and calcareous shales is present that differs materially from the great masses of .thick-bedded limestone of the Fredericksburg. 
In extent the . members of the Washita are very similar to the Edwards limestone, especially the lower members that rest directly on the Edwards. The uµpermost members have been eroded for the most part, but there are still present a very great number of particles of the "Exogyra arietina" (Del Rio) clay and the Vola (Buda limestone}, whose mesa-like structure is a characteristic feature of the topography. 
The lowest members of the Washita series is the Fort Worth or Wash­ita lime$tone. Tliis formation carries a large proportion of the ~eposits of quicksilver so far exploited. This limestone outcrops at Terlingua postoffice and vicinitv, and all the develoµment in that neighborhood haa been carried on in this formation. Its thickness is apparently somewhat more than 100 feet, and may be considerablv more, as it is impossible to establish the exact demarkation between its base and the upper bed 
THE TERLINGUA QUICKSILVER DEPOSITS. 
of the Edwards. The lower beds of the Washita are heavy and thick, while the upper portion is quite thin-bedded and has present in it numer­ous strata of marly limestone of only a few inches thickness. The color of the limestone varies from bluish at the base to almost pure white at the top. The characteristic color of the weathered surface is gray except where traversed by iron veins, when it becomes reddish brown. The for­mation is greatly faulted, and in a number of places has been locally metamorphosed. by igneous intrusions. Veins of calcite and aragonitc cut the formation in every direction. In some localities the char" acteristic fossil of the Fort Worth formation "Kingena wacoensis" is abundant. 
Above the Fort Worth limestone is a series of clays, argillaceous and arenaceous shales, and thin-bedded limestones, of a blue green and brown color. This formation is the stratigraphic equivalent of the "Exogyra arietina" beds or the Del Rio clays. The thickness is from 60 to 100 feet, and in all cases it . is covered with a capping of hard white lime­stone to which is due its preservation from erosion. These clays carry large quantities of iron pyrite and gypsum. In no case, however, has cinnabar been discovered in them, although it is abundant in the Fort Worth limestone immediately below. Fossils are present in great abund­ance, the most common varieties being N odosaria texana, Exogyra arietina, Exogyra drakei, Gryphaea pitcheri, and numerous Echinoderms. 
'rhe Del Rio clays are always capped by a white, extremely pure lime­
stone, whose thickness approximates 100 feet. It weathers in a rather 
characteristic manner, the exposed surfaces breaking up into a mass of 
angular fragments. The undecomposed rock possesses a very distinct 
conchoidal fracture, a .feature very noticeable at California Hill and 
Olay Mountain in the Terlingua district. The stratigraphic position of 
this limestone indicate that it is the equivalent of the Buda limestone 
of Prof. R. T. Hill. So far as known this limestone does not carrv 
quicksilver, although in many places it is cut by numerous calcite veins. 
Fossils are not abundant except in the lowest beds. Several forms of 
Gryphaea were recognized. 
THE UPPER CRETACEOUS. 
In many localities in the Terlingua district the Buda limestone, the 
uppermost member of the Lower Cretaceous series, is overlaid by a great 
series of sediments, several hundred feet in thickness, characterized by 
a great development of lime shales, flags and clays. The highest divis­
ions of the formation represent another period of thick-bedded limestonP 
deposition. 
The lowest member of this division is the Eagle Ford formation. It 
is made up of yellowish, thinly laminated argillaceous, arenaceous and 
calcareous material. In some instances beds of clav 8 to 10 feet in thick­
ness occur in the series, while at other times bands of comparatively 
pure limestone are present. The most of the section, however, is made 
up of limy flag stones varying in thickness from 4 inches to 2 feet. The 
beds are traversed in all directions by seams of gypsum and calcite 
Pyrite is also present, though in most cases it has been oxidized by expos­
ure. The veins in the clays and shales in a number of instances have 
carried cinnabar and native mercury. 
THE TERLINGUA QUICKSILVER DEPOSITS. 
The Eagle Ford formation is rich in fossils, the most common genen being "lnoceramus" and "0.strea." . 
Owing to its physical characteristics the Eagle Ford format10n hai been denuded from the various uplifts in the district, and is presen1 most con;;picuously where it has been faulted into the position it now occupies. The formation is shown in great development on all fou1 sides of the Lower Cretaceous block, the finest exposures being south of Terlingua, where the upturned edges of the incline<} strata on the down-throw of the greal Fresno fault may be seen. The thickness here is over 500 feet in the exposed beds. Somewhere between the Eagle Ford formation and the Austin chalk, the next highest division, there has been a break, but the complete section has not been worked out. The upper parts of the Eagle Ford are chalky and grade somewhat grad­ually into the chalk which is exposed near Lajitas on the Rio Grande and in the Fresno canon. The horizon, which has been called Austin chalk, may be simply the upper part of the Eagle Ford formation. In the Fresno it allows a thickness of about 100 feet, while a somewhat greater thickness _was _observed ne_ar Lajitas. E~s.t of the 'l'e~linra.cr~k 
the same formation is exposed m many localities. Associate with it are beds of clay and lignite, some of which may prove of value in the future. 
TERTIARY. 
It is unnecessary to go into detail with regard to the rocks overlying the Cretaceous. The Tertiary is mainly interesting as being the proba­ble age of the igneous intrusions that stimulated the ore-bearing solu­tions from which the quicksilver was deposited. While some limestones and shales are present, most of the material is of volcanic origin, rhyo­litic and andesitic muds, and tu:ffs, accompanied by volcanic agglome­rates and conglomerates of sedimentary material with volcanic cement. The Tertiary beds themselves do not, so far as known, carry quicksilver; 
STRUCTURAL GEOLOGY. 
The Terlingua area as a whole lies on the eastern flank of the Conti­nental divide, but the mountain-making forces have been at work, although in a somewhat modified form. The immense series of deep sea sediments of Lower Cretaceous times, with the deposits of the con­stantly shallowing Upper Cretaceous sea, formed originallv a section of about 2000 feet without structural break. Some time after the close of the Cretaceous, probably in the Eocene Tertiary, there was a series of disturbances causing an uplift of the Cretaceous strata. These uplifts resulted in a number of great faults having a northwest and southeast trend. The f~ult movement was accompanied by folding, which, how­ever, resulted m a great number of minor faults, due to the brittlenes8 of the beds imolved. 'rhe amount of displacement on the different side~ of the faults vary from less than 100 to more than 1000 feet. 
.\crompanying the faults, or the disturbances causino-them was a series of volcanic flows. It is probable -that these flows ~ontinu~d for a long period after the main disturbance, and that minor changes in the strnctnre took place after each flow. The main development of the vol­canic rocks are on the three sides, north, east and west, of the Cretaceou" 


\
-, 
F"ssure Veins to Fault Lines. 
Dia.gram showm. g Relations of ' 
THE TERLINGUA QUICKSILVER DEPOSITS. 
uplift of 'l'erlingua. On three sides the rocks of the Cretaceous have been faulted and are now covered by great masses of igneous material. The Chisos mountains may have been .formed at this period. These mountains occupy a region caused by the great block fault between the Cretaceous limestones · of Terlingua and Grand Canon mountain and those of the Carmen range, east of Boquillas. 
'l'he Terlingua uplift itself, by which is meant the area of J;ower Ore~ taceous limestones, between Fresno Caiion and Terlingua creek, may then be considered the elevated portion of the country, left in its pres­ent position by the subsidence on either side of it of the Cretaceous lime~ stones under their great loads of volcanic material. The north and south limits also represent fault lines. The actual position of the faulh are obscured by the detrital material in the valleys, but their presence is indicated by the steep, pitching monoclines at the north and . south ends of the uplift. As stated elsewhere, the exposures of the Eagle Ford beds of the Upper Cretaceous are confined to these valleys, but all the evidence goes to show that they have shared in · all the disturbances equally with the Lower Cretaceous, and their absence on the uplift is due simply to the fact that they have been eroded since the movements took place. 
It will be seen, then, that the structure, in a large way, is easily under­stood. The minor disturbances, with the secondary effects of the great disturbances, cause the most complicated problems with which the geolo­gist in the region has to deal. 
In addition to the great northwest and southeast faults along the Fresno canon and east of Terlingua creek, there are parallel breab between, accompanied by more or less displacement. In most instances the displacement becomes greater from north to south, and the valleys caused by their presence cut the southern monocline at right angles. In still other instance.s these minor faults differ somewhat in direction from the main faults and run into them at high angles. On the uplift, these faults involve on the surface the rocks from the Buda or Vola limestone to those of the upper part of the Edwards limestone. Between the great fault we.st of the Croesus canon and the great fault west of McKinney and Parker's mine there are five of these faults. Between the mines of the Terlingua Mining Company and: those of the Colquitt-Tigner Com­pany are three faults, all having a direction of N. 50 W. The displace­ment in two is 100 feet, while in the third it is over 200 feet. The valleys and ridges owe their existence to these caru;es. The greatest of the sec­ondary faults bas a somewhat more westerly direction. It is near the main Fresno fault and runs into it a half mile south of California Hill. !t is through this fault that the igneous material forming this hill was mtruded. The downthrow in this case is to the east, and is several hun­dred feet. Nortbwest of Two Cone mountain this fault is represented by a deep valley, at the bottom of which are exposed the rocks of the Del Rio and Buda formations. 
Normal to the northwest-southeast faults are a large number of "till small~r breaks, where the displacement in some cases is only a few inches. In still others these breaks seem to have been accompanied by no dis­placement whatever. Itis along the line of these minor disturbances that most of the quicksilver is found, and their nature will be more fullv dis'­cussed under the treatment of the vein system. · 
THE TERLINGUA QUICKSILVER DEPOSITS. 
THE IGNEOUS ROCKS. 
'l'he discussion of the subject of the igneous rocks of the Terlingua district will be confined to the statement of their location, relation to the sediments and the ore deposits, with a short petrographical descrip­tion of the most common varieties. No attempt will be made to enlarge on the nature of their various relations with each other, nor to discuss fully their chemical and mineralogical characteristics. These questi@ns may lie discussed in a separate paper, when more time will have been given to their proper investigation. 
In three localities upon the Terlingua uplift the igneous rocks act­ually cut the Lower Cretaceous Limestones. In two of these instances, that of California Hill and of Olay mountain, in the vicinity of Terlin­gua postoffice, they occur as old volcanic plugs, whose upper . portions have been eroded. Both these plugs are now :flanked by the limestones arid shales of the Buda and Del Rio formations. These rocks have been locally metamorphosed on the contacts, slaty cleavage having been induced in the shales. The third instance of volcanic material within the bounds of the uplift is that. seen at Black Mesa. It is probable that here the volcanic material never penetrated ·the Lower Cretaceous, as in the cases just mentioned, but formed a laccolite between the Edwards limestone. and the ove:i:lying beds. Black Mesa, described else­where, owes its existence to this intrusion. 
In the thin-bedded formations of the Eagle Ford, along the Fresno fault and in the neighborhood of Terlingua creek, there are many b08Ses, laccolites, dikes, sheets and almost every other type of volcanic structure. Near the McKinney and Parker. mines are two small intrusions, while one and one-half miles north is a considerable :flow. These flows not only affect the character of the rqcks with which they are in contact, but cause various degrees. of displacement' from their original positions. The beds yield readily, and while the disturbances in the immediate neighborhood of the flows are often violent, the effects are not widely extended. 
A common type of structure in the Upper Cretaceous area of Terlin­gua creek valley is the lava capping of the sediments. In some instances, as Cigar Springs mountain, the mass of lava upon the sediments is sev­eral hundred feet thick, while at Study Butte, east of Terlingua creek, the capping is about 40 feet thick. It is in the capping that the only quicksilver in igneous rocks has been found. 
PETROGRAPHY. 
Petrographically considered; the rocks of the Terlingua district and its surroundings form very interesting studies. A considerable variety is present, and while chemically considered they are, in a num?er of instances, closely related, they exhibit a variety of structure and miner­alogical composition, due in great measure to the circumstances under which they were ejected. The same magma that in a surface flow with­out considerable thickness, would yield concisely crystalline or vesicular lava, in a boss or volcanic neck of any extent, would yield a finer grained porphyritic variety. While it is true that there has been com:id­erable dii!erentiation in the magmas furnishing the volcanic material, even when the eruptions have been practically contemporaneous, it is also 
--~---­

Dia11:rammatic Section of Black Mesa. 
MOUTll OF CRQE$U8 o.a.NoN, 
THE TERLINGUA QUICKSILVER DEPOSITS. 
true that in the great flows al-Ong the Fresno Canon a distinct relation­ship may be traced between the various flows. . 
But not all of the material is related closely enough to be considered differentiations from the same magma, as strongly contrasting types are present and often in close proximity. An interesting problem would be solved by a close study of the relations of the various volcanics in the :field, with respect to their composition, method of occurrence and time of outflow. It has been impossible to give the proper attention to this side of the question here. 
The rocks most commonly encountered, however, belong to two strongly contrasted groups, viz.: a series of basic basaltic rocks, and a more extensive series of acidic rocks, including phonolites, andesites and rhyolites. · 
A number of petrographic slides have been made of rocks from various localities. 'The phonolitic rocks may be represented by the out­flow at California Hill, the basaltic by the flows at Clay mountain and the foothills of Grand Canon mountain, the andesites by numerous varie­ties from the Fresno Canon and Cigar Springs mountain, and the rhyo­lites :from Study Butte and Black Mesa. 
Many other localities show different varieties, but as they are not in close association with the quicksilver deposits they will not be described. 

Ideal Section of California Hill, showing Relation of Phonolite and Sediments. 
PHONOLITE. 
California Hill, as before explained, is the remains of an ancient vol­canic neck. It is of comparatively small extent, and its surface where exposed is greatly weathered. Associated with it are the limestones and shales of the Buda and Del Rio formations. 
In the hand specimen, the rock is of a greenish gray, rather fine grained, porphyritic variety. Wben broken from boulders where intru­sions are fresh, it breaks with a conchoidal fracture and gives out the ringing sound that originally gave phonolite its name. 
Under the microscope the most abundant minerals of this rock are seen to be feldspars rich in the alkalis. They occur both as phenocrysts and as the chief element in the ground mass. The most prominent is usually the sanadine variety of orthoclase. The phenocrysts, which are usually much decomposed, are of a tabular habit, and are frequently twinned after the Carlsbad law. 
THE TERLINGUA QUICKSILVER, DEPOSITS. 
The plagioclase feldspars, which are generally confined to the ground mass, show the albite twinning. 
The nepheline of the rock is in most cases decomposed to zeolites, but there. can still be distinguished the basal planes of hexagonal prisms, giving hexagonal and square sections. · 
'l'he most common ferro-magnesian mineral of the rock is amphibole. It occurs jn idiomorphic crystals and sometimes exhibits resorption phe­nomena. Of the pyroxenes the most common variety is augite. Biotite has not been identified, nor have hatiyne and nosean. Magnetite is rather more common than in most phonolites and minute crystals of zircon are present. 
The rock from California Hill bears a close resemblance to the phono­lites from Uvalde county, as described by Prof. Cross in the "Uvalde Folio of the Geologic Atlases," page 4. The igneous rocks described by Prof. Cross have very much the same relation to the Cre~eous sedi­ments as is found between the sediments and eruptives in the Terlingua area. 
BASALT. 
Structurally Clay mountain bears a close resemblance to California Hill. The same sediments occur in connection with ihe eruptive core, and the same local metamorphic effects have been produced on the sedi­ments. The extension of the igneous matter is from a line of weakness in the rocks caused by one of the northwest-southeast ~eries of faults. Although locally called Clay mountain, the rocks forming the hill only rise a few hundred feet above the surrounding surfaces. 
In the hand specimens the rock has a dense black, close grained appearance, with masses of glassy looking material scattered in through it. This glassy material proves to be volcanic · crystals, when viewed under the microscope. 
In thin section the rock is seen to be made up of a ground mass of :fine grained plagioclase feldspars, probably anorthite, pyroxene and magnetite. The latter mineral is quite abundant and occurs both as octahedra and in grains. The augite, which occurs in the ground mass in the shape of granules, is also present quite commonly as phenocryats, where they show good crystal forms with octagonal cross section, fre­quently exhibiting twinning. · . 
The feldspar phenocrysts, which are labradgrite, show albite-lamella­tion, occasionally combined with µericline and Carlsbad twinning. 
The most prominent -0f the phenocrysts are those of olivine. They are of large size and although some crystals show corrosion, are gener­ally quite fresh. In some slides the olivine was noted as being altered into serpentine. 
The rock res~mbles quite closely the basaltic material from the foot­hills of the Grand Canon mountain. 
RHYOLITE. 
The Black Mesa uplift, described elsewhere, has been the location of two eruptions of different age. The first and most extensive of the dis­turbances caused the strata to assume their present shape. Subsequently a flow of lava of slightly diff~rent character was .ejected from a point north of the older outflow. Smee the later eruption the whole district 
THE TERLINGUA QUICKSILVER DEPOSITS. 
has been subject to the action of hot springs and silicification has been very extensive. The original character of the rocks has, in a great :r;nea&­ure, been hidden, but the chaxacteristics of a rhyolite lava may still be recognized from the material present. . . 
Even before silicification this rock must have been the most acid rn the field. Original crystals of quartz are abundant, and may be seen in the hand specimen. The rock is light colored and vm:y hard, and often shows layers of a stony nature, which, under the microscope, are seen to be spherulitic. The ground mass varies in different specimens from glassy to crypto-crystalline, its true character often being obscured by alteration. 
Next to quartz, which occurs in dihexahedral crysrals, the most abundant phenocrysts are orthoclases of tabular habit. A very few crys­tals are present. It may be noted that the micas are almost lacking in all the rocks of the Terlingua district and vicinity. 
The rhyolite from Study Butte east of Terlingua creek is almost iden­tical with the rock just mentioned, except for the smaller amount of free 

Ideal Section of Study Butte, showing Sediments and Rhyolite Capping. 
quartz :present in it. At this place it occurs as a cap fl.ow of about 40 feet in thickness. The portion of the lava near the contact with the sediments is locally changed. 
ANDESITE. 
Although andesite is, on the whole, the most abundant of the lavas in the Terlingua district, it has not been found in direct association with the ore deposits. The flows along Fresno Canon and at Cigar Springs mountain are beautiful and typical examples of augite-andesite, and need not be described in detail. Along the Fresno numerous outflows differ with respect t-0 .structure from compact fine grained to porous vesic­ular material. Much of the volcanic ash and the volcanic tuffs to the west of Fresno Canon are of andesitic character. 
The andesite from Cigar Springs mounrain has augite developed to an extraordin_a:y ~xtent, ~ut _there is an en.tire absence of amphibole. In some localities rn the district east of 'l'erlrngua creek the porphyritic 
THE TERLINGUA QUICKSILVER DEPOSITS. 
texture of the andesite passes insensibly into the granitoid texture of diorite. 
RELATION OF VOLCANIC ROCKS TO THE DEPOSITS. 
Although the existence of the deposits of quicksilver depend o~ !-he presence of volcanic rocks, the relations are indirect. The deposition of the ore was dependent on the presence of hot springs, which were undoubtedly caused by the volcanic rocks. As pointed out by Prof. Becker (Monograph XIII, U. S. G. S., p. 417), such springs are most likely to occur at a very moderate distance from lava, but several miles may intervene. In the Terlingua district all the deposits are within a very short distance of volcanic rocks of some nature. In only one case is the cinnabar actually associated with the volcanic rock directly, but its . deposition undoubtOO.ly took place subsequent to the flow of the vol­canic material. 



CHAPTER Ill. 
The Deposits. 
MERCURY MINERALS. 
A number of mercury compounds exist in the natural state, but only a few are abundant enough to be considered useful as ores of the metal. In the Terlingua district, in addition to the most common varieties, cin­nabar and native mercury, there are present small quantities of meta cinnabarite, the black sulphide of mercury, in the amorphous state; terlinguaite, a new species, which is, according to Prof. S. L. Penfi£:ld, the oxychloride of mercury; calomel, or the chloride of mercury, and a compound of mercury and antimony which as yet has not been definitely determined. It is probable that other scientifically interesting but commercially unimportant species will be identified from this field. By far the most common of the ores is cinnabar, or the sulphide HgS which contains, when pure, 13.8 per cent. sulphur and 86.2 per cent. mercury. The cinnabar is generally mixed with impurities such as clay or oxide of iron. In the Terlingua district the cinnabar occurs in a number of forms. Beautiful crystals of a ruby-red color, often three­quarters of an inch long, have. been found, intimately associated with calcite and native mercury. The crystals are usually acicular prismatic, but are occasionally of a thick tabular habit. The prismatic crystals have been observed only in calcite veins. Large quantities of cinnabar that is crystalline occurs in granular masses, often of large size. These masses show distinct grains and under the microscope exh~bit crystal :faces. The color of the granular aggregates varies from bright vermil­lion to dark reddish brown. The cinnabar also occurs in large amor­phous masses, sometimes admixed with the granular material. The amorphous variety presents the same variation in color as does the gran­ular. 
THE TERLINGUA QUICKSILVER DEPOSITS. 
The native quicksilver is present in a number of localities in the field and sometimes in considerable quantites. It is generally intimately mixed with crystalline masses of calcite, occurring in the interstices between them, in the form of globules. Cavities in the calcite veins have been pierced that yielded over twenty pounds of the native metal. Native mercury has also been found in the clay fillings of seams. In this case the globules are so fine as to be almost invisible to the naked eye. Native mercury also occurs in a close grained eream-colored lime­stone. 
A8SOCIATED MINERALS. 
In the Terlingu.a district the ores of mercury are associated with few metallic minerals except those of iron. Of the iron minerals the oxides are much more abundant than pyrite; In the deposits of quicksilver ore in rocks of the Lower Cretaceous formation the presence of the sulphide is extremely rare, but in deposits in the Eagle Ford formation the pyrite is quite closely associated with the cinnabar. Hematite and limonite occur in about equal proportions and with few exceptions are present in all the workings. 
Next to the iron minerals the most common metallic mineral is the 
oxide of manganese, pyrolusite. This mineral is quite common in the 
veins in the Lower Cretaceous, and is present in small quantities in the 
deposits of the Upper Division. In a few instances psilomelane was 
noted. 
The presence of mixtures containing small quantities of arsenic and 
antimony, and perhaps selenenium has been noted. So far as known, 
no compounds of silver, lead, copper or zinc are present. Gold has been 
found in the pyrite from the Eagle Ford. 
Among the gangue materials by far the most common is calcite. A noteworthy fact in connection with the deposits is the total absence of crystallized quartz, usually one of the most commooo of the ae.so­ciated minerals. In a number of instances the clayey material pres­ent in the vein contains considerable quantities of silica, and in a few openings chalcedonic material is present, but in the deposits in the neighborhood,of Terlingua postoffice there is a total absence of it. 
'l'he calcite is the chief vein material, and is present in a number of forms. 'I'he most common is the ol'dinary calcite in great masses of rhombic prisms, dog-tooth spar of scalenohedral form, satin spar, of fibrous and silky structure, and amorphous chalk material. The various varieties of calcium carbonate show variations in color from purely trans­parent and pure white to red and black, due to the presence of iron. In the case of the dog-tooth spar, the crystals exhibit a zone-like struc­ture. Often the interior of the crystal is colored red by the iron oxide, while the exterior shell is perfectly transparent. 
Aragonite is a common gangue mineral in the district, and in some ca.ses ifi; crystals are of consirlerable size. Dolomite and barite occur spar­ingly, and are confined to the veins in the Upper Cretaceous formations. 
· Gypsum is often present in the veins, ~specially in the thin-bedded clays and slates of the Eagle Ford format10n. The gypsum is present both as selenite and silver spar, and occasionally in long stalk-like crys­tals, especially in caves. 
In one instance in the district bituminous material is found asso­
THE TERLINGUA QUICKSILVER DEPOSITS. 
ciated with the quicksilver. This will be referred to when the deposit in question is described. Fluorspar has also been found. 
VEIN MATERIAL. 
Among the materials, the brecciated limestones and clays are o.f great importance, and will be discussed in connection with descriptions of veins in which they occur. 
THIN SECTIONS OF MERCURY MINERALS. 
A number of thin sections of mercury minerals have been studied under the microscope. The associations· are always very similar, the only exception being the chalcedonic slides from Section 100. Here the cinnabar occurs as granules in narrow bands in chalcedonic materials. 
In all other slides studied the cinnabar is associated with calcite, being crystallized in direct contact with it. The cinnabar itself usually shows no crystal faces, but are crystalline aggregates. Microscopically, how­ever, many beautiful crystals were examined. 
THE ORE DEPOSITS. 
'l'he mining operations that have been carried on in the Terlingua district have been practically all on the surface. The ore has been found along certain lines that bear definite relations to the structure of the rocks, and in masses that seem to have no visible definite rela­tionship to the rocks or to other deposits. There are distinctly defined calcite veins that contain large quantities of quicksilver ore, while con­tiguous parallel veins of precisely the same general character may not carry a trace. Masses of brecciated limestone and iron-sfa,ined clay material may carry large quantities of cinnabar or may be C'Ompletely devoid of it. The position of the depOBits is influenced by the system of faults already mentioned. 
The deposits in the neighborhood of Terlingua postoffice which include the workings of the Marfa and Mariposa Company, the Terlin­gua Mining Company, the Colquitt-Tigner Company, and numerous small prospects belonging to various companies or individuals, are all in the limestones of the Upper Cretaceous, between the upper members of the Edwards limestone and the base of the Del Rio clays. Although the Buda limestone and the Del Rio clay are present in manv localities within the neighborhood, in no case have they been knowri 'to contain deposits of quicksilver. The greatest number of the deposits will be seen to be in the Fort Worth limestone, which formation is the present sur­face of the faulted block referred to elsewhere as the Terlingua uplift 
Mention has been made of the parallel system of northwest and south­east faults, whose trends are from north 50 east to north 30 east. In two i~stances ~eins approximately parallel to these co~rses. have been quick­silver bearrng, but nearly all the ore has been and is berng obtained from fissure veins whose direction is approximately normal to these directions. In close proximity to local disturbances caused by the injection of vol­canic material, as at California Hill and Clay mountain, the direction of the veins is variable, and in some instances veins that are parallel 
THE TERLINGUA QUICKSILVER DEPOSITS. 
at some points of their courses run into each other. However, without considering the local variations it may be stated tha.t the approxima.te directions of most of the quicksilver bearing veins is northeast to south­west. 
The veins are the results of the filling of the fissures caused by the disturbance of the rocks. It is unnecessary to give various types of vein~ encountered in the broad subject of ore deposits, but an attempt will be made to describe only such kinds as exist in the field under discussion. 
FORMS OF DEPOSIT. 
In a discussion of the form of the deposits carrying quicksilver o:re it must be borne iri mind that they are the results of conditions similar to those present in a large proportion of all metaliferou.s deposits. The fissures and spaces formed by dynamic forces were filled by depositions from ore bearing solutions that contained, among other things, mercury. Haid these solutions not been of a certain chemical and physical nature 
Section of a Lateral Extension of the Excelsior Vein, Section 38, Block Gt2. 
t.hey could not have held the mercury in solution, and had not the con­ditions . been changed, these solutions would not have deposited their bur­dens. 
'rhe depo~its, as seen at present, exhibit the effects of the forces, and it is our purpose to state what these effects are. 
As explained elsewhere, the facilities for observation have been lim­ited to what is practically the surface. In many instances, however, the surface characteristics are sufficient to allow an intelligent estimate of the conditions below the surface. 
FISSURE VEINS. 
There are several types of deposit carrying the quicksilver ore in the Terlingua district. The most usual one is the fissure vein filled with calcite gangue carrying cinnabar and the iron oxides. These fissures are of variable width and linear extension, but taken altogether are the most persistent of all the forms of deposit. The veins of this type are in two systems, having courses at right angleR to each other. The north­
THE TERLINGUA QUICKSILVER DEPOSITS. 
east-southwest veins are the most productive of quicksilver, those normal to this series rarely carrying even a trace of the metal. In most cases the :fissure is practically vertical, although slight dips have been observed. This type of vein is most common in the parts of the district most remote from the volcanic d:i.sturbances. A typical example is the Excelsior vein, the property of the Colquitt-Tigner Company on Sec-·· tion 38, Block Gl2. The vein: is a distinct well filled :fissure varying in . width from 8 inches to 3 feet. It has been opened for a distance of several hundred feet along its course, northeast and southwest, and has . been sunk on to a depth of over 80 feet in one place. Near the west end of the present workings it has been displaced by a lateral thrust of about 30 feet. The surface of the ground here iS represented by the thinnest bedded division of the Fort Worth lim:egtone, the strata being from 1! to 3 feet in thickness with the layers of marly material between the harder portions. In the lower part of the workings, where the lime­stone is thick bedded and solid, the ore bearing vein is confined to nar­row limits, often a :fuw inches only, but where the :fissure traverses the 

Section of ordinary Fissure Vein 
thin-bedded portions mentioned, the vein material extends laterally into . the bedding planes several feet. 
The filling of the vein is largely calcite. Usually a distinct banding arrangement is visible, the bands differing in color, size of crystals, and amount of iron and cinnabar present. Generally in the calcite veins the cinnabar is in crystalline aggregates, but amorphous masses are sometimes present in connection with the crystalline variety. Vuggs , frequent~y occur in this type of vein. A common variety is made up of an exterior shell of limonitic material with an interior lining of calcite crystals, generally of the 'dog-tooth spar variety. The crystals of ,:par are thinly ~oated with smi;i.11 crystals of cinnabar, causing the appear-· ance of ~ohd crystals of cmnabar. In no cases has the cinnabar been found actually crystallized within the calcite, but the calcite crystals are often filled with iron colored material. 
From the Bxcelsior vein masses of almost pu~e cinnabar weighing sev­eral hundred pounds have been taken. The verns are by no means uni­formly rich. Often the ore bearing streak may diminish t<J a thread and :::pread out several feet. The cinnabar is generally near the center 
CALIFORNIA HILL FROM THE EAST. 
CRYSTALS OF ARAGONITE IN CALCITE. 
THE TERJ,INGUA QUICKSILVER DEPOSITS. 
of the vei.n, but stringers extend not only through the calcite to the walls of the vems, but sometimes for short distances into the country rock. 
The iron associated with· the calcite and cinnabar in the fissure veins is always in the form of the oxides, when the wall rocks are the Lower C~eta~eous series. In no instance was undecomposed pyrite found in v~ms m these formations when cinnabar was present. Veins in the Del Rio clay often carry considerable quantities of pyrite, but no cinnabar is present, nor does a careful analysis of the masses of pyrite reveal the presence of the metal. The oxides are both limonite and hematite, crys­talline and amor.phous. They are often accompanied by oxides of man­ganese. The fillings of the true fissures are generally confined to these materials. Sometimes, however, masses of clay are encountered in the vein. The clay often contains finely divided native mercury, but more often it i.s quite barren of the metal. 
Section of Brecciated Vein. 
SHEAR VEINS. 
. In the veins just discussed, of which the Excelsior is a type, there pas been practically no displacement. The strata on opposite sides of the vei:n occupy corresponding positions. A very common type of the fissure vein is the variety in which there has been movement, attrition and stress along the fissure that have resulted in movement accompanied by brecciation. In a great number of instances in the Terlingua district slickensides have been observed whose appearance indicates that the movement had been almost horizontal, with little or no vertical displace­ment. A number of the fissures, however, ~hawed a combination of the two movements. The least common type of the brecciated or shear vein is the one in which the displacement is vertical without a horizontal thrust. In fact, it is reasonable to suppose that the horizontal move­ment produces a greater shearing effect upon the limestones than do the vertical thrusts. 
In width these brecciated veins vary from 2 to 10 feet, and the walls are not nearly so well defined and distinct as in the ordinary fis­sure. rrhe material between the walls is in great measure broken frag­
THE TERLINGUA QUICKSILVER DEPOSITS. 
The stratified :filling of the space between the walls does not carry cin­nabar in this vein. The same character of material is found in several other veins in the :field, but the material itself is always barren. It is quite common, however, to :find ore between this material and the walls. 
IRREGULAR DEPOSITS. 
:From the point of view of ore contents, perhaps the most productive of all the classes of deposits in the Terlingua district are the irregular deposits that have taken place in :fissures and spaces caused by varioui; combinations of forces, the resultant effects of which have been appar­ently detached ore pockets, stock-werken, chambers, impregnations, retic­ulated veins and so forth. The most conspicuous example of this class 

Fault Vein on Section 39, Block G12. 
of deposits are seen in the working just west of the Marfa and Mariposa Company. The space between the hill and the fault to the west is almost filled with surface workings, in nearly all of which is cinnabar. The ore occurs in chutes between limestone, or clay walls, in calcite veins, in clay, in stringers in the solid lime rock, and in pockets that have no apparent connection with a fissure system. The zone of fracture seems to have been the passageway of rich ore-bearing solutions, whose burdens were deposited in whatever space was available. A curious feature, however, is the fact that in the overlying Del Rio shales and in the phonolite of the hills, the cinnabar is lacking. 
The cinnabar is found in clay deposits that have been formed by the washing of the triturated vein material into basins in the limestone. In connection with the cinnabar in these resident clays are considerable quantities of gypsum. Pieces of charcoal have also been found. 
THE TERLINGUA QUICKSILVER DEPOSITS. 
The pockets of cinnabar found in such associations are sometimes very large; instances have occurred in the field where several tons of almost pure mineral have been taken out. These pockets may be taken out so that not a sign is left to indicate that ore has been present. 
CHALCEDONY VEINS. 
Among the variations from the ordinary type of deposit with calcite and iron :fillings may be noted a series of veins exposed in the workings of Mr. Lowe on Section 100, Block Gl2. These deposits are a mile northwest of Black Mesa. Here there is an extremely limited amount of calcite, the vein :filling being chalced-0ny, flint, iron and manganese. The limestone has been silici:fied extensively. The :fissures are not so well defined as to wall rock as are the calcite veins, but are of consider­able width, though the ore-bearing portions are narrow. The cinnabar occurs in minute stringers or threads in an extremely hard chalcedonic gangue, with which is associated large quantities of limonite and hema­tite, with the oxides of manganese. 
The neighborhood of Black Mesa contains many of the so-called iron "blow-outs,'' most of which contain traces of cinnabar. So far, how­ever, only small quantities of ore have been discovered and its associ­ation is not favorable for mining and sorting. The deposits are unique, however, on account of the gangue material associated with the cinnabar. The origin of the gangue material can be referred only to the former presence of hot alkaline springs which held in solution the silica and mercury. 
ARAGONITE VEINS. 
West of Terlingua postoffice in Sections 44, 45 and 48, numerous veins have been discovered carrying more or less cinnabar. The vein;; are characterized by a decrease in the quantity of calcite, aragonite being the chief vein material. Fissure veins are not so common as bedded veins in this portion of the district. The prospects opened up have shown some good ore, though little development has taken place. 
DEPOSITS OF THE UPPER CRETACEOUS. 
Cutting the thin-bedded shale, slates, clays, and limestones of the Eagle Ford formation of the Upper Cretaceous ore numerous :fissures carrying calcite, clay, iron oxides, iron sulphide, gypsum, cinnabar and native mercury. The character of the rocks covered by the :fissures is such as to cause variations in the width, course and dip of the veins. The wall rocks are rarely well defined, the vein material penetrating them often for considerable distances. The veins often, too, pinch out altogether and then suddenly reappear. 
Only one of these veins has been exposed to any considerable extent. McKinney and Parker have opened a vein in such material and have taken out a considerable quantity of good ore. In these workings the vein structure is sometimes entirely invisible, the ore being carried apparently along a zone in the stratified rocks. The characteristic ore from these workings is found in a black lime shale which dips at a high angle. The shale has seemed to be in a measure the channel for the ore 
THE TERLINGUA QUICKSILVER DF...POSITS. 
solutions. Cinnabar of a dark reddish brown color, with which is asso­ciated much pyrite occurs in considerable quantities and it carries a lit­tle gold, $2.40 per ton. Associated with the shale are zones of calcite, which also carry cinnabar and native mercury. The shale is rich in car­bonaceous and bituminous matter, which has interfered considerably when the ore was heated in retorts. Some oil has been obtained from the retorts. 
Northeast of the property of McKinney and Parker are numerou1; openings showing the presence of cinnabar, but development has not been sufficient to enable one to discuss their nature fully. 
In the neighborhood of the McKinney and Parker workings are two small andesitic outbreaks, which undoubtedly exerted an influence on the formation of the deposits. 
DEPOSITS IN RHYOLITE. 
East of Terlingua creek on Section 216, Block G4 are prospects show­ing cinnabar in an association slightly different from the ordinary types. 'l'he rocks involved are the thin-bedded sediments of the Eagle Ford formation, including limestone, shale, clays and marls, all of which are capped by a :flow of rhyolitic lava. In the limestone underlying the lava, in the clays underlying the limestone, and in the lava itself are numerous veinlets of cinnabar often unassociated with any other min­eral. The discovery of these deposits has only recently taken place, and up to the present no distinct vein has been discovered. The presence of the veinlets in the rocks, however, would indicate that an ore channel as yet undiscovered has been connected with them. The cinnabar, which is generally crystalline, is of a dark color and is unaccompanied by native mercury. In the clay shales considerable marcasite is present. The lime­stone immediately underlying the lava cap has been metamorphosed but still contains considerable quantities of bituminous matter. The rhyolite is badly shattered and decomposed. The cinnabar in it occupies minute spaces :from which some of the material forming the rhyolite has been dissolved and removP.d. 
CHAPTER IV. 
Mining and Reduction. 
METHODS OF MINING. 
As stated elsewhere the methods of mining employed in the Terlingua district have been up to the present of rather a simple and crude char~ acter. The mining machinery in use is confined to picks, shovels, drills and sledges. Windlasses are used in the shafts, few of which are over 20 feet in depth ; and in the deepest shaft in the field, about 80 feet (August, 1902) the material was hoisted to the surface in rawhide buckets upon the backs of the Mexican miners, who climb the notched poles or chicken­ladders with great agility. 
The location of the vein is generally determined by trial workings of 
THE TERLINGUA QUICKSILVER DEPOSITS. 
~urface m~terial in a horn spoon. The heaviness of the cinnabar makes its. separat10n from the calcareous and ferruginpus materials of the vein quite easy, and the presence of cinnabar can be detected when only a small amount is present. 
The calcite veins are almost indistinguishable on the weathered sur­faces of the limestone, as the calcite takes the same tint as the crumbling ~ock.. 'l'he veins containing considerable quantities of iron, however, are m evidence on account of the rusty color imparted to the material. In the 'ferlingua district there are many of these iron veins whose course may be traced for considerable distances by means of the distinct rusty outcrops. 
After cinnabar has been found in a vein its course is traced by shallow pits along it, from which washings are taken. The veins are generally quite narrow, often less than 1 foot. But whatever the width, the usual custom is to excavate a pit from 3 to 8 feet in width along the course. Portions of the excavated material showing cinnabar are thrown into sep­ar:ate piles, according ro the apparent richness. In the open cut work" along the veins one object has been the opening up of the ore to sight. In view of the irregularity of the deposits, the liability of the ore to dis­appear from a vein, this method has been a most useful one to empoly. 
The companies operating in the field have so far been satisfied to take the ore where it is closest to the snrface. It is questionable whether the ore near the surface would be easier to mine than ore in depth, but at least it is "there." The deposits are assumed to continue in depth, but no important attempts have yet been made to prove it. 
In addition to the open cut method of following the vein, the ore is obtained by the method of drifting along the course of the vein from the shallow shafts. Tunnelling has been carried on in a few instances where the topography has been favorable, but a very large proportion of thP. ore has been obtained from workings open to daylight. 
The deposits differ greatly in the ease with which they may be worked. A large proportion of the calcite veins carrying cinnabar are narrow, which entails the removal of some of the wall rock. Generally these lime­stone walls are hard and compact and require considerable powder to break. 
In the brecciated veins and the veins with clay filling, the vein material generally has a sufficient width to make the removal of the walls unnec­essary. 
The hardest material in the field to mine is the ore that occurs in the chalcedonic gangue. The cinnabar occurs as thin plates and stringers in massei:; of silica of flint-like appearance. The accompanying vein mate­rials however, are fortunately generally quite soft. 
'l'he veins traversing the thin-bedded foundations of the Upper Cre­taceous as the deposits at McKinney and Parker's, are accompanied by calcar~us clay and shales, and are as a rule easily mined. 
The ore at the prospects east of Terlingua creek belonging to Mr. Study, occurs in stringers in a decomposed volcariic rock. This material is soft and easily worked. 
HANDLING THE ORE. 
After being taken from the openings the ore is sorted by hand and as much as possible of the waste is discarded. The fine material, which is 
THE TERUNGUA Qurc:KSILVER DEPOSITS. 
often quite abundant, is tested by means of washings in the horn spoon. 'rhe ore is put into piles according to richness, and is traJ1.sported to the furnaces by means of ore wagons drawn by mules. The haul is often ove1 a mile in length and the roads are bad. The installation of trams or cables would seem to be desirable in some of the workings. 
The ore wagons discharge their loads either on the floors of the cmsh­ers or in piles from which it is taken by wheel barrows to the crushe;rs. 
THE PLANTS. 
The crushers used at both reduction works are of the Blake type of,jaw crusher. They have capa~ities greater than the furnaces, and it is neces­sary to run only a few hours of the day. The crushers are operatro. by Fairbanks-M-0r.se gasoline engines, which are more convenient than the steam engines on account of lack of water and fuel. The crushed mate­rial is carried by belt conveyers to the ore bins. From these bins, which are above the level of the top of the furnaces, the ore is taken through chutes into cars of a cubic yard capacity. The ore put into the furnace at the top descends through the arrangement described elsewhere, and is burned. The spent ore is drawn from the base of the furnace into iron cars and dumped into the canons. 
TREATMENT OF THE ORE. 
The extraction of mercury from cinnabar, which is practically the only ore of importance of this metal, is effected either by oxidation of the sul­phur by the air, and the volatilization of the liberated metal, or by the use of reagents, with which the sulphur enters into combination, while tlie liberated mercury is distilled and condensed. In the former case, which applies to the continuous furnaces in operation in the Terlingua district, the operation may be expressed .simply by the equation: 
HgS+02=S02+Hg. When lime is present with the cinnabar and heat is applied, the reac­tions may be represented by this equation : (HgS) ,+( CaO) ,= (CaS) 3+Hg,+CaSO,. This is the reaction that takes place in the retort. 
RETORTS. 
Although at present all the quicksilver produced in the Terlingua dis­trict is from continuous furnaces, when the :field was :first opened a con­siderable quantity of metal was produced from retorts, about ten of which were operated in various parts of the district. 
The largest amount of quicksilver from retorts was produced by Lind­heim & Dewees, whose plant was situated on Terlingua creek, about ten miles from the mines, as it was found easier to haul the rich ore to the wood and water than vice versa. Here several hundred flasks of quick· silver are said to have been produced, the ore consumed having been very rich cinnabar. In fact only very rich ore can be treated by the retort method, as the waste is v~ry great. The retorts were found to be very i::hort-lived, and burned out rapidly in spite of precautions taken to pre­vent it. 
BOTTOM OF CROESUS CANON. 

MEXICAN CLIMBING LADDER WITH SA.CK OF ORE. 
TH~; TERLINGUA QUICKSILVER DEPOSITS. 
J\lcKinney and Pnrker produced considerable quicksilver from retorts at their mine; and ?ifessrs. Bell, Gaughran and Coltrin produced a few fiaslrn. \.Vhile it is impossible to get exact figures, it is probable that about one thousand flnsks were produced by this means. 
THI': FURNACES. 
The furnaces used in quicksilver reduction in the Terlingua district all belong to the same class of continuous furnaces. They are slight modifi­cations of the Scott-Htittner furnaces used so extensively in California, and were built by Mr. Robt. Scott himself. · 
Three furnaces have been built, one of 40-ton normal ore capacity belonging to the Terlingua Mining Company, and two 10-ton furnaces belonging to the Marf.a and Mariposa Company. The latter compan7 have the condensers arranged in battery form, allowing the last four con­densers of the eight to be used by both furna ces. 
Prof. S. B. Christy has given a very complete description of these types of furnaces in his "Quicksilver Redµction at New Almaden," published in the Transactions of the American Institute of Mining Engineers, Vol. XIII, page 547. He gives many plans, sections, and dimensional meas­urements, which are highly interesting and important, but which would be useless to repeat here, as his discussion has covered the ground quite thoroughly. 
The California, or rather New Almaden, practice of .separating the ore into classes of various sizes and richness, as "tierras," "granzas," and "granzita," is not employed at Terlingua. The ore has a large proportion of fine material in it as it is mined, and the large lumps are as a rule crushed to about 1 to 2 inches, which would place it in a class between the "granzita" and "tierras" of California. The average of from 1 to 3 per cent. corresponds also to the value of the California ore of the class men­tioned. 
It may be remarked in passing, that the operators in the Terlingua field have been mo.st fortunate in having the benefits of the results of long years of experimental work in quicksilver reduction. The furnaces employed have been evolved with much labor and expense, and it has been possible for the Texas miners to attain good results without passing through the long and expensive experimental stages. Of course, some slight modifications have been made from the California types, but for the most part they are quite unimportant. The scarceness of water has made it necessary to cool the condensers by air entirely, and has al.so been prohibitive of allowing the fines of ore to be made inlo "adobes." 
In general the idea of the furnace is as follows: It utilizes series of inclined shelves placed in the opposite walls of narrow vertical shafts. These shelves retard the descent of the columns of fine ore. The shelves are inclined at an angle of 45 degrees to the walls, and each shelf is, therefore, perpendicular to the next lower one in the opposite wall. 
Thus, ore fed into the furna ce from the ho·pper at the top runs from one f'helf to the other until it reaches the bottom, when it forms a con­tinuous zig-zag column of ore from the top to the discharging apparatus. Th e rnd walli< of the ore chambers are pierced with rectangular openings, allowing the flames to pass from the fire place through the ore on the shelves to the vapor chamber, and from there they pass into the condens­ers. Arches over the fire-box and across the vapor chambers cause tht-air 
THE TERLINGUA QUICKSILVER DEPOSITS. 
and fumes to make four passages across the furnace before going into the condensers. This, of course, renders the furnace more economical of fuel and less liable to waste on account of the high temperature of the gases, as they go into the condensers, than a single passage of the flames would. The arch~ cause the air that enters the fire place to be drawn through roasted ore, thus heating the air and absorbing quic:ksilver vapor from the ore. Then the hot products of combustion pass through the partly roasted ore, raising its temperature, and then pass back and forth through the comparatively cold ore of the upper part of the chamber. This method has the advantage of heating the cold ore and cooling the hot fumes, which when they leave the furnaces for the condensers are only slightly above the boiling point of quicksilver. 
The device at the base of the ore chamber for discharging the burnt ore is easily operated, and is arranged in such a manner as to allow the same quantity of unburnt ore to enter the furnace from the hopper at the top as is drawn from the bottom. The frequency and quantity of dis­charge and charge of the burnt ore is, of course, regulated by the capacity of the furnace. 
In the 40-ton furnace the ore remains in the ore chamber somewhat over thirty hours. 
In speaking of the · Scott and Huttner furnaces, Prof. Chritity says, in the article already referred to: "They utilize the principle of opposed currents; they allow the ore to cool in the furnace itself before it is drawn, thus utilizing the heat and removing the last traces of Quicksilver. The stirring of the ore is entirely automatic and very thorough; for each time the ore passes from one shelf to the next opposite one the ore which lay at the bottom of the layer, next to the surface of the upper shelf, and out of contact with the air, is on the next lower shelf brought to the i,ur­face where it is directly exposed io oxidation. This operation is repe>1ted 20 to 30 times according to the number of shelves in the chatnber. The feeding and discharge of the ore and waste is affected with a minimum of labor and without the use of power. Add to this that the whole operation is under perfect control and may be modified at .any time, according to the nature of the ore, without stopping the regular operation of the fur­nace, and also that the repairs are slight and inexpensive, and we have a very good showing for the furnace." 
CO~DENSERS. 
As pointed out by Prof. Chrh1ty in his article on "Quick~ilver Con­densation at New Almaden" (Tranisactions of the American Institute of Mining Engineers, Vol. XIV, page 206) the complete condensation of mercurial fumes in a large way presents numerous practical difficulties. The quicksilver fumes from the roasting furnace are often less than 1 per cent. by volume of the various products of combustion with which they are mixed, and the proportion by weight is also small. This, of course, makes it necessary that a very large volume of gas must be cooled t-0 allow the quicksilver to be liquefied, and the whole mass must be kept moving to furnish draft for the furnaces. This draught makes it easy for considerable quantities of very finely divided mercury to be carried off through the smoke stack. The liquid mercury, on account of its high gravity, is liable to find its way into walls and foundations. The sul­
THE TERLINGUA QUICKSILVER DEPOSITS. 
phuric acid formed by oxidation of the sulphurous acid in the fumes attacks the material from which the condensers are made. 
The principles upon which the most successful condensers have been constructed are as follows: 
1. 
Cooling of the furnace fumes by contact with large radiating i>Ur­faces exposed to the air. 

2. 
Sedimentation of the condensed quicksilver particles in enlarged chambers where the velocity of the gaseous mixture is reduced. 

3. 
Constant exposure to friction surfaces, cross-currents, and vortex motions to remove the globules of metal by calling into play the force of adhesion. 


The condensers in use have been built on these principles. The mate­rial is brick, which is acted on less than any other available material for furnace construction. 
The conden~ing systems of these furnaces consist of brick chambers connected to the furnace by pipes. These chambers are tall, narrow structures, divided into compartments having openings about 2 feet square at the top and bottom ·to allow cleaning. These openings are closed by iron plates held in position by wooden bars across the front, and are made tight by setting with clay and ashes. The floors of the con­densers, which are very carefully constructed of cement, slope each way from the center to tfl.e sides, so as to allow the condensed mercury and acid water to be delivered to the side, and to facilitate the handling of the soot. Along each side of the condensers are inclined gutters of brick, about 18 inches deep and 9 inches wide, which carry the condensed mer­cury and acid water to receiving vats. 
The condensers are built with air spaces between them to facilitate the cooling of the fumes. No water backs are used on the Terlingua plants, the cooling being entirely due to radiation. The fumes after leaving the furnace pass into the first condenser near the top, pass down the com­partment on that side, thence through an opening in the partition wall into the other compartment of the conden:>er, up which they pass to be discharged into the next of the series o·f condensers through iron pipes. These connecting pipes have valves to regulate the draft. 
The plant of the Terlingua Mining Company has all the condensers, eight in number, arranged in a straight row. The first condensers are used as a dust chamber, and little or no mercury is obtained from it, on account of its high temperature. Most of the mercury is obtained from the second and third chambers, while scarcely any is obtained from the last three. Between the eighth condenser and the smoke stack an arrangement has been devised for increasing the draught through the condensers by means of a fire, thus pulling the gases along the line of communication between the condensers. 
The plant at the works of the Marfa and Mariposa Company are arranged somewhat differently, as is seen in the diagram. The two con­densers next to each of the two furnaces in this case yield a great pro­portion of the mercury, with very little after the fourth or the first in the battery used by the two furnaces in common. 
PRODUCT OF CONDENSERS. 
The condensers when cleaned yield other materiab besides the quick­silver, which are to be taken into account. Ore dust is invariably prceent 
THE TERLINGUA QuIC:KSILVER DEPOSITS. 
in the first condenser; in fact, as before mentioned, this condenser at the Terlingua Mining Company's mill yields little quicksilver and is used for a dust chamber. Considerable quantities of ore dust beyond the first condenser furnishes evidence that the furnace is not working properly. 
The whole series of condensers have the interiors coated with i;ioot, which covers walls, roofs and floors. This soot is due to the unburned carbon and hydrocarbons from the wood used as fuel. 
Large quantities of quicksilver are mechanically intermixed with this soot, the greater proportion of which is removed by mechanical treat­ment. As to the percentage of quicksilver that the soot carries, it depends entirely on the position of the condenser with regard to the fur­nace. The soot contains in the cool condensers large quantities of acid water, while in the hot ones it contains little or none. In the condern~ers remote from the furnace the soot is intimatelv mixed with acid water and becomes a black slime carrying very small quantities of finely divided quicksilver. 
The methods used in cleaning the condensers is as follows : The iron manhole at the base of the condensers is opened and the operator removes the soot that has accumulated along the lower walls and the. floor, by means of a long hoe, made of square pieces of thick rubber, supported by iron plates, the handle being attached at the center. The rubber is used to prevent wear on the floors and walls. The soot is drawn down the inclined floor to the manhole and is there kneaded back and forth with the hoe. This causes the quicksilver particles to cohere and run out of the soot into the channels leading to the receiving vats. Before reaching the vats, however, the quicksilver runs through settling boxes of wood and is filtered through charcoal. From the bottom of the settling boxes it flows through a goose neck into the vats. By this means it has been freed from particles of soot and acid water and is "dry" and ready for bottling. The operations from the gutter to the vat are of course con­ducted by gravity. 
When the soot at the manhole has been worked until most of the quick­silver has been removed, the residue is taken from the floor and treated outside. When the soot on the floor is too dry to readily yield up its quicksilver, water is added; when too wet, dry ashes are added. From long experience the workmen who are in charge of the "clean-ups" have come to recognize the exact amount of moisture necessary for the easiest working off the soot. The method of handling the hoe in stirring and kneading the soot is also of great importance. 
After the soot has been taken from the floor of the condensers it is 
placed on an inclined sheet iron box, under which a fire has been built. 
Here water or ashes are added from time to time as is necessary, and 
practically the same operation as was used on the floor of the condenser 
is gone through. The quicksilver that is freed from the soot goes down 
to the lower end and runs into a sheet-iron bucket. The residue of the 
soot from this method of working is charged back info the furnace. The 
waste from the soot, therefore, is significant, as it goes through the fur­
nace time and again. 
The operation of cleaning the condensers is carried on without inter­rupting the working of the furnace. Only one manhole at a time is opened and the inward draught is sufficient to prevent the escape of fumes. At Terlingua, once a week is the usual frequency for cleaning the condensers that carry most of the quicksilver, though in some ca.ses 
THE TERLINGUA QUICKSILVER DEPOSITS. 
they are cleaned oftener. The last condensers of the series are very sel­dom cleaned. 
At stated intervals the condensers are cleaned out in a more complete and thorough manner than is the case when the ordinary cleanings take place. The furnace is·shut down and all the walls, floors and roofs of the various condensers scraped and cleaned. Considerable quantities of metal are obtained from these clean-ups. 
After one of these clean-ups, or when a new furnace is started, a con­siderable time elapses before the walls are coated and the condensers produce. 
As to the percentage of loss that takes place in the furnace and con­densing operatiqns, no definite data can be given. The custom in the Terlingua field is for the furnace to make its own assay, i. e., the per­centage of the ore is calculated from the number of tons heated and from the amount of quicksilver produced. Systematic sampling and assaying of the ore before roasting is not practiced, and for this reason no definite knowledge of the efficiency of the furnace can be obtained. 
Prof. Christy has pointed out that the sources of loss may be classified as follows: ·1. Furnace Loss : Loss in residues from roasting furnaces. 
2. 
Condenser Loss: Loss of vapor or liquid in condenser structure. 

3. 
Chimney Loss: Loss of quicksilver in escaping gases, either in the form of vapor or as quicksilver "mist." 


Of these sources of loss, the first two are unimportant, as it is possible to prevent them by proper construction and skillful management, and close watchfulness· of the residue dump, and the draft. The escape of gases through the chimney, therefore, must account for the most serious losses. 
After the quicksilver has passed through the filtering box into the vats it is ready for bottling. The standard unit of the quick.silver lrade is the "flask," which contains 76i pounds of the metal. These fl.asks are cylin­drical wrought iron vessels, fourteen inches long and five inches in dia­meter. 'rhe stopper consists of a threaded plug which screws firmly into the top of the fl.ask. Before filling the empty flask is set upright into a frame and fastened firmly. The mercury, which has been weighed in an iron bucket with a spout, is then poured in. The screw plug is then inserted, and is tightened by means of a long lever. In this way leakage is prevented. The flasks are now stacked to wait shipment. 
CHAPTER V. 
Mode of Occurrence of Ores-Future Possibilities of Field. 
MODE 01!' OCCURRENCE. 
Although at present there are no active hot springs in the vicinity of 'rerlingua district, all indications point to the fact that at one time they were extremely active. Actual sinter deposits are not common, but it must be borne in mind that erosion has taken place and superficial evi­dences would be destroyed. The great development of vein materials 
THE TERLINGUA QUICKSILVER DEPOSITS. 
which could only be deposited from solution is ample proof of their existence. The extensive cave system of a later period :IB also important as indicating conditions with which was associated underground water. 
The discussion of details of theories explaining the presence of the mercury would be out of place here. The theories formulated by Prof. Becker in connection with the California deposits seem to be perfectly applicable here. A summary will be quoted. 
In his "Monograph upon the California Quicksilver Deposits" (Mono­graph XIII, U. S. G. S, p. 473), in summarizing his views upon the solution and precipitation of cinnabar and other ores, Dr. Becker says: 
"The waters of Steamboat Springs are now depositing gold, probably in the metallic state; sulphides of arsenic, antimony and mercury; sul­phides or sulphosalts of silver, lead, copper and zinc, iron oxide and possibly also iron sulphides, and manganese, nickel and cobalt com­pounds, with a variety of earthy minerals. The sulphides, which are most abundant in the deposits, are found in solution in the water itself, while the remaining metallic compounds occur in deposits from spring~ now active or which have been active within a few years. * * * A sulphur bank ore deposition is still in progress. The waters of the two localities are closely analogous. Both oontain sodium carbonate, sodium chloride, sulphur in one or more forms, and borax as principal constit­uents, and both are extremely hot. * * * In attempting to dei:er­mine in what form the ores enumerated can be held in solution in such waters, it is manifestly expedient io begin by studying the simplest pos­sible solutions of the sulphides, especially cinnabar. * * * 
It was found that, provi<led a small quantity of sodi:c hydrate be pres­ent, one molecule of mercuric sulphide unites with two molecules of sodic sulphide to form :freely soluble sulphosalt, and that an excess of sodic hydrate is without effect upon the solubility. Even when sodic hydrate is entirely absent, mercuric sulphide is freely soluble in aqueous solutions of sodic sulphides, though the contrary has repeatedly been asserted; but either one molecule of mercuric sulphide then unites with three of sodic sulphide instead of two, or a mixture of sulphosalts nearly corresponding to this compound is formed. 
"Sodic sulphydrate when cold is absolutely without effect upon mer­curic sulphide, but when the mixture is heated in a water bath, the sul­phydrate is decomposed and sodic sulphide is formed; it unites with mercuric sulphide in the proportion of four molecules of the former to one of the latter. A perfectly limpid solution results. The same compound is produced when mixtures of sodic sulphide and sodic sul­phydride are brought in contact with mercuric sulphide. The presence of sodic carbonates demonstrates the solubility of mercuric sulphide, but does not prevent solution. Ammonium carbonate completely prevents solution at temperatures below boiling point, but not at 145° C. 
"These facts suffice to lead to important conclusions with reference to spring waters, such as those mentioned above. Wben natural sodic car­bonate is treated with sulphydric acid at ordinary temperatures, sodic sulphydrate forms. At temperatures approaching the boiling point, it is probable that a certain quantity of sodic sulphide is also produced. At these higher temperatures either of these sulphur compounds will dis;;olve cinnabar and the presence of sodic carbonates will not prevent ~olution. These conclusions are amply verified by direct experiments. 
"Mercuric sulphide may be wholly or partially precipitated from solu­
THE TERLINGUA QUICKSILVER DEPOSITS. 
ti~ns in the sulphosalts in many ways: by excess of sulphydric or other acids, by borax and other mineral salts, by cooling (especially in the presence of ammonia), and by dilution. In the last case, a certain quan. 
tit,Y ?f metallic quicksilver, as well as mercuric sulphide, is formed, and this is very probably one of the methods by which native quicksilver has been produced in nature. * * * 
"Natural solutions of sodic carbonates and sulphides, which are com­mon components of hot spring waters, are thus capable of dissolving at least :five of the principal metals, as well as sulphur, arsenic and anti­mony. Combinations of these elements form a large part of minerals found in mines. There is little or no doubt that the cinnabar of the California deposits has been dissolved and precipitated as indicated above, * * * but I by no means assert that natural deposits of cinnabar have never been produced in any other way." 
FUTURE POSSIBIUTIES. 
The natural questions that come up in the discussion of the Terlingua district are whether or ,not there will be in the future a larger develop­ment in the present area known to be quicksilver bearing, and whether this area is likely to be extended and other workable deposits discovered 
The first question can be answered in the affirmative, there being reason to suppose that the deposits continue in depth. It is not at all certain that the veins, where distinct veins have been exploited, will be quicksilver bearing indefinitely, but there seems to be no very good reason for believing that they should not carry ore in some quantity through the whole Cretaceous series, which, in the district, is certainly more than 1500 feet thick. 
The only tenable theory as to the original source of the quicksilver is that it comes from "below." This is indefinite, it is true, but is more reasonable than theories referring the contents of the veins to origins within the country rock traversed by the veins, or to the theory that the quickEilver solutions came from "above,'' depositing their contents in pre-existing :fissures. . 
If the veins continue to be ore bearing in depths, which is at present an assumption that has not been proved, as only exploitation could prove such points, it is very possible that they will not carry such high per­centages of ore as they at present carry at the surface. 'I'he great mine& in California were extremely rich at surface, but as they became deeper they became poorer. In the nature of things, there are certain condi· tions of heat and pressure that would be most favorable for the deposi­tion of the minerals from solution. These conditions may exist in zone8 that are comparatively near the surface, but it is not reasonable to sup­pose that these conditions prevail only at the surface. The conditiom for deposition may become less and less favorable as the deposit increases, for the reason that the heat and pressure being greater as the depth increases, the minerals in solution would not be freed from the solu­tion. 
1'he original source of the mercury is unknown. The eruptives that pierce the sed~ments are of a comparatively la~e a~e. Analyses o~ these rocks have failed to show the presence of qmcksilver. The sediments underlying the Cretaceous in this dist~ict are not visible in any out­crops for long distances, and at present it cannot be stated whether they 
THE TERLINGUA QUICKSILVER DEPOSITS. 
rest on the Paleozoics that are seen in the mountain ranges one hundred and twenty-five miles to the north; or whether the Triassic or J.urassie here takes a place in the geological section. Only a detailed study of the geology of the country as a whole can determine these points. 
The future development of the district as now c1mstitu:ted will depe:nd" to a considerable extent on the finding of ore in depth. While a con.. siderable quantity of ore has been taken from the surface, and while it is true that a great deal of surface territory known to be quicksil~~1':; bearing has not been touched, to become a great factor in the quicksill ver production of the world, the ores must be proven to be s0metbing more than surface deposits. It must not be understood that it is ~ ~ary for profitable mining that the ore be continuous in depth. · On fllj contrary, the easily worked surface deposits furnish eheap ore, and. it ii on this very account that so little exploitation in depth has been mad~ The operators view the question in this light: "Here we have ore. on the surface. We can take it out with pick and shovel. Why sink shafj;s/ run levels, install hoists, etc., etc." They are not disposed to .·take , chances along the line of development when they have surface ore 1n sight. This is unfortunate for the geologist whr;i endeavors to make ,,az study of the form and character of the deposits, nor is it entirely certajiu, that the methods in vogue are the most profitable for the miner. How•{ ever, it is only a question of time when on some of the properties :a( least systematic explorations in depth will be carried on. As mentioned'• elsewhere, a few efforts in this line have been made. 
As to the question of the extension of the field, we are still in the realm of speculation. ·The field has grown from its original small area, and it is certainly possible foi: it to grow very much more. Ore has been found in the various subdivisions of the Cretaceous, U'pper and Lower. It is found in the massive Caprina limestone and the thin-bedded mads and Eagle Ford shales. Such fori:nations, with accompanying volcanoeit. of the same types found in connection with the quicksilver, occur north, south, east and west of the present district. Cinnabar has been :found on the Mexican side of the river a:t · a distance of less than twen~ miles from the Terlingua mines, in identically the same surround• ings. The territory intervening is of the same geological fo~­tion. 'l'he Grand Canon mountains are made up of the same identical strata, and have the same volcanic flows cutting through theni . . ' The flat between these mountains and the dome-like uplift of the Cretaceous rocks of Terlingua shows exposures of the .same sediments that carry the quicksilver at McKinney & Parker's mine. The country east .·of Fresno Caiion and sout~ ?f Alamo de Ca:;sario (McGui:rk's ranch) .pJ:e­sent the same characteristics. From Terlmgua creek to the foothllls of the Chisos mountains the same series of sediments and associated erup• tives that carry the quicksilver at Study's mine are present. 
It is thus readily seen that in so far as territory favdrable to the occut,., rence of the metal is ooncerned there is a great extent of it. Part of it has been prospected very thoroughly, th'ough other parts h~ve been somewhat neglected, notably, the Grand Canon mountain. Quicksilver has been found in small quantities in many· places, in considerable quan­tities in a few places. The development of the future will depend largely on the degree of success attained by the mines that are at present in operation. 
LINDHEIM 4' DEWEES' FOBTY·FIVE•TON FURNACE. 

OPEN CUT IN ORE, BTUDY'B MINE, SECTION 216, BLOCK G4. 
THE TE1U.I!'<iUA Qu1cKs1r.n:u DEPOSIT:-<. 

CHAPTER VI. 
CO:IIP.\:\IES Ol'EHXl'[:\C:. 
At the present time (Augu~t. 1~0.'2) tlH·re is one l:OllllJHll.\' in tlil' field actually produl:ing quic:ksil\-('r. the :.\forfa 1md :\Iariposa l'Olll]HlllY. The fun;i.a.ce of the Terlingua :\lining Company 1rns c:lo.~ecl clown iu :\lay. In acld1t1on to these, the Colquitt-Tigner Mining Comrnny and :\lc:Kinney & Parker arc mining ore, but are not treating it. Tlic former c·umpanY, however, has a furnace in the cour:;e of construction, arnl 1rill l;t::gin j)]'i:•­ducing in a fow mont.h~. In addition to the~L~, thc·n· arL' a 11u;11hc·r of e:ompanics and individuab 1rho 01rn ore-bearing JJl'(l['L'l'ty, 11·hid1 fo:· \'arious reasons are not being operated. 
Geologically considered, the propcrtic-; 111<1)' lie a11 cli~cu~"ecl togc·tlwr, as the types of the veins, etc., arc confined to no particular prnpertie­L'Xccpt where noted in other disca~sions. The claim map accompanying this report will be useful in showing the geographical posit;on of th<· various holdings. 
A very brief discussion will be given of the eompanies at prrsent ope1·­ating without attempting to go into detail in regarcl to thr orr rlcpo<it:­or their various properties. 
The }iarfa and Mariposa Company, from whose property a large· pn,­porlion of the total output of the field has been produced, are the 011·11­ers of a e:omiderable number of claims located upon State lane!. ancl ir, addition hold several sections of patentr<l Janel. The ore minrcl In-tl1c· company has been taken from patrntPd Scrtions 41 anrl ;)fl. aml from claims located on Sections fiS, 40, 38. GO arnl 70 of Rlock G1'2. _\ t present. most of their operations arc ronfinecl to (-Jw proprrh· p]o,(• t(, the reduction worb. The proprrtY southwest of California Hill ha.' Yielded and is still yielding a comiclera blc percentage of the ore producerl. The richest deposits that hal'e hern vet founrl in the fiel<l arc loeated here, the ground workc•1l being the north11·p"i. part of: private :::lc·c:tior: 
59. The development eonsists of mm1crons open cuts, shallow shaft" and drifts along the vein just beneath the surface. X car the contact between the sediments and the ig110ons roek of California Hiil pro.<pcct shafts are hcing· sunk, ancl a tnnnel i< hei ng rnn into the body of tlw hill on the contact betll'rcn the Drl Rio rlay and the eruptiYe. Ho1YCH'l' . .>erions attempts to clisco1·pr the clcpths of the clcpo;:its han' not a;: ~-e1 IJcen maclc. After tlw snrfaee on' has been exhausted other methods of minirn.r will have to he adopted. 
'Th~ depositf\ in the lornlit.1· ju;:t mcntiQllC(l are quite irregnlar. Tht> proximit.y to the igneom outflow li~s cansecl a local flishubance that has in a great mea;;urc c-aused the Hrcgnlar1h·. 'The rlepo.,1t" arr nor continuous, but arc apparently the result of the deposirion of mineral from an ore hearinp: "olntion tlrnt pcrmcntwl the irregnlarl~-frac·tnred and lirccciatecl zone 11et1n'en the volcanir onthreak nnrl the northwe.•t ancl sontheast fa11U-to the 11·r;;t. 
\Vithin thi-nrea t1w cinnainll' is not a(·f'ornp:inierl ln· n,: large a prc•­portion nf f'il kite 11;: i.: cornmonlr rnconnterccl in the fli;:triet. 'Thr iro;1 
THE TERLINGUA QUICKSILVER DEPOSITS. 
bearing solutions have been much in evidence, and practically the whole of the limestones is permeated and colored. 
East of California Hill considerable ore has been taken out, but at present the workings are idle, although the deposits are by no means exhausted. 
The company owns several claims on Section 39, from which most of the ore treated in the furnace before the acquisition of the California property was taken. The distance from the furnace is the chief disad­vantage of this locality. It is probable that in the future a furnace will be built to handle this ore. 
The company owns two 10-ton Scott furnaces, which are kept in con­
stant operation. An average of  one  hundred miners are upon its pay  
rolls.  
THE  TERLINGUA  MINING COMPANY.  

This company, formerly Lindheim & Dewees, are the owners of a number of claims on State Sections 40, 60 and 70, in addition to owning outright a number of patented sections, among whieh are 33 and 39. 
'fhey have mined considerable ore .from extensive cuts on Section 40 and 39. The veins are generally distinct fissure types on Section 40, while considerable ore has been obtained from the fault vein on 39, which is described elsewhere. · 
The company owns a 40-ton Scott furnace, which was started in oper­ation near the beginning of the year. Litigation has prevented the con­tinual operation of the properties of this company. This is reported to have been settled and the development will continue rapidly. The fur­nace was started in January, and closed down in May. 
THE COLQUITT-TIGNER COMPANY. 
This company owns claims on Section 38 and 44, and in addition con­-ro1s a number of other properties. Most of the ore mined has been taken from the Excelsior vein, which is described elsewhere. A ten-ton furnace is being built. 
M'KINNEY & PARKER. 
This company holds several claims on Section 70. A considerable quantity of ore has been taken from workings on the property, whose characteristics have been described elsewhere. This company has retorted a small quantity of quicksiher, and has some high class ore on its dumps. No furnace has been built. 
Many individuals and companies own claims that have been worked only sufficiently to comply with the mining law. 
LABOH CONDITIONS, ETC. 
The labor of mining in the Terlingua district is performed almost entirely by Mexicans. The prices paid per day of ten hours' work ranges · from $1.00 to $1.50, according to the experience of the miner. It is doubtful whether this class of labor is economical even at the low wage rates. The Mexican miner, when closely superintended, can do a great 
THE TERLINGUA QUICKSILVER DEPOSITS. 
~mount of labor, but left to his own resources he displays a surpris­mg lack of intelligence. If they can be worked in compact bodies and can be under ~he eye of a white boss at all times they are fairly efficient, but scattered m small groups along an extensive open cut they can do a surprisiJ?-gly small amount of work. As handlers of powder they are n?t effic1e:i;it. However, they are indispensable on account of their har­dmess, bcmg able to stand the very high temperature of the summer months. 
The foremen and mill hands are almost invariably white men, whose wages range from $2.50 to $5.00 per day. . The operating expenses of plants in the Terlingua district are mcreased by the scarcity of wood and water. The methods of procuring water have been described elsewhere. Wood, which is hauled from dis­tances of twenty-five miles, is sold at from $4.50 to $6.00 per cord, but these prices are rising all the time as the wood gets scarcer. Up to thP present time little timber has been needed in the mines. A few poles have been brought from the Chisos mountains for the construction of ladders and windlasses. 
The haulage item is quite serious in the district. The most advan­tageous arrangement is to give contracts to the Mexican teamsters for delivering the ore at the furnaces from the various workings. 
The buildings of the furnace plants are expensive on account of the difficulty in getting the irons and timbers for construction. Fortunately, excellent brick is made from clay deposits in the neighborhood by Mr. Harry Dryden. 
THE PRODUC'rION. 
The Terlingua district, as a producer of quicksilver, has had to encounter many drawbacks, which have resulted in keeping the produc­tion down to a much lower figure thah would have been the case had the district been situated under more normal conditions. 
Among the causes that have held back production may be mentioned the remoteness of the district from adequate transportation facilities, adverse climatic and labor conditions, lack of capital on the part of a number of the owners of good properties, and uncertainties in respect to laws governing the occupation of mineral bearing land, with which was coupled litigation respecting land lines and titles. 
The latter causes have been, in a great measure, removed by process of law, and it is entirely probable that development will be carried on steadily in the future, and an increased yearly output may be looked for for some years to come. 
Except the production from the various retorts in the field, the whole output of quicksilver up to the enu of 1901 is to be credited to one 10-ton Scott furnace, operated by the Marfa and Mariposa Company In 1901 this single furnace produced 2932 flasks of quicksilver. During the current year there were in operation two 10-ton Scott furnaces belong­ing to the Marfa and. Maripo~a .Company, and one 40-.t?n Scott furnace belonging to the Terlmgua Mmmg Company. In add1ti~n to these fur­naces there is another 10-ton furnace of the same type bemg constructed for the Colquitt-Tigner Mining Company, which will be a producer 
hPfore the end of the -year. 
THE TERLINGUA QmcKs1Lv1rn DEPOSITS. 
In some cases in the field valuable property is lying idle from lack of means to work it properly. In still other cases holders of land having paying quantities of ore upon it are refraining from develop­ment for rnrious reasons. Owners of detached claims whose production would not warrant the construction of furnaces are at present unable to realize upon their resources. It is possible that this difficulty will in the future be obviated by the construction of custom furnaces for the purchase and treatment of ore. Should the district develop toward the east, a .custom furnace in the neighborhood of Terlingua creek would be in an advantageous position for the treatment of ore. In addition, such a location would be easier of access from the railroad station at Mara­thon or Alpine than are the present producing ·mines and furnaces. 
Although some ore was mined in the district in 1899, it was not until the following year that any considerable quantity of metal was produced. So far as can be ascertained from operators in the field the production in 1899 was confined to fourteen fl.asks. In 1900 the pro­duction was increased considerably. A number of retorts were in opera­tion during that year, and in Augm:t the first furnace was put into operation. The production for this year was 754 fl.asks, exclusive of the quicksilver produced by Lindheim & Dewees in their retorts on Ter­lingua creek. The exact amount of their production is not available, but it was several hundred flasks. 
In 1901 the total production was 2932 fl.asks, giving a total produc­tion for the field up to the end of that year of 3700 fl.asks exclusiv.e of that of Lindheim & Dewees. 
No figures are available for the determination of the total a~ount of ore treated in order to furnish this output. The ore treated by the retort method carried a much higher per cent. of mercury than the fur­nace ore. The per cent. of the retorted ore was reported as ranging from 8 to 25. In ·the case of the ore treated by furnace, the average per­centage of mercury in the ore treated will hardl:v exceed 3 per cent. It is claimed by operators in the field that one-half per cent. ore can be profitably treated in the furnace. 
A small quantity of the quicksilver from the Terlingua district ha5 been sold at the Shafter silver mines, but practically all the product goes to New York and to San Francisco. The prices have fluctuated sEghtly, but have been fairly steady. The limit prices have been $48.00 to $44.00 per flask f. o. b., the average price obtained being $45.00. The value of the quicksilver produced in the field up to the end of 1901 was $267,500. 
The output from the Terlingua district furnished about 10 per cent. of the total production for the United States, which in 1901 amounted to 29, 727 fl.asks, of which California contributed 26, 720 fl.asks, Texas 2,932, and Oregon 75. 'l'he aggregate value of the total pruduction for the year was $1,382,305. 
'l'he demand for quicksilver, while quite steady, is comparatively small. This is due, in great measure, to its restricted use. A very large propor­tion of all the metal produced is emplo~red in amalgamation of ores and in the manufacture of Yermillion. A small amount is consumed in medi­cine and arts, w the price of it is regulated by the demand for it in the two instances cited abon\ and as a result fluctuation in th(;) price of silver affects the prirc of quicksiln'r. At present, however, the demand for it 
THE TERLINGUA QUICKSILVER DEPOSITS. 
is quite strong, a considerable quantity being exported to Mexico for pur­poses of amalgamation and to China for making pigment. 
Unl~ss, therefore, commercial conditions change materially, or more extensive and more easily worked deposits are opened up, the price of the me~al will remain comparatively stable, and production ~ven under such disadvantages as exist in the 'l'erlingua field will be profitable. 
CHAPTER VII. 


Quicksilver-Occurrence, Production, Prices, Etc. 
BY 
WM. B. PHILLIPS. 
In the Mineral Hesources of the United States, 1892, United States Geological Survey, Dr. George F. Becker has a condensed paper on Quicksilver Ore Deposits. In this he gives a table showing the min­erals associated with a number of quicksilver deposits in various part,; of the world, arranged so as to set forth the prevalent, abundant. occasional and rare minerals that have been found. He quotes from 28 localities, and the minerals observed, up to that time, were bitumen, free sulphur, stibnite (sulphide of antimony), and other antimonial ores, realgar ( sul­phide of arsenic), mispickel ( sulphide of arsenic and iron), gold, silver ores, galena (sulphide of lead), chalcopyrite (sulphide of iron and cop­per), zincblende (sulphide of zinc), pyrite and marcasite (sulphideE: of iron), millerite (sulphide of nickel), quartz, calcspar, gypsum, fiuorspar, barite (heavy-spar, sulphate of barium), ahd borax. Of these the pyrite and marcasite are 1.he prevailing minerals, occurring in 20 of the 28 localities; then come quartz and calcspar. Bitumen is abundant in 8 localities. Gypsum is abundant in 3 localities only, so that it is rela­tively unimportant. 
The presence of bitumen and bituminous compounds (they are abund­ant in 8, met with now and then in 5, and rare in one instance, alto­gether in 14 case$ out of 28), is a noteworthy fact. 
In order to present the matter in a convenient form a table has been prepared somewhat on the lines of Dr. Becker's table, but with no attempt to arrange the associated minerals in the order of relative frequency of occurrence. 'l'he minerals mentioned have been found in quicksilver deposits in different ~ocalities. .To the table is ~lso added information respecting the geological formation and the associated rocks. 
No attempt has been made to givE! this data for any but the districts of commercial importance, the quicksilver deposits of Canada, Germany, China, Japan, Australa.~ia, P~ru, .Unit~d States of Colombia, etc., not coming within the scope of this d1scm:.s1on. 
THE TERLINGUA QuwKsn,YER DEPOSITS. 
Table showing the Geological Formation, Associated Rock: and Min­eral& in productive quicksilYer deposits: 
Geolog·ical
Country. I 
Formation. 
-
(" pper Triassic. 
A u~tria. 
I 
I I I 
'Eoce ne. ('l'ertiary) Italy. 
Cretaceous. 
I 
Cretaceous 0! 
Mexico. 

Jurassic? 
Carboniferous.
lRussla. 
Upper Silurian and Devonian.
Spain. 
I 
E1<rly Cret,.ceous or late Jurftsslc. ln the Tertiary.
United st..tes. 
and in Quarter-nary Alluvium.
1 
I ! 
Associated Rocks. 
Dolomite. Sandstone. Schists. Slates. 
Various lav>LS, such as trachyte, andes­itc, rhyolite, &c. 
Iarly limestones and clays. 
Porµhyr·y. Li m e­ston". Slates. 
Sandstone. Quartz­ite. 
Slates. Limestones. Sandstones. Schists. Diorite. 
Gmi:.itic d e t r i t u s. Limestones. Shales. Serpentine. Sanil­stones. S 1at es. 
RhyolitP, andesite. bOiSOilt, &c. 
Associated .i\I inerals. 
Quartz; feldspar; mica; horn­\Jlende; calcite; pyrite: epsoro­ite; Copperas; gypsum; idrialite; 
graphite; anthracite; bitumen; 
CHlcium phOSpbate; fiUOl'Spar:marcasite; b:Lrite; calomel. 
Bitumen; free sulphur; realgar:py1·ite; marcasite: quartz; calc­
spar; gypsum. 
Silver and antimony ores; gypsum:calcspar; ftuorspar; free sul­phur; quartz; calomel. 
Stibnite; pyrite; calcspar. 
Calcspar; pyrite; galeua; quartz;barlte; arsenical pyrite. 
Calcsp,.r; pyrite: barite; quart,z; gyr.sum; borax; stibnite: free su phur; mispickel; chalcopy­rite; bitumen; rnarcasite; mil­
lerite; gold a.nd silver ores; 
ftuorspar; copiH.pite; knoxvillite; rediugtonite; calomel; terlin­
guaite. 
The minerals of natural occurrence which have been found to oontain quicksilver are given in the following list (Dana, A System of Mineral­ogy, 1900). As remarked under the heading cinnabar this is the only important source of the metal. 
Amalgam: A compound of mercury and silver containing from 27.5 to 86.3 per cent. of silver, the remainder being mercury. Color, silver­white. In isometric crystals; also massive in plates, coatings and grains. Hardne&s 3 to 3.5. Gravity 13.75 to 14.1. Gives silvery luster when rubbed on copper. 
Ammiolite: A compound of mercury containing antimony and cop­per, with a little sulphur and ir-0n. The content of mercury varies from 
19.8 to 23.6 per cent. It is an earthy powder of a deep red, or scarlet color. It may be antimonate of c-0pper mixed with cinnabar. Rare. 
Aragotite:  A volatile hydrocarbon related to idrialite.  Rare.  
Arquerite :  A species of amalgam.  
Barcenite:  Related to ammiolite, but contains no copper.  May be an  

antimonate of mercury. Rare. 
THE TERLINGUA QUICKSILVER DEPOSITS. 
Oalomel: Chloride of mercury, containing, when pure, 15.1 per cent. of ?hlorine a~d 84.9 per cent. of mercury. Tetragonal crystals. Color, white, yellowish gray, yellowish white and brown. Hardness 1 to 2. Gravity 6.48. Translucent. Fracture conchoidal. Sectile. Not abun­dant enough to be regarded as a source of mercury. Native corro3ive sublimate (the other chloride of mercury) is reported to have been found in the desert of Atacama, Chile. 
Cinnabar : Sulphide of mercury; when pure, contains 13.8 per c~nt. of sulphur and 86.2 per cent. of mercury. Has an uneven fracture. Hardness (talc=l) 2 to 2.5. Crystallizes in rhombohedrons and trape­zehedrons; also massive. Color, cochineal r€d, sometimes brownish-red 
and dull gray.  Gravity (water=l)  8 t-0  8.2.  Chief  source  of quick­ 
silver.  
Oinnabarite:  Same as cinnabar.  

Ooccinite: Iodide of m..-cury. CoJor, fine red to yellow, sometimes green and greenish gray. In needle-like crystals; also massive. Rare. 
Ooloradoite: Telluride of mercury. Color, iron black to gray. Hard­ness, 3. Gravity, 8.62. Has metallic luster. Massive, and granular. Rare. 
Guadalcazarite: A sulphide of mercury containing zinc and selenium. Rare . 
. Idrialite: A hydrocarbon containing mercury. White when pure, but in nature always colored blackish or brownish by bituminous substances. Rare. 
K ongsbergite: A species of amalgam. 
Lehrbachite: A compound of mercury with selenium and lead. Color, lead gray, steel gray and iron black. Massive, and granular. Brittle. Gravity, 7.80. Rare. 
Leviglianite: A species of guadalcazarite containing iron. 
Livingsl!onite: A double sulphide of mereury and antimony, contain­ing from 14 to 22.61 per cent. of mercury. Metallic luster. Color, bright lead gray. In slender prismatic crystals, and resembles stibn~te. Hard­ness, 2. Gravity, 4.81. Rare. 
Mercury: Native. Sometimes contains a little silver. Rare. 
Metacinnabarite: Same composition as cinnabar, but occurs in iso­metric crystals ; also massive and amorphous. Luster metallic. Color, grayish black. Streak black. · Brittle. Hardness, 3. Gravity, 7.81. No t abundant enough to be important as a source of quicksilver. 
Onofrite: A sulphide of mercury containing selenium. Rare. 
Tennantite: A variety of tetrahedrite, containing a double sulphide of mercury and copper with sulphide of antimony. It may ;.;ontain <llso iron, zinc, silver, lead, cobalt and bismuth. Rare. 
THE TERLINGUA QUICKSILVER DEPOSITS. 
Terlinguaite: An oxy-chloride of mercury from Terlingua, ~rew.ster county, Texas, of yellowish color. Complete analyses and examinations not yet made. · 
Tiemannite: A compound of mercury and selenium; may contain,. also, a little cadmium and lead. Luster metallic. Color, steel-gray to . blackish lead gray. Streak nearly black. Brittle. Hardness, 2.5. Grav­
ity, 8.19. Rare. 
Tocornalite: Silver iodide containing mercury, the percentage ri::1ing to 3.90. Color, pale yellow. Granular and massive. Compare coccinite. Hare. 
Sulphate of mercury has been observed as a product from tli.e quick­silver furnace;; at Idria, but is not of native origin. 
The production of quicksilver in the United. States in 1900 was 28,317 flasks of 76i pounds each, or a total of 21,662,505 pounds. By far the greater amount of this was yielded by the 0.lifornia mines, Texas and Oregon alone of all the other States contributmg to the output. Quick-. Eilver mining began in California prior to 1850, but reliable statistics are available only since that year. In 1850 the production was 1,723 flasfil;, all credited to New Almaden. From 1850 to 1861; inclusive, the New Almaden mines, in Santa Clara county, alone produced 250, 720 flasks, an average of 20,893 flasks per annum. Up to the close of 1899 these mines produced 972,231 flasks, an average of 19,444 flusks a year for 50 years, and they are still heavy producers. The Redington minee, California, began shipping in 1862, and yielded to the close of 1899, 108,648 flasks, an average of 2,859 flasks a year for 38 years. The New ldria mines, California, produced, between 1858 and 1866, .17,455 fiae.ks, and are credited with 150,600 flasks ·to the close of 1899, an average of :l,502 flasks a year for 43 years. In 1873 the Great Western began ship­ping, and is credited with 89,691 flasks, an average of 3,322 fl.asks .a year for 27 years. The Sulphur Bank began shipping in 1874 and is credited with 93,274 flasks, an average of 3,886 flasks a year for 24 years, no returns having been made for 1?97 and 1898. The Napa Cons<ilidated began shipping in 1876 and is credited with 114,317 flasks, an average of 4,763 flasks a year for 24 ye~rs. These are the principal producing mines in California, although the Great Eastern is credited with 30.409 flagks, the :Mirabel with 28,806 flasks, the Aetna with 26,912 flasks, the Altoona with 16,077 fl.asks, the Abbott with 5,903 flasks and various other mines with 194,154 flasks, to the close of 1899. The total production of all the California mines from 1850 to 1899, inclusive, is 1,831,022 flasks, and of this amount the New Almaden mines have produced nearly one-loalf. 
The maxinium production in any one year by any one mine was ·17,­19-l flasks, by the New Almaden in 1865. To the close of 1899 all of the <inicln:ilver produced in the United States was from California, with the except.ion of 65 flasks from Oregon in 1887 and 1000 flasks from Texat: in 1899. • 
The product.ion and value of qnicksilYer in the United States from 1880 to 1900, inclusive, is given in the following table, taken from "The 1\fineral Resources of the United States," U. S. Geol. Survey, .1901: 

PEAK OF ERUPTIVE ROCK (ANDEBITE) NEAR CALIFORNIA HILL. LOOKING EAST FROM CALIFORNIA HILL. 
Tim TEHLINGUA QuicKSILYEH DEl'O~IT~. 
l'ru<111t·tinn ;111d \°;1l1w of Quivbiln·r in 1l1 L~ l'n itl'd Stc1k~, I:-;:-;11-J !ilJO. 
Flnsk..; of ; li1 po11 1Hl~: 
Year. 
1880 ... ............ 
1881. .. ........ ...... 
1882................ 
1883 .... .... ......... 

1884................. 
1885 .... .. ... ........ 
1886................. 
1887................. 
]888.......... ....... 
1889................. 
1890 ........ ... 
l8Bl................. 
18H2..... .. .......... 
1893 ........ ......... 
18HL.... ..... ...... 
1895 ........... ...... 
1896.......... ....... 
18H7 ................. 
1898........... ...... 
18!lfl .... ............. 
1900 .... .......... ... 

'I'otal and a \'erag-c ........ 
V;.Jue. Pro­duction. Per flaslc Total. 
$ (i0,8.51 52,732 59,926 
46,i25 
3UJ13 
32,073 

29.981 
33,82;) 
33,250 
2il,484 
22,926 

22. ~l04 
27 ,993 
30,Hi4 
30,4Hi 
:36.104 
30, 765 
26,648 
31,092 

30.~54 
28.3li 
725,523 
; 
30.00 $ 1, lfll.780 
29.00 
28.20 26.1\3 
29.34 
24.85 
%.3:) 
42.2-5 
42.50 
44.95 
52.50 4H.61 
H.49 :36.75 
30.71 
37.03 
34.63 
37 .28 :38.23 4i.70 4(i.00 
;37 46 
1.764,679 1,487 .042 1,253.6;{2 
~136.327 
1g1;1s9 1,060.000 1,429.000 1,413,125 l,190,500 1,203,615 
1.036.386 1,245,689 1,108,527 
934,000 1.337,131 1,075,449 
993,445 1,188,ti2i 1,452.745 t,302.586 
27,175,900
1$ 
Imports and Exports of Quicksilver into and from tJie l:n;te<l :-)tares, ] 880-1900: 
Ye:11-. 
1880.................1 
1881...... ... ........ 
1882................. 

188:3.............. .. . 
1884................. 




i~~~::::::::::::::::: 1 
188/.............. ··· I 
1888................ .1 
1889.. ............... 
1890 .... ....... .. ....1 
1891.. .............. 1 
1892 ............ ... .. 
1"iH:3.......... ....... 
18!lL......... ...... 
1895................. 

1 
1~96.. ............... 
l~~)I ... . . . . . . . . .... 
18HR................ 
lt-:B9......... ........ 
lfl00..... ............ 

Total, 
ur J:<'la~ks.... 
Imports.
(Duty 7 cts. pe1· pound.) 

Qmcntitypounds. 
Im,700 138,517 5m,898 1.552,7:38 13ti,615 
257 .659 629,888 419,934 132,850 3-il,514 802,Sil 12:3,966 9fl,318 
U ,772 i 15,001 :305 4.'i,53!J 81 
1:31 2,t:i16 
ii,45~.920 
11.541 
Value. 
$ 	48,463 57 '7:33 
233,057 i)93,3(i7 H,035 90,416 24!1,411 171,431 56,997 1()2,064 H5,801 61,355 
40.133 17,400 
(j 
7,008 118 
20,Hi 51 83 
1.051 
$ 2,200,1:33 
Exports. 
Quantityflasks of 76Y, Value. 
lbs. net. 
37 .210 35,107 33.815 30,072 7,370 6,802 8,091 11,394 
10,ti84 5,111 2,069 3,714 3,518 
16.6:31 H,408 15,542 19.!.IH 
13.17:3 12,8:30 16,51 i 10,172 
'324,234 
$ 1.119.9.j2 1.025,299 98S,4-34 so8.3;>:l 199.(i8ii 209, 153 
204.956 441, 112 406.89!:1 
213.711 
93,192 145,502 13:3,626 .542,410 
391 .528 -t82.085 618,4:31 ;394,;)4[1 H0,58i ti0!J,ii8(i 425.8'.2 
$ 9,881,494 
THE 'fERLINGUA QuICKSILVEH DEPOSITS. 
From 1880 to and including 1885 the returns are for the fiscal year ending with June; from 1885 on for the·year ending with December. 
During this period of 21 years the production was 725,523 fl.asks and the imports 71,541 fl.asks, a total supply of 797,064 flasks. The export<! were 324,234 flasks, so that, disregarding stocks on hand, the total domestic consumption was 472,830 fl.asks, an average of 22,315 fl.asks a year. This is about what the country at large will consume ]n amalga­mation, for pigments, medicinal preparations and other like purposes. Dividing this period into 3 groups of 7 years each, we find that from 1880 to and including 1886 the average annual domestic ccnsumption was 28,644 flasks; from 1887 to and including 1893 it was 24,289 flasks; and from 1894 to and including 1900 it was 16,084 flasks. 
By far the greater amount of quicksilver used is in the amalgamation of gold and silver ores, so that a decreasing domestic consumption would mean that the mills are using less quicksilver, or that a considerable ror­tion of the gold and silver formerly won by amalgamation is now ob­tained through smelting processes. Perhaps both these causes are oper­ative, but we can not pursue the matter further at this time. 
According to The Mineral Industry, 1892-1901, the average price per flask of quicksilver in San Francisco and London was as follows: 
Average Price of Quicksilver per fl.ask in San Francisco and London, 1850-1900: 
Year.  San~ Francisco.  London.  Year.  San Francisco.  London.  
£. s. d.  £. s. d.  
1850 ........  $ 99.45  14 1 3  1876......  $ 44.00  9 18 9  
1851.. .. ....  66.~3  13 0 0  1877 ......  37.30  8 6 3  
1852 ........  58.32  10 8 9  1878......  32.90  6 16 3  
1853.. ......  55.45  8 8 9  1879......  29.85  7 6 3  
1854 ........  55.45  7 10 0  1880......  30.35  6 17 3  
1855 ........  53.55  6 13 9  1881......  28.97  6 6 8  
1856........  51.65  6 10 0  1882......  28.43  5 19 0  
1857 ........  49.73  6 10 0  1883......  26.83  5 7 3  
1858 ........  47.82  7 7 6  1884 ......  29.34  5 10 4  
1859........  63.13  7 2 6  1885 ......  30.52  5 17 4  
1860 ........  53.55  7 0 0  1886 ......  35.44  6 9 7  
1861........  42.10  7 0 0  1887......  38.73  7 8 2  
1862.......  36.35  7 0 0  1888 ......  40.11  8 1 11  
1863 ........  42.07  7 0 0  1889 ......  45.71  8 11 0  
1864 ........  45.90  8 5 0  1890......  52.01  9 5 0  
1865.. ......  45.90  7 18 9  1891.. ....  43.29  8 0 2  
1866........  51.63  7 8 9  1892 ......  38.80  6 14 0  
1867 ........  45.90  6 18 0  1893 ......  40.42  
1868 ........  45.90  6 rn 6  1894 ......  34.39  
1869 ........  45.90  6 16 6  1895 ......  39.06  
1870.. ......  57.37  8 8 0  1896 ......  36.86  
1871.. ......  63.10  10 10 0  1897 ......  38.56  
1872........  65.98  11 10 0  1898 .. ....  39.37  
1873........  80.32  16 0 0  1899 ......  44.29  
1874.. .. ....  105.18  22 10 0  1900 ......  50.10  
1875.. ......  84.15  16 18 9  

NOTE-In 1893 London prices ranged from £ 11 5 s. to £ 5 1 s. 6 d. In 1894 from £ 10 7 s. 6 d. to £ 5 10 s. In 1895 from £ 9 t.o £ 5 10 s. In 18!16 from £ 7 7 s. 6 d. to £ 6 7 s. 6 d. In 1897 from £ 8 to £ 6 16 s. 3 d . In 1898 from £ 7 15 s. to £ 7. fo 1899 from £ 9 12 s. 6 d. to £ 7 15 s. In 1900 from £ 9 12 s. 6 d. to £ 9 2 s. 6 d. 
59
THE TERLINGUA QuICKSILYER DEPOSITS. 
In 1~98 the San Francisco price ranged .from $43.00 to $39.00 for domestic and from $38.00 to $35.00 for export; in 1899 from $52.00 to $42.00 for domestic and from $47.00 to $37.50 for export; in 1900 from $52.00 to $48.00 for domestic and from· $47.50 to $45.00 for export. 
The price of quicksilver for exportation is alwavs lower than for metal intended for domestic use, the tariff being subtracted from the domestic quotations. 
From the table it will be seen that since the year 1894 to the close of 1900 the average price of _quicksilver, per flask of 76! pounds net, has ranged from $34.39 to $50.10, domestic. Unless otherwise stated the quotations given are for domestic. 
For purposes of comparison the quicksilver production of the various countries, since 1894, is given in the following table, the :figures being taken from the volumes of The Mineral Industry, the metric ton of 2204 pounds there employed being converted into flasks of 76! pounds net. The .American, Russian and Italian flasks contain this amount, the Mexi­can flask 75 pounds, and the Spanish flask 76 pounds. The Mineral Industry uses, at times, the figures given in the .Annual Metal Circnlar of W. T. Sargant & Sons. 
Qilicksilver Production of the 'World, since 1894, in fla!'ks of 76! pounds net: 
United
Russia. 
Spain. 
Total.
Year. 
AusLria. 
Canada. 
Italy.· 
Mexico. 
States. 
5,fi37 
47,624 
30,416 113,841
1894 ........ 


15,010 .......... 

7 ,433 
7,721 
119,188
1895 ........ 

15,413 
72 
5,733 
12,503 
42, i54 
4,609 
3fi,104 \ 
14,971 
30,765 117,239
1896 ........ 

57 
3,802 
6,280 
17,775 
43,589 
1897.. ...... 
15,326 
8,470 
49, 783 
26,648. 123,492
8 
5,511 
17 '746 
119,516
1898 ........ 

14,125 ........... 

4,984 
10,169 
10,429 
48,717 
31,0rl21 
30,454 110,602
1899 ........ 

10,371 
39,095
5,906 
9,334
15,442 ... ······· 
1900 ........ 

j!~,3li 101,953
15,845 
........... 

6,338 
2,651 
9,795 
32,007 
During the 7-year period ending with 1900 there was a decrease of 11,888 flasks in the world's production, shared by Italy, Spain and the United States. .Austria gained 835 flasks, Mexico 1,930 flasks, and Rus­sia 4,158 flasks .. There was a gain of 6,923 flasks and a loss of 18,811, making a net loss of 11,888 flasks. During this period Italy lost 1,095 flasks, Spain 15,617, and the United States 2,099. The Spanish produc­tion has been declining for. several years . 
.A brief description of the quicksilver industry in the several countries will now be given. 
AUSTRIA. 
The principal mines are at Idria, a town in the western part of Cami­ola, in the southwestern part of the Empire. Cinnabar wa:; discovered here between 1490 and 1497, and the mine<> shared with the .Almaden mines, in Spain, almost the entire quicksilver trade for four centuries. The ore-bearing rocks are of Upper Triassic age, the sandstones ~md schists of Carboniferous age that occur above the ore having been placed there by dislocation. The foot wall of the ore-bearing beds is magne~ian limestone, with small veins of calcspar and layers of flint. .Above this 
THE TERLINGUA QUICKSILVER DEPOSITS. 
comes a 30-foot bed of what is locally called sandstone, but which R. 1\feier has shown to be a bedded tuff-like stone consisting of quartz, fold­spar, mica and hornblende. Above this lies a bed of soft, bituminous ~late which carries the ore. 
The hanging-wall of the slate carrying the ore is a bed of dolomite of a thickness of 120 feet, either close-grained, as a conglomerate or as a breccia, and it carries cinnabar in the crevices. Above this is a bed of gray clay slate, ±80 feet thick, which sometimes carries native qu~ck­.~ilver on its planes of fracture and bedding, with occasional trace" of cinnabar. In it are lens-shaped inclusions of pyrite, containing quick­:,;ilver.. In addition to pyrite, the dolomite and the clay slates contain also graphite, anthracite, calcspar, epsomite (sulphate of magnesia), cop­peras and g);psum. 
The content of quicksilver in the ore varies from 0.60 per cent. to 1 per cent, the average being nearer the lower figure. Th coarse hand­picked ore, from an inch to 4 inches in size, carries generally 0.35 per cent of metal (7 pounds per ton); the medium size<l ore, from-! inch to 1 inch, 0.50 per cent. ( 10 pounds per ton), and the fine ore, up tot inch ~ize, 0.9 per cent (18 pounds per ton). The finer material i~ thus seen to carry nearly three times as much metal as the .coarse material. 
It has been customary at Idria to concentrate the ore from 0.65 per cent. to 0.85 per cent. before sending it to the furnaces. 
When the old furnaces, that had been in use for more than 100 year,;; were torn down in 1868 to 1878, there were recovered from the masonry, foundations, etc., 150 tons of quicksilver, equivalent to 4,322 flaPk~, which had been absorbed during this time. The loss at present may be taken at about 8 per cent., which, with an ore of 1 per cent, would m1'an that the burned ore would contain 0.125 per cent. of quicksilver. 
At Idria the ore-bearing slates do not cary a uniform amount of quick­silver, and pockets of ore are not infrequent. Cinnabar is found also in a limestone conglomerate and in a dolomitic breccia. There are also beds of a dark bituminous sandstone and slate intermixed wiih dolomite which are ore-bearing. In this latter case when cinnabar is present the rnndstones and slates are highly bituminous and generally carry pyrite. Idrialite (a hydrocarbon containing quicksilver) and anthracite are nlso found. 
Four varieties of ore occur. The first is free from bitumen and con­tains small pieces of dolomite and, invariably, pyrite and native quick­silver. The content of mercury in this variety runs to 67.77 per cent. The second variety has a steel-gray lustre on a fresh surface ;rnd is rnry pure, the content of metal running to 80.81 per cent. It contains cirma­har mixed with bitiumen. Idrialite is sometimes found in this variefr as a bituminous, earthy mineral of liver color ( quecksilberlebererz ). Where this is noted the ore is of the third class. 
The fourth claes is known as coral ore from the occurrence of coral and other fo.sils, which are found in the slate beds. This coral-ore is remarkable in containing 56 to 57 per cent. of phosphate of lime, irnd 4 to 5 per cent. of ftuorspar. In addition it contains bitumen and a compound of phosphate of lime and iron. In this connection it is inter­t'sting to note that corals have been found in association with the Texa."­einnabar and that ftuorspar is one of the minerals found in th8 ore-veim:. 'fhe recent discoven, hv the writer, of beds of cream colored limestone. clo;::ely resern hling ;::~rnclstone, and dolomitic conglomerates carrying phos~ 
THE TERUNGUA QUICKSILVER DEPOSITS. 
phate of lime north of the Terlingua quicksilver district and south of Agua Fria, Brewster county, Texas, would tend to bring the Tr!xas deposits into some correllation with the deposits at Idria. Add to these the further facts that bituminous shales are abundant in the Terlingna district and that pieces of asphalt have been found in the sandstones along Terlingua creek and the correllation becomoo closer. Pyrite occurs also in the bituminous shales near Terlingna and is not infrequently associated with the cinnabar. 
At Idria native quicksilver has been found near the surface, but not in depth. 
In this connection, although the locality is not in Austria, but in the Pfalz, Germany, may be mentioned the occurrence of quicksilver ore in Permian slates, sandstones, flints and conglomerates, through which there have been eruptions of melaphyr and porphyry. The mercury cPm­pounds present are native mercury, amalgam, calomel, metacinnabarite, and gray copper ore (mercurial). The following other minerals have also been found: pyrite (sometimes silver-bearing), limonitc. hematite, siderite, galena, gray copper ore, chalcopyrite, stibnite, pyrolusite and psilomelane, calcspar, barite, quartz, flint, chalcedony. Especially worthy of mention is the occurrence of asphalt. 
A peculiar feature of the deposits near Moschel is that the ore occurs not only in the sandstone, but in the porphyhy as well, a notable instance of an eruptive rock carrying ores of quicksilver. In this connection, rompare the occurrence of cinnabar at the Study mine, Sec. 216, Block G4, Brewster county, Texas~ 
CANADA. 
At Kamloop's Lake, east of the Fraser river, British Columbia, cinna­bar occurs with calcspar and quartz in zones traversing a gray telclspathic and dolomitic rock. The country rock, through which the ore-bearing zones run, is a dark greenish-black acidic eruptive rock of Tertiary age and contains pyroxene and olivine. It has been called picrite. Through this there are small fomres of dolomitic material carrying cinna­har. The larger fissures carry a rock shading from tufa 10 rhyoiite, containing, at times, disseminated crystals of cinnabar, another instance of the ocurrence of cinnabar in eruptive rock. 
It is possible that some of the dark red earth used as a pigment by the former inhabitants of that region, mentioned by the J e.;,up Archffio­logical Expedition in its recent reports, contains cinnabar, although nuth­ing has been said on this point. The Indians in Brewster county, Tcxa~, used cinnabar as a pigment. 
The quicksilver industry in Canada has not yet assumed much ccim­mercial importance. 
ITALY. 
The principal deposits are at l\Ionte Amiata, in Tuscany, and occur in the Tertiary (Eocene). They were worked as far back as 1000-1200 
A. D. 
Between 1890 and 1897 the Siele works treated 48,353 tons of ore, the content in quicksilver varying from 20 per cent. in 1890 to 1.20 per c:~nt. in 1897. The Monte Amiata works, between 1893 and 1897, treated 
THE TERLINGUA QUICKSILVER DEPOSITS. 
73,177 tons of ore, the content in quicksilver varying from 1.:JO per cent. to 1 per cent. The average content of the Monte Amiata ore in quick­silver is from 0.30 per cent. to 0.8 per ·cent., and by the use of the Cer­mak-Spirek furnaces and condensers ore of 0.30 per cent. can be profit­ably t.reated. This represents an ore carrying but 6 poun1fa of quick­silver per ton of 2,000 pounds, and is probably the lowest limit of economical working. The most complete returns, however, are from the furnaces using an ore of 1.20 per cent. It is stated by Vincente Spirek that a plant costing $30,000 will sucoessfully treat 45 torui of ore of this grade every day, with a loss of 4 to 5 per cent. of metal, after the con­densers have become impregnated with the mercurial vapors. The cost of producing a flask of quicksilver, excluding general charges, li> placed at $30. 
lfEXICO. 
Near Arichuivo, Chihuahua, there is cinnabar in porphyry. Near Guadalcazar, San Luis Potosi, there is cinnabar in gypsum and lime­stone, with calcspar and fluorspar, the content of metal varying from 2 to 3.5 per cent. A mile to the east is porphyry and granite. In 1893 the ore carried 4.05 per cent. of quicksilver, and the extraction was 8:~.56 per cent. In 1894 the ore carried 1.95 per cent. of quick.silver and the extraction fell to 81.87 per cent. 
The principal producing mines are near Huitzuco, Guerro, where t.liere are pockets and veins of cinnabar in disturbed and metamorphosed lime­stones and slates. The ore, which also carries silver and antimony; is found at or near the tops of small hills and occurs as a soft, sandy, clay­like filling in crevices that often radiate from . a common cP,nter. The average content of the ore in quicksilver is about 1.70 per cent., rmt the extraction is very low, about 50 per cent, although ore of 0.62 per cent. has been worked. 
The Nueva Potosi deposits, San Luis PoU:>si, were worked 2!5 years ago and have been reopened. The ore carries less than 1 per cent. of quick­silver, but is said to exist in large bodies easily mined. The Montezuma district, in San Luis Potosi, may also be mentioned, especially the Dulces, N ombres mines, where ore of 30 to 70 per cent. quicksilver has been found in a ferruginous gangue. 
RUSSIA. 
The deposits of cinnabar near Nikitovka, Government of Ekaterino­slav, were discovered by A. M:inenkov in 1879 and opened in 1886. They occur in a carboniferous sandstone, in folds in the main anticlinal of th(} Donetz coal basin. The ore is iound not only in the sandstone proper, but also in a quartzite, which has been much fractured. The quartzite is the richer material and the ore occurs in its crevices.· Stibnite and pyrite are present, as also a bituminous, or other carbonaceou"1 substance, which endoses crystals of cinnabar of imperfect development. 'l'he aver­age yield of the ore, between 1888 and 1897, was 0.65 per cent. ( 13 pounds per ton), the production during this period being 19, 192 fla;:ks. The furnaces used are of the Spirek-Schernia design, ih1p1vved by Auer­baC"h, and it is claimed on what appears to be good authority, that ore of 0..±0 per cent (8 pounds per ton) can be profitably treated. 
THE TERLINGUA QUICKSILVER DEPOSITS. 
SPAIN. 
The quicksilver deposits at the Almaden min&'!, Ciudad Real, are the most famous in the world, not only on account of the length of time they have been worked (before the Christian era), but al.so and particularly on account of their extent and richness, and the amount of metal taken from them. They occur in clay slates of upper Silurian. and Devo!lian age, with interstratified beds of limestone and sandstone. The slates themselves seldom contain cinnabar, and when it is found in them it occurs on the bedding planes and in very small veins. The wall rock for the most part is composed of bituminous slates and quartzites, which alternate with schists, fine grained sandstones and limestones. There are two kind of sandstone, white and black, the former being the richer. In the black sandstone the cinnabar is distributed in an irregular man­ner in particles and as a coating. The white sandstone is sometimes so full of cinnabar that it is difficult to say just where the cementing mate­rial begins. The limestone also carries ore and thin veins of calcspar, carrying ore, penetrate the otherwise barren slates. 
The most important deposits are those of San Francisco and San Nich­olas, where the thickness of the ore-body is about 20 feet. These beds, or veins, are separated from each other sometimes by a soft slate, two or three feet thiek, but at a depth of 810 feet they are worked as one, the distance across being 67 feet. The deposits carry a great deal of quartz and the cinnaoor is found penetrating this, or else concentrated into pockets. There are cavities containing native quicksilver. Geodes of calcspar occur and .in them pyrite and galena. Yellowish-red cinnabar of stalactitic form, and probably of recent origiit, has been found at the Concepcion Nueva mine, at Almadenejos. Fragments of .fiorite (an eruptive rock occurring in the vicinity) have been found in the deposits and LePlay thought that there was an intimate connection between the occurrence of the ore and the existence of the ·eruptive rock. The con­troversy over · the exact nature of tliese deposits, whether they are true veins or beds, has never been settled. The wasteful methods of mining and treating the ore, described by C. E. Hawley (American Journal of Science, Vol. XLV, Second Series, pp. 9-13), in 1868, have been super­seded by modern appliances. The Almaden ores carry from 7 to 8 per cent. of quicksilver, although in the district ore of much smaller content of metal is worked, as, for instance, by El Porvenir Company, which has treated ore of 1.20 per cent. But even allowing that lean ores do occur and are treated, the fact.remains that the Almaden deposits are probably the richest now worked, and they have been operated for nbout 2600 years, the earliest records dating from 700 B. C. 
In speaking of these deposits Von Cotta says* : "The uncommon breadth or massiveness of this quicksilver occurrence is very remarkable. It is-not very strange to find ores, which occur as frequently in the earth's crust, as tho.se of iron, copper, lead, or zinc, locally aggregated in massive deposits; but in the case of a metal such as mercury and its ores, which relatively occur so rarely, and in so few localities, such a massive aggre­gation is certainly astonishing." 
The minerals associated with the cinnabar at Almaden are calcspar, pyrite, galena, quartz, barite, calomel and arsenical pyrite. 
*Treatise on Ore Deposits, Prime's Translation, pp. 400-401. 
THE 'fERLINGUA QUICKSILVER DEPOSITS. 
UNITED STATES. 
Quicksilver ores have been mined in California, Oregon and Texas, by far the largest producer being California. 
The California deposits have been most carefully studied hy Dr. Geo. 
F. Becker, and the results of his observations were published in Moµo­graph XIII, Uniwd States Geological Survey. 'l'he Thirteenth Annual Report of the State Mineralogist, 1896, also has mueh in~ting matter, and Arthur Lakes, in Mines and Minerals, March and April, 1~l:l9, has two good articles on the New Almaden mines, and R: B. Symington, in The Jlineral Industry, Vol. VII, 1898. . 
The California deposits occur principally in metamorphosed M:esm:oic beds, either of early Cretaceous or late Jurassic age, although there are dep~its in the Miocene, and to some extent in alluvium of the Quarter­nary. Becker calls the deposits "chambered veins," and they occur in zones which have been much fisured and fractured. The ea.rly Creta­eeou.s or late Jurassic ·rocks, which hold the ore, , appear to be composed to a great extent of granitic detritus. The volcanic · rocks. of the ,vicinity, such as rhyolite, andesite and basalt, are related to the ore-system, and at New Alilladen there is a long rhyolite ·dike near and almost pa.rllllel i:o the general fissure system carrying the ore. . 
In Colusa: county cinnabar occurs in an altered serpentine; in Lake county, in seams in shale near contact with serpentine, as also, in '1azd opaline serpentine and in a greenish-gray sandstone with seam~ of ser­pentine. In Napa county, cinnabar occurs in sandstone at a contact of argillite (clay-slate), and in black chalcedony. In Santa Clara county, New Almaden, "the ore occurs in shoots and bunches in a brecciated zone along a contact of serpentine and shale, the vein matter ·being chiefly serpentine, generally richer near the hanging wall, and becoming poorer in depth M the vein matter becomes harder."* 
The New Almaden mines have ·been developed to a depth e:Eeeding 2,500 feet. 
In The Mineral Industry, Vol. I, 1892, there appeared a table giving the quickt:ilver production of California from 1850 to the close of 1892. From this it appears that the yield of metal during this period varied from 36.74 per c:ent., in 1850, to 1.22 per cent., in 1892. The -cost per flm>k varied from $11.98, in 1881, to $46.57, in 1892, the co~t per flask being given from 1871to1892, but not previous to the former year. In 1897, 28,650 tons of ore gave 474,300 pounds qf metal, an average yield of 0.83 per cent. In 1898 the Napa Consolidated Quicksilver Mining Company treated 32,489 tons of ore, the average yield of which was 
0.80 per cent. The average receipts were $35.8.9 per flask and the aver­age cost $21.33. During the same year the New Idria Quicksilver 'Min­ing Company treated 18,627 tons of ore, with an average yield of 1.03 per cent. The average receipts were $35.86 per flask and the average expense $17.48. The Aetna Consolidated Quicksilver Mining Company, in 1898, treated 18,394 tons of ore, which yielded 0.72 per cent. of metal. The average cost was $26.55 per flask. 
In 1900 the Aetna Consolidated treated 11,888 ton.s of ore and obtained 1,945 flasks, a yield of 0.63 per cent., while the New Idria Company 
*Abstract in The Mineral Industry, Vol. V, p. 464, of article in 13th Annual Report of the State Mineralogist of California, 1896. · 
STUDY BUTTE, SECTION 216, BLOCK G4. 
CLAY MOUNTAIN FROM THE SOUTH. 
THE TERLINGUA QurnKsrLYER DErosrTs. 
treated 20,638 tons and produced 3,990 flasks, a yield of 0.1-! pl'r cent. The practice in California nm1· seems to be to treat all nrnterial that carries more than 0.50 per c·ent of metal, or 10 ponncls o.f quic-ksihcr per ton of rock, this being \\'Orth about $6. 
The minerals associated with the quieksiln'r dcpo,,its of California are: bitumen, free sulphur, stilmite, and other ore;; of antimonY. rni"­pickel, gold and :0ihcr ore~, clrnlcopYrite, pyrite, niarca~itl', rnillPritc, quartz, ealcitt>, baritc, and borax. 
OREGOX. 
A deposit of cinnabar was opened in Lane county in JSDD. and a -!O ton furnace erected. There is .~aicl to be a large amount of l01r grade on·, <lveraging, perhaps, 0.50 per cent. There are deposit.~ abo iri Doug-la;; county. The production, howewr, has been small, 233 fia:0!-::s during the year 1900. Xo description of the deposits is available. 
TEXAS. 
The deposits of cinnabar at and near Terlingua, Brewster r:rmnty, are de.scribed by Mr. B. F. Hill in this Bulletin. They were first noticed by Prof. Wm. P. Blake in the Transactions of lhe American Institute of J1Iining Engineers, Vol. XXV, 1895, pp. 68-76. A nobce of the cfo­covery had previously appeared in The Bullion, Los Angeles, Cal., August 14, 1894. The El Paso papers also noticed the diseown. a.~ also The Manufacturers' Record, Baltimore, Md. Since thd time the deposits have been described by H. W. 'rurner, in i:he T"·entY-first Annual Report of the Unit€d States Geological Surve~· ; by E. P. Spnld­ing in the Engin.eeri:ng and Mining Journal. Vol. LXXI, N•i. 2-!. June 15, 1901, and by Robt. T. Hill, in the i'ame journal, Vol. LXTY, :\o. 10, Septern ber 6, 1902. 
As Prof. Blake's article was the first to appear ancl contains the re-ult" 
of his observations when the district had not been prospected much. n 
full abstract of it will he given. It is as follows: 
"The elevation of the "Camp is shown by the aneroid barometer b he 
:3,250 feet above tide. The nllev of the llio Grande. marked bY its 
fringing groves of cottonwood trees, i.s in full view for several miles. 
The mountains acros::: the horcler in Mexico are also clearlv ~l·en, a~ 'rell 
as the high range on the ~out.beast, known as Los Chi.,os, culminatinf'. in 
Emory Peak, and the peculiarly ~lrnpe(l peaks known as the ':\Iule Ecn;:.· 
all noted landmarks. 
From "Marfa to th<> Tre;; Lenguas tlw direction i,, near!~· ~onthcn;:t. 
fo!J.owing a wickh· crroclccl valley in table-lands. whieh ar<' genC'rnlly 
capped with a harrl l11wr of hasalti(' lam. S('Cll to· the best advantage at 
the Alamitos ranclw. ancl in the Church mountain:=:. near Collin;:c.n·;: 
rancho. An isolntccl conical mountain. rising from th(' liro.i<lfr crocll'cl 
country to tlw eastward of the Church mountain.", has a tlat top ancl is 
eviclentlv a remnant of former mesa, left ~tancling as a monnml'nL a-if 
to show" whn t an p11nrn10us amount of makrial has !wen ~"·ppt 1nrny to 
the Gulf Jiy c•rn.-inn aJH1 degradation. 'l'hc eclges of the horizontal heel:; 
ean he seen. from a tli.~tanee. anfl the mountain kno\l·n aF San Diego P c·ak 
donlitil'>'s ;11ford" a Yery complete ancl int<.'resting sc>c-tinn of the ('J1tire 
~eril'>' nf IH'lis frorn the laYa rap to the lo\n•r strata of the· Cn•tnc:con~. 
THE TERLINGUA QurnKsrr.vER DEPOSITS. 
"The beds of which this peak and the ma-;as along the Alamitos and 
the upper branches of the Tres Lenguas are chiefly formed, are remark­
able for their whiteness and homogeneity, and appear to consist chiefly 
of an indurated volcanic mud. It is an amorphous mass, in which there 
is a large amount of clay and silica; but it is without well-defined struc­
ture or stratification. It is remarkable for the general absence of oxide 
of iron. It is fusible and would appear to be a mass resulting from the 
breaking up of feldspathic rocks. The thickness is probably not less 
than 500 feet, and it extends over a wide area, east and west, as far as 
the edges of the high mesas can be seen. The general uniformity of 
composition of this deposit is broken toward the top of the mesas by a 
bed · of conglomerate and breccia, 10 feet or more in thickness, made up 
chiefly of red and brown porphyritic iot:Ko. J ·1e uu i::. es lieing, in part, 
well rounded, show the action of currents of considerable force and 
extent. This.stratum contrasts strongly with the white sediments above 
and below, and makes a dark-colored belt or band through the hills vis­
ible for miles on either side. 
"In descending the valley of the Tres Lenguas, there is a marked tran­sition from the volcanic beds to those of unquestionable Cretaceous age. At first, thick masses of finely bedded blue and yellow shales are encoun­tered, and in the broad, flat surfaces countless casts of Inoceramus reveal their proper horizon. The strata, at first lying apparently horizontal, are found to be cleft in various directions by faulting planes, with large blocks partly upturned and evidences of extreme lateral pressure, by which the shale.s along the faults are buckled upward and crushed. The shales are succeeded by limestones, massive, light colored; nodular, and rugose in structure. 
"The cinnabar occurs both in massive limestone and in a siliceous shale and a white, earthy, clay-like rock, and in part in a true breccia of grayish-white siliceous shale, den:se and compact, embedded and cemented in a red and chocolate-colored ferruginous mass, also dense and hard. The white blocks or included fra!mlents of the shale exhibit a concentric arrangement of coloring ~ o::ride of iron disposed . in bands and thin sheets, deposited in the substance of the shale by the absorption of ferruginous solutions, penetrating from withol!t inwards along the surfaces of the fragments. These deposited coatings or layers coniorm in general to the exterior forms of the mas.ses, and succeed each oiher like the concentric layers seen in agates and chalcedony. The colored depositions may also be seen surrounding tube-like or thread-like chan­nel.s, which have permitted the inflow of solutions bearing not only iron salts, but also those of quicksilver, and leaving behind, in the substance of the rock, layers of iron oxide and of ·cinnabar concentrically disposed. 
"While the genesis of the cinnabar is here shown to be essentially like that of the iron oxide, it is smaller in quantity, and is so far separated from the ferruginous bands· as to show a great difference in the conditions of deposition. The cinnabar is more generally crystalline than amor­phous; it is not found in such continuous coatings or layers in the white shale as the iron oxide, but is in distinctly separate grains and small but brilliant rhomboidal crystals, having the brilliant red color charac­i eristic of vermilion. There are also considerable masses of snow-white argillar,eous rock, in which cinnabar is found in minute crystalline grains spread in bunches here and there through the mass, and often not observ­able until the mass is rubbed or bruised with a pick or hammer, when 
THE TERLINGt:A QurcKsrLnm DEPOSITS. 
the reel e:olor of vermilion appears. In such ma.sses there is apparer.tly a complete absence of ferruginous matter. The soft, white, chalk-like ma&ses of rock do not appear to l>e so favorable to the Cl'Yf~tallization ·
)f the cinnabar as the more clcme and siliceous portions of the rock, resembling chert, or fl.int, where the cinnabar is in distinctly formed (·rystals sprinkled through the rock, much like the occurrence of cinnabar in the siliceous gangue of the clt>posits of Buckeye Rancho, California. 
. "In addition to these disseminated crystalline granules in the brec­uatecl shale and in the more massiYe white rock, there are amorphous lrnnches of cinnabar found in the shales and in the limest-0nes and the lJreccia. This cinnabar is not, ho\\·ever, in the hard masses like those of the New Almaclen mine in California, nor is it in veinlets, as there found, traversing the rocks, but it is soft and friable and has a light vermilion colm'. Calcite is associated "·ith it, but, w far as observed, no petroleum or bituminous exudations. Some of the larger masses of cinnabar bunches, weighing 2 or 3 pounds of nearly pure mineral, were taken out of an open cut where the shale appears to be the parent rock; but I noted also some small bunche.s of the cinnabar in the compact blue lime­stone. 
"There are several points on the line of about 1,000 feet in length, along a shallow ravine, where open cuts have been made t-0 a depth of a foot or two, revealing the presence of cinnabar in each and in the soil mixed with the croppings. This linear distrihution of the t:innabar is indicative of a vein-like occurrence, or it may be the re~mlt of a cropping of a certain bed or stratum. The openings whir.b had been made were not deep enough to show conclusively the real conditions of occurrence. In wme places the appearance favored the conclusion that the ore is inter.stratified or bedded; in others, it seems to occur along ::i fissure or fault plane, and it is most probable that both of these forms of occur­rence will be found to exist. 
"There is a second line of cropping a few rods north of the first and higher up the hill, and in the midst of the hard limestones. This i..s in the midst of a "·ell-defined breccia of iron oxide, and the masses of cinna­bar are closely associated with it. ::\lasses of iron oxide, rock and ci1ma­bar, weighing a hundredweight or more, can be broken out from the croppings here; but no 'rnrk has been clone to develop this ground in depth. The cinnabar croppings may be traced for a few feet each way. and the breadth does not exceed 18 inches or 2 feet. This occurrence does not appear to be conneded with the series of croppings beforc­described, and it iias a more decided resemblance to a fissure deposit c:· impregnation. 
"The existence of several out.crop.s of a ferruginous breccia, with :rncl 
without cinnabar. is indicatiYe of breaks in the beds in the nature of fo­
'3ures (fault plai{es, probably) , accompanied by rupturing and crushng 
of the rocks b." Yiolcnt moYements under preE.'3ure. Other evidences of 
rlssuring and of metalliferous impregnation through the fissures arc vis­
ible in the neigh horhood in the many vertical cracks in the lirncstDne 
strata, marked by the lateral depo.-;ition of oxide of iron on both sicles. 
Such deposits are estL·nsin~ and sh-0"· that there has been an abullllant 
-;upply of iron-bearing solutions. 
"The best place in "·hich to sink for the better development of the 
•)re in quantity "·ould appear to be at the brecciated cropping on the hill in the linw~tonr. This place .';e0ms the most promising. 11' limestone. 
6S THE TERLINGUA Qu1cKSILYER DEPOSITS. 
l1l'i11g the llllll'l' ,;o]ubll' rod;:. nwy contain hirge Lunches Lelow, where the nrl' ha" nl·t·n11rnlatl'd by replacement. Tlw conditions for wo:rking these dl'po,it~ of cinrn1bar are not as fayorable as could be wished. The bril­liant color of the ore "·oulcl permit of its being utilized aE vermilion; lrnt there is 110 \niter near the place for concentrating it. Considerable , 'l'l' rnuh1 i>L· taken out of the loose earth along the main cropping-: if watl'r c-ould lw had to wash it. A supply of wood for fuel can be had ;dong tlw Hio l~rande, and could be deliYered at the mines for probably ~;i or $(i prr (·Ord. ~.\.lthough a comiderable quantity of high-grade ore 11·hid1 \rould be11r tnmsportation could be selected by culling, there would n·main <1 larger quantity of low-grade which would be practically uselr;s,s, Tlwn· Im~ not wt been sufficient work done on the croppings to show sat­i,facrorily \rhat quantity of ore of a desirable awrage percentage can be l'.\jll'l°tC'll. '' 
Corn,idering that Prof. Blake Yisitecl the district when there was a!mo,..:t no deYrlopnwnt, his remarks are certainly Yery much to the point. \rhat he said in 1895 is true today, and the denc>lopment of the district is no,1· preceding in the direction he indicated, among the brecciated 
•kpo~its in the limL·~tonc on the hills. 
::\Ir. E. P. ::lpnlding, in the article already alluded to, thought that rhc main bdt of workable ore was about 6 miles from east to west and ;thour. .'2 mile;; from north to .~outh. The limits of the field have been t·on:::idernbly extl'nded. d'nring the last 16 months, so that it is now thou~d1t. that li5 miles .from east to west and -+miles from north to south. <lr !ill ,;:quan· mill'.~. w111 be found to. be ore-bearing at intervals. He nMed the existence of H'ry rieh pockets and bunches of ore, some of them t«irrying from -+O to 82 per cent.of metaL and considered that the deposits . genrr111ly were replacements due to ascending solutions. Without com­lllitring him...:r•lf. "·hich, considering the fact that the deepest shaft at the tinw of his Yisit \1·as onh 65 feet, he could hardlv have been war­ntntl't1 in doing. he ,.:a~·s that 'the deposits gin' one the 'impression of not iwing dcql ,;eatl)rl. At the same time, he ah'o says that there are reasons for ,.:uppo::;ing that the>· nrc. 
The qm•stion of tlie dl'ep ,,:cateclness of the r1cposits must be left to the minl'r. and ,,.l' ,..:hall h<1YC to 1nrnit further clewlopment. The greater part of the nilh·nc·c· thus for to hcmd i~ in f;wor of the continuation of the c1L·po,its through t.he limesto1w holc1ing tlwm, about 1,700 feet. 
In "Jh·aking of the ou·urrence of cinnabar in the district, Mr. Spald­in~· "nrs that he obscned it in cwn da~s of rock found ther0 even as a l·n~ti11~ un lmsnlt. an l'ruptiw rod;:. \Yhile hr \n1S there h; witnessed tlw npening of <1 pocket of cinnabar, from which two men in half a da,v took nl1ont '211 tons of ore 11ssnying from -±0 to 15 per cent. of metal and \rorth from $1'2.000 to $10.000. Frnm the ,..:ame localitv there were ol1tai 1wt1 ,;vn·nil lmnrlrr>t1 to1;s of ore enrrying from 1 to 2" per cent. of llll'tal. Thi,;: rid1 ]JOckN \\"11:" found within two feet of a place that had ''l'l'll pronon1Jl"ed barren. Othl'r imtances might be giwn of the clos~ ~l'i-!Tl',!.!"<l tion of t lw~e poeket,;:. for w h ilr· thl•rc nm v be, and often is, a vi"' ihle t·omwr-tinn lil't1n•l'll t1ro or more• p<wkl't.~ ii1 rhe form of stringeri' (hi ln,; J. or other l'Yi dl'Jh·es of like' na 1.nrc, yet the pockets stand for thE.m­"l'IYl'" antl t"<ll1 oftl'n !Jc so eomplctely 'tripper1 of ore as to leave but "t·<tlltY t·Y1rlt•rn·p nf ir,.: fnrnwr l'si,;tcnn>. Jn thi . ..: \l";;Y thcY rr>mincl onP of thl' JH>t·kl'I" nf zinc-orl' in tlw .Joplin di,;triet. ::\[o., ·or of the pockets of l111111111rt· ( \,r..1rn nrt·) in tlw :-;j]nrin11 c·]ny,; of .\lnbama. 
CINNIBAR-BEARING CRETACEOUS CLAYS, M'KINNEY AND PARKER'S. BANDED STRlTCTURE IN CINNABAR ORE. 
THE TERLINGUA QUICKSILVER DEPOSITS. 
~rof. Robt. T. Hill, in the article already alluded to, considers the region, as a whole, to be made up of marine Cretaceous tiedimentary rocks, tilted, faulted, fissured and metamorphosed. 
In the Upper Cretaceous, the Montana division (Eagle Pas1:1), with its seams of lignite and coal, lies in the valley of Terlingua creek and its tributaries between Terlingua and the Chisos mountains. In the Lower Cretaceous, the Georgetown (Fort Worth) and Edwards limestone of the Fredericksburg division are composed of about 1,700 feet of a massively bedded white limestone, in which flints, fossil Rudistes, Requienias and Gryphrea abound. These hard limestones have been of grwJ influence upon the typography of the country, as they have resisted er-0sion and now stand out prominently. The Del Rio clays, earring the .fvssil N odo­saria, have, on the contrary, yielded to erosion. The Buda limestone of the Washita division of the Lower Cretaceous, has also been sufficiently hard to withstand the ero.sion, but as it is thin and underlaid by the friabie Del Rio clays, it now appears as a cap rock. 
The Cretaceous strata have not only been greatly deformt>d and dis­turbed, with a resulting fault system in monoclinal blocks, thE•y have also been cut through by numerous ·di.ke.s and necks of igneous rock, some of them of rare types. 
Pr-0f. Hill says: ''While no igneous rocks are encountered immedi­ately within the mineralized ground, the surrounding country is the site of some of the most remarkable igneous phenomena in America. About two miles north -0f the inine.s there is a conspicuous volcanic neck. Some ten mile8 to the west the eastern edge of the great Bofecillos fissure erup­tion and flows are encountered. Twenty-five miles to the east are the remarkable volcanic necks of the Chisos mountains rising some 5,000 feet ab-Ove the plain, while between them and the quicksilver country are many later necks, stocks, and monticules of more basic igneous rocks." 
But there are igneous rocks in very close association with the Creta­ceous limestone carrying cinnabar, as, for instance, at California Hill, where a notable neck of what was at first thought to be andesite, but now proves· to be phonolite, intrudes itself. At Study Butte, also, east of Terlingua creek, . cinnabar has been found in rhyolite and its decomposi­tion products. These localities are described by Mr. B. F. Hill in his rep-0rt. In the light -0f our present knowledge, it mu.st be held that there is, in some localities within the Terlingua district, a very intimate con­nection between the mineralization of the limestone (and clays) and the intrusions of igneous rock. 
Such phenomena have been seen during the last few monthR and were not commented on by earlier ob.servers owing to the lack of dt~velopmcnt. New discoveries have been made and new data gathered within the last 
year. 
Prof. Robt. T. Hill regards the deposits 9s replacements due probably to ascending vapors, and refers them to the Mexican rather than to the American type, inasmuch as they are irregular bodies of ore in pipes, stringers, mantillas and pockets. He thinks it probable that the ore will be found in depth almost, if not entirely, throughout the entire thickness of the limestones, 1,700 feet. As remarked in thE' report of 
M:r. B. F. Hill, the greatest depth now attained in mining operations is less than 100 feet, good ore being found at the botton of the shaft. The ore near the surface having yielded good returns, the miners have felt under no necessity of sinking. This state of affairs can not continue 
THE TERLINGUA QUICKSILVER DEPOSITS. 
indefinitely, and the ore will have to be proved in depth if the district is to become of greater importance as a source of quicksilver. 
For the information of these who· may wish to know more about the actual conditions in the quicksilver districts of Brewster county it may be as well to add a special part dealing with the region as it is today in respect of transportation, living, etc. 
Terlingua, the center of the-industry, may be reached from any one of three stations on the Southern Pacific Railroad and by way of San Antonio or El Paso. From southeast to northwest these stations are Marathon, Alpine and Marfa, distant from San Antonio 379, 411 and 438 miles, respectively. The distances from El Paso are as follows: Marfa, 196 miles; Alpine, 223 miles; Marahon, 254 mile.s. 
Up to this time most of the business with the quicksilver districts has been carried on through Marfa, the county seat of Presidio county. From this point to Terlingua there is a stage line, carrying the mail and making two trips a wee'k, going down by way of Alamito (Dysart Post­office was at Alamito, but has been discontinued), McGuirk's Ranch and Fresno Ca:iion. According to the United States Postal Map of Texas, March, 1901, the distance from Marfa to Terlingua is 100 miles. The run down is made in one ancl one-half to two days, and the return fare is $13.50. Marfa will soon be in telephone connection with Terlingua, the charge being $1.00 per conversation of moderate length. 
Freight rates, by wagon, from Marfa to Terlingua are 60 cents per 100 pounds, with a half rate back on quicksilver. Houshold furniture, being bulky, is at a special rate and arrangements have to be made with the freighters in each case. At Marfa, the price of lumber varies from $22 to $30 per thousand, and in freighting it down an allowance of 3 to 4 pounds per foot is made. 
The elevation at Marfa is 4689 feet and at Terlingua 3274 feet, so that in the distance of 100 miles the decrease in altitude is 1415 feet, or a trifle over 14 feet per mile. The road is fair, considering all too cir­cumstances of the case, although it could be greatly improved from the Fresno Canon to Terlingua. A saving of 20 or 25 miles could be made by the construction of a road from McGuirk's Ranch direct to Terlingua, and thus avoid the long detour into and thrO!Ugh the Fresno Ca:iion, but the cost would be in excess of the present requirements of the district. 
Along the road from Marfa to Terlingua water is to bfl found at Bagel's Ranch, 12 miles; Alamito, 30 miles, and to the east of the road between Bagel's and Alamito, in Alamito creek; at the two wmd mills near San Jacinto Peak, 10 miles below Alamito; at an earth tank 15 miles below San Jacinto Peak and in some tinajas (natural rock tanks) between San Jacinto and the earth tank; at McGuirk's Ranch, 20 miles below San J acinto, and for several miles in Fresno Canon. After leav­ing Fresno Canon there is no more water until one reaches Terlingua creek, 20 miles, or the Rio Grande, 12 miles. 
From Alpine to Terlingua is about 85 miles, the road going down to the west of Elephant Mesa and by way of Butcher Knife and Adobe Walls. The road is fair and water can be obtained along it at intervals. 
'l'here is regular freighting from Alpine to Terlingua at 50 cents per 100 pounds. The price of lumber varies from $17.50 to $27.50 per thou­sand. Elevation of Alpine, 4485 feet. 
From Marathon to Terlingua it is 83 miles, the air-line distance being 
taken at 66 miles. The return trip for wagons is made in about a week. 
THE TERLINGUA QUICKSILVER DEPOSITS. 
'I'he freight rate is 50 cents per 100 pounds on merchandise, machinery, lumber and all classes of goods either way, except when full freight is secured each way, the rat.e in this case being 40 cents per 100 pounds. The price of lumber at Marathon varies from $18 to $30 per thousand. The elevation at Marathon is 4043 feet. The road to Terlingua passes by the old government post at Pena Colorado and thence across the Marav:illas creek to Del Norte Gap at easy grades. Through this gap there is a good road 20 feet in width, and it proceeds by ea.By grades into Green Valley. It follows this valley for about 45 miles and then crosses the divide below Adobe Walls into the valley of Terlingua creek. 'fhere are same steep grades along this divide, but they arP not long. Loads of 6000 and 7000 pounds have been hauled from Marathon to Terlingua by six Spanish mules. The watering places between Marathon and Ter­lingua are as follows: Pena Colorado, 4 miles; Pena Colorado to Mara­villas creek, 12 miles; Maravillas creek to Jackson's first tank, 14 miles; J"ackson's first tank to J acik.son's second tank, 8 miles; Jackson's second tank to Adobe Walls, 23 miles; Adobe Walls to Terlingua creek at Mrs. Reed's, 6 miles; Mrs. Reed's to Cigar Springs, 8 miles. After leaving Cigar Springs there is no more water, the supply for the quicksilver dis­trict at Terlingua being obtained principally from this place, distance 9 miles. 
The road from Marathon to Terlingua joins the road from Alpine to Terlingua near Butcher· Knife, 45 miles from Alpine, wherr: water can be obtained the greater part of the year. With respect to water, there is not much to choose between the three routes, but with respect to distance Marathon has some advantage, with perhaps a better grade. The differ~ enee of elevation between Marathon and Terlingua is 769 feet, as against 1415 for Marfa and 1211 for Alpine. 
With respect to facilities for outfitting, the three towns offer about the same inducements. . There are excellent stores at each place and they carry large and va.ried assortments of goods needed in the country. There is scarcely anything that can not be obtained from these stores, and one finds the proprietors at all times ready to be of any assistance possible. 
In going into the quicksilver country it is well to remember that there are no hotels, lodging houses, restaiurants or other places of public enter­tainment. There are three good stores at Terlingua and one can buy everything necessary at any one of them, but it is necessary to provide one's own bedding, etc. During the greater part of the year out-door life in the southern part of Brewster county is pleasant enough, but dur­ing the early summer months and before the rains begin the temperature becomes excessive, at times, from 11 a. m. to 4 p. m. The nights are delightful, even when the. extreme ?eat of the he~t drives one out of the sun during the day. Durmg the wmter the cold is seldom severe enough to require the use of an overcoat. Ice forms at night over the little pools along the creeks and in the cant~n, but seldo~ more t?an half an inch in thickness. Snow may fall occasionally, but it rarely hes on the ground longer than a day or two. Work in the open air can be carried on every day of the year without serious inconvenience except for the heat during the month preceding the summer rains. These rains begin sometimes in June but generally not until July and August, and last until the mid., dle of September. It seldom rains between the first of October and the first of May, so that it is necessary during these months to haul water 
THE TERLINGUA QUICKSILVER DEPOSITS. 
for domestic purpose.;;. After the rains begin and the natural ~nd arti­ficial tanks are filled it is not necessary, of course, to haul water so far. It may become necessary, a.s the district grows in population and impor­tance, to install a pumping plant at some point on Terlingua creek, or the Rio Grande, and pump water into a storage-reservoir above the camps, or to drill for water in the flats and along the "draws~' at the foo( of the hills. Water in the camps is now costing f:rom 1 cent to ll cents per gallon in 350-gallon tanks, and it retails at prices varying from 2 to 2~ cents per gallon, these prices maintaining from about the first of October to the first of May. The question of obtaining water by boring has not yet been taken up by any of the companies, although it is prob­able that a great deal of water could be so secured and it is likely that it would be of as good quality as that now furnished by Cigar Springs and Terlingua creek. Larger storage reservoirs could also be constructed so as to hold more of the rain that falls during the summer. On tlie whole, the region is arid, but it does not deserve the name of desert that has been applied to it. A great deal of rain falls durimr the summer, and as the country is sparsely settled and will be so for some years, water collected in great reservoirs would be suitable for all purposes. There are many canyons and "draws" that could be thus utilized to great ad­vantage. 
The fuel problem is another thing that will have to be considered. At present the furnaces rely upon such wood as can be brought in by the Mexicans, and they gather it up wherever they can find it.. In the course of time, however, the present sourcoo of supply will be exhausted and it is likely that within two years the stringency of the fuel question Will be felt. In the Chisos mountains, 25 miles to the east, there is much oak, piii.on. cedar and juniper, and this supply may be drawn upon. But the cost of wood hauled 25 miles will become a serious item. There is also a fair supply of wood 15 to 20 miles west of north from Terlingua, and this may be used. The nearest coal is about 16 miles, but it has not been Qpened enough to allow one to expre&<i an opinion relative to its extent or qmility. Between Lee Cartwright's and Rough Run there is a seam of lignitic coal, somewhat bituminous in places, but it has not been opened. At the Kimble coal pits, on Rough Run, about 20 miles from Terlingua, there is a fair coal, as also at Chisos Pen, 3 miles northwest of Gano Spring, which is in Section l. Some work has been done at the Kimble pits and at Chisos Pen, but not enough to warrant one in pro­nouncing upon the workable nature of the coal. The country is badly broken by intrusions of igneous rock and it is likely that the continuity of the coal seams has been much disturbed. Still, it is likely that enough coal could be obtained for local purposes, and the attention of investors should be turned in this direction. 
Some samples of coal were obtained by the writer from the seam near Cub Spring, Section 60, Block G4; from the Kimble pits in Section 44, Block G4; and from the Chisos Pen, Section 40, Block G4, in Mai:-ch, ~902. The old openings, . made a year or so previous, had fallen in and it was not possible to get under cover. The samples,_ therefore, repre­sent the coal that could be secured near the surface. It is possible that the coal from under good cover would be somewhat better. The analyses were made by Mr. 0. H. Palm in the laboratory of the Survey. 

LOOKING NORTH FROM DEWEES' STORE. 
ON EXCEI.SIOR VEIN'COLQUITT-TIGNER. 
THE TERLINGUA QurcKSILVF.R DEPOSITS. 
ANALYSES OF BREWSTER COUNTY COALS. 

Cub Spring.  Kimble Pits.  Ch!sos Pen.  
Moisture ........................ . ....  10.65  4.74  1.16  
Volatile and combustible matter. . . . . . . . . .  50.9;1.  29.84  32.79  
Fixed carbon . . . . . . . . . . . . . . . . . . . . . . . . . .  19.52  49.84  44.53  
Ash .. .. ......... ., .. ... ·...... . .......  18.92  15.58  21.52  
100.00  100.00  100.00  
Sulphur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  0.86  1.26  3.39  
British Thermal Units . ... .. .... ... . ....  8,432  11,887  11,958  

The Cub Spring coal is lignitic, but the coal from the Kimble Pits and from Chisos Pen is more bituminous, especially that from the latter locality. The Kimble Pits and Chisos Pen are about 20 miles from Ter­lingua and OD the east side of Rough Run. Cub Spring is in the Christ­mas mountain district, 3 miles north of the Kimble Pits. Of the three localities the Kimble and Chisos Pen would appear to ~er better induce­ments to the prospector than the other. 
Locations for coal have been made on the eastern side of Block G4 in the even numbered sections from 36 to 66, inclusive, these being the pub­lic sections, but for the most part the claims have been allowed to lapse. Very little work has been done and that little of a desultory character. From the Kimble Pits some coal was taken out and hauled to Boquillas, where the Kansas City Smelting and Refining Company operatP.d a sil­ver-lead mine during the lastfew years. Some of the coal could be coked in a recovery oven, but it does not seem to be well adapted to the bee­hive oven. Without systematic prospecting no opinion can be given of the value of this coal field for commercial purposes, but there i.s enough coal for the quicksilver furnaces at Terlingua. 'l'he general situation is such as to militate against the existence of large bodies of coal, for the distri.ct has been greatly disturbed by intrusions .of igneous rocks, At the Chisos Pen, for instance, the lava flow is almost in immediate con­nection with the coal and forms the capping to the sandstone roof of the coal. This condition exists south of the Christmas mountain all the way along Rough Run, a distance of 20 miles. At intervals along this section coal outcrops can be observed, but at no place was there more than 14 inches of coal to be seen, vii., at the Kimble Pits. It is the pur­pose of the Survey to examine the coal fields of Brewster county more in 
detail when the topographic maps now in preparation shall have been completed. A topographic corps of the United States Goologieal Survey is now at work in·that part of the county and the maps will be ready during the spring of 1903. 
PRESENT AND POSSIBLE RAIJ,ROAD FACILITIES. 
As already remarked, the only railroad now within reach of the quick­silver districts is the Southern Pacific, the shortest distance to it being about 83 miles, viz,, at Marathon. The Mexican & Orient, known locally as the Stillwell Road, may penetrate into the district, but the route which appears to commend itself would carry it some distance to the northwest of Terlingua. 'l'his road is building to a connection with the 
THE TERLINGUA QUICKSILVER DEPOSITS. 
Bay of Topolobampo, on the eastern side of the Gulf of California, through Chihuahua. In Texas the road has been located from Chili­cothe, Hardeman county, near Red River, to San Angelo, Tom Green county, and is under construction from Chilicothe to Sweetwater, Nolan county. 
From San Angelo to Presidio, Pre.sidio county, the location has not been made. l£ the road should cross the Southern Pacrfic at Paisano Pass, west of Alpine, it would probably follow the general course of Alamito creek to the vicinitv of San Jacinto Peak and then strike for the mouth of the Concho ri~er, at Presidio, and thence to Chihuahua. By this route the nearest available point to the quicksilver districts would be about 50 miles. l£ the crossing of the Southern Pacific is made at Marathon the road would probably pass through Del Norte Gap and into Green Valley. 
Considering Presidio as the objective point, the most feasible route from Green Valley would appear to be by way of San J acintu Peak and to the northward of it, for the country to the south soon becomes very rough and the rugged mountains that fringe the Frenso Canon would entail costly construction. In either case, therefore, whether the road crosses at Paisano Pass or at Marathon it is not likely that the quidk­silver districts would be brought nearer than 50 miles to rail. This, however, would be a considerable saving as against 83 miles to Mara­thon, 85 miles to Alpine and 100 miles to Marfa. 
But for some time to come it is likelv that the Southern _Pacific will 
supply all of the transportation required in the development of the dis­
trict, notwithstanding the fact that all merchandise has to be hauled 
from 80 to 100 miles after leaving the railroad. A metallurgical pro­
duct that sells for 60 cents a pound will stand a good deal of hauling. 
The development of the district will proceed along the economic lines 
indicated by the nature of the deposits. While rich pockets of ore are 
often met with, yet the chief reliance will have to be upon au ore yield­
ing about 1 per cent. of quicksilver. Such ore can be profitably treated 
under the conditions that exist at present and that are likely to maintain 
for several yea.rs. It is, of course, somewhat to the disadvantage of the 
district that the deposits have not been explored in depth. Until this is 
done the importance of the district as a permanent producer of quick­
silver will be open to question. The deposits that lie near the surface 
will be worked out within a comparativ€ly short time, although they are 
now sufficient for the demands made upon them. The furnaces now built 
and under construction can use 75 tons of ore per day, which, at an aver­
age yield of 1 per cent., would represent about 570 flasks a month. Rich 
pockets of ore may increase the capacity to 800 flasks a month. The pro­
duction during the year 1902 is likely to be about 5000 flasks, all drawn 
from surface deposits or those that may fairly be considered as such. 
It is probable that new finds will be made, for there is much activity 
in the district. The construction of a custom furnace would do much 
towards development, but this is not to be recommended unless sufficient 
ore is controlled by the operator to enable him to run independently. 
But a custom furnace would secure the richer ores that are heing taken 
out by prospectors and for which there is now no market. A 10-ton 
Scott furnace can be built for $15,000 and with a yield of 1 per cent. of 
quicksilver would produce $120 worth of metal a day. 





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101 
98 



2.5' 
26 
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LINK 

299 
Block 
TERLINGUA 
MINING DISTRICT 




BREWSTER CO., TEXAS. 

0 Y.+ ft 
/, 
SCALE -I MILE 
W OWashington, Del. 

296 
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28()
295 


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STAR 
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