Late Cambrian and early Ordovician faunas from the Wilberns formation of central Texas

dc.contributorNicholls, Harry,-99.0833,31.0333,30.4667
dc.creatorWinston, Donald, 1931-
dc.descriptionTo obtain a print version of this publication visit: and search for: RI0062. "Reprinted from Journal of paleontology, v. 41, no. 1, Jan. 1967," c.f. cover.
dc.description.abstractThe San Saba Member of the Wilberns Formation of central Texas is mostly coarse-grained, trilobitic limestone that grades eastward to dolomite and contains sandstone intervals in its westernmost exposures. Faunas from the limestone place the middle part of the San Saba within the Trempealeauan Stage (Saukia zone) of the Upper Cambrian, but the uppermost part belongs to the Lower Ordovician. Three subzones within the Saukia. zone are described. In ascending order they are: the Saukiella junia subzone containing Bayfieldia, Briscoia, Corbinia, Euptychaspis, Eurekia, Saukia, Saukiella, Stenopilus, Triarthropsis, and Finkelnburgia; the Saukiella norwalkensis subzone containing Bayfieldia, Bowmania, Briscoia, Calvinella, ?Dikelocephalus, Eurekia, Euptychaspis, Heterocaryon, Idiomesus, Keithiella, Leiocoryphe, Macronoda, Plethometopus, Prosaukia, Saukiella, Stenopilus, Theodenisia, and Finkelnburgia; the Corbinia apopsis subzone containing Acheilops, Apatokephaloides, Corbinia, Eurekia, Idiomesus, Leiobienvillia, Leiocoryphe, Plethometopus, Theodenisia Triarthropsis, Apheoorthis, Finkelnburgia, Glyptotrophia, and Nanorthis. Trilobites of the Saukiella junia and Saukiella norwalkensis subzones are closely allied to those of the Trempealeauan of the upper Mississippi Valley, whereas the trilobites of the Corbinia apopsis subzone represent an influx of the Hungaia magnifica fauna. The low Ordovician faunas are subdivided into two zones. The lower zone is named the Missisquoia zone and contains Highgatella, Homagnostus, Hystricurus, Missisquoia, Parabolinella, Symphysurina, Apheoorthis, Conotreta and Syntrophina. It correlates closely with a low Ordovician fauna from Vermont described by Shaw. The upper zone is the Symphysurina zone and contains Clelandia, Homagnostus, Hystricurus, Jujuyaspis, Symphysurina, Apheoorthis, and Syntrophina. It correlates most closely with the Symphysurina zone of Utah and Nevada. New trilobite species are Acheilops masonensis, Bayfieldia simata, Bowmania sagitta, Briscoia llanoensis, Calvinella procera, Clelandia texana, Corbinia apopsis, Corbinia implumis, Euptychaspis jugalis, Homagnostus reductus, Keithiella patula, Leiobienvillia leonensis, Leiocoryphe halei, Missisquoia inflata, Missisquoia nasuta, Saukiella planata, and Symphysurina bubops.
dc.description.departmentUT Libraries
dc.description.departmentBureau of Economic Geology
dc.format.dimensions66-96 p. : ill., map, plates. ; 26 cm
dc.publisherUniversity of Texas at Austin. Bureau of Economic Geology
dc.relation.ispartofVirtual Landscapes of Texas
dc.relation.ispartofReport of Investigations
dc.relation.ispartofseriesReport of Investigations (University of Texas at Austin. Bureau of Economic Geology), no. 62
dc.subjectPaleontology -- Cambrian
dc.subjectPaleontology -- Ordovician
dc.subjectPaleontology -- Texas
dc.titleLate Cambrian and early Ordovician faunas from the Wilberns formation of central Texas

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