Geologic map of the Dry Branch Quadrangle, Kerr and Gillespie Counties, Texas

Dry Branch quadrangle is in the Edwards Plateau province southwest of the Llano region. It is near the margin of the plateau, and Johnson Creek and some of its tributaries, such as Dry Branch, Falls Branch, Fessington Branch, and Welch Branch, have cut into the plateau in the southern part of the quadrangle.

The geology of the Dry Branch quadrangle is shown on a planimetric map, and the only topographic map available is the reconnaissance 30-minute Kerrville quadrangle. Elevations ranging between 1,819 and 2,254 feet were determined during traversing for control, but neither the highest nor the lowest elevation was reached. However, it is estimated that the relief within the quadrangle is about 460 feet, ranging between about 1,800 and 2,260 feet.

The quadrangle is mostly within the Guadalupe River drainage basin and is drained by Johnson Creek and its tributaries, such as Fall Branch, Dry Branch, Fessington Branch, Welch Branch, Smith Branch, Rough Hollow, and Bad Man Draw. Klein Branch and Scott Branch, tributaries of the Pedernales River, drain the northeastern portion of the quadrangle.

Dry Branch quadrangle is on the southwestern side of the Llano uplift, and Cretaceous rocks crop out in all of the quadrangle. The depth to faulted and gently dipping Paleozoic rocks is probably only a few hundred feet beneath the more deeply incised streams. Essentially horizontal Cretaceous rocks form the outcrops in the quadrangle.

Broad discussions of the stratigraphic, structural, economic, and geophysical problems of the region are given in references cited below. This publication on the Dry Branch quadrangle is one of a series of similar publications, an index to which is shown on the opposite page. The reader is referred to the index map to locate other quadrangles mentioned in the present text.