Wilberns Formation showing San Saba Member

Wilberns Formation showing San Saba Member
State Texas
Name Wilberns Formation showing San Saba Member
Geologic age Late Cambrian
Lithologic constituents
Major
Sedimentary > Carbonate > Dolostone (Bed)
Minor
Sedimentary > Carbonate > Limestone (Bed)
Comments Dolomite and limestone, thickly to thinly bedded; dolomite is mostly sparsely cherty; ls. moderately glauconitic. In SE area dolomite, fine- to v. fine grained, yellowish-gray to brownish-gray and medium-gray; NW mottled ls. in part girvanella-bearing, comes in at base. In NW area mostly ls., chiefly granular, moderately glauconitic, light- to medium-gray and greenish-gray, locally stromatolitic bioherms in lower part become dolomite westward and thicken into a north-south reef extending almost to the top of the San Saba, west of the reef many sandstone beds characterize the upper part of the Member; fossils are mostly calcitic trilobites in ls., some gastropods; Thickness 215 to 325 ft.
Stratigraphic units Moore Hollow Group
References

Bureau of Economic Geology, 1981, Llano sheet, Geologic Atlas of Texas, Bureau of Economic Geology, University of Texas at Austin, scale 1:250,000.

Bridge, J., Barnes, V.E., and Cloud, P.E., Jr., 1947, Stratigraphy of the Upper Cambrian, Llano uplift, Texas: Geological Society of America Bulletin v.56, no. 1, p. 109-123.

Bureau of Economic Geology, 1976, Brownwood sheet, Geologic Atlas of Texas, Bureau of Economic Geology, University of Texas at Austin, scale 1:250,000.

Bureau of Economic Geology, 1992, Geologic Map of Texas: University of Texas at Austin, Virgil E. Barnes, project supervisor, Hartmann, B.M. and Scranton, D.F., cartography, scale 1:500,000.

NGMDB product
Counties Blanco - Burnet - Gillespie - Llano - McCulloch - Mason - San Saba