In east-central Texas, or the area between the Colorado
and Trinity Rivers, the Wilcox Group (lower Eocene) is divided
into three formations. Up section they are the Hooper,
Simsboro, and Calvert Bluff. At Alcoa and Butler, lower Calvert
Bluff sediments are exposed. The Calvert Bluff Formation
conformably overlies the highly resistive, massive, fluvial Simsboro
Sand and is recognized by its finer grain size, as reflected
in reduced resistivity on normal curves, and by the first
Future utilization of aggregate resources in urban areas must be considered during early planning stages of an urban complex. This is of particular importance because urban land values are commonly greater than the mineral value of these low-unit-value materials, and the use of the land for construction pre-empts exploitation of the aggregate materials. In addition, zoning restrictions may also prohibit resource exploitation of urbanized land.
Over 7,000 miles of lineations have been observed on aerial photographic mosaics of the Texas Coastal Zone. These lineations, in part, represent the surface traces of faults originating in the Tertiary sediments and propagating through the Quaternary sediments. The extrapolation of subsurface faults from specific oil and gas reservoirs are commonly coincident to lineations in those areas. Some extrapolated fault traces weave back and forth across lineations for 10 to 20 miles and then coincide with another lineation and follow it for 20 miles.
