The purpose of this paper is to present a system of encoding rock data for multiple uses that include (1) mapping subsurface stratigraphy for economic exploration, (2) cataloging borings used in subsurface waste disposal, and (3) building a library of natural resource information.

Coal is found in six areas in Texas, including the large North-Central Texas field, a distinctive cannel coalfield in Webb County, and Late Cretaceous-age coals near Eagle Pass.

This field guide is designed to provide an opportunity to observe a variety of facies that are the fundamental blocks with which principal depositional systems have been fabricated. Available data is provided and a genetic interpretation is proposed.

The Fredericksburg Group is one of three groups of rocks which comprise the outcropping Lower Cretaceous sediments in north central Texas. Four formations form this group; from the base upward these are the Paluxy, Walnut, Comanche Peak and Edwards (fig. 1).

The Allamoore district of Hudspeth and Culberson counties, Texas, has become one of the most significant talc-producing areas of the United States. Exploitation of talc deposits in the district began in 1952 with a cumulative production of 120,000 tons through 1957 (Flawn, 1958).

The Texas Coastal Zone is marked by diversity in geography, resources, climate, and industry.

The Eastern Shelf was a constructional platform developed on the margin of the sediment-starved Midland Basin during Late Pennsylvanian and Early Permian time. A mixed terrigenous-carbonate sedimentary province characterized the shelf during most of its history.