The information contained in this circular was gathered by a unit of the WPA Mineral Resources Survey of Texas, a project sponsored by The University of Texas, Bureau of Economic Geology.

Gravel deposits are found in Henderson County in the stream terrace deposits of the Trinity River and its tributary, Cedar Creek. These deposits were examined in detail in the vicinity of Trinidad. It was found that four terrace levels contain gravel.

A mineral resource survey of Texas has been started by the Works Progress Administration, with the Bureau of Economic Geology of The University of Texas acting as sponsor. The purpose of the survey is to assemble information and make it available to the public.

In the north and northeast parts of Clay County, an area of approximately 70 square miles is covered by fluviatile deposits, including the present stream valleys and the ancient terraces, or flood plain remnants, of Big Wichita and Red rivers.