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base of the Fredericksburg at Decatur. In the sands at this point are thin indurations, often less than a foot thick, the last northward indication of the Glen Rose beds which to the southward are so well developed into great limestone formations.

The following composite section in the vicinity of Decatur will give a general idea of the formations in these regions (see fig. 15):

From Decatur northwestward to Bowie, 28 miles, the Basement sands have their greatest development. This includes a great thickness of pack sand, with a few bands of clay and pebbly conglomerate, which extends from the Upper Coal Measures near the Permian contact