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How to explain this comparatively deep valley, and the clogged up channel is difficult. The stream, when one flows, is plainly overburdened. In some way it may be connected with the Quaternary lake deposits of the Llano Estacado. It may even be a case of reversed drainage, or, if not, a valley formed in times when the water supply was greater than at present.

South of Big Spring the valley is quite different, being here cut into the bed rock not only in the channel proper but runs into the surrounding country. The sharp erosion at this point indicates a young drainage and it seems very much as if the headwater erosion of a rejuvenated stream was now employed in removing the detritus with which the stream bed has been clogged in earlier times. The Concho river farther west is a similar instance of this peculiar drainage.

Beyond Arroya rocks appear, the geological position of which I am unable to give. These are white limestone, weathering chalky white. They may be a part of the lower Trinity.

Beneath these, near Quito, east of Pecos City, a compact well-jointed red sandstone occurs, dipping gently southeast. This, I believe, to be Permian, though I can offer no definite proof of this, since there are no fossils and I have not studied their relation with beds above and below which may be possible further south.

A company recently organized has commenced developing this sandstone, which promises to be one of the best in Texas, and to rank well with the building stones of the west. It is of a beautiful red, uniform in color and texture, easily worked, yet durable and in every way adapted to the best uses in building. Considerable stone has already been contracted for The company was, at the time I passed, engaged in boring a well which had already passsed through one hundred feet of red sadstone. This, coming as it does, below what appears to be the base of the Trinity, seems to indicate a Permian age.