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RESULTS.

GENERAL GEOLOGY.

TRANS-PECOS TEXAS.

In this district the rocks of Carboniferous age, which had been previously described, have been traced and mapped over a larger area; the age and relations of certain conglomerates, which have been a disturbing element in the study of the region, have been decided; the exact stratigraphic relationship between the schists and the red grit has been determined, through sections fortunately laid open by the torrential rain storm which occurred in the latter part of the summer. Some fossils have been secured, which, although badly preserved, will, it is hoped, give an idea as to their geologic age. The extent of the crystalline schists, which near Eagle Flat are associated with strongly metamorphosed cherty limestones, true marbles, etc , is found to be much greater than was suspected. This is the series of rocks which I suggested in the First Annual Report were probably the equivalents of the Texan system of the Central Mineral District.

THE CANADIAN RIVER—RIO GRANDE SECTION.

The complete results of this section can only be approximated roughly before further study is had of the materials collected It comprises the work of Prof. Cummins, Dr. Comstock, Mr. Taff and myself, and embraces formations from the Carboniferous to the Quaternary. To summarize it briefly:

The boundary of the Staked Plains is described, and its topographic features clearly stated. The strata covering the surface are all found to be of later Tertiary age, certainly not earlier than the Loup Fork Beds, and probably Pliocene in part. These beds thicken toward the northwest, and at the northern scarp of the plains rest directly upon rocks of Triassic age. The Triassic rocks underlie the Plains material as far south as the thirty-third degree of latitude, or a little lower, beyond which point a thin series of the Cretaceous rocks appears between the Triassic and Blanco Canyon beds and thickens towards the south.

On the western side of the Plains the erosion of the Pecos river has cut through the Plains material and underlying formations to its present channel. The determination of the Cretaceous age of the Tucumcari beds, and that these beds are higher in that system than the