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GEOLOGY.
PREVIOUS WORK.
Nothing very definite has heretofore been determined of the geology of the Staked Plains. The various parties of observers who have traveled across the county in various directions, and who have seen it at different points, have reached different conclusions.
Professor Jules Marcou, in 1853, passed along the northern escarpment and across an arm of the highest plateau at one point. From the facts collected he concluded that the upper plateau was Jurassic, and so colored his map, published at a later day.
Professor Geo. G. Shumard, in 1855, passed across the extreme southern edge of the Plains and along the Pecos river to the mouth of Delaware creek. He reports only the Cretaceous, having collected a great many characteristic fossils of the Cretaceous period on his trip. He was geologist on the Marcy exploring expedition of Red River, in 1852, and saw the eastern escarpment of the Plains at the mouth and along Palo Duro canyon to its source. He placed the strata of the Staked Plains in the Cretaceous.
Wm. P. Blake made a report upon the geology of the route explored by Captain Pope, in 1854, near the thirty-second parallel. In speaking of that part of the route between Big Springs and the Pecos river he says: "The age of the overlying rocks of a lighter color are also obscure; but there is much reason to regard them as Cretaceous and Tertiary. The only fossils which I found in the collection from the Llano are Cretaceous, and serve to indicate the development of that formation at the Big Springs of the Colorado and a point on the Llano twenty miles east of the sand-hills."
In the First Annual Report of the Geological Survey of Texas, 1889, I gave a brief mention of the strata of the Staked Plains under the name of Blanco Canyon Beds, and said: "The only fossils found in this bed were some of the larger mammals and a species of turtle. Enough was found to show the strata to be of much more recent date than the Cretaceous, which is found at the foot of the Staked Plains further southward."
In the Second Annual Report of the Geological Survey of Texas, 1890, in a further report under the name of Blanco Canyon Beds, I stated that the strata was probably the equivalent of the Green river beds of Hayden." The intention was to say White river beds.
"Pacific Railroad Reports, Vol. II., p. 17, supplement.
Since it is objectionable to have double names for formations, and for the further reason that the beds are found far from Blanco Canyon, I will hereafter designate them as the "Blanco Beds."