66 PROCEEDINGS OF THE ACADEMY OF [1894. 



same bed which contained the same invertebrate fossils, at a point 

 about twelve miles south of the fort. 



The Permian red beds are traversed conformably by layers of 

 gypsum at different horizons. The sand bed below the cretaceous 

 limestone is sometimes consolidated into a sandstone, which forms a 

 ledge near the summit of the bluffs. From fifty to seventy-five feet 

 below this and in the red beds, is a bed of saccharoidal limestone. 

 This limestone is luminous when struck or scratclied with a metallic 

 object, like a similar limestcme which occurs in some of the silver 

 mines in Utah in the Wasatch Mountains. 



At the locality already referred to, twelve miles south of Fort 

 Supply on a low ridge of the Cretaceous terrane, we observed a white 

 discolorati(jn, as though two or three cartloads of a chalky material 

 had been deposited there. Prof. Brown was so fortunate as to find 

 in it the fragments of a solitary superior molar tooth of Profo- 

 hippus jierditiis, which determined the age of the material as the 

 Loup Foi-k, or Uj^per Miocene. Careful search failed to reveal 

 another fossil, and it is evident that we have here the last remnants 

 of a formation which has been almost entirely removed by erosion. 



With the view of further determining the extent of the Comanche 

 and Loup Fork formations, we left Fort Supply and went by rail to 

 Miami, which is a village in Roberts County of the Panhandle of 

 Texas, south of the Canadian river. For several miles before reach- 

 ing Miami, the railroad runs between steep bluffs, which form, the 

 southern border of the flood plains of the Canadian river, and are 

 the escarpments of the outlying tracts and fingers of the Staked 

 Plains. They are about two hundred feet in elevation, and include 

 two hard strata, while the great mass is sandy clay, or sand in a few 

 localities. One of the indurated beds is at the summit of the bluffs, 

 forming the surface of the plain, and is about six feet in thickness. 

 The softer argillaceous bed below it varies from fifteen to fifty feet, 

 when the second impure sandstone is reached, which has a thickness 

 of about eight feet. The one hundred and fifty feet below this is 

 friable, so that the construction of the escarpment is such as to keep 

 it more or less perpendicular. Tlie general appearance of the blufis 

 is closely similar to that of the Blanco beds at the typical locality 

 one hundred and fifty miles south, at the jxiint where the Brazos 

 River issues from the Staked Plains in the Blanco Canyon. In order 

 to ascertain whether this formation is the Blanco or the Loup Fork, 



