AGE OF THE ARAPAHOE AND DENVER. 233 



developed in Colorado, but, as Mr. Hatcher admits, its separation from the 

 Fox Hills is arbitrary, and neither brackish-water shells, plants, nor coal 

 beds arc present to indicate its identity with the Laramie. The assignment 

 <>f this sandstone tu the Ceratops beds is supported only by absence of 

 unconformity and the similarity of the heavy sandstone to the thin beds 

 of the upper series. 



The fossil-hearing- member of the Ceratops beds consists, in Mr. 

 Hatcher's language, '"of alternating sandstones, shales, and lignite, with 

 occasional local deposits of limestones and marls. The different strata of 

 the series are not always continuous, a stratum of sandstone giving way to 

 one of shales, and vice versa. This is especially true of the Upper two- 

 thirds of the beds." "The shales are quite soft and loosely compacted, 

 composed mostly of clay with more or less sand in places. The prevailing- 

 color is dark-brown, hut they are sometimes red or bluish." "The lignites 

 occur in thin seams, never more than a few inches thick, of only limited 

 extent, and with many impurities. At no place in the 'Ceratops beds' of 

 this region have workable coal beds been found." "Intercalated with the 

 sandstones, shales, and lignites, are quite local deposits of linn-stones, clays, 

 and marls. The latter are composed almost entirely of fresh-water shells, 

 fragments of bone, teeth, etc." "All the deposits of the 'Ceratops beds' of 

 this region bear evidence of having been laid down in fresh waters. Among 

 the invertebrate fossils found iu them, only fresh-water forms are known. 

 There is no evidence that marine or brackish waters have ever had access 

 to this region since the recession of the former at the close of the Fox Hills 

 period." 



This description of the Converse County Ceratops beds shows them 

 to be quite different from the Laramie of Colorado, or of southern Wyo- 

 ming, but similar in many ways to the Arapahoe beds, or to the strata 

 of debatable age in other localities. It would not be justifiable to assert 

 at present that the beds of the true Laramie never possess such a variable 

 character and such a loose, friable texture as is shown l>v the strata 

 in question, but it is certainly fair to point out that this constitution is met 

 with in the post-Laramie and later fresh- water deposits, and that so eminent 

 an authority on the Laramie and associated formations as Mr. R. C. Hills 



