HELL CREEK BEDS, CERATOPS BEDS AND EQUIVALENTS 205 

 15. CONVERSE COUNTY, WYOMING, AREA. 



We may now take up the consideration of the celebrated "Cera- 

 tops beds," a direct northern extension of which are those just 

 mentioned in Weston County. 



In 1889 Marsh^^ gave the name of " Ccralops beds" to a series 

 of beds characterized by the presence of an extensive fauna of the 

 then little known group of quadrupedal, horned, herbivorous dino- 

 saurs. He did not then, nor indeed subsequently, give any very 

 definite account of either the geographic location or stratigraphic 

 position of the beds, beyond stating that they were in the 'Laramie 

 of Woyming,' and that the horizon "has now been traced for nearly 

 800 miles along the eastern flank of the Rocky Mountains. " Of the 

 position he says: 



They are fresh-water or brackish deposits, which form a part of the 

 so-called Laramie, but are below the uppermost beds referred to 

 that group. In some places, at least, they rest upon marine beds 

 which contain invertebrate fossils characteristic of the Fox Hills 

 deposits. 



It was reserved for Professor Marsh's assistant, Mr. J. B. Hatcher, 

 to give the first definite and precise information on these points. 

 The principal, and what may be called the typical, "Ceratops beds" 

 are really of very limited extent, occupying a strip about 15 miles in 

 width from east to west, by 30 miles in length from north to south, 

 in the northeastern part of Converse County, Wyoming, along Lance 

 Creek and the area drained by the lower portions of Docgie, Cow, 

 Buck, and Lightning creeks. This area furnished not only all of 

 the Ceratopsidas described by Marsh from Wyoming, but fully 95 

 per cent of the entire group known at that time. The "Ceratops 

 beds" are best exposed along the eastern and southern borders of a 

 synclinal basin, and according to Hatcher are 3000 feet in thickness, 

 though Dr. T. W. Stanton and myself, when we visited the area in 

 1896^^ concluded that they could hardly exceed 2000 feet, but as a 

 large portion of the beds are exposed at a low angle in a broad, flat, 

 grassy plain, it is impossible to measure the beds with a great degree 



" Am. Jour. Sci. (3), vol. 38, 1889, p. 501. 



"* Bull. Geol. Soc. Am., vol. 8, 1896, pp. 128-137. 



