J. B. Hatcher — Ceratops Beds of Wyoming. 135 



Art. XYII. — The Ceratops Beds of Converse County, 

 Wyoming ; by J. B. Hatcher. 



In the December number of this Journal for 1889, Prof. 

 O. C. Marsh gave the name Ceratops beds to certain strata in 

 the upper Cretaceous of Wyoming, Montana, and Colorado, 

 containing the remains of horned Dinosaurs (Ceratopsidce) and 

 many other reptilian and mammalian forms. 



Of these beds, those in the northeastern portion of Con- 

 verse county, Wyoming, are best known and have been most 

 thoroughly explored. Fully ninety per cent, of all the verte- 

 brate fossils described by Prof. Marsh from the Ceratops beds 

 were found in this region. This fact is sufficient to warrant a 

 more detailed description of the stratigraphical and geograph- 

 ical position of the beds, and of their geological and litholog- 

 ical characters, than has yet appeared. Not only has this 

 region proved especially rich in vertebrate fossils, but the 

 Ceratops beds seem to have attained a greater development 

 here than has been noticed elsewhere. Since the" present 

 border of the beds is nearly that of the eastern shore of the 

 fresh-waters in which they were deposited, and erosion has 

 exposed, many continuous sections in them down through the 

 underlying Fox Hills sandstones and into the Ft. Pierre shales, 

 this region offers exceptional advantages for determining the 

 position of the Ceratops beds and for establishing their age 

 upon stratigraphical as well as paleontological evidence. 



Geographical Position of the Ceratops Beds. 



The Ceratops beds of Wyoming have thus far been explored 

 only in a very limited region in the northeastern part of Con- 

 verse county. Going north from Lusk, a small station on 

 the Freemont, Elkhorn, and Missouri Valley railroad, they 

 first appear about twenty-five miles from that place, occupy- 

 ing the summit and northern slope of a yellow sandstone 

 ridge extending in a westerly direction from Buck creek to 

 Lance creek and crossing the latter stream near the mouth of 

 Little Lightning creek, a small tributary from the west. A 

 short distance west of Lance creek, the Ceratops beds pass 

 under other beds composed of very similar material, and pre- 

 sumably of Cretaceous age. From Buck creek, the eastern 

 border of the Ceratops beds has been traced in an almost con- 

 tinuous exposure, extending northeasterly to the Cheyenne 

 river, and crossing this stream a short distance below the 

 mouth of Lance creek. From this point, it takes a more 



Am. Jour. Sci. — Third Series, Vol. XLV, No. 266.— February, 1893. 

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