140 J. B. Hatcher — Oeratqps Beds of Wyoming. 



above, is here regarded as the dividing line between the Fox 

 Hills and Ceratops beds. But this decision, it must be admit- 

 ted, is quite arbitrary, and the evidence in its favor is negative 

 rather than positive. The only reason for placing the over- 

 lying 400 feet of non-fossiliferous sandstones in the fresh- 

 water series is the absence of fossils in them, which may per- 

 haps be accounted for by the destruction of the marine forms 

 brought about by the change from salt to fresh-waters. The 

 overlying non-fossiliferous beds may have been deposited in 

 the fresh-waters before fresh-water forms had distributed them- 

 selves over this region. The sandstones of the entire series 

 are very similar, and since there is entire conformity through- 

 out, it is absolutely impossible to determine just where the 

 marine beds end and the fresh-water beds commence. The 

 Ceratops beds of this region are a natural sequence of the Fox 

 Hills. The materials composing both were evidently derived 

 from a common source. The only safe criteria for distinguish- 

 ing one from the other are their fossils. 



The Overlying Beds. — Along their eastern border, the Cera- 

 tops beds are occasionally nnconformably overlaid by Miocene 

 clays and conglomerate. But these deposits, if they ever 

 extended over any considerable portion of the region now 

 occupied by the Ceratops beds, have been almost entirely 

 removed by erosion. To the west of Lance creek, the Cera- 

 tops beds pass under a very similar series of sandstones, shales, 

 and lignites, of about the same thickness, and conformable 

 with them. In this series, the sandstones are more massive 

 than the underlying sandstones ; the shales contain more sand ; 

 and the lignites are more frequent, of a better quality, and 

 attain a greater thickness, as shown at the Shawnee coal-mine 

 on Shawnee creek, where a single bed of coal is 10 feet thick, 

 and of a quality sufficiently good to enable it to be profitably 

 mined for commercial purposes. Thus far no vertebrate or 

 invertebrate fossils have been found in these beds, but they 

 contain a rich fossil flora, representatives of which have been 

 sent to Prof. F. H. Knowlton of the National Museum, with 

 a request for his opinion as to the age of the beds, based upon 

 the evidence afforded by the fossils. Upon no other evidence 

 than a general similarity to known Laramie deposits in other 

 regions, they are here regarded as Upper Laramie. 



Age of the Ceratops Beds. 



In a series of articles commencing in the April number of 

 this Journal for 1889, Prof. Marsh has referred the Ceratops 

 beds to the Laramie, mainly upon evidence afforded by their ver- 

 tebrate fossils. Owing to the fact that ver}^ few vertebrates 



