THE MORRISON FORMATION 667 



4. Chocolate, reddish, and variegated shales and variable sand- 

 stones of the Morrison. Only upper part here exposed. 

 Total thickness probably 300 or 400 " 



The general section of the region includes the entire Upper Cretaceous 

 and a considerable thickness of Red Beds and Paleozoic. 



Under the guidance of Mr. Edward Felch, who has had personal 

 knowledge of all the vertebrate collecting that has been done in the 

 neighborhood, I visited the various quarries that were worked by 

 Marsh, Cope, and Hatcher, and determined that they are all on 

 horizons below the Comanche fossiliferous bed and below the sand- 

 stone immediately underlying it. It is evident therefore that the 

 Morrison formation is no more closely related to the Dakota near 

 Canyon City than it is at other localities. 



Extent 0} the Comanche Sea. — It has now been shown that the 

 Comanche sea extended as far northwest as Canyon City, Colorado, 

 and that its sediments overlie the Morrison in an area more than 

 100 miles wide. How much farther it extended in that direction is 

 not known, as no special search for paleontologic evidence has yet 

 been made, though the recent discovery by Prof. S. W. Williston 1 

 of Comanche species of fish teeth in the "upper part of the Atlanto- 

 saurus beds" near Lander, Wyoming, suggests the possibility of 

 much greater extension. 



This leads to the question whether the Fuson and Lakota forma- 

 tions, which have been differentiated from the Dakota in the Black 

 Hills, should be identified respectively with the Comanche shaly beds 

 and the underlying sandstone which hold the same stratigraphic 

 positions in southern Colorado and New Mexico. Such an identifi- 

 cation is plausible, and yet it seems to me that it is not warranted 

 by the evidence now in hand. The Fuson formation is apparently 

 non-marine, and, judging from the descriptions, its lithologic char- 

 acter is different from that of the Comanche shales and sandstones. 

 It contains a flora which is comparable with that of the lower Poto- 

 mac, and has nothing in common with the Dakota flora, which is 

 of much later type. On the other hand, the Comanche 2 of Colorado 



1 Journal of Geology, Vol. XIII (1905), p. 347. 



2 The term Comanche throughout this paper is used as a general term of cor- 

 relation — not as a formation name. 



