STRATIGRAPHIC POSITION OF JUDITH RIVER FORMATION 745 
Williston* notes a “startling resemblance” between the Wyo- 
ming Laramie [Lance Creek] fauna and that of the Judith River and 
Belly River series. Of course, if they are equivalent to each other, 
as we claim, this resemblance is not so startling. Williston, how- 
ever, is not alone in mentioning this resemblance. Hatcher’ 
himself says: 
When considered in its entirety, the vertebrate fauna of these beds [Judith 
River beds] is remarkably similar to, although distinctly more primitive than, 
that of the Laramie [Lance formation]. Almost or quite all of the Laramie 
[Lance formation] types of vertebrates are present, though as a rule they are 
represented by smaller and more primitive forms. 
However, it remained for Dr. O. P. Hay fully to bring out this 
resemblance and demonstrate the equivalence of the Judith River 
and Lance formations. Having demonstrated, as he supposes, 
that there was a nearly complete change in the fauna and a consid- 
erable change in the flora between the time of the deposition of the 
Lance Creek beds and those known as Puerco and Fort Union, he 
says: 
I will endeavor to show that the fauna of the former beds is closely 
related to that of the Judith River. This close relationship of the two faunas 
has been recognized, it may be truthfully said, by all paleontologists who have 
given attention to the subject. 
In his discussion of the relationship of the two faunas Dr. Hay 
begins with the fishes and follows with the tailed amphibians. He 
quotes Hatcher, who says eight species of fishes have been described 
from the Judith River deposits. Of these Hatcher says: 
While they give an indication of the character of some of the fishes that 
inhabited the waters of this region in Judith River times, they are at present 
known from such insufficient material as to render them of little value for 
purposes of correlation, as is abundantly evidenced by the apparent similarity 
existing between the fish remains known from these beds and those from the 
Laramie [Lance formation]. This similarity is so striking that some paleon- 
tologists have been led largely from such evidence to correlate the Judith River 
t Science, N.S., XVI (1902), 952. 
2 Bull. U.S. Geol. Surv., No. 257, 1905, p. 107. 
3 Reprint from the Proc. Ind. Acad. Sci., Twenty-fifth Anniversary Meeting, 1900, 
pp. I-27. 
