STRATIGRAPHIC POSITION OF JUDITH RIVER FORMATION 747 
peton, not to mention the more highly developed fauna yet to be discussed, is 
very striking. Had there occurred at both levels only some pebbles of three 
peculiar forms or compositions, instead of the three genera, the conclusion 
would have been inevitable that there was some particular connection between 
the two formations. 
When we realize that there is no interval between the Judith 
River beds and the Lance formation, allowing the deposition of 
thousands of feet of marine strata, we see that there is no remark- 
able reappearance of Myledaphus and its companions, but that 
they have simply coexisted in beds of the same age at different 
localities. As to Champsosaurus and the Crocodilia, it will serve 
our purpose here just to quote Dr. Hay, who says: 
Coming next to the reptiles, it may first be noted that species of Champ- 
Sosaurus occur in the Judith River beds, in the Lance Creek beds, in those of 
the Hell Creek region, and in the Puerco. It is probable that the species vary 
from one formation to the other. The same statement can probably be made 
regarding the crocodiles. These genera, common to all three of the formations 
under discussion, may be left out of consideration; although it must not be over- 
looked that, none the less, they aid in binding together the formations in which they 
are found. As to the crocodiles, it may be mentioned that Williston recog- 
nized, in teeth and scutes found in the Lance Creek beds, Leidy’s Crocodylus 
humilis, originally described from the Judith River region. From the Judith 
River beds of Alberta, Lambe described Leidyosuchus canadensis. Mr. C. W. 
Gilmore will soon describe a second species of the genus, collected last summer 
in the Lance Creek beds of Converse County, Wyo. 
The sentence italicized by the writer in the above quotation is the 
one specially pertinent to the present discussion. 
As regards the turtles which have been especially studied by 
Dr. Hay, he says: 
My study of the fossil turtles indicates that the species of these animals 
rarely pass from one epoch to another. If they have ever done so, they passed 
from the Judith River into the Lance Creek epoch. There are five or six 
species of Judith River turtles which are represented in the Lance Creek and 
Hell Creek beds by turtles of identical or very closely related species. Most 
of these are marked by such peculiar sculpture that they are easily recognized 
and some of them likewise are represented by excellent materials. 
Dr. F. H. Knowlton has recently shown conclusively that, of 
the sixteen species of turtles accredited by Hatcher to the Judith 
t Knowlton, Proc. Wash. Acad. Sci., XII (1911), 51-65. 
