746 A. C. PEALE 
beds with the Laramie |Lance], disregarding the more important evidence afforded 
by the dinosaurian fauna and the stratigraphy. 
The italics above are the writer’s. Here again we run up against 
the stratigraphic misapprehension already alluded to. As to the 
dinosaurian evidence, as we shall presently see, its trend is the same 
as that afforded by the fishes. It is axiomatic that only the species 
common to any two or more formations are of any use in corre- 
lating them. Lepidotus occidentalis Leidy, described in 1856 from 
the Judith River beds, has been found by Williston? in the Lance 
formation of Converse County, Wyo., and by Barnum Brown in the 
Lance formation in the Hell Creek region. With this Lepidotus 
Williston found also another species, Myledaphus bipartitus, named 
by Cope from the Judith River beds. This seems to be a ray 
according to Hay, who says: “The rays are almost wholly inhab- 
itants of salt water; hence the persistence of this Judith River 
fresh-water form is somewhat remarkable.’ Another species of 
Diphyodus, a genus founded on a jaw fragment from a Canadian 
locality, is said by Hatcher to be common both in the Judith River 
beds of Montana and in the Laramie [Lance] deposits of Converse 
County, Wyo., and a species of the same genus was found by Bar- 
num Brown in the Hell Creek beds. The tailed amphibians, which 
Hay says are at all times rare fossils, are all referable to the genus 
Scapherpeton, and five species were described by Cope from frag- 
mentary material obtained in the Judith basin of Montana. Willis- 
ton found one species in the Lance formation and Brown reported 
a species from the Hell Creek beds. Hatcher considers the 
batrachia of the Judith River beds of no special importance in 
determining the age of the deposits or in correlating them with 
other formations. Dr. Hay, however, referring to them says:4 
While it is true that these fishes and amphibians are mostly represented 
by fragmentary remains, these remains are usually characteristic and capable 
of accurate comparison. That Myledaphus should reappear after an interval 
allowing the deposition of 1,000 feet of marine strata, and probably some 
hundreds of feet of fresh-water strata, is remarkable enough; but that it should 
reappear in company with its old companions, the rare Diphyodus and Scapher- 
t Bull. U.S. Geol. Surv., No. 257, p. 67. 
2 Bull. Amer. Mus. Nat. Hist., XXIII (1907), 842. 
3 Hay, op. cil., p. 20. 4 Hay, op. cit., pp. 20, 21. 
