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strata and probably some hundreds of feet of freshwater strata, is re- 
markable enough; but that it should reappear in company with its old 
companions, the rare Diphyodus and Scapherpeton, 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 com- 
positions, instead of the three genera, the conclusion would have been in- 
evitable that there was some particular connection between the two for- 
mations. 
Champsoscurus, Crocodiles.—Coming next to the reptiles, it may first 
be noted that species of Champsosaurus 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 croco- 
diles. These genera, common to all three of the formations under discus- 
sion, may be left out of consideration; although it must not be overlooked 
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 
recognized, 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, 
Wyoming. 
Turtles —As regards the turtles, certain genera have already been 
mentioned as appearing not to pass the line between the Lance Creek for- 
mation and the Puerco and Fort Union. My study of the fossil turtles in- 
dicates 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. I shall take 
the pains to give some details. 
Compsemys? obscura Leidy was originally described from beds 
probably belonging to the Lance Creek epoch and found at Long Lake, 
N. Dakota. Not much of it is known, but the sculpture is distinctive. 
