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River epoch to that which witnessed the deposition of the Lance Creek and 
Hell Creek beds. Nevertheless, nothing can impair the force of the evi- 
dence that many species included among the fishes, the tailed amphibians, 
the turtles, the crocodiles, the champsosaurians, and the carnivorous and 
herbivorous dinosaurs are represented in both formations by closely re- 
lated forms. The remarkable thing about the matter is that the faunas of 
the two formations, separated by so great a thickness of strata, should be 
so similar. We must conclude that deposition went on rapidly in that in- 
terval, so that it may not have been so long as otherwise might appear. 
There could hardly have been movements of the land in that region that 
produced any considerable changes of climate. During the Bearpaw epoch 
the sea probably quietly invaded a part of the territory that had previously 
been occupied by the Judith River animals; but around the border of this 
invading sea the turtles, the crocodiles, and the many genera of the dino- 
saurs continued their existence and their evolution undisturbed until that 
sea retired. And doubtless had all those animals in that region been 
destroyed there was an extensive territory, nearly the whole of North 
America as far as the Atlantic, that harbored similar forms, from which 
territory new recruits could swarm in. As far away as New Jersey there 
were living herbivorous and carnivorous dinosaurs not greatly different 
from those of the Judith River beds. This appears to be true, that what- 
ever happened to the plants between the time of the Judith River and the 
Lance Creek beds, nothing of serious importance happened to the animals. 
By those who insist on elevating the deposits of the Lance Creek 
epoch into the Tertiary, a persistent effort has been made to minimize or 
nullify the significance of the presence of dinosaurs. As long ago as 1880 
Heer wrote thus (Arctic Flora, vol. 6, pt. 2, p. 7): 
Der Agathaumas von Black Buttes beweist daher keineswegs, dass 
dort eine Tertiir-Flora zn gleicher Zeit mit einer Kreide-Fauna gelebt 
habe, wie Prof. Cope dies behauptet, denn ein einzelnes Thier macht so 
wenig eine Fauna aus, als eine Pflanzenart eine Flora. Wir kénnen daher 
Hrn. King nicht beistimmen, wenn er, mit Cope und Marsh, die Laramie- 
Gruppe zur Kreide bringt. 
Mr. Cross and Dr. Knowlton have argued that the dinosaurs might 
have continued on into the Eocene, and in fact did so. As to the verte- 
brate paleontologists, it is not probable that any of them would have as- 
serted that this was impossible and some of them have granted the possi- 
bility. In holding that the dinosaur beds belong to the Mesozoic, they 
