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in the fauna and flora, and the utter want of connection between 
any of the Cretaceous and Tertiary phenomena as seen in 
England, speak of an almost inconceivable and perfectly im- 
measurable hiatus. Of the supposed passage beds in Europe 
many are Eocene, but I believe that in America the gap is at 
least partly filled up by the Dakota and overlying so-called 
Cretaceous strata. The true age of these, possessing a molluscan 
fauna and a flora of strangely Eocene aspect, mingled with Am- 
monites, Baculites, Inocerami , and Dinosaurians, is far older thlaljPt 
our Eocene, but certainly n^wer than our Chalk, 
has^lwp^e be^n are of transition age, 
of the greatest of HKe geological gaps. The Chalk, 
oceanic natureSnust formerly have been of immense 
the patches still exterifaiflg over wide areas are but 
Throughout ages preceding the Eocene time and ever since until 
the present day it has been incessantly worn and denuded, to 
what extent we imperfectly see in the enormous beds of shingle 
and sand in the Eocenes, Pliocenes, and Pleistocenes, and in 
the gravels of the present sea bed. 
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