THE REIGN OF MAMMALS. 201 



of the European Lectonia was an event which reaches down 

 within the grasp of human tradition, the drainage of the 

 American Lectonia was an event shrouded in the obscuri 

 ties of the pre-Adamic ages. Thus again we discover that 

 the &quot; New World&quot; is in reality the oldest. 



This broad expanse of Tertiary waters stretched across 

 the western part of Dakotah and Nebraska. At the same 

 time, the Mexican Gulf, though outlined somewhat after the 

 modern fashion, was left a hundred miles more extended 

 than at present on the west and north, and reached its long 

 arm up the valley of the Mississippi to the mouth of the 

 Ohio, beckoning to the cooler waters of the North to come 

 and lave its tropic shores. This arm was the southern 

 representative of the Gulf of the St. Lawrence. The pe 

 ninsula of Florida was a coral reef. A broad belt of the 

 Atlantic States to New York was yet a sea-bottom, and 

 the Pacific yet held possession of the lowland zone of the 

 western slope. Now the Missouri River came into exist 

 ence, born of the great central sea. Still the Niagara Riv 

 er thundered away in an ancient excavation, which, like the 

 work of the men of Nineveh, was destined to be buried be 

 neath the rubbish of coming ages, and lie a long time un- 

 remembered. Now the eastern ranges of the Rocky Moun 

 tains were first lifted above the deep. During subsequent 

 ages they underwent further upheavals, while the waters 

 of the Gulf and the great oceans were rolled back to their 

 present positions. 



The epoch which followed the last great upheaval, and 

 witnessed the events transpiring on the shores of the 

 American Mediterranean, marked the dawn of the present 

 order of things. All subsequent time has hence been 

 styled Cenozoic. The populations which swarmed upon 

 the earth during each preceding epoch disappeared in turn, 

 and their places were occupied by forms generally more 



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