GEOGRAPHICAL DEVELOPMENT OF THE AMERICAS 101 



occur and are not mere guesses to bolster up a tottering hy- 

 pothesis, there is abundant evidence to prove. 



In the Paleocene, or most ancient epoch of the Tertiary 

 period, the geographical condition of North America was ap- 

 proximately as follows : The continent had attained nearly 

 its modern outlines and on the Atlantic and Pacific coasts 

 probably extended farther seaward than it does to-day. Florida, 

 however, and perhaps a narrow strip of the northern Gulf 

 coast were still submerged, the Gulf of Mexico opening broadly 

 into the Atlantic. It is very probable that the continent was 

 connected with the Old World by a land occupying the site 

 of Bering Sea and perhaps also by way of Greenland and the 

 North Atlantic ; and there is some evidence, though not al- 

 together convincing, that it was also joined to South America. 

 The great mountain ranges were largely what they now are, 

 though subsequent upheavals greatly modified the Rocky 

 Mountains, Sierra Nevada and the ranges of the Pacific coast, 

 while the lofty St. Elias Alps of Alaska were not in existence. 

 The region of high plateaus, between the Rockies and the 

 Sierras, was much less elevated than it is now. The Appala- 

 chians, which were of far more ancient date than the western 

 ranges, had been worn down by ages of weathering and stream- 

 erosion into a low-lying, almost featureless plain, with some 

 scattered peaks rising from it here and there, of which the moun- 

 tains of western North Carolina were the highest. In general, 

 it may be said that while the average height of the continent 

 above the sea-level may have been as great or greater than at 

 present, yet the inequalities of surface appear to have been 

 less marked, and both along the Atlantic coast and in the in- 

 terior were vast stretches of plains. 



The Paleocene formations of the western interior are of 

 non-marine or continental origin. In northwestern New 

 Mexico is the typical area of the Puerco and Torrejon, a series of 

 beds 800 to 1000 feet in thickness and for the most part quite 

 barren of fossils, but there are two horizons, one near the top 



