GEOGRAPHY OF THE EMPIRE OF REPTILES. 197 



later geological agencies. Probaly large portions of Green 

 land and other arctic lands had emerged, besides the prin 

 cipal portion of the West India Islands. 



The climate of the period was much warmer than that 

 of the same localities in the present age. Coral-builders, 

 and other marine animals now restricted to tropical regions, 

 then flourished throughout the whole length of the conti 

 nent, from latitude 60 north to the Straits of Magellan on 

 the south. The superior warmth of former age s of the 

 world is probably due, in some measure, to the more highly 

 heated condition of the globe a source which, through all 

 ages, has been undergoing a gradual diminution. It has 

 also been suggested that the connection which existed be 

 tween the Gulf of Mexico and the Arctic Ocean permitted 

 the Gulf Stream to flow through the centre of the conti 

 nent, and thus, while it carried a tropical temperature far 

 toward the north, ameliorated the climate of the regions to 

 the east of it, as the same ocean stream now moderates the 

 cold of high latitudes upon European shores. Thus, while 

 the Northern States were terra firma, the rich cotton-fields 

 of Alabama and Texas were gathering their calcareous sed 

 iments beneath the Gulf of Mexico. Fleets might have 

 sailed over the rolling prairies of Kansas andDacotah, and 

 the anchor of the mariner might have fastened in the sum 

 mit of Pike s Peak. But fleets of Nautili, and their cousins 

 the Ammonites, were the only keels that plowed that Med 

 iterranean sea, and the polyp and the oyster were the only 

 mariners that cast their anchor on the sunken ridges. East 

 ward, the broad rolling plains of Illinois and Ohio were 

 adorned with a growth of sub-tropical vegetation, and the 

 west wind of even a winter sky breathed softly over its 

 never-fading foliage. But the shining cities of the West 

 were not there. The kingly alligator alone disturbed the 

 waters of the Ohio. The railroad car, the church spire, the 



