212 INFLUENCE OF GEOLOGICAL STRUCTURE. 



made up of a few wide and regular slopes ; one 

 from the Appalachians westward to the Mississippi ; 

 another, more uniform and far more extensive, from 

 the Rocky Mountains to the Mississippi ; and a third 

 from the sources of the Mississippi and the great 

 lakes north to the Arctic Sea. A very remarkable 

 feature of this region is the great uniformity of the 

 whole surface, and the regular and gentle ascent 

 from the Gulf of Mexico to the head-waters of the 

 Mississippi, reaching in that space an elevation of 

 not more than 1000 or 1200 feet, and again ascend- 

 ing in a similar manner from the banks of the Mis- 

 sissippi to the foot of the Rocky Mountains. Be- 

 tween the Alleghanies and the Mississippi the sur- 

 face is broken into hills, and embraces the most fer- 

 tile territory in the United States. About 400 miles 

 west of the Mississippi a barren desert commences, 

 which extends back to the Rocky Mountains, cover- 

 ing a breadth of between 400 and 500 miles, and 

 from Missouri, in latitude 56°, to Mexico. 



Influence of the Geological Structure of the United 

 States upon its Inhabitants. — Professor Silliman re- 

 marks,* that " it is perfectly apparent to geologists 

 that the scenery of a country is not more exactly 

 stamped by its geological formations than are the 

 manners and employments of its inhabitants. The 

 bleak hills and long winters of New-England are un- 

 favourable to the most extensive and profitable agri- 

 cultural pursuits, while the extensive and deeply-in- 

 dented seacoasts, abounding with harbours, head- 

 lands, rivers, and inlets, naturally produce an im- 

 pulse towards the ocean, which, conspiring with the 

 original adventurous character of the population, 

 sends them roving from the Arctic to the Antarctic 

 Circle, till the wide world is laid under contribution 

 by their enterprise. Their numerous streams and 

 water-falls furnish the cheapest means for moving 



* Appendix to Bakewell's Geology, p. 483. 



