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 v/pon its Inhabitants —Froiessor 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 v^ide 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. 



