GENERAL GEOLOGICAL FACTS AND PRINCIPLES. 7 



Mountains, the Green Mountains, and the Adirondacks. Farther 

 south the Highlands of New York and New Jersey, the South 

 Mountain of Pennsylvania, the Alleghanies, the Blue Ridge, and 

 the other southern ranges make up the great eastern continen- 

 tal mountain system. In western New York and Ohio we find a 

 rolling, hilly country; in Kentucky and Tennessee, elevated table- 

 land, with deeply worn river valleys. Indiana, Illinois, Iowa, and 

 Missouri contain prairie and rolling country, more broken in southern 

 Missouri by the Ozark uplift. In Michigan, Wisconsin, and Minne- 

 sota the surface is rolling and hilly with numerous lakes. In Ar- 

 kansas, Louisiana, and Mississippi there are bottom lands along the 

 Mississippi and Gulf, with low hills back in the interior. Across 

 Arkansas and Indian Territory runs the east and west Ouachita 

 uplift. West of these States comes the great billowy prairie region, 

 and then the chain of the Rocky Mountains, consisting of high, 

 dome-shaped peaks and ridges, with extended elevated valleys 

 (the parks) between the ranges. Some distance east of the main 

 chain are the Black Hills, made up of later concentric formations 

 around a central, older nucleus, and also the extinct volcanic dis- 

 trict of the Yellowstone National Park. In western Colorado, Utah, 

 and New Mexico, between the Rocky Mountains and the Wasatch, 

 is the Colorado plateau, an elevated tableland. This is terminated by 

 the north and south Wasatch range and is traversed east and west 

 by the Uintah range. West of this lies the region called the Great 

 Basin, characterized by alkaline deserts, and subordinate north 

 and south ranges of mountains. Next comes the chain of the Sier- 

 ra Nevada, and lying between it and the Coast range is the great 

 north and south valley of California. This rises in the compara- 

 tively low Coast range, which slopes down to the Pacific Ocean. 

 To the north, these mountains extend into eastern Oregon and 

 Washington, with forests and fertile river valleys. These topograph- 

 ical features are important in connection with what follows, for the 

 reason that the ore deposits especially favor mountainous regions. 

 Mountains themselves are due to geological disturbances upheav- 

 al, folding, faulting, etc. and are often accompanied by great ig- 

 neous outbreaks. They therefore form the topographical surround- 

 ings most favorable to the development of cavities, waterways, 

 and those subterranean, mineral-bearing circulations which would 

 fill the cavities or replace the rock with useful minerals. 



1.01.05. GEOLOGICAL OUTLINE. I. New England, New York, 

 Neio Jersey, and Eastern Pennsylvania District. In New Eng- 



