462 United States. 



and other minerals, except in its northern extension 

 formed of archean rock. 



3. The great river basin of the Mississippi, a Central 

 plain of glacial and river deposit, rising gradually from 

 the Gulf to the headwaters for more than 1200 miles, 

 and nowhere over 1,000 feet above sea level; the 

 richest agricultural section, 700,000 square miles, 

 more or less, in extent. 



4. The plateau, rising towards the Rocky Moun- 

 tains from 1,000 to 5,000 feet above sea level, some 

 870,000 square miles in extent, a region of scanty 

 rainfall, hence of prairie and plain, but mostly rich 

 soil of undetermined depth, capable of prolific pro- 

 duction where sufficient water supply is available. 



5. The Rocky Mountain region, rising from 5,000 

 to near 10,000 feet (except some higher peaks), an 

 arid to semi-arid district of rugged ranges, covered 

 mostly with forest growth, often open and of inferior 

 kind, with tillable soils in the narrow valleys, requiring 

 irrigation for farm use; a mining country, rich in 

 gold and silver, extending over 150,000 square miles. 



6. The Sierra Nevada Mountain Range, including 

 the Coast Range, rarely over 7,000 feet elevation, 

 arid to semi-arid on the Eastern slopes; humid, and 

 supporting magnificent forest growth on the Western 

 slopes; some 190,000 square miles. 



7. The Interior Basin, lying between the two 

 preceding mountain ranges, some 400,000 square 

 miles; for the most part a desert, although in parts 

 supporting a stunted growth of pinon and juniper, 

 and, where irrigation is possible, productive. 



