grass, sage-brush and cactus, haying but slight rainfall and depending on irrigation (q. v.) to render it profitable to cultivate. In the north the plain drains into the Great Lakes and forms the lake region; in the south, where it meets with the Atlantic plain in Alabama, it drains to the Gulf and forms the Gulf region, which extends from Georgia and Florida far into Texas. The great rivers of the Mississippi valley are the Missouri and the Mississippi and their chief branches, as the Ohio, Minnesota, Wisconsin, Yellowstone, Dakota, Platte, Des Moines, Illinois, Kansas, Arkansas, Red and Yazoo, to say nothing of such tributaries of the Ohio as the Cumberland, Tennessee or Wabash or of the tributaries of the other chief branches. Many of these and their tributaries extend from 1,000 to 2,000 miles. The Mississippi valley is also bordered by the world's largest bodies of fresh water, which the St. Lawrence connects with the Atlantic, while Wisconsin, Minnesota and Michigan are noted for numerous small lakes.
The Pacific slope comprises the most varied region of the United States, broken by great plains and lofty mountain-valleys 10,000 feet above the sea, descending by great steps to the lower levels. It has huge cañons — river-beds thousands of feet deep; arid plains; heavy forests in the north; and a great basin without drainage to the sea. Here is the famous Great Salt Lake of Utah. Its rivers are the Columbia and its branches; the San Joaquin; the Sacramento and the Colorado of the west, all flowing into the Pacific.
The drainage-systems of the United States number five, and have already received full description in the article on America (North). They comprise the Atlantic, Gulf (including the Missouri-Mississippi system also), Great Basin, Lake and Pacific river-systems. (See articles on each topic). They give the country 100,000 miles of inland navigation — the most extensive in the world. Among the minor lakes, in distinction from the Great Lakes, may be mentioned Champlain, Moosehead, Oneida and its famous sister-lakes in New York, Salt Lake and Tahoe. (See these titles).
Natural Features. No country equals the United States in beauty, grandeur and variety of scenery. Among the many interesting features are Crawford Notch, Delaware Water-Gap, the Hudson Highlands and Palisades, Watkins Glen, Niagara Falls, Luray Cave, the Natural Bridges in Utah and Virginia, Harper's Ferry, Mammoth Cave in Kentucky, the vast prairies, the inland seas, the mighty streams of the interior, St. Anthony and Minnehaha Falls, the Dalles of the Wisconsin, the Pictured Rocks, the passes of the Missouri and of the Columbia through the mountains, the falls of the Yellowstone, Snake and Missouri Rivers, Yellowstone Park, the hot-springs and the geysers, Yosemite Park and Falls, the Big Trees, Royal Gorge, Grand Cañon and the Yellowstone Cañon. (See articles under titles above and Geography, Geology and Geological Survey.)
Climate
The climate of a country stretching over 24½ degrees of latitude and ranging from coastal plains to lofty mountains and tablelands varies greatly. In most parts of the land it is extremely changeable, with great variations of temperature between summer and winter. The Atlantic states are colder than European countries in the same latitudes, but the Pacific coast has a climate as mild as Italy's. The Gulf states and Georgia and South Carolina verge toward a subtropical climate. The rainfall is plentiful, except in some parts of the west, and is distributed throughout the year, except on the Pacific coast, where it occurs in spring and in winter. There also is every variety of soil, including prairie lands covered with rich mould, sometimes 25 feet deep, and the sterile, arid plains of the Utah or Great Basin. (See Agriculture, America, Cold Wave, Rain and Soil.)
Resources
These consist of the natural products of the soil and the waters, as minerals, forests, native plants and animals and fish and other aquatic animals. Their vast variety and abundance, with the great range of climate, make the United States a world in itself able to raise almost all products of the temperate and the tropical zones. For the flora and fauna see America and articles on such subjects as, e. g., Corn or Deer.
Minerals. These include coal, copper, gold, iron, lead, mercury, nickel, platinum, precious stones, silver, zinc and such building-stones as granite, limestone, marble, sandstone, slate and trap. (See articles under titles above.) Aluminum, asphalt, clay, gypsum, mineral springs, natural gas, petroleum, Portland cement, phosphate-rock and salt also abound. (See articles on each.) In the production of aluminum, coal, copper, iron, lead, natural gas, petroleum, quicksilver, phosphate-rock, silver and steel the United States ranks first; in producing gold it stands second; in zinc third. In 1910 the production of gold was 4,657,018 ounces or $96,269,100; of silver 57,137,900 ounces or $30,854,500; of coal (anthracite and bituminous) 501,596,378 metric tons worth $629,557,021; of iron 27,303,567 tons; of steel 26,049,919 tons, the value of the steel and iron tonnage together being $1,000,000,000; and of lead 372,227 tons worth $32,755,976. In 1910 all mineral products were worth $2,003,744,-
