The Atlantic slope of the United States is well supplied with water, and many of its streams afford extensive navigation. The Hudson is noted for its fine scenery; the Potomac is one of the noblest of American rivers; and important streams flowing to the Atlantic are the St. John, the Penobscot, the Kennebec, the Merrimac, the Connecticut, the Delaware, the Susquehanna, the James, and the St. John’s, nearly all navigable in their lower courses.
The chief rivers flowing to the Gulf of Mexico are the Appalachicola, the Mobile, the Pearl, the great Mississippi, the Sabine, the Trinity, the Brazos, the Colorado of Texas and the Rio Grande.
Of the many large Alaskan rivers the principal are the Yukon and the Kuskoquim. The Fraser is a swift and strong river; the great river Columbia is noted alike for its navigation, its salmon fisheries, and its enormous cataracts. The Rio Colorado, whose waters flow to the Gulf of California, traverses a desert plateau. Here nearly every watercourse runs in a deep-walled cañon, a narrow valley with precipitous sides, often of prodigious height.
In the plateau of Central America the largest lake is that of Nicaragua, nearly equal to Ontario in extent, and only one hundred and thirty-one feet above the level of the sea. (See further under the respective countries of North America.)
Climate.—Largely determined by the direction of the mountain ranges. Five climatic regions, viz., an arctic region, whose mean temperature is less than thirty-two degrees Fahrenheit; an Atlantic temperate region, extending as far as the Mississippi, with abundant rains and dense woods; an inland temperate region, dry, with steppes or prairies; a Pacific coast region, and a tropical region.
Political Divisions.—The political divisions of North America are:
(1) Danish America,[8] which includes Greenland and three small islands of the Virgin group in the West Indies.
[8] The Danish West Indies were transferred to the sovereignty of the United States in 1917 at the purchase price of twenty-five million dollars.
(2) British North America, in which division we may place the Dominion of Canada, Newfoundland, Labrador, the Bermudas, the numerous British West Indian islands, and British Honduras.
(3) The United States, including the detached territory of Alaska.