taining the form of a broad, elevated plateau, bordered by lofty ranges, with many volcanic peaks. In the neighborhood of the equator, in Ecuador, are many notable peaks, among them Tunguragua, 16,690 feet; Cotopaxi, 19,613 feet; Chimborazo, 20,498 feet; Antisana, 19,335 feet; Cayambe, 19,186 feet; and Piohincha, 15,918 feet. From this knot of lofty volcanoes the system falls off in altitude northward toward the Isthmus of Panama and the shores of the Caribbean Sea, splitting into three ranges, which trend away from one another to the north and northeast.
East of the Andes the level of the land descends rapidly to the llanos of the Orinoco, the valley of the Amazon, and the pampas of Argentina. This great area, comprising by far the greater part of South America, is but slightly diversified by hills, forming mainly an immense plain. In eastern Brazil is a mountain system standing on a broad plateau, and composed of many ranges, trending in general parallel to the coast, and having collectively a great breadth. The highest point in this system is Itatiaia, with an altitude of 10,340 feet. A similar but smaller plateau occupies much of the area of the Guianas. See Andes, etc.
The islands pertaining to this grand division belong mainly to North America. In the Arctic Ocean these land bodies are numerous and large, Greenland, almost continental in area, being the largest of them. West of Greenland, across Smith Sound, is the great extent of Grinnell Land, and south of this island are North Devon, Cockburn Land, and Baffin Land, with many other large islands to the west, including Bathurst, Melville, Prince of Wales, and North Somerset islands, and Prince Albert and Banks Land, the whole forming an extensive archipelago in the Arctic Sea. In Bering Sea, on the northwest of the continent, are many smaller islands, while the chain of the Aleutian Islands, stretching in a great curve, convex southward, from the point of the Alaskan Peninsula, partly separates Bering Sea from the Pacific. On the east side of the continent, the great island of Newfoundland partially closes the mouth of the Gulf of St. Lawrence.
Mainly within the tropics, and lying between the northern coast of South America and the southeast coast of the United States, are the West Indies, with Cuba, Haiti, Jamaica, and Porto Rico, known collectively as the Greater Antilles, and many smaller islands grouped about and stretching away from them. They are the unsubmerged portions of a mountain system. On the north side are the Bahamas, consisting of a large number of small coral islands, and on the southeast, stretching in a broad curve, convex to the east, to the south American coast, are the Lesser Antilles, all small, and many of them of volcanic origin. The best known among them are Guadeloupe, Martinique, and Trinidad. South America has few islands, the Falkland Isles, east of the Strait of Magellan, being the largest, if we except Tierra del Fuego, at the south end of the continent. Off the west coast, and under the equator, are the Galapagos Islands, once prominent as a source of guano.
Hydrography. North America.—While most of North America is drained into the Atlantic, yet great areas are drained into the Pacific and Arctic oceans. The Rocky Mountains, i.e., the easternmost ranges of the Cordillera, carry the continental divide, and most of the ranges and valleys of this system are drained westward to the Pacific by the Colorado River of the west, through its marvelous cañons to the head of the Gulf of California, by the Sacramento to San Francisco Bay, and by the Columbia, the Fraser, Copper, and other rivers. The northern and northeastern slopes of the system, as well as most of Alaska and much of the Yukon province of Canada, are drained by the great river Yukon to Bering Sea. The northern part of the great central depression of the continent sends its waters to the Arctic Ocean by way of Mackenzie River. Farther south the land is drained to Hudson Bay by the Nelson and other rivers, and to the Atlantic directly by the chain of the great lakes, Superior, Michigan, Huron, Erie, and Ontario, and the River St. Lawrence. The waters of the southern part of this depression are collected by one of the greatest rivers of the earth, the Mississippi, with its branches, the Ohio, Missouri, Arkansas and Red rivers, and are carried to the Gulf of Mexico. The coast-land of the Gulf of Mexico itself is drained by a number of rivers on either side of the Mississippi. The Atlantic slope of the Appalachian mountain system is drained to the Atlantic by many comparatively small rivers.
Besides the great lakes of the St. Lawrence system. North America contains many large bodies of water. In Canada are Great Bear and Great Slave and Athabaska lakes in the Mackenzie River system: lakes Reindeer, Winnipeg, Manitoba, and Lake of the Woods, which are drained to Hudson Bay, and Lake Nepigon, tributary to the St. Lawrence system. In the northern United States are thousands of small lakes, which, in common with those of Canada, were formed by the Laurentian glacier. In the Cordilleran region are many lakes, some of glacial origin, like Pend Oreille and Flathead, others of volcanic origin, like Yellowstone Lake, while many occupy desert valleys and have no outlet, like Great Salt, Carson, and Walker lakes. See Yukon River; Mississippi, etc.
South America.—South America is for the most part drained into the Atlantic Ocean, the Andes forming a great and continuous watershed; and while three great river systems carry most of the waters to the sea, yet a number of secondary but by no means small rivers aid them in this work. In the extreme northwest of South America, the Magdalena drains the region in which the Andes separate into diverging ranges before their subsidence. The area of its basin is not great, but the enormous rainfall sends great volumes of water through this river channel into the Caribbean Sea. The entire length of the Magdalena, independent of its windings, is not over 700 miles. The great valley at the extreme north of South America, lying between the Andes on the west and the plateau of Guiana on the east, is drained by the Orinoco, which, although not more than 1200 or 1400 miles long, not counting the windings, carries an immense volume of water into the Atlantic, because it, too, lies almost wholly within the belt of excessive rains. Between the Orinoco and the Amazon there are a number of short rivers draining the plateau of Guiana, and heading chiefly in the watershed between this section and the valley of the Amazon on the south. Next in order, proceeding southward on the
