HYDROWIAPHY. A mcrica.—While most of North Ameriea is drained into the Atlantic, yet great areas are drained into the l'gcific 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 canons 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 On tario, and the River St. Lawrence. The waters of the southern part of this depression are col lected by one of the greatest rivers of the earth, the Mississippi, with its branches, the Ohio, Mis souri. 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 sys tem is drained to the Atlantic by many compara tively small rivers.
Besides the great lakes of the St. Lawrence system, North America contains many large bod ies of water. In Canada are Great Bear and Great Slave and Athabaska lakes in the Macken zie River system; lakes Reindeer,Winnipeg,Man itoba, and Lake of the Woods, which are drained to Hudson Bay. and Lake Nepigon, tributary to the St. Lawrence system. In the northern Unit ed 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 vol canic origin, like Yellowstone Lake, while many occupy desert valleys and have no outlet, like Great Salt, ('arson, and Walker lakes. See YuKors RIVER; MISSISSIPPI, etc.
South A in crica.—South America is for the most part drained into the Atlantic Ocean, the Andes forming a great and continuous water shed ; 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 diverg ing 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 wind ings. 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 head ing chiefly in the watershed between this section and the 'valley of the Amazon on the south. Next in proceeding southward on the Atlantic coast. is the mighty Amazon itself, whose system drains the great valley included between the plateau of Brazil on the southeast, the plateau of Guiana on the north, the Andes on the west, and the highlands of the Cordillera Geral and Matto Grosso on the south, thus em braving about one-third of South America. The Amazon pours a vastly greater quantity of water into the ocean than any other river on the globe. The plateau of Brazil is drained chiefly by the Tocantins, which flows to the north and empties into the Par5 estuary; a number of smaller streams which flow northeast and enter the Atlantic between the mouth of the Para and Cape St. Roque; the Silo Francisco, which has a generally northeastern direction, and a few smaller streams which drain the short eastern slopes along the whole extent of coast be tween the mouth of the Silo Francisco, lat. 10° S., and the estuary of the Plata. lat. 35° S. The Plata, which receives the waters of the Parana, Paraguay. and Uruguay. drains the whole of the south central part of South America, from the Amazon watershed in lat. 15° S. to lat. 35° S., and embraced between the coast sierra on the east and the Andes on the west. This great river system has been compared with the Missis sippi River system, with which it has certain features in common. South of the Plata are a number of rivers, including the Colorado, Negro, and Chubut. On the Pacific coast the drainage is effected by short, torrential streams scarcely worthy the name of river. See AMAZON; OR INOCO, etc.