Andes

the principal mountain system of South America. On the theory that a range of mountains is a wrinkle in the earth's crust, the Andes and the Rocky Mountains do not seem to be parts of the same great fold. Although intervening mountains connect the two systems, the southern extension of the Rocky Mountains sinks into the Pacific westward of South America. The general direction of the Andes, the countries traversed, and the table-lands inclosed, may be seen at a glance at the map. In height and extent the Andean system is second only to the Himalayas. In mass it may be compared with a huge embankment about 4,400 miles in length, having a width of from 20 to 250 miles, and an average height of nearly 2 1/2 miles. The total bulk may be represented in cubic feet by the figure five followed by fifteen ciphers-a mass about equivalent to the silt that at its present rate would be carried downstream by the Mississippi in three-fourths of a million years. If all the rivers of the world were to play on the Andes, they would require 135,000 years to sweep the mountains away; yet, as compared with the bulk of the earth, the entire range is but a blade of grass resting on a watermelon. For a great part of the length the Andes are a broad embankment from 6,000 to 11,000 feet high, with a ridge of peaks rising still higher, like battlements along either edge. Along the top of the embankment, and between these border walls, are the great upland plains or valleys in which, at their greatest expansion, Pizarro discovered an ancient civilization and effected the conquest of Peru. Bolivia and Peru border here.

The highest peak, not only of the Andes but of the New World, and the loftiest volcano in the world is Mt. Aconcagua, 23,290 feet above the sea. At the latitude of Lake Titicaca, one of the largest elevated lakes in the world, the Andean system is at its widest. Toward the north the border ranges approach and knot together in the vicinity of Quito, one of the most intensely active volcanic regions of the globe. Cotopaxi and Chimborazo are here. The equator here crosses an extinct volcano 19,534 feet above the sea. This is the greatest height attained by the equator in its entire course, and is the only region where the equator passes through perpetual ice and snow. By glancing at a map of South America it may be seen that from this knot the mountain ranges radiate like a fan through Colombia. At its southern termination the Andean system runs along the water's edge in a single high ridge, about twenty miles wide, to Cape Horn, though much broken by arms of the sea. The Strait of Magellan cuts off Tierra del Fuego altogether.

See South America; Deserts; Titicaca; Equator; Peru; Colombia