The next great division of the range is defined on the north by the Maipo Pass and by Las Demas Pass on the south. Its principal heights are between 16,000 and 17,000 feet. From Las Demas on, few are over 10,000 feet, and, beyond Copahue, near the source of the Bio-bio River, the average is about 9000. Beyond the volcano Tronador (the Thunderer), in the latitude of Lake Llanquihue, and as far as Lake Buenos Aires, it consists of a series of Swisslike mountains, still decreasing in height, but with an occasional high peak, such as San Valentín (12,720 feet), and glaciers growing ever larger and more numerous. San Valentín towers in the midst of an elevated ice field eighty miles long and thirty wide and sends down two great glacial streams, one to the south and the other into the San Rafael Lake, where the ice glides along the bottom until it breaks into fragments that drift away in the channel of Morelada. All these places can now be reached by railroad or steamer. No conception of the Chilean country as a whole can be formed, however, unless it is understood that it is naturally divided into zones, as characteristically dissimilar as are the various grand divisions of the United States. For instance, there is the Magellan and Fuegian region, where, to the east of the mountain ranges, the great Argentine pampa extends clear down through Tierra del Fuego, and where, as the climate is too rigorous to invite agricultural pursuits, the principal industry, and the only important one, aside from a small amount of lumbering and gold mining, is the raising of herds of sheep and cattle. With the exception of the ranchers and the ten or twelve thousand people of Punta Arenas—which is the only port of call in these parts, and is, therefore, the distributing and shipping point for all the enormous expanse of country round about, including the southern section of Argentine Patagonia—the inhabitants are of the lower order of Indians and live in the forests, supporting themselves by hunting and fishing, just as they did before they ever saw or heard of a white man.