Argentine Patagonia is for the most part a region of steppelike plains, rising in a succession of 13 abrupt terraces about 330 ft at a time, and covered with an enormous bed of shingle almost bare of vegetation. In the hollows of the plains are ponds or lakes of brackish and fresh water. Towards the Andes the shingle gives place to porphyry, granite, and basalt lavas, animal life becomes more abundant and vegetation more luxuriant, acquiring the characteristics of the flora of the western coast, and consisting principally of southern beech and conifers. The high rainfall against the western Andes and the low sea surface temperatures offshore give rise to cold and humid air masses, contributing to the ice-fields and glaciers, the largest ice-fields in the Southern hemisphere outside of Antarctica.
Tierra del Fuego is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The main island Isla Grande de Tierra del Fuego is divided between Chile and Argentina, and a group of smaller islands including Cape Horn. Today's economic activity in the northern part of Tierra del Fuego is dominated by petroleum extraction while in the south tourism, manufacturing and Antarctic logistics are important.