South America and Antarctica are joined by an island chain very similar to the island chain of the Caribbean. A submarine ridge across the Drake Strait is analogous to the Isthmus of Panama. The Palmer Peninsula of Antarctica lies at the same relative latitude as Iceland; but, having the cold Humboldt current instead of the warm Gulf Stream, is uninhabitable by a native population.

The island arc, the so-called Southern Antilles loop, swings east, north, and west to Tierra del Fuego, thence northward.

The Strait of Magellan is glacially excavated in the eastern end, and possibly faulted on the west. The Strait is the only sea-level break in the Cordillera for 8,000 miles. Chilean oil production lies north and east of the Andes on both sides of the Strait. Production, now about 20,000 barrels per day, is from a basal Cretaceous sand lying on a Jurassic quartz porphyry.

Chile itself is divided into three main divisions--the coastal mountains, a central valley probably a graben, and the Andes themselves.

The coastal range is a granitic continental batholith of Mesozoic, or earlier, age.

The Andes, one of the highest ranges in the world, is composed of metamorphic and sedimentary rocks. Principal uplift is Cretaceous and later. Severe earthquakes began in May 1960 in the southern coastal area and are still continuing.