686 R. A. F. PENROSE, JR. 



higher Andes range to the north would look like if it were submerged 

 sufficiently to permit the sea to invade its lower parts. The islands 

 appear to be the upper parts of old mountain peaks, and the numerous 

 straits, channels, and bays, with their great depth and precipitous 

 sides, appear to mark the courses of the old canyons and valleys 

 now submerged. Whether the submergence is now at the maximum 

 depth to which it has ever reached, or whether there has been some 

 uphfting since the period of maximum submergence, is a question 

 which cannot be fully discussed within the limits of the present 

 article. 



The rocks of southern Patagonia and Tierra del Fuego have not 

 been much studied, but from the little that is known of them, it may 

 be said that in the mountainous areas they are much like those of 

 other parts of the southern Andes, granites, various igneous rocks, 

 and slates being common; while in the low pampas country in east- 

 ern Patagonia and the northeast part of the main island of Tierra del 

 Fuego, more or less soft, sandy and argillaceous strata predominate, 

 probably belonging mostly to the Mesozoic and Cenozoic eras. 

 Not only in its geology but in other respects, a large part of southern 

 Patagonia and Tierra del Fuego is a little-known country. Various 

 expeditions, especially those of the British ships the Adventure and 

 the Beagle, have prepared good charts of the strait and neighboring 

 waters, with accurate measurements of the depth of water and other 

 nautical data most valuable to the navigator. These observations 

 have been supplemented by later Chilean, American, French, and 

 other expeditions. The outlines of most of the land-areas have also 

 been fairly accurately mapped, and some of the mountains have been 

 plotted and measured, but there are vast areas of country almost 

 unknown beyond their shore lines. The advent of the sheep-raiser 

 and the miner are rapidly giving us knowledge of some of these 

 regions, but such information, though better than nothing, is neces- 

 sarily vague. 



DISCOVERY AND DISTRIBUTION OF THE GOLD DEPOSITS 



Gold is said to have been discovered in southern Patagonia by 

 the Chileans over forty years ago, and is supposed to have been 

 known to the native Indians at a much earlier date, but it has been 



