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of the Andes at many places. Here and there, however, evidences of glaciation do not extend as far north as they along that coast were great peat marshes extending from do on the west coast. The South American continent rises abruptly from the Peru as far south as the Strait of Magellan. The sea covered what are now the plains of Patagonia and Argen- ocean’s floor along nearly all its coast line, but the abrupttina, and there was a wide bay between the low Andes ness of the continental margin is more marked Physical ridges on the west and the Uruguayan peninsula on the on the western than on the eastern side. Con- geotours of equal depth along the west coast show g™Phy. east. In the early part of Tertiary times the land sank some- that from Valparaiso to the Isthmus of Panama, a distance what, but the geography of much of the eastern coast was of 3000 miles, the great not greatly different from its present form. Prom Santa Andes ranges are but the Catharina to Victoria on the coast of Brazil the shore was upper or subaerial portions very nearly where it now is. From Victoria to Cape St of mountains rising from Koque the shore line was from a few miles to a hundred bases that lie 10,000 feet miles farther inland than it is at present. Much of the below the surface of the coast belt, however, was covered by freshwater lakes, and Pacific Ocean. South of in the Amazon valley region it is possible that these lakes, Valparaiso the 10,000-feet or some combination of lakes and estuaries, extended far contour moves far off the coast, but opposite the Strait up the valley. In Tertiary times, probably at the end of the Eocene, of Magellan it approaches great changes took place in the geography of South again within a distance of America. The entire continent rose to an elevation 150 miles. East of Patamuch greater than that at which it now stands. The gonia the 1000-feet contour coast lines were carried oceanward on all sides, so that is so far from the coast the continent was enormously larger than it is at pre- that it passes to the east of sent. The coast line was 200 miles to the east of the the Falkland Islands, showAbrolhos Islands, which were then a part of the mainland, ing that this group stands and 300 miles east of Victoria, Brazil. The Falkland upon a submerged contiIslands were also a part of the continent, and it is nental shelf. From the even probable that South America joined New Zealand mouth of the Bio de la Plata Eastern Brazil. and Australia through the antarctic regions. Denudation northward the 1000-feet subwas very active during this period, and enormous quan- marine contour keeps at a tities of the Eocene sediments were removed from the distance of from 50 to 150 miles off the shore, nearly to land. Towards the close of Tertiary times the continent Bahia, Brazil; from Bahia northward clear around Cape St sank again until the sea entered the Orinoco and Amazon Boque this line is close to the shore, and the ocean’s bottom valleys and made an island or group of islands of the is steep, dropping abruptly to a depth of 5000 feet. The highlands between Brazil, Venezuela, and the Guianas. land relief of the continent of South America is characDuring this period the valleys of Magdalena and Cauca terized by—(1) the great range of lofty mountains which, and of Lake Maracaibo were covered by great bays. with its narrow coast plain, follows its west coast from its Still later a slight elevation added to the continental land northern to its southern extremity ; (2) comparatively low area the lower portions of the Orinoco, Amazon, and La and flat plains that slope eastward and southward from Plata valleys. During the Tertiary period volcanic activity the base of these mountains down the drainage basins of culminated on the continent. The Andes rose, partly by the Orinoco, the Amazon, and the Paraguay ; (3) the continental uplifting, partly by faulting and folding, and high table-lands of Eastern Brazil. The physical features partly by an upbuilding by the volcanic ejectamenta, from of the west coast are bold. South of latitude 41 , the a series of comparatively low ridges to be the great moun- coast is characterized by a vast system of fjords and tain chain of the world. Volcanic activity, which had islands, probably produced by the recent submergence of previously characterized the west coast region, increased a region of bold mountains and steep-sided valleys. The enormously, lava sheets were poured out along the entire many islands, including Chiloe, Wellington, and Tierra length of the continent, and enormous lava and cinder del Fuego, are the higher portions that have remained cones were built up about the craters. This volcanism above water; while the Strait of Magellan (properly was not confined to the Andes, but extended to the Magalhaes), Smyth Channel, and the other deep fjords Patagonian plains, the highlands of the Paran& basin, the that indent this coast line are the submerged valleys. Abrolhos Islands, and as far east as the island of Fernando The scenery in Smyth Channel is remarkably fine ; the de Noronha. In recent times volcanic activity has entirely snow-clad mountains are visible on the east, while here ceased along the eastern and north-eastern parts of the and there glaciers flow down nearly or quite to the sea. continent, and it has also subsided greatly, though it has Some of the islands are steep-sided peaks, mostly barren not ceased altogether, along the west coast. The earth- and uninhabited, and, in some cases, reaching an elevaquakes that still disturb the west and north-west coast of tion of 4000 feet. The Strait of Magellan is 400 miles the continent are more or less the result of this diminished long, from 4 to 20 miles wide, and very deep. North of latitude 41° the coast is but little indented, and there volcanic action. During Pleistocene times the southern end of the con- are but few good ports. From Cape Horn, where the tinent as far north as latitude 27 on the west coast southern submerged end of the Andes forms the islands of was covered with glaciers moving away from the mountain Tierra del Fuego to the Isthmus of Panama, the great ranges. North of 27° the glaciers did not flow down as Cordillera range follows the coast line closely, and at an far as the present sea-level, but they moved farther down even distance from it. The belt between the ocean and the slopes of the higher portions of the Andes than they the mountains has an average width of about 40 miles, do at present. During a portion of the Glacial epoch and on rare occasions, when the weather is favourable, the southern end of the continent stood at a somewhat the mountains are visible from the sea nearly all the way lower elevation than at present, and the sea covered the from Panama to the Strait of Magellan. Along the plains of Patagonia and La Plata. On the east coast northern part of the continent, from Panama to Guayaquil,
