Page:Encyclopædia Britannica, Ninth Edition, v. 4.djvu/267

Rh foot, are the other high points of these ranges. The southern coastal range, or the Serra do Mar, begins immediately north of the Bay of Rio do Janeiro, where the Oragos or Organ Mountains, with sharp peaks, rise to perhaps 7500 feet, and follows the line of the shore south ward at varying distances fpom it to near the 30th parallel. The line of tho Serra do Espinha90 is prolonged northward by another maritime chain or plateau edge, more distant from the ocean, forming the eastern barrier of the great valley of the Ilio Sao Francisco, and terminating where tho river turns eastward to reach the sea. A range of high plateaus, probably from 3000 to 4000 feet in general elevation, and named collectively the Serra das Vertentes, or the range of the watersheds, but bearing a multitude of different names in its local sections and branches, extends westward from the Serra do Espinhac^o, nearly at right angles to its direction, traversing the entire country in curving lines inland for upwards of 2000 miles to where the plateaus of Brazil terminate on the great bend, and the cataracts, of the &quot;Rio Madeira. This very extensive range divides the waters flowing northward to the lower Amazon and to the Atlantic shores of the north-east, from those tributary to the great basins of the Paraguay and Parand in the south Its highest known portion is that called the Montes Pyrenees, between the heads of the Tocantins and Paranahyba in the province of Goyaz, one of the summits of which has been found to be perhaps 9600 feet above the sea (H. R. Dos Genettes, 1868). Long branches ramify northward and southward from the Vertentes; the principal of those trending northward is that which, leaving the main line of division at the Pyreneos, curves round the basin of the Sao Francisco, terminating in many minor branches on the coast on eacli side of Cape S. Roque. A lateral branch from this divides tho streams of the Tocantins and of the northern Paranahyba. Farther west the Cordillera Grande of Goyaz runs north from the Vertentes, separating the Araguaya and Tocantins, and still more inland minor ranges mark out the basins of the Xingu and Tapajos. A southward arm of the Vertentes, or rather a series of plateaus extending from it, divide the Paraguay from the Alto Parana, and run into Paraguay as the heights of Amambahy, which have an elevation of little over 2000 feet above the sea where they cross the frontier. These are the main lines of height, but over the whole of the plateau of Southern Brazil a great number of lesser ridges run oat from these between, each of the tributary river basins. The extremely level character of the great northern lowlands may be judged of by this, that the banks of the Amazon where it enters Brazil at Tabatinga, more than 1500 miles in a direct line from the sea, are not more than 250 feet above the ocean level, and a continuous navigation is afforded by its tributary the Rio Negro, the Casiquiare, and the Orinoco, to the northern coast of the continent.

The great constituent of all the mountain ranges of the southern highlands of Brazil appears to be gneiss, varying from schistose to coarse-grained arid porphyritic, or homo geneous and granitic ; and though much of it if seen in a small specimen would be and has been described as granite, the larger masses are always stratified. These rocks are of great thickness in the province of Rio, and tho Serra do Mar and Serra daMantiqueira are wholly composed of them; not only does gniess form the great coast belt from Maranhao to the mouth of the Rio de la Plata, but it sends off a band into Minas Geraes and Goyaz, where the Pyreneos range and a great part of the mountain region are composed of it. The same rock shows itself in the cataracts of the Tocantins, Xingu, Tapajos, and Madeira, as well as in the Parima Moun tains north of the Amazon basin, showing that the high land of Brazil is probably everywhere underlaid by it. Clay-slates with auriferous veins occur in Miuas Geraes and in the vicinity of Cuyab.4 in Matto Grosso, everywhere so meta morphosed that all trace of fossils has been obliterated. True Carboniferous strata occur iu Brazil, the coal basins lying just south of the tropic, and being a coasMormation not known northward of Rio. Carboniferous rocks also occur on the Guapore, a tributary of the Madeira on the Bolivian frontier. Red sandstones occupy. a large area in the province of Serigpe, underlying the Cretaceous forma tion. The Jurassic rocks, which extend on the Andes from Chili to Peru, appear to be altogether wanting in Brazil. Cretaceous rocks very probably underlie the great plain of the Amazon ; they do not appear on the coast south of the Abrolhos rocks in 18 S., but they occur at intervals north ward, and have been examined on an affluent of the River Purus in the upper basin of the Amazon. These appear to have been deposited at a period when the northern part of Brazil was more depressed, while the southern mayhavo been higher than it is now. Tertiary clays and ferruginous sandstone, in horizontal and undisturbed beds, overlie the Cretaceous rocks unconformably on the coast plains outside the plateaus and in the Sao Francisco valley ; the hori zontal deposits of the plateau of Sao Paulo evidently belong to the same group. Surface &quot; drift &quot; deposits, ascribed with the greater amount of probability to the agency of glacial ice, though the hypothesis has been much dispiited, occur as a great sheet of pebbles and overlying clay, extending over an im mense area of the empire, over the whole of the provinces south of Rio, over Minas Geraes in the north-eastern coast provinces, and in the valley of the Amazon westward to the confines of Peru, and not only on the hills but over the lower &quot;campos.&quot; Deposits of immense boulders of trap and gneiss, evidently the moraines of former local glaciers, were first described by Professor Agassiz, who found them at many points along the coast land. True coral reefs occur at irregular intervals along the northern Brazilian coast from the Abrolhos islets, which rise on the submerged border of the continent from a less depth than 100 feet, as far as the shores of Maranhao. They lie in patches at short distances from the coast, leaving navigable channels between them and the mainland. Another class of reefs, also termed &quot; recifes,&quot; but of totally different origin, are the consolidated stone beaches, such as those seen at Porto Seguro, Bahia, and Pernambuco (where the reef forms the breakwater of the harbour) ; these are of precisely uniform character, and have been described by Professor Hartt as the consolidated cores of an ancient beach which has been separated from the mainland by the encroachment of the sea. (Geology and Physical Geography of Brazil, by Ch. Fred. Hartt, 1870.) The limestones of the upper Sao Francisco basin have celebrated bone caverns, which have been made a special object of study by the Danish naturalist Lund. In some of these the remains of extinct animals of high antiquity have been found, such as those of the mastodon, glyptodon, mylodon, toxodon, and megatherium ; and with these the stone implements and remains of man, so buried with the bones of the extinct fauna as to leave no doubt that man was contemporaneous with them.

No volcanic appearances have been observed in Brazil. Warm springs occur in several provinces ; those of Itapicurii in the province of Bahia have temperatures varying from 88 to 106 Fahr. and are saline; the hot springs of pure water in Santa Catharina range from 9G to 1 1 3 Fahr., and there arc a great number of alkaline springs about the district of Santa Cruz, in the province of Goyaz, ranging up to 119 in temperature. Near the village of Caldas in Minas Geraes the hot wells are very voluminous, and their somewhat sulphurous waters have temperature^ between 