Thus do we remark a singular incoherence and lack of symmetry in the physiography of Brazil, largely due to geological conditions. Yet Brazil is a land which has been immune from violent geological disturbances from an early time. Such oscillations as there have been have not brought to being enormous mountain chains or intensive foldings of the rocks, such as are so marked elsewhere in South America. Flat bedding or low angles mark the geological horizons since the Devonian Age, and since that age it would seem that none of Brazil has been beneath the sea. There are eruptive rocks in the Devonian and carboniferous beds, but since the Palæozoic epoch it does not appear that there has been any volcanic activity. These devastating forces of Nature seem to have had their vent on the western side of the continent. The Palæozoic beds of the interior are of red sandstones, and these have their place in marked degree in the economics and appearance of the landscape. The formation of the country has been interestingly described by a well-informed recent writer, whom we may quote here. * * * * * "The high plains of the interior, which shed their waters both north and south, have never been of economic importance; the valley of the Amazon has been developed only of late years, and its population is as yet small. It is therefore the tableland of the Atlantic seaboard, from Uruguay to Ceará, that constitutes the soil of historic Brazil. Through its length of 1,800 to 2,200 miles this tableland presents the greatest variety of aspect, and has no hydrographic unity. Its height is greater to the south, where it reaches some 3,200 feet. This general slope from south to north is revealed by the course of the San Francisco. In Brazil the name of Borburema is employed to denote the northern portion of the plateau. This old geographical term deserves preservation, as it represents a region which has its own peculiar characteristics. The dry season there is a long one, and the Borburema does little to feed the small seaboard rivers which flow fan-wise into the Atlantic; for the plateau in that region slopes gently to the sea.