It is in this region, after receiving the Apure, that the Orinoco leaves the granitic chain of mountains and flows eastward to the Atlantic, dividing the impenetrable forests of Guiana from the grassy plains on which the vault of heaven seems everywhere to rest as on the horizon of the ocean. Thus the elevated cluster of the Parime mountains, which occupies the entire space between the sources of the Jao and the Caura, is surrounded on three sides, to the South, to the West, and to the North, by the Orinoco. Below Carichana the course of the river is uninterrupted by rocks or rapids to its mouth, excepting at the whirlpool of the Boca del Infierno (Hell’s mouth) near Muitaco, where, however, the rocks which occasion the rapid do not extend across the entire bed of the river as at Atures and Maypures. In these lower parts of the river in the vicinity of the sea, the only danger feared by the boatmen is that of encountering the great natural rafts, consisting of trees torn from the banks by the swelling of the river, against which canoes are often wrecked during the night. These rafts, covered like meadows with flowering water plants, remind the spectator of the floating gardens of the Mexican lakes. After this rapid review of the course of the Orinoco, and of its general relations to the surrounding country, I pass to the description of the Falls of Maypures and Atures. Between the sources of the rivers Sipapo and Ventuari a granite ridge projects from the elevated mountain group of Cunavami, and advances far to the west towards the mountains of Uniama. Four streams, which may be said to mark the limits of the cataracts of Maypures, descend from this ridge; two, the Sipapo and the Sanariapo, on the eastern side of the Orinoco; and two, the Cameji and the Toparo, on its western side. Near the Missionary village of Maypures the mountains retire and form a wide bay open to the south-west. The foaming stream flows at the present time at the foot of the eastern mountain declivity, and far to the west we recognise the ancient bank now forsaken by the water. A grass-covered plain, only about thirty feet above the present highest level of the river, extends between the two chains of hills. The Jesuits have built upon it a small church formed of the trunks of palm trees.