Eastward of the Berbice, and greatly inferior in size to the Essequibo, is the Corentyn, which has its source near the equator, and forms the boundary of the British colony. A few Indians of various tribes dwell on its banks near the mouth, but above their last settlement desolation reigns supreme. On the rocks near its banks may be seen a few rude carvings, the handiwork of a race long passed away. Day after day the voyager on its waters passes amid the wildest and most romantic scenery,--amid numerous islands, rocks, and rapids; but no human beings are seen--not a light canoe on its waters, not an habitation on its banks. At length, after a nine days' voyage, enormous rocks appear heaped together, opposing progress; vast chasms yawn beneath his feet when he lands, and at certain places the streams sink into the earth as if by magic, to reappear where least expected. A thundering noise is heard, and a mist hovers in the air, in which thousands of birds disport themselves,-- marking the position of the great cataracts of the Corentyn. The scene, however, is too vast to be beheld in its full grandeur from any single point of view. No waterfall in the territory surpasses them in grandeur. The fierce Caribs, in the days of their power, inhabited the banks of the river, engaged in carrying into slavery the people of other tribes from far and near; but they, and those they oppressed, have passed away--a few families only of their descendants remaining here and there--the one to boast of the prowess of their ancestors, the other to tell the tale of their woes. THE DEMERARA RIVER. High up the River Demerara--on which George Town, the capital of the colony, is built--where the river forces its way through the dense forest, is a fall of great picturesque beauty. Here, says Mr Brett, the cataract precipitates itself in one body over the rocky barrier; and huge masses of rock, crowned with stately trees, divide it into channels ere it reaches its lower bed. Of these channels, there are two large ones in the centre, with smaller ones on either side. All are filled with great boulders, over which the dark waters toss and dash until they roll into the wide basin below, covering its surface and margin with masses of yeasty foam. The length of the fall appears to be three or four hundred feet, though the perpendicular difference between the levels of the river above and below is sixty-five feet. Three-fourths of this cataract is hid from view by the luxuriant forest which clothes its sides and covers its islands. The misty spray--rising, when the river is full, from the channels between the tall trees--the rushing noise, and a glimpse of the torrent here and there, show imperfectly its divided course. Could a clear view be obtained of it, it would be found to contain a spectacle full of beauty and interest.