"On reaching that lip, and peering over the giddy height, the wondrous and unique character of the magnificent cascade at once burst upon us. It is rather a hopeless task to endeavor to convey an idea of it in words, since, as was remarked on the spot, an accomplished painter, even by a number of views, could but impart a faint impression of the glorious scene. The probable mode of its formation may perhaps help to the conception of its peculiar shape. Niagara has been formed by a wearing back of the rock over which the river falls; and, during a long course of ages, it has gradually receded, and left a broad, deep, and pretty straight trough in front. It goes on wearing back daily, and may yet discharge the lakes from which its river flows. But the Victoria Falls have been formed by a crack right across the river in the hard, black, basaltic rock which there formed the bed of the Zambesi. The lips of the crack are still quite sharp, save about three feet of the edge over which the river rolls. The walls go sheer down from the lips without any projecting crag, or symptom of stratification or dislocation. When the mighty rift occurred no change of level took place in the two parts of the bed of the river thus rent asunder; consequently, in coming down the river to Garden Island the water suddenly disappears, and we see the opposite side of the cleft, with grass and trees growing where once the river ran, on the same level as that part of its bed on which we sail. "The first crack is, in length, a few yards more than the breadth of the Zambesi, which by measurement we found to be a little over eighteen hundred and sixty yards, but this number we resolved to retain, as indicating the year in which the fall was for the first time carefully examined. The main stream here runs nearly north and south, and the cleft across it is nearly east and west. The depth of the rift was measured by lowering a line, to the end of which a few bullets and a foot of white cotton cloth were tied. One of us lay with his head over a projecting crag, and watched the descending calico, till, after his companions had paid out three hundred and ten feet, the weight rested on a sloping projection, probably fifty feet from the water below, the actual bottom being still farther down. The white cloth now appeared the size of a crown-piece. On measuring the width of this deep cleft by sextant it was found, at Garden Island, its narrowest part, to be eighty yards, and at its broadest somewhat more. Into this chasm, of twice the depth of Niagara Falls, the river, a full mile wide, rolls with a deafening roar; and this is Mosi-oa-tunya, or the Victoria Falls.