The rocks are broken in two along a line which here crosses the river, and the beds we have seen while coming down the canyon for the last 30 miles have dropped 800 feet on the lower side of the line, forming what geologists call a "fault." The volcanic cone stands directly over the fissure thus formed. On the left side of the river, opposite, mammoth springs burst out of this crevice, 100 or 200 feet above the river, pouring in a stream quite equal in volume to the Colorado Chiquito. This stream seems to be loaded with carbonate of lime, and the water, evaporating, leaves an incrustation on the rocks; and this process has been continued for a long time, for extensive deposits are noticed in which are basins with bubbling springs. The water is salty. We have to make a portage here, which is completed in about three hours; then on we go. We have no difficulty as we float along, and I am able to observe the wonderful phenomena connected with this flood of lava. The canyon was doubtless filled to a height of 1,200 or 1,500 feet, perhaps by more than one flood. This would dam the water back; and in cutting through this great lava bed, a new channel has been formed, sometimes on one 273 powell-canyons-171.jpg KANAB CANYON, IN THE RED WALL LIMESTONE. 274 CANYONS OF THE COLORADO. side, sometimes on the other. The cooled lava, being of firmer texture than the rocks of which the walls are composed, remains in some places; in others a narrow channel has been cut, leaving a line of basalt on either side. It is possible that the lava cooled faster on the sides against the walls and that the center ran out; but of this we can only conjecture. There are other places where almost the whole of the lava is gone, only patches of it being seen, where it has caught on the walls. As we float down we can see that it ran out into side canyons. In some places this basalt has a fine, columnar structure, often in concentric prisms, and masses of these concentric columns have coalesced. In some places, when the flow occurred the canyon was probably about the same depth that it is now, for we can see where the basalt has rolled out on the sands, and--what seems curious to me--the sands are not melted or metamorphosed to any appreciable extent. In places the bed of the river is of sandstone or limestone, in other places of lava, showing that it has all been cut out again where the sandstones and limestones appear; but there is a little yet left where the bed is of lava. What a conflict of water and fire there must have been here! Just imagine a river of molten rock running down into a river of melted snow. What a seething and boiling of the waters; what clouds of steam rolled into the heavens! Thirty-five miles to-day. Hurrah!