ONE must not think of a mountain range as a line of peaks standing on a plain, but as a broad platform many miles wide from which mountains have been carved by the waters. One must conceive, too, that this plateau is cut by gulches and canyons in many directions and that beautiful valleys are scattered about at different altitudes. The first series of canyons we are about to explore constitutes a river channel through such a range of mountains. The canyon is cut nearly halfway through the range, then turns to the east and is cut along the central line, or axis, gradually crossing it to the south. Keeping this direction for more than 50 miles, it then turns abruptly to a southwest course, and goes diagonally through the southern slope of the range. This much we know before entering, as we made a partial exploration of the region last fall, climbing many of its peaks, and in a few places reaching the brink of the canyon walls and looking over precipices many hundreds of feet high to the water below. Here and there the walls are broken by lateral canyons, the channels of little streams entering the river. Through two or three of these we found our way down to the Green in early winter and walked along the low water-beach at the foot of the cliffs for several miles. Where the river has this general easterly direction the western part only has cut for itself a canyon, while the eastern has formed a broad valley, called, in honor of an old-time trapper, Brown's Park, and long known as a favorite winter resort for mountain men and Indians. May 30.--This morning we are ready to enter the mysterious canyon, and start with some anxiety. The old mountaineers tell us that it cannot be run; the Indians say, "Water heap catch 'em"; but all are eager for the trial, and off we go. 134 CANYONS OF THE COLORADO. Entering Flaming Gorge, we quickly run through it on a swift current and emerge into a little park. Half a mile below, the river wheels sharply to the left and enters another canyon cut into the mountain. We enter the narrow passage. On either side the walls rapidly increase in altitude. On the left are overhanging ledges and cliffs,--500, 1,000, 1,500 feet high.