From there on, the first few miles were about the same as the day before. Then we ascended an abrupt bluff, that looked in the distance like an impassable castellated wall, and suddenly found ourselves on an elevated _mesa_ or table-land, the very embodiment of dreariness and desolation. On all sides, it was a vast, outstretched plain, of coarse sand and gravel, without tree, or shrub, or living thing--even the inevitable mescal and cactus here disappeared. Behind us, to the north and east, there was a weird succession of grand terraces and castellated mountains, reminding one of portions of Wyoming. On our right, to the west, the ever-present Coast Range loomed along the landscape, barren and ghostly. To the south, all was a dead level, panting and quivering beneath the sun, as he neared the zenith, except where here and there a heavy mirage obscured the view, or vast whirlwinds careered over the desert, miles away--their immense spirals circling upward to the very sky. These last, on first sight, we took for columns of smoke, so erect and vast were they. But soon they rose all along the southwestern horizon, one after another, like mighty genii on the march, and our driver bade us look out for a Yuma sand-storm. We had already here and there found the sand drifted into ridges, like snow-banks, where sand-storms had preceded us, and had heard ugly accounts of them before leaving Wilmington; but, fortunately, we escaped this one--the whirlwinds keeping away to the southwest, where they hugged the Coast Range, and in the course of the afternoon obscured the whole landscape there. This was now the Colorado or Yuma Desert in earnest, without bird, or beast, or bush, or sign of life anywhere--nothing, in fact, but barrenness and desolation, as much as any region could well be. A large portion of it is so low, that the overflow of the Colorado often reaches it during spring freshets, and remains for weeks. In travelling over this portion, now baked dry and hard beneath the sun, we had frequent exhibitions of mirage, on a magnificent scale. One day in particular, we had been driving since early morning, over a heavy sandy road, with the sun blazing down upon us like a ball of fire, with no water since starting, our poor mules panting with heat and thirst, when long after noon we observed--apparently a mile or so ahead--what seemed like a great outspread pond or lake, with little islands here and there, their edges fringed with bushes, whose very images appeared reflected in the water. The scene was so perfect, that the driver and T. both insisted it must be water; however, I inclined to believe it mirage, as it afterwards turned out, but the optical illusion was so complete in this and other instances, that when later in the day we really did approach a veritable sheet of water at the Laguna, we all of us mistook this for mirage also. Here, however, we found a body of water a mile long by half a mile wide, surrounded by