In the spring of 1870 I again started with three boats and descended the river to the Crossing of the Fathers, where I met a pack train and went out with a party of men to explore ways down into the Grand Canyon from the north, and devoted the summer, fall, winter, and following spring to this undertaking. In the summer of 1871 I returned to the rowboats and descended through Marble Canyon to the Grand Canyon of Arizona, and then through the greater part of the Grand Canyon itself. Subsequent years were then given to exploration of the country adjacent to the Grand Canyon. On these trips Mr. Gilbert, the geologist, who had been with Lieutenant Wheeler, and Capt. C. E. Dutton, were my geological companions. On the second boat trip, and during all the subsequent years of exploration in this region, Prof. A. H. Thompson was my geographical companion, assisted by a number of topographical engineers. In 1882 Mr. C. D. Walcott, as my assistant in the United States Geological Survey, went with me into the depths of the Grand Canyon. We descended from the summit of the Kaibab Plateau on the north by a trail which we built down a side canyon in a direction toward the mouth of the Little Colorado River. The descent was made in the fall, and a small party of men was left with Mr. Walcott in this region of stupendous depths to make a study of the geology of an important region of labyrinthian gorges. Here, with his party, he was shut up for the winter, for it was known when we left him that snows on the summit of the plateau would prevent his return to the upper region before the sun should melt them the next spring. Mr. Walcott is now the Director of the United States Geological Survey. After this year I made no substantial additions to my geologic and scenic knowledge of the Grand Canyon, though I afterward studied the archæology to the south and east throughout a wide region of ruined pueblos and cliff dwellings. Since my first trip in boats many others have essayed to follow me, and year by year such expeditions have met with disaster; some hardy adventurers are buried on the banks of the Green, and the graves of others are scattered at intervals along the course of the Colorado. In 1889 the brave F. M. Brown lost his life. But finally a party of railroad engineers, led by R. B. Stanton, started at the head of Marble Canyon and made their way down the river as they extended a survey for a railroad along its course. Other adventurous travelers have visited portions of the Grand Canyon region, and Mr. G. Wharton James has extended his travels widely over the region in the interest of popular science and the new literature created in the last decades of the nineteenth century. And now I once more return to a reminiscent account of the Grand Canyon, for old men love to talk of the past. The Plateau Region