In the space of one hundred and seventy-six years the Lower Mississippi has shortened itself two hundred and forty two miles. That is an average of a trifle over one mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oölitic Silurian Period, just a million years ago next November, the Lower Mississippi River was upward of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing rod. And by the same token any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long, and Cairo and New Orleans will have joined their streets together, and be plodding comfortably along under a single mayor and a mutual board of aldermen. There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact. Green River Much more has been written about the Green River and the main stem of the Colorado than about the Colorado above the confluence (the former Grand River), because all but one of the early float trips began on the Green. The first reports concerning Powell’s memorable voyages of 1869 and 1871 were his articles published in Scribners Monthly during 1874 and 1875 followed by his formal 1875 report “Exploration of the Colorado River of the West and Its Tributaries.” As pointed out by Porter (1969, p. 21), however, Powell’s narrative is written _as if_ everything chronicled therein occurred during the first trip. Events which actually occurred in 1871 and 1872 are reported as happening in 1869. There is no mention of the personnel of the 1871-72 party, nor is there an indication that there even _was_ a second trip. The engravings illustrating the report were made from photographs taken by Beaman and Hillers between 1871 and 1874, but this fact is not noted. For these reasons, Porter’s account contains Powell’s diary of the first (1869) trip and many of the missing photographs, plus his own beautiful color prints. Much more complete and accurate accounts of the 1871 voyage than those of Powell, including many of the photographs taken by Beaman and Hillers, were given by Dellenbaugh (1902, 1962), who was a member of Powell’s 1871 expedition.