In the course of explorations made to the eastward of here, between the 38th and 40th parallels, I observed glacial phenomena equally fresh and demonstrative on all the higher mountains of the White Pine, Golden Gate, and Snake ranges, varying from those already described only as determined by differences of elevation, relations to the snow-bearing winds, and the physical characteristics of the rock formations.
On the Jeff Davis group of the Snake Range, the dominating summit of which is nearly thirteen thousand feet in elevation, and the highest ground in the basin, every marked feature is a glacier monument--peaks, valleys, ridges, meadows, and lakes. And because here the snow-fountains lay at a greater height, while the rock, an exceedingly hard quartzite, offered superior resistance to post-glacial agents, the ice-characters are on a larger scale, and are more sharply defined than any we have noticed elsewhere, and it is probably here that the last lingering glacier of the basin was located. The summits and connecting ridges are mere blades and points, ground sharp by the glaciers that descended on both sides to the main valleys. From one standpoint I counted nine of these glacial channels with their moraines sweeping grandly out to the plains to deep sheer-walled neve-fountains at their heads, ****** a most vivid picture of the last days of the Ice Period.
I have thus far directed attention only to the most recent and appreciable of the phenomena; but it must be borne in mind that less recent and less obvious traces of glacial action abound on ALL the ranges throughout the entire basin, where the fine striae and grooves have been obliterated, and most of the moraines have been washed away, or so modified as to be no longer recognizable, and even the lakes and meadows, so characteristic of glacial regions, have almost entirely vanished. For there are other monuments, far more enduring than these, remaining tens of thousands of years after the more perishable records are lost. Such are the canyons, ridges, and peaks themselves, the glacial peculiarities of whose trends and contours cannot be hid from the eye of the skilled observer until changes have been wrought upon them far more destructive than those to which these basin ranges have yet been subjected.
It appears, therefore, that the last of the basin glaciers have but recently vanished, and that the almost innumerable ranges trending north and south between the Sierra and the Wahsatch Mountains were loaded with glaciers that descended to the adjacent valleys during the last glacial period, and that it is to this mighty host of ice streams that all the more characteristic of the present features of these mountain ranges are due.
But grand as is this vision delineated in these old records, this is not all; for there is not wanting evidence of a still grander glaciation extending over all the valleys now forming the sage plains as well as the mountains. The basins of the main valleys alternating with the mountain ranges, and which contained lakes during at least the closing portion of the Ice Period, were eroded wholly, or in part, from a general elevated tableland, by immense glaciers that flowed north and south to the ocean. The mountains as well as the valleys present abundant evidence of this grand origin.
