A Few Days After Making These Interesting Discoveries, I Found Other
Well-Preserved Glacial Traces On Arc Dome, The Culminating Summit Of
The Toyabe Range.
On its northeastern slopes there are two small
glacier lakes, and the basins of two others which have recently been
filled with down-washed detritus.
One small residual glacier lingered
until quite recently beneath the coolest shadows of the dome, the
moraines and neve-fountains of which are still as fresh and unwasted
as many of those lying at the same elevation on the Sierra - ten
thousand feet - while older and more wasted specimens may be traced on
all the adjacent mountains. The sculpture, too, of all the ridges and
summits of this section of the range is recognized at once as glacial,
some of the larger characters being still easily readable from the
plains at a distance of fifteen or twenty miles.
The Hot Creek Mountains, lying to the east of the Toquima and Monito
ranges, reach the culminating point on a deeply serrate ridge at a
height of ten thousand feet above the sea. This ridge is found to be
made up of a series of imposing towers and pinnacles which have been
eroded from the solid mass of the mountain by a group of small
residual glaciers that lingered in their shadows long after the larger
ice rivers had vanished. On its western declivities are found a group
of well-characterized moraines, canyons, and roches moutonnees, all of
which are unmistakably fresh and telling. The moraines in particular
could hardly fail to attract the eye of any observer. Some of the
short laterals of the glaciers that drew their fountain snows from the
jagged recesses of the summit are from one to two hundred feet in
height, and scarce at all wasted as yet, notwithstanding the countless
storms that have fallen upon them, while cool rills flow between them,
watering charming gardens of arctic plants - saxifrages, larkspurs,
dwarf birch, ribes, and parnassia, etc. - beautiful memories of the Ice
Age, representing a once greatly extended flora.
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, making 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.
The flanks of all the interior ranges are seen to have been heavily
abraded and ground away by the ice acting in a direction parallel with
their axes. This action is most strikingly shown upon projecting
portions where the pressure has been greatest. These are shorn off in
smooth planes and bossy outswelling curves, like the outstanding
portions of canyon walls. Moreover, the extremities of the ranges
taper out like those of dividing ridges which have been ground away by
dividing and confluent glaciers. Furthermore, the horizontal sections
of separate mountains, standing isolated in the great valleys, are
lens-shaped like those of mere rocks that rise in the channels of
ordinary canyon glaciers, and which have been overflowed or
pastflowed, while in many of the smaller valleys roches moutonnees
occur in great abundance.
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