Israel C. (Israel Cook) Russell.

Glaciers of North America; a reading lesson for students of geography and geology online

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Parker Creek glacier they were numerous and in all stages of growth
and decadence. Some of the blocks of stone were poised horizontally
on pedestals of ice ; others were inclined southward, or had been partially
dislodged, and in some instances they had fallen and were lying on the
southern side of pinnacles which had formerly supported them. Sketches
of some of the more characteristic examples observed, drawn to a scale
of about one foot to the inch, are here shown.


The largest glacier table was observed near the center of the Parker
Creek glacier, a few hundred feet from its terminus. This is a block of dense
volcanic rock measuring 24 X 33 X 10 feet, and was supported by a column
of ice eight feet high on its northern and six feet high on its southern side,
and six to eight feet thick. The smallest observed blocks that are able to
protect the ice beneath sufficiently to form columns as the general surface
melts away were found to be about 16x10x10 inches ; when smaller
than this they sink into the surface in a manner that is well known to all
alpinists. Small pebbles are frequently seen at the bottom of little ice
wells five or six inches deep, but good examples of sand cones and some of
the other minor details of glacier surfaces were not observed.



Ice Pyramids. As the forms included under this name furnish a
detail of glacier surfaces not described before the glaciers of the High
Sierra were examined, I shall transcribe my notes concerning them at
some length.

On the lower portion of the Mount Lyell glacier, more especially than
in any other observed instance, the surface bristles, over large areas in the
neve region, with acute pyramids of snow-ice from a few inches to fully
three feet in height, with bases having a diameter of perhaps one-half
their height.

At the base of each pyramid on its northern side, there is invariably a
stone, sometimes measuring five or six inches in diameter, or a number of
loose pebbles, or a handful of dirt, which is usually depressed somewhat
below the general surface of the neve. The side of the pyramid rising


above the stone, i.e. the northern face, is usually concave, in horizontal
sections, and invariably composed of clear, compact ice, while the remainder
of the structure is of the ordinary porous ice forming the glacier surface.
Sometimes the nearly horizontal lamination of the glacier ice can be seen
in the pyramids. A direct relation is noticeable, too, between the size and
shape of the stones and the height and form of the ice pyramids rising
above them.

In seeking an explanation of these phenomena, the only hypothesis that
seems to satisfy the observed facts, assumes that a stone or mass of dirt
lying on the surface of a glacier becomes heated and melts the porous ice
beneath, and that the water thus formed freezes again into compact ice,
which resists the sun's heat more thoroughly than the surrounding porous


ice, and hence is left as the general surface melts away. In nearly every
instance, the stone at the base of the pyramid had been carried northward
as it melted its way downward, thus forming the steep, northern slope of
the pyramid, and at the same time tending to prevent the formation of a
prominence on the northern side of the sunken block. The pyramids
always point toward the noonday sun, hence the compact ice formed on
the northern side of a pebble is more exposed than the ice on its southern
side, and is, therefore, more rapidly melted.

Moraines. No well-marked medial moraines were noticed on any of
the Sierra Nevada glaciers. The reason for their absence is because the
glaciers are simple ice streams, without tributaries. Lateral moraines
resting on and inclosed in the ice at the margins of the glaciers were seen
in many instances, and could be traced without difficulty to the cliffs from
which they came. Terminal moraines, however, are common, and occur
at the lower limit of every glacier observed, and owe their existence to
the moderate amount of morainal material scattered over the surfaces
or contained in the glaciers, without being concentrated into medial
moraines. The terminals are remarkable for their size, when compared
with the extent of the parent ice streams, indicating that the process now
observed has been going on essentially as at present for a long term of
years. The terminal moraine now forming at the lower extremity of
Mount Dana glacier is approximately 1000 feet long by 30 or 40 feet
broad, and apparently 100 feet or more deep. Below this, and partially
united with it, is a second ridge of debris of somewhat greater dimen-
sions, which is followed by other similar crescent-shaped piles lower
down the gorge. The corresponding moraines at the extremity of
Mount Lyell glacier are considerably larger, as are also the still more
typical terminals at the foot of the Parker Creek glacier. In some
instances these moraines were coated with loose rubbish and dirt that
would be swept away by a single storm, indicating that they had received
their last addition within a very few months.

The bottom of the Dana glacier was seen to be heavily charged with
stones, pebbles, and sand, and to rest on a bed of boulders of a consider-
able thickness. This subglacial deposit may with propriety be termed a
ground moraine.

Glaciated Surfaces and Scratched Stones. The rock surfaces in
the immediate neighborhood of the Sierra Nevada glaciers are frequently


polished and covered with grooves and scratches, but it is usually impos-
sible to determine whether this is the work of existing ice streams, when
somewhat more extended than at present, or whether it is a part of the
vast glaciation imposed upon all the High Sierra during the glacial epoch.
In some instances, however, there does not seem room for doubting that
the markings were made during the past few years.

At the immediate foot of Mount Dana glacier, we found a number of
stones that were battered and worn and exhibited planed and scratched
surfaces, in many respects similar to the glaciated stones found in the
ancient moraines of New England. These occurred but a few feet from
the ice foot, and their bruises and scratches are, without question, the
work of the present glacier.

Glacier Movements. That the small ice bodies of the Sierra Nevada
have a true glacial motion is apparent from the nature of the crevasses
and the curved courses of the dirt bands that cross them. Measurements
of the movements of these glaciers have been made in only a few instances.
The rate of the flow of the glacier on Mount McClure was determined by
John Muir, who found that its maximum movement near the center was
about 47 inches in 46 days (from August 21 to October 6, 1872). A
more extended notice of these interesting observations is given in record-
ing "previous observations" a few pages in advance.

Glacier Mud. The Tuolumne river has its source at the foot of
Lyell glacier. At its birth it is a rivulet, turbid with silt ground fine by
the moving ice from beneath which it issues. At the foot of the Dana
glacier there is a small lake confined in a rock basin, which has a peculiar
greenish-yellow color due to silt held in suspension. The water escapes
from this lake through a moraine piled on the rim of the basin, and is
gathered again into other depressions farther down the canon. The
waters are thus filtered of matter in suspension, and the lower lakes are
clear and blue, like hundreds of other lakelets and tarns scattered over
the surrounding glaciated area. The sediment contributed to these glacial
waters is so extremely fine that it requires days and perhaps weeks to settle.

Ice Tongues. In the steep walls of the amphitheatres overlooking
the neve's of the glaciers here considered, there are frequently deep, nar-
row clefts leading toward the higher peaks. In many instances they are
partially filled with ice, which shoots up above the ne>es in tapering


tongues some hundreds of feet in height and at so steep an angle that it
is impossible to ascend or descend them without cutting steps. These
ice tongues are interesting features of the Sierra glaciers and are also
known to occur at the heads of similar ice streams in Wyoming.
One of them, in the shadow of a precipice, is shown on Fig. A, Plate
2. Whether they have glacial motion or not, has never been deter-
mined. They appear to have originated from the freezing of waters
flowing from adjacent areas, and not to have been formed entirely by
the consolidation of neVe* snows, after the manner of true glacier ice.

Red Snow. While Mr. Gilbert and myself were examining the
neve portion of the Mount Lyell glacier, we noticed that our foot-
prints in the snow had a bright pinkish tint, while the undisturbed
surface appeared white or perhaps grayish white. At the lower border
of the neve* the color became more distinct and could be plainly seen
in the untrodden snow, and in some instances the borders of rills
were outlined by delicate pencilings of crimson. In all cases the
" red snow " was superficial, or at most only covered by a thin layer
of fresh snow. Some of the coloring matter collected was examined
under the microscope a number of months later and found to consist
of red globules from 150 to 200 millimeters in diameter, which were
determined to be the minute algae known as Protococcus.

Surface Melting. Our examination of Mount Lyell glacier began
one August morning before sunrise, when the vast amphitheatre in which
the ice is cradled was hushed in the profound stillness peculiar to
mountain tops. As the sun rose above the granite spires to the
eastward and flushed the snow fields with a ruddy light, little rills started
here and there on the glacier, gradually gathering strength as the
sun's warmth increased, and by noon brooks of considerable size were
rushing down channels of ice, but sooner or later they plunged into
crevasses and were lost to sight. At midday the murmur of water
was heard everywhere over the glacier. As the chill of evening came
on the music of the streams gradually ceased, and by sunset a death-
like silence reigned over the frozen region.

That this noonday melting has more than counterbalanced the
annual additions received during the years previous to our visit, seems
evident from accounts of the former extent of the snow fields of the High
Sierra. The observations bearing upon this point are given below. From


all that has been learned concerning the fluctuations of the glaciers of
California, it appears that like those of Switzerland, they are subject to
periodic changes, due principally to climatic oscillations. Since their dis-
covery they have apparently not been increasing.


Although giving precedence to my own observations in describing the
glaciers of the High Sierra, it is not my intention to ignore the reports of
those who preceded me in the same field.

John Muir. An anonymous article on the "Living Glaciers of Cali-
fornia," which appeared in the Overland Monthly for December, 1872,
and now known to have been from the pen of John Muir, is, so far as I
can learn, the first announcement of the existence of glaciers on the Sierra
Nevada. Mr. Muir states that in October, 1871, he was among the
mountains of the Merced group and found a living glacier, with very
recent moraines at its foot, from beneath which issued a stream of turbid
water. Further observations revealed dirt bands, crevasses, and lateral
moraines, thus leaving no doubt that the " snow bank," as it had pre-
viously been considered, was an actual glacier. Other similar ice bodies
were examined by Mr. Muir, on Mount Lyell and Mount McClure ; and
from the top of the former peak he saw a dozen snow and ice filled
cirques on neighboring mountains.

In August, 1872, Mr. Muir placed five stakes in the glacier on Mount
McClure, for the purpose of demonstrating whether or not it had true
glacial motion. Four of these stakes were ranged in line from the east
side to a point near the middle of the glacier, the first being 25 yards
from the east bank ; the second, 94, the third, 152, and the fourth, 225
yards respectively. On observing the stakes on October 6, forty-six days
after being placed in position, it was found that No. 1 had been carried
down the glacier 11 inches ; No. 2, 18 inches ; No. 3, 34 inches ; No. 4,
47 inches. Stake No. 4 was near the middle of the glacier, and its dis-
placement was thought to indicate the maximum motion of the ice.
Stake No. 5 was placed about midway between the head of the glacier
and No. 4. Its motion was 40 inches in forty-six days. These measure-
ments, though not as detailed and perhaps not as accurate as could be
desired, are yet sufficient to demonstrate, as claimed by Mr. Muir, that
the ice in this instance had true glacial motion. In this example, as in


most normal glaciers, the greatest movement was near the middle of the
ice stream.

The Mount McClure glacier, when visited by Mr. Muir, was approxi-
mately half a mile long and of about the same breadth in the widest part,
and was observed to be traversed in the southeast corner by crevasses
several yards long, but only about a foot wide. The Mount Lyell
glacier, in 1872, is stated to have been about a mile in length by a mile
in breadth.

Mr. Muir also describes narrow, high-grade canons, called " devil's
slides," " devil's lanes," etc., which occur about the higher peaks and are
frequently occupied by ice. In one of these gorges the ice was found to
have a motion of a fraction of an inch a day. These small ice bodies
are what I have called " ice tongues " in describing my own observations.
It is to be hoped that further information concerning their origin and
behavior may be obtained, since, so far as is known, they do not appear in
more heavily glaciated regions.

In an article entitled, "In the Heart of the California Alps," 1 Mr.
Muir gives some account of the glaciers about Mount Hitter, combined
with enthusiastic descriptions of the magnificent scenery of the Sierra.
In another article from the same pen on "Living Glaciers of California," 2
several illustrations of glacial scenery are introduced, together with
popular descriptions of numerous neVes and ice fields.

Joseph L<e Conte. Professor Joseph Le Conte visited the High
Sierra during the summers of 1872 and 1873, and in company with Mr.
Muir examined the summit of Mount Lyell. 3 In describing the records
of the ancient glaciers that once filled the Tuolumne valley, Le Conte
says, that what interested him far more than anything else seen during
his journey " was that on the main branch of the Tuolumne river, far up
among the cliffs and peaks of Mount Lyell, still exists a living glacier, in
a feeble state of activity, it is true, but certainly living." Professor Le

1 Scribner's Monthly, vol. 20, 1880, p. 345.

2 Harper's Magazine, vol. 51, 1875, p. 769. A brief account of the discovery of
glaciers in the Sierra Nevada, and of some of their more prominent features, may be found
in a charming book by John Muir, entitled "The Mountains of California," London, 1894.

3 A portion of the observations made during these journeys was published in a paper,
" On some of the Ancient Glaciers of the Sierra," Proceedings of the California Academy of
Sciences, vol. 4, 1872, p. 159; and also in a more extended form, in the American Journal
of Science, Third Series, vol. 5, 1873, p. 325. See also Le Conte's "Elements of Geology,"
revised edition, 1882, p. 602.


Conte accepts Mr. Muir's measurement, and concludes that "the glacier
motion still exists"

Mount Lyell glacier appears to have been more completely hidden by
snow when examined by Le Conte in 1872 than when seen by the present
writer ten years later. Le Conte's account, from the American Journal
of Science, referred to above, is as follows :

" Here, then, on Mount Lyell, we have now existing, not a true glacier,
perhaps, certainly not a typical glacier (since there is no true glacier ice
visible, but only snow and neve, and certainly no protrusion of an ice
tongue beyond the snow field), yet, nevertheless, in some sense a glacier,
since there is true differential motion and a well-marked terminal
moraine. It is, in fact, a glacier in feeble old age, a feeble remnant of the
Tuolumne glacier, a glacier once of great proportions and playing an
important part in mountain sculpture, but now in its second childhood."

Le Conte found the surface of the snow on the neve of the Lyell gla-
cier " traversed in a direction at right angles to the slope by sharp blades
of half-compacted ice about two feet apart and two, three, four, or even
five feet in height ; . . . the crests of the blades were not continuous,
but irregular, both in outline and trend, very much in this respect like
ripple marks or like waves." 1 The explanation offered suggested by
Mr. T. C/ Gardner is that the blades are due to the action of the sun on
wind-ripples formed on the surface of the neve.

Geological Survey of California. In the publication of the Geological
Survey of California, no mention is made of existing glaciers in the Sierra
Nevada. The frontispiece of Volume 1 (Geology), showing Mount Lyell
as seen from Tuolumne valley, and also a sketch of the summit of the
peak, forming Figure 73, indicate that the mountains were then far more
heavily mantled with snow than in 1882 and 1883. Professor J. D.
Whitney, formerly State Geologist of California, in his work on " Climatic
changes of later geological time," 2 says, "It may be stated that there are
no glaciers in the Sierra Nevada proper and none in the Great Basin or
Rocky Mountain ranges, at least south of the parallel of 42 . With the
exception of some recent discoveries said to have been made in 1878, in
the Wind River range (about latitude 43) by the U. S. Geological Sur-
veying party, of which no definite account seems as yet to have been pub-

1 American Journal of Science, Third Series, vol. 5, 1873, p. 332.

2 Memoirs of the Museum of Comparative Zoology of Harvard College, vol. 7, 1882,
no. 2, p. 25.


lished, it may be stated that there are no proper glaciers anywhere within
the limits of the United States (Alaska not included) except around the
great isolated volcanic cones of the Pacific coast. There are certainly
none in the higher portions of the Sierra Nevada or the Rocky mountains,
these most elevated regions having been sufficiently explored to ascertain
that fact." It will be noticed that this passage was published in 1882, or
ten years later than Muir's and te Conte's observations cited above. On
page 30 of Professor Whitney's work, the notes of Messrs. King and
Gardner made in 1868, while exploring the eastern slope of Mount Ritter,
are transcribed as follows : " In a deep cul-de-sac which opens southward
on the east slope [of Mount Ritter] lies a bed of ice 200 yards wide
and about half a mile long. It has moved down from the upper end
of the gorge for 30 or 40 feet this year, leaving a deep gulf between the
vertical stone wall and the ice." In connection with these observations
Professor Whitney remarks that " it is doubtful whether these residual
masses of ice can with propriety be called glaciers."

Clarence King-. Mr. King also rejected Mr. Muir's observations, as
is shown by several emphatic passages in his Report of the Exploration of
the 40th Parallel, 1 but adds no new information on the subject.

Conditions Favoring- Observation. From these quotations it will
be seen that the question of the existence of glaciers in the Sierra Nevada
has been decided differently by different observers, who perhaps saw the
mountains under diverse conditions as regards their snowy covering. In
winter the glaciers are so deeply snow-covered that no one would suspect
their existence ; it is only late in summer, when the snows have decreased
to a minimum, that they are to be seen to the greatest advantage. That
Mr. Muir was correct in classing many of the snow masses among true
glaciers, has been sustained by recent studies, but the observations on
which his decision was based, were not sufficiently extended to convince
several geologists who visited the mountains when more completely snow-
covered than at the time the measurements referred to above were made.


It is necessary in the present volume to restrict attention to living
glaciers, but in passing, I may mention that all of the higher portions of
the Sierra Nevada, excepting the very highest peaks and crests, were

1 Vol. 1, pp. 447, 448.


loaded with snow during the glacial period, so as to form a vast neVe*
from which large ice streams flowed in various directions. The glaciers
that went westward were far larger than those that descended the pre-
cipitous eastern escarpments. In several instances the ancient glaciers
were majestic rivers of ice 30 or 40 miles long. The present ice
bodies are the shrunken remnants of these ancient ancestors, or else mark
the beginning of a new cycle, the former glaciers having been completely

In the High Sierra to the westward of Mono lake, the more pro-
nounced topographical features resulting from the ancient glaciation are
conspicuously displayed. The broad-bottomed valley leading northward
from Mount Lyell was formerly occupied by the great Tuolumne glacier.
This received an important tributary from the region about Mount Dana,
the path of which is deeply engraved in the topography of the country.
The glacier formed by the union of these two ice streams flowed down
the Tuolumne canon for 30 or 40 miles, with a depth of between 2000 and
3000 feet ; and it is believed to have occupied the Hetch-Hetchy valley,
but its full extent is not known. Other magnificent glaciers having their
sources about Mount Lyell and Mount Ritter descended the Merced and
San Joaquin valleys, which, like the Tuolumne canon, were greatly modi-
fied by ice erosion. To the eastward of the divide between the drainage
to the Pacific and the Great basin, the paths of the ancient glaciers are
definitely recorded by the smoothed and rounded contours of the valley,
they occupied. Their channels are frequently fringed with lateral
moraines, which in some instances were carried beyond the mouths of the
canons and prolonged upon the plain as parallel embankments. This
feature is especially illustrated by the moraines at the mouths of Bloody,
Parker, and Rush Creek canons in Mono valley. At Bloody canon and
Parker creek two separate extensions of the glaciers are recorded by the
morainal embankments. The glacier that flowed down Bloody canon at
first advanced upon the plain with a slight deflection to the right and
built out a pair of huge morainal embankments ; subsequently the ice
retreated at least as far as the mouth of the canon, and then advanced a
second time with a deflection to the left, i.e. northward, and formed
a pair of parallel embankments, still larger than the first. Two similar
advances of the Parker Creek glacier are recorded by the very perfect
morainal embankments still remaining. The ice stream which formerly
occupied the valley of Rush creek was by far the largest that entered the
Mono basin, and left many features of interest. As shown by smoothed


rock surfaces and by well-preserved moraines, this glacier was over 1500
feet thick where it left the canon; before reaching the plain it was
divided by a high rocky spur into two branches. The more southern
branch deposited terminal moraines in such a way as to obstruct the
outlet of the valley and cause a reversal of the stream when the glacier

The evidence left by ancient glaciers in the Sierra Nevada is a part of
the records of a Great Ice age found throughout the northern half of
North America and in many other parts of the world, and falls properly
in a history of Pleistocene times. The records of this history can be
properly understood only by comparing them with similar inscriptions
now being made. The study of existing glaciers is thus a preparation
for the still greater task of deciphering the records of periods of ancient



Online LibraryIsrael C. (Israel Cook) RussellGlaciers of North America; a reading lesson for students of geography and geology → online text (page 6 of 24)