March 3, igoo.j; 
J^OREiST AND STREAM. 
16b 
The Harriman Alaska Expedition. 
II.— A Small Talk About GlacierB. 
Chief among the objects of interest in Alaska are its 
;tupendous glaciers. To more than one traveler the 
jight of these has made real for the first time all that he 
has read of the enormous power of such rivers of ice 
and the influence that they have exerted in earth sculp- 
ture. 
We are accustomed to think of the world as change- 
less, of the hills and mountains as immutable, and of earth 
and sea as being of all things the most lasting. Yet 
fact we know that this is not true, that all over the 
SI 
certain extent plastic; in other words, it can be made by 
pressure to take certain forms, as wax does, though of 
course it is not soft like wax. Dr. Kane speaks of a 
table of ice 8 feet thick and 20 wide, supported only at the 
sides, which in two months' time, while the temperature 
was constantly below the freezing point, became by its 
own weight so deeply bent that its center was depressed 
5 feet. By pressing ice through a round hole it may 
be made to take the shape of a long cylinder, or ice by 
pressure may be made to copy a seal or a mould. This 
being the case, we inay understand how this great ice 
sheet moA-ed forward, adapting itself to the inequalities of 
the land, filling up valleys, climbing mountain sides, ovei'- 
topping them and then flowing down beyond them. The 
motion of the ice sheet was slow, but it was sure. It 
a 
FACE OF MUIR GLACIER, WITH 
Photo by E. S. Curtis. Copy 
world change is constantly taking place, that volcanoes 
spout out lava, increasing the size of mountains; 
that snow and water and frost are constantly tearing 
off or breaking away fragments of other mountains and 
carrying them down toward the plain; that the thunder- 
ing waves of the sea are continually breaking upon the 
shore, '-emoving it in one place and adding to it in 
another; and that for the last few centuries man, with his • 
3xe and his grubbing hoe and his plow, is altering the 
face of the earth, enabling the rain and the brooks and 
the rivers to pick up and carry away the soil, which is at 
last transported to the ocean and tends to fill it up. In- 
stead of being permanent, therefore, the earth which we 
inhabit is unstable. The elements in their ceaseless 
action, the earthquake at intervals, and man during the 
short time that he has inhabited it are changing its surface 
continually. 
We know too that in very ancient times the face of the 
land which we inhabit was very different from what it 
is now. The mountains were higher, and so the valleys 
deeper. Great areas of the land, now mountain and plain, 
fertile farm, arid stock range, or peaks only ti^aversed 
by the wild animals, were once the bottom of the salt 
sea. And in the earth or the rock over which we now 
pass are often seen the bones or shells of the marine 
inimals which were born and lived and died and were 
covered up in these ancient times, to be seen by us to-day 
is stones which have the shape of animals. 
These high motintains have been cut down by the 
action of the elements; the valleys in part have been 
filled up, and this ancient sea bottom covered by soil 
wrhich was once a part of the tops and sides of these 
mountains. This work has been going on for all time; 
it is going on to-day, and it will continue to go on until 
I is going on to-day, and it will continue to go on. 
One of the most potent agents of this denudation was 
iCe, although the length of time during which this agent 
lias acted is small by comparison with the age of the 
arth. Over much of this continent it has now almost 
ceased to act, yet in the furthest north it is still doing 
[he work which once it did pver t4ie whole of the north- 
ern Nortli America. 
That division of geological time in which mammals 
liad their greatest development is called the tertiary 
period. And it was during the ages which immediate^' 
followed the close of that period that the whole northern 
North America was covered with an enormous ice sheet 
thousands of feet in thickness. Beneath this frozen mass 
were deeply buried the whole of British America, all 
of New England, a very large portion of the Middle 
States and much of the Rocl-cy Mountains. In northern 
New England the upper surface of this ice sheet was at 
least 6.000 feet above the sea level, while it is estimated 
that still further north it was not less than 13,000 feet in 
thickness. This vast mass was not, as might be thought, 
at rest. Instead, it had a general slow, but more or less 
constant motion southward. This was the only direction 
in which it could move, because to the south the ice 
was constantly melting and disappearing, while to the 
north it was always firm and unyielding, and tended con- 
stantly to increase in thickness, and to push away a 
portion of the mass in the direction of least resistance. 
This pressure was constant and ever increasing, and 
urged on by it, the ice sheet moved steadily southward, 
creeping up high mountain slopes, and them, when their 
summits w«re reached, overtopping them "and pushing 
its way down on the other side. 
It is a matter of common knowledge that ice is to a 
BERGS AFLOAT AND AGROUND, 
right by E. H. Harriman. 
flowed onward slowly, as molasses would flow on a cold 
day, but better still, is the illustration employed by Prof. 
Dana, who says : "If stiff pitch be gradually dropped over 
a horizontal surface it will spread and continue to do so 
so long as the supply is kept up, and if that surface rises 
at an angle in one direction and there is no escape in the 
other, it will first fill the -space to the level of the edge 
and then drop over and continue onward its flow. So 
America it no longer exists, except that on some high 
mountains and in the north, fragments of it are left in 
the glaciers found there and in ice masses now covered 
with soil, which often bear luxuriant vegetation. Such 
remnants are found only in high northern latitudes or on 
lofty mountains, where the melting of the ice in summer 
does not greatly exceed the snow fall of winter. The 
grandest well-known glaciers of the temperate zone are 
those of Switzerland, but one must travel to the Arctic 
to witness the most stupendous exhibitions of their work. 
Glaciers are simply rivers of ice, of varying thickness 
and extent, having their origin above the level of the 
perpetual snows by which they are fed. Though in its 
origin a glacier consists merely of compacted snow, this 
snow, as it advances down the mountain side, is grad- 
ually changed by pressure into an ice-like mass, and as it 
reaches the point where there is alternate melting and 
freezing, it becomes true ice. The glacier tends con- 
stantly to move in the direction of the least resistance, 
and follows the inequalities of the ground, thus moving 
in a bed not unlike that of a river. Yet as the momentum 
of such an enormous mass is almost inconceivably great 
it acts as an enormous plow, which cuts a furrow both 
wide and deep. In its course, it scrapes away the surface 
soil and the loose stones, and reaches down to the bed 
rock, against which it continually grinds and wears itself 
away. In its course it picks up and carries away with it 
gravel, pebbles, boulders and sometimes great masses of 
rock, and these, whether torn away from the sides of its 
bed or dropping on the ice from overhanging cliffs, are 
likely at last to reach the bottom of the channel which it 
has made. Here they are rolled along, crushed beneath 
the mass of the ice against or into the rock over which 
it is passing, which is thus scratched and scored or has 
its irregularities of surface smoothed and planed off or 
sometimes is highly polished. In glacial regions such 
surfaces are frequently seen, as well as the smoothly 
rounded knolls of rock called sheep backs or roches 
moutonnees. Such surfaces exist over much of northern 
North America, though usually covered up by earth and 
vegetation, 
The debris carried along in and against the glacier i.-; 
constantly being ground up like the grain between two 
mill stones, and the water of the stream formed by the 
melting ice is charged with this pulverized rock. Such 
streams therefore are milky in color, and can often be 
recognized by this character far away from their source. 
On either side of the glacier and at its lower end — if it 
does not reach the sea — and often in the middle of it, are 
great heaps or windrows of sand, gravel, stone and great 
rocks, which have been pushed before it or to one side 
by the ice mass as it travels along. These accumulations 
of glacial debris are called moraines, lateral, terminal or 
medial, according to their positions. 
Although a glacier is, in fact, a river of ice, it acts 
very differently from a river of water. Thus the cross 
profile of the stream valley is shaped like a V, while in 
the glacier valley the same profile is like a wide U. The 
curves of the stream's course are irregular, sharply bend- 
ing from side to side, as any one may see who looks 
down from a height on the course of a river flowing 
through the valley. The curves of an ice river, on the 
other harid, are slow and sinuous, and the mass changes 
its direction very gradually. 
It was about noon when the ship entered the Muir 
BURIED FOREST NEAR MUIR GLACIER. 
Photo by E. S. Curtis. Copyright by E. H. Harriman. 
glaciers, if the accumulation is adequate, may go across 
valleys and over elevated ridges." 
It rnay be asked where did all this ice come from and 
how did it accumulate to the enormous thickness already 
named i* The answer is simple: It is the accumulated 
excess of the precipitation of many ages over the annual 
melting. The ice of the great ice sheet of the glacial 
period was merely compacted snow, and the climatic 
conditions were such that each season more snow fell 
than was melted, and so the ice sheet grew. 
If the winter's snow fall is 60 inches and the summer is 
so cool that of this snow but 50 inches melts, the ice 
upon which the snow falls will receive an annual increase 
of thickness to the amount of 10 inches of uncompacted 
snow, a very slight thickness. If the ice sheet to-day 
does not cover any considerable portion of the country 
in which we live, it is because the summers are so long 
and warm that the snow and ice melt fast, and that for 
this reason the edge of the. ice sheet has crept further 
and further to the north, so th^t now on the continent o£ 
Inlet, and steamed along toward the great glacier at its 
head. Icebergs soon began to appear; at first small, 
later much larger. Some were pure white; others dirty; 
others white above where they were partially melted, and 
beneath a beautiful blue. The light falling through the 
ice gives this color, and it is reflected back from the 
water in the purest, most delicate sea green. 
The Muir Glacier, which we were now approaching, 
is rapidly receding. Twenty years ago its front stood 
tw-o miles further down the bay than now, so that to-day 
ships sail up over nearly two miles of water, which was 
formerly occupied by the ice. The front of the tremend- 
ous glacier, which was the first that we had seen near 
at hand, is two miles wide and perhaps 200 feet in height. 
From its face great bergs break off at frequent intervals, 
and fall with a tremendous roar into the water below. They 
are deeply submerged, spring out of the water again, so 
as almost to clear it, go down again, and so rise and 
fall many times, and at last, after reeling and bobbing 
about on the surface find a point of equilibrium and slowl|; 
