The Cecil Whig. [volume] (Elkton, Md.) 1841-current, 1876-01-01
THE GREAT ICE SHEET.

least, to contemplate, in these sultry Sum-
enveloped all the northern part of our con-
tinent, and of the globe as well.
All have seen the immense boulders, call
ed "lost rock - in some sections, scattered
over the northern part of the United States,
which have little or no resemblance to any
mass Of rock in place anywhere in their
vicinity, and have perhaps asked the ques-
ton: Where did they come from also
the heaps of sand, gravel and cobble stones
Of various sizes, which form many of our
ridges, knobs and hills, and which are
totally unlike any fixed rock near them.
Some of these have coarse and fine pebbles
promiscuously mixed together and others
show beds of qualification in which the
coarse and fine seem to be sorted and ar
ranged by themselves. Some, too, have
doubtless seen the parallel scratches on the
surface of rocks, and noticed, as the In
dams did before them, that they all have
one direction, and that is usually north and
south. Now all these phenomena are at
tributed to single cause, and that is the
great sheet of ice which Nature stored up
ages ago without the necessity of protect
ing it in an ice house. The transported
boulders, of all sizes down to pebbles and
even fine sand, and the scratches upon the
rocks, are clear indications of movement
on very large scale. And if one takes
the trouble to search for the place whence
these erratic boulGers came, he will invari-
ably find that it is north of the position in
lance from few miles to several hundreds
1t will very frequently be found that these
masses of stone could not have reached
their present resting place without crossing
intervening mountains, valleys, lakes, and
sometimes parts of the ocean. They are
often perched in very singular and almost
inaccessible places. There is very large
one on the summit of West Rock, New
Haven, under which the regicides are said
to have taken refuge after the restoration.
Some are so nicely poised in their position
that they can be easily rocked by a child,
though they weigh tens of tons. One of
the most noted of these cratic blocks is
called Pierre Bot, of fine granite, which
now rests on the Jura, 800 feet above Lake
Neufchatel, near the early home of Pro-
fessor Agassiz This has 4 solid content
of 40, 600 cubic feet, and was transported
from Mount Blanc across Switzerland, a
distance of sixty or seventy miles. Through
the influence of their world renowned fell
low townsman, the city authorities of Neuf-
chatel have constructed a promenade to it.
To explain the transportation of these
wanderers from their homes, various theo-
ries have been advanced, as the effects of
floods, or of powerful mud currents, gas
explosions of great violence, hurting rocks
in all directions, and drifting ice, carrying
boulders on its mass and depositing them
many others fail to satisfy the observed
conditions, and utterly fall to the ground
in presence of the facts. To our lamented
Agassiz belongs the credit of first attribut-
glacial action. But he was not the first to
observe that boulders were carried long
distances by land ice. More than twenty
years before Agassiz announced his concu-
NJ. Carpenter: "Our glaciers had for
merly much longer extent than at present
Our whole valley was occupied by vast
glacier extending as far as Martisny, as is
proved by the boulders found in the vicinity
of this town, and which are far too large
for the water to have carried them thither."
Charpentier adds that he afterwards re-
ceived similar explanations from mountain
GERS in other parts of Switzerland; once, in
1884, from a woodman, when he had at the
very time in his pocket paper advancing
the same theory, which he was then going to
Lucerne to submit to a convention of Swiss
naturalists.
In 1886, Agassiz became acquainted with
Charpentier and was made familiar with
his Investigations. Soon after, he (Agas-
siz) carried the theory beyond the limits of
the Swiss Alps, and made it embrace a
sheet of snow and ice extended enough to
cover continent. Having noticed that
the markings in the region of the Alps
below the glaciers were the same as those
found beneath the ice mass, he compared
these with similar appearances in Northern
Europe and Asia, which were generally
ar ri cd 70 tho nraot flood and ba
bold generalization that all were due to the
very same cause, and that one vast sheet
of ice must have covered all the northern
regions of the globe. While these theories
at first met with great opposition, they are
now universally accepted.
According to Agassiz, the sheet Of ice
extended in this country as far south as
South Carolina or Alabama, and was thick
enough to cover all the mountains Of the
eastern part of North America with the
exception of Mount Washington. This
peak projected, a lone sentinel on that vast
waste of ice, two or three hundred feet.
In the latitude of northern Massachusetts,,
he eonceives the ice to have been between
two and three miles thick; and it held it's
direct southerly course in spite of the noun
tains and ridges over which it moved, as is
indicated by the direction of the parallel
grooves it made, and the trains of boulders
which it left. The boulders were all torn
off, by the advancing ice sheet, from the
projecting rocks over which it moved, and
carried or pushed as "bottom drift"
scratching and blowing the surface over
which they passed, and being scratched and
polished themselves in return, till they were
finally brought to rest by the melting of the
ice. They were not carried as far south as
the ice sheet extended, seldom beyond the
parallel of 400 N. The native copper of
Lake Superior was drifted four or five hun
bred miles south; and the pudding stones
of Roxbury, Mass, were carried as far
south as the Island of Penikese.
The tough, elastic, compact clay, called
in this country "hard pan" and in Scot
land "tll, is described as the oldest de-
Of, y ,Iar