The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1876-10-20
The Origin OF the Great Lakes.

At the meeting of the Scientific Asso.
citation in Buffalo, paper was read boy
Prof. j. :. Newbery, of Columbia Col
lege, attempting to explain the origin
OF the Great Lakes Of this country. He
states that the sequence OF events in
the formation of the Great Lakes seem
10 have been somewhat a. follows:
l. The Laurentian belt north Of the
Great Lakes, which has been a land
surface since the beginning of the
Fal@ozoic era, was formerly high
mountain range, the degradation Of
which has supplied the m, chanical ma
terials which compose the sheets Of
PalVozoic rock that surround it, The
erosion Of these highlands has continu-
ed uninterruptedly till the present day,
and was specially rapid during the
period.
?. Previous to the glacial period, the
elevation OF this portion of the Cont
nent was considerably greater than now,
and it was drained by river system
which flowed ~ a much lower level than
at present. At that time our chain of
lakes-Ontario, Erie and Huron APP
parently formed portions of the valley
of river which subsequently became
the 81. Lawrence, but which then flowed
between the AdirondaCks and Appala-
chians, in the line of the deeply buried
channel of the Mohawk. passing through
the trough of the Hudson, and empty
ing into the ocean 80 miles southeast of
New York. Lake Michigan was appar-
emily then part of river course
which drained Lake Superior asd emp
tied into the Mississippi, the Straits Of
Mackinaw being not yet opened.
3. With the approach Of the cold pc
Rod, local glaciers formed on the Lauren
tian Mountains, and, as they increased
in size, gradually crept down ON 10, and
began 20 eNcavate, the plateau which
bordered on the west and south. The
excavation of our lake-basins was be-
gun, and perhaps in large part effected,
IN this epoch.
f. As the cold increased and reached
It's maximum degree, a great ice-sheet
was formed by the enormously in
creased and partially coalcscing local
glaciers OF the former epoch. This
man-lObed ice-sheet, or compound gla-
cier, moved radiatingly from the south,
southwest, and western slopes Of the
Canadian highlands; its Ohio lobe
reaching as far south AS Cincinnati.
The effect OF this glacier upon Lake
Erie and Lake Ontario would be %
broaden their basins by impinging
against aud grinding away, with incon-
cciyable power, their southern margins.
.. With the amelioration of the eli
mate the Widespread ice-sheets Of thc
period OF intensest cold became again
local glaciers, which completed the al
ready began work of cutting out the
/ lake-basins At first the glaucier whic h
had before flowed over the watershed
in Ohio was SO far reduced as 10 bee uu-
able TO oyertop its summit, but, defect
ed by IL, il flowed along its base, spend
ing its energies in cutting the shallow
basin in which Lake Erie now lies.
o.. The melting Of the glaciers was
accompanied, perhaps occqsioned, by a
sinking Of the Continent, which pro-
/ crossed until the waters OF the Atlantic
flowed up the alley OF the 81. Lawrence
TO Kingston, and up the Ottawa 10
Arnprior The Valleys of the St. Law
renee and the Hudson were connected
by way of Lake Champlain, and thus
the highlands Of New England were left
as an island. II is also possible that
the sea-water penetrated 10 the lake
basin through the Valley Of the Mo-
hawk and through that Of the Missis-
sippi, but Of this we have no evidence
in the presence Of marine fossils in the
surface-deposits. The great area OF
+ excavation in which the lakes lie was
+ probably at this time filled 20 the brim
with ice-cold fresh water.