The Van Buren press., 1894-09-29
NlAoARA.s FORMATION.
Story Of the Great Lakes hs Read In til,
Rocks.

Story Of the Great Lakes lis Read in the
Rocks.
Much newlight on the Quaternary his.
tory of the great lakes tributary to the
st. Lawrence river has been contributed
In three recent papers by Mr.. F. f. Tay-
lor, all published within the short time
since Mr.. G. X. Gilbert's writing on
"The Niagara River as Geologic
Chronometer.' Supplementing the
earlier observations and studies of
Whittlesey, Newberry, Gilbert, Spencer,
Lawson, Leverett, Wright, Baldwin
and the present writer, among others,
these latest explorations and discus
sions by Mr.. Taylor enable us to form
very definite and closely-connected
historical statement of the relation
ships of the ice-damned lakes which
preceded the present Laurentian lakes,
and of their dependence on the gradual
departure of the ice sheet on the ac-
tompanying northward uplift of that
region.
The largest element of uncertainty
in the estimate of seven thousand years
for the post-glacial period, from the
retreat Of the ice sheet to the present
time, drawn from the rate of recession
Of the falls of Niagara, consists, as
Mr.. Gilbert has shown, in the proba
bility or possibility that some consider
able next following the melting away
of the ice upon the area crossed by the
Niagara river the outlets of Lakes SUI
perior, Michigan and Huron may have
passed to the st. Lawrence by more
northern course, flowing across the
present watershed east of Lake Nipis-
sing to the Mattawa and Ottawa rivers.
Mr.. Taylor's observations now indi-
cate, however, if interpreted oil the
hypothesis Of glacial lakes (which is
believed by Mr.. Gilbert and by the ma.
jority of other geologists of America
to be the true view, that the gracial
Lake Warren, filling the basins of SUI
perior, Michigan, Huron and Erie, con-
tinued with its outlet flowing past Chi:
cago to the Des PLANES, Illinois and
Mississippi rivers, while the country
including Lake Superior, the northcrn
part of Lake Huron and Lake Nipis-
sing-that is, the whole northern side
of Lake Warren--as uplifted about
three hundred and fifty to four hum
dred and fifty feet along its extent of
six hundred miles from east to west.
The existence of Lake Warren was
terminated by the recession of the ice
sheet from the area between Lakes
Erie land Ontario, when the Niagara
river began to flow and to channel the
gorge six miles below its reccding falls,
from which the computation for the
time since the Ice Age is derived. The
Niagara gorge measured the time after
the outflow past Chicago ceased, Lake
Warren being then succeeded in the
basins of the upper lakes, above Erie,
by the glacial Lake Algonquin, while
in the Ontario basin the ice-bound Lake
Iroquois outAowed past Rome, N. Y,
by way of the Mohawk and Hudson to
the sea.
Seven-eighths of the differential up
lifting which carried the watershed
east of Lake Nipissing above the level
of Lake Algonquin had taken place be-
fore the northeastward retreat of the
ice sheet uncovered the Niagara area.
For some later time the ice barrier
must have remained upon the Mattawa
and Ottawa areas, forbidding any out
flow there from Lake Algonquin; and it
seems very probable that within that
time the continuation of the uplift had
raised the watershed SO high that no
discharge from the upper lakes ever
passed over it. During the ensuing
existence of Lake Iroquois the Ontario
basin was undergoing a rapid north
ward uplift, which doubtless was
shared by the Nipissing area, SO that if
any outflow occurred there it must
have been very brief, being ended
when the land east of Lake Nipissing
rose higher than the present course of
outflow by the ST. Clair and Detroit riv-
ers to the Erie basin and Mag
ara river. The duration Of the outlet
to the Mattawa could probably have
been only few hundred years at the
longest, if it ever existed. With this
possible exception, the present vol
ume of the Niagara river has been
maintained during all the time of its
gorge erosion. Only an insignificant
addition to the estimate of seven thous-
and years can, therefore, be required
by the division of the waters of the up
per lakes.
The view held by Taylor, Spencer
and Lawson, that the high shore lines
around the great Laurentian lakes arc
of marine formation, seems to be in
consistent with the total absensc of
marine fossiliferous beds everything the
glacial drifts in all that region. So far
as the sea did extend, after the further
recession of the ice sheet permitted il
to come into the st. Lawrence and Otta-
wa valleys and into the basin of Lake
Champlain, marine fossils abound, but
none are found above the Thousand
islands at the mouth of Lake Ontario.
We may, therefore, confidentally ac-
cept the Niagara gorge as measure OF
all the time since the departure of the
ice sheet from the northern United
States.
In recent paper in the journal o1
Geology" Mr.. Andrew NJ. Hansen, OF
Norway, notes the approximate con.
currence of about thirty Independent
measurements and estimates of the
duration of the post-glacial period
which have been made in North Amer
lea and in Europe, all coming within
the limits of five thousand and twelve
thousa nd years. He accordingly says
"With full regard to legitimate cal
culation of probabilities, it may be pre-
dicted that the number of seven thou
- 4 4 s,
ly an exact estimate of the duration Of
post-glaciai time as can ever be ex
pected. Ware Upham, in Nature.
Higher Education Doomed.