The Ottawa free trader. [volume] (Ottawa, Ill.) 1843-1916, 1877-08-11

4, ,Io late meeting of the Scientific ASSoci-
.;o,, =, RnAnlo Il papcr was read by Prot New
her.v. attempting to explain the origin OF lhe
great lakes in this country. He asserts the Sc
9urncr of events in the formation OF the great
lakes to have been as follows;
The Laurcntian belt north of the great
lakes which has been Il land surface since the
PalpoZolc era was formerly hlgh mountain
ranrc. the degradation Of which has suppllcu
the mechanical materials which compose me
sheets of Palpozoc rock that surround IT, The
erosion of these highlands has continued unln-
lterruptedlv till the present day, ana was SPe-
ciallv rapid during the period.
. Previous to The glacial period, the eleva-
tion of this portion of the continent was con
eidcrably greater than now, and II was drained
| Inv . river system which flowed at much
| lower level than at present. At that time our
| chain of hkcs-OntariO, Erie, and liuron-ap-
Iparently brmed portions OF the valley OF rlv-
| or which subsequently became the ~. Law
renee butwhich then flowed between the Adj
irondacksand Apalachians, in the line of the
Ideenly.bu,ied channel of the Mohawk, passing
through tie trough of the Hudson, and emp,
tving intothe ocean, eighty miles southeast OF
| New YorE. Lake Michigan was then appa,
rently p,rt of a .rivercourSe when drained
Lake Superior and emptied into the MiSsissip-
nj the Straits Of Mackinaw being not yet
opened
>. Withthe approach of the cold period, To-
cal glacics formed on the l4aurentlan noun
tainS, and as they increased in size, gradually
crept down on to, and began to eXcaVate tne
plateau which bordered on the west ana south
| The cXcaration of our lakebasins was begun,
and pcrhaps in large part effected in this epoch
4 As the cold increased and reached It's
maximum degree a great iCc-shcet was formed
by the enormously increased and partially Co
| aiescing local glaciers Of the former epoch
| This man-lObcd iCc-shect or compound GA
cicr. moved radiatingly from the south, south
west. and western slopes of the Canadian hlgh
LANDS, its Ohio lobe reaching rs far south rs
Cincinnati The effect of this glacier upon
Lake Erie and Lake Ontario would be tt
broaden the basins by impinging against anc
rrinding away with inConCeivable power, thell
southern margins
! With the amelioration of the climate the
widespread icc-Shcct of the period OF lntenseS'
cold became again local glaciers, which com
pletcd the already begun work OF cutting on
The lake basins. At first the glacier which haC
before flowed over the watershed in Ohio wa!
81 far reduced as to be unable TO Overtop it
summit. but. DETECTED by it, it flowed along it
hasc, spending its energies in cutting the shall
low basin in which Lake Erie now lies.
I 6. The meeting of the glacier was accompan
led. perhaps occasioned by a sinking Of thu
continent, which progressed until the waters o
the Atlantic flowed up the Valley of the st
Lawrence to Kingston, and up the Ottawa tt
Superior. The valleys of the st. Lawrence an'
the Hudson were connected by way OF Lake
Champlain, and thus the highlands OF New
England were left as an island. 1t is $50 pos
sibie that the sca-water penetrated to the LAKE
basin through the valley of the Mohawk an'
through that of the Mississippi, but Of thi
we have no evidence in the presence OF marin
fossils in the surfaccdepoSits. The great are
of excavation in which the lakes lie was prof.
ably at this time filled to the brim with ice
cold fresh water