1885.] Glacial Origin of Presque Isle, Lake Erie. 867 
vicinity ; but after a personal investigation and inquiry of civil 
engineers, he came to the conclusion that the land is composed 
entirely of sand, clay and rolled pebbles of foreign and native 
rocks. 
History shows that this material has not only been changeable 
in form, but small quantities have from time to time been trans- 
ported from the western to the eastern portion by the waves. 
These changes must have been in progress prior to its discovery, 
and of course the peninsula was situated further west than it is 
now. This we may regard as a clue to the origin of the penin- 
sula however hypothetical it may seem to be. The material 
being almost identical with glacial drift that is scattered all over 
Northwestern Pennsylvania, which in some places is nearly 200 
feet in depth, and may have had the same origin, having been 
deposited at the same time about twenty miles west of its present 
site, where the Devonian strata dip gently under the surface of 
the lake. At that point a vast quantity of glacial drift was 
shoved upon the sloping rocks during the ice age, and that de- 
posit has been the sport of the waves ever since the retreat of the 
great northern glacier. Professor I. C. White, of the Pennsylva- 
nia State Geological Survey, says: 
“The varied character of the northern drift deposits can be 
well studied along the shore of Lake Erie, towards the Ohi 
State line, where they constitute a terrace bluff from fifty to eighty 
feet high, out of which the waves are constantly removing the 
clay and fine sand into the Jake leaving the coarse sand, pebbles 
and boulders to be daily rounded and polished on the beach.” 
At the close of the ice age the waves began to wash away the 
finer particles from the bluff of drift, and as the current of the 
water was down the lake in a north-eastern direction—the storms 
Moving generally the same way—the probability is that a bar of 
‘sand was formed at some favorable place east of the starting 
point, upon which other material was driven year after year 
until an island or peninsula was formed. At some later period 
more powerful storms broke up the western portion and carried 
it along to or beyond the eastern extremity, while it was being 
constantly enlarged by sand from the original source, and from 
the bluffs and watershed along the shore, which was brought 
down by numerous streams. In this way let us imagine the bar 
an island or a peninsula, and alternating perhaps with 
each other until the erratic bodies‘of land appeared to the first 
white settlers of this region in form of a peninsula. 
ERIE, PA., AUGUST, 1885. 
IX. 
VOL. XIX.—NO, 57 
