Savannah morning news. [volume] (Savannah) 1868-1887, 1882-04-14
VESTIGES OF THE GLACIAL Pc
Rod.
Lecture before the National History
Society by Professor G. r. Wright
on the southern Limits Of abe
American Continental Glacier.

At the meeting of the Boston Society Of
National History the other evening, Pro-
fessor G. F. Wright, of Oberlin, O., gave
an account of the discoveries made last
summer by him and Professor H G.
Lewis concerning the southern limits of
ice-action otherwise called the terminal
moraine) in Pennsylvania during the
glacial age. These investigations were
made under the direction of Professor
Lesley, who has charge of the elaborate
geological survey now in progress in
that State. Previous to last summer
Mr.. Clarence King had, first in 1876,
through a paper of Mr.. Wright's
before this society, called attention
to the terminal mOraine at
Woods Hole. Subsequently. Warren
Upham, taking up this clue, had fol-
lowed it through Cape Cod and Long
Island, where the line joined on to that
discovered by Professor Cook, of New
Jersey, reaching the sea at Perth Ambov,
Just below New York, and crossing the
Delaware river at Belvedere, a little
above Easton, Pa. From this point the
line of the terminal moraine was seen
laid down upon map fifteen by ten feet,
displayed for the first time to scientific
society, crossing Northampton county
by general northwestern course to the
centre Of Monroe county; thence west
ward, crossing the Lehigh fifteen miles
above Mauch Chunk, aud the Susque-
hanna, twenty miles below Wilkes
barre; thence by nOrtlwesterlY course
through Columbia county, rising to the
summit of the Alleghanies, in Lycoming
county, and crossing them diagonally
through Tioga and Potter counties,
where the general elevation of the
country is upward of 1000 feet. From
Potter county the moraine enters Cat
taraugus county, n. Y, and continues
to trend northward as far as Little Val
ley, six miles north of Salamanca, where
it makes sharp turn to the southwest,
funning nearly parallel with the Allie
ghany river to COlumbiana county,
Ohio. TIE whole length of the line ex-
plored this last summer is about 400
miles. The signs of glacial action
abruptly cease along this line, and it is
marked by special accumulation of I'm
stratified material composed of clay,
scratched stones and granite boulders
which have been transported hundreds
of miles. North of that line the signs
of glaciation are everywhere apparent;
south of it there are no scratched stones,
no transported bOulders, aud no
'till" or boulder clay. Where
streams cut through the line.
however, boulders of granite and
quartzite have been transported by
water and deposited in terraces and
jersey, in which DR.. c. @. Abbott has
y0o1ooolifbio MI &c io a
delta terrace thus formed when the river
was fifty feet higher than now. Every
stream to the westward which rises in
the glaciated region and flows through
the unglaciated region, has formed cor
responding terraces and deltas, and is
full of interest. The lecturer urged that
thorough search for pal@olithic imple-
ments should be made in all such forma.
tions. The majestic proportions of the
great ice movement are seen in the fact
that it advanced as far south upon the
mountains as in the valleys; for ex-
ample, the valley between the Kltta-
tinny and POcono mountains, though
twenty miles wide and one thousand feet
deep, caused but slight detection of the
ice front to the south. The same is true
where the mOraine crosses the valley of
the east branch of the Susquehanna
The grand detection of the line to the
nOrthward is evidently due to variations
in the forces which were pushing from
behind Now that an accurate knowl-
edge of the southern limits of the CONT
mental glacier is being obtained, it will
be possible to get a variety of approx
mate estimates of the quantity of erosion
which has taken place since the great ice
age, and so a more correct idea of its an
tiquity Full accounts of this subject
will appear in the report of the Penn
sylvania geological survey. Arrange
ments are in progress for Mr.. Wright to
continue the exploration through Ohio
during the coming summer.