276 H. 0. Lewis—Supposed Glaciation in Pennsylvania, 
ArT. XXXV.—On supposed Glaciation in Penne south of 
the Terminal Moraine ; by H. Carviti Lewis, Professor of 
Geology in Haverford College. With a map (Plate IV, but 
not numbered. 
In a “Report on the Terminal Moraine in Pennsy!vania 
and Western New York,’ I have said (p. 45) that “with the 
exception of a narrow district which I have called the inge, 
the line of drift hills which crosses Pennsylvania lies at the 
precise edge of the drift-covered district,” and (p. 48) that this 
terminal moraine is a “line separating the glaciated from the 
non-glaciated regions.’ 
But in his letter of Seiiaan Professor J. P. Lesley, the 
State Geologist, in referrin ng to the limit of glaciation, makes 
oy following statemen 
wo remarkable cs nomena, however, stand in the way of a 
Bioditive and final assertion respecting the limit of the southward 
extension of the obi ba ice, in spite of the well-marked line of 
its terminal moraine, viz: scratches observed on the mountains of 
Schuylkill and Dauphin County ; and vast grooves or note hes in 
the crest of the Kittatinny mountain, for i om no explanation is 
tn ee by the drainage system of the country. 
1) ns the first very little can be said, but that little 
is import 
4in 1850-51 Professor Edward Desor of Switzerland, and my- 
self, observed glacial scratches pointing southward upon the bare 
outcrop of conglomerate which makes the crest of Locust mout 
tain west of Ashland. The testimony of the sage Se cages 
ist to their genuineness is sufficient. We were both site! 
fectly well acquainted with the asiite and sli of ‘ sree es? 
and felt sure that these polished surfaces, grooves, etc., were 7 
of that kind, nor could they have been pr roduced in that way ; br 
they crossed the eroded edges of the beds. 
“Some years afterward I observed horizontal gr rooves 
traversing the natural vertical east wall of the small and unique 
notch in the crest. of the Fourth mountain where it is crossed by 
the turnpike from Harrisburg to Halifax. The opposite sae | 
all had 
wall had been cut to the vertical by the engineers, and 
covered with sections of blast holes; but the east wall had not 
been touched, and was covered with horizontal glacial Lege” 
and scratches crossing the densiy pul -dipping bed-pla is 
this case I had no one with me to verify the Sserratiet , ut 
feel as sure of the nature of the exhibition as in the form 
4 The Wind Gap is one of the eee and most inexplic- 
atte ‘features of the earth’s surface. . . . I am not aware that auy 
Bag ig Z. Second Geological Survey of nee Harrisburg, 1884 
2. xi. 
: 
4 
: 
a 
24 
4 
