J. C. Smock—Thickness of the Continental Glacier. 345: 
have stood above the ice. Bowlders and drift earth cover its 
flanks and constitute much of the surface material to within a 
vertical distance of 50 to 100 feet of the top. On the crest of 
the ridge the ledges of grayish white conglomerate are much 
broken up and lie in blocks. None of them show any glacial 
markings. Nor are there any erratics or drift earth on this 
crest. The absence of characteristic glacial phenomena leads 
© the conclusion that the ice did not attain this height. The 
Mountain is 2025 feet high and the glacial limit may, there- 
fore, be put at about 2000 feet. The whole country to the 
fastward and southeast, including the Kittatinny Mountain— 
at the Delaware Water Gap was covered by the glacier, and on 
it glacial markings are common 
vania Geological Survey, who has examined Pokono Knob is 
still more positive. He says: “During the past year (1881) I 
made the survey of Monroe County and ascended Pocono — 
the ‘ownship was subjected; for no appearance o fs 
Slacial scratches can be found on their sides or — . 
€se driftless peaks are about sixty-five miles north of - ais 
dere, the most southern point reached by the glacier in 
D f ise in th er slo 
elaware Valley. And the rate of rise in the upp 
Letter to the ‘author of this paper from Professor White, Morgantown, W. 
* 
Va., April 34, 1882 ; 
t The Geology of Susquehanna County and Wayne County,” by I. C. White, 
Harrisburg, 188), pp. 25 and 158-159. 
