J. OC. Smock—Thickness of the Continental Glacier. 341 
870 feet.* It is safe to conclude from these heights that the 
thickness of the ice sheet in this southern loop of the Hudson 
Valley was at least 200 to 400 feet. Other localities farther to 
the west and northwest furnish data of like nature. At Felt- 
ville in Union County, a bowlder limit is recognized at an 
elevation of 400 feet above tide. On Second Mountain, west 
of Feltville, there are scattered bowlders up to 440 feet. The 
general level of the sandstone plain on the east side of the 
First Mountain range is 150 feet, giving a difference of 250 to 
0 feet as a measure of the ice at this point. Again, at Long 
Hill, near Chatham in Morris County, the glacial drift is 
Wrapped about the north foot of the ridge and pushed forward 
to the south on each side, The upper bowlder limit here is 
890 feet high. The Passaic River, flowing in the bottom of the 
ed sandstone valley on the east of this hill, is 177 feet above 
tide or 200 feet below the bowlder line. Another locality, 
exhibiting like phases in the drift, is on Snake Hill, near Den- 
ville, also in Morris County. On the northern point of this 
sharp and rocky ridge of gneiss the moraine is traceable at an 
elevation of 670 feet, but scattered bowlders as high as 7 
~ feet indicate the latter elevation as the ice limit. The crest 
line of this range is 910 feet high. On each side the drift 
Three ranges, 
‘ng drift phenomena. Separate masses of glac 
found lying about the northern ends of Potsdam — 
tidges, while the intervening valley is filled with exceedingly 
P. ana Lewis, Jr., in a note to Professor Dana in this Journal, III, vol. xin, 
. 235, 
