1883. 99 LARS HAIN YOACS Sez. 
At the southern portion of the range, where it trends off decidedly 
toward the southwest, the glacial movement nearly conformed to the 
course of the valley, the upper part of the sheet scraping obliquely 
over the summit of the range. 
The main body of the coarser detritus, gneiss, quartzyte, etc., from 
the Adirondacks, Helderbergs, and Catskills, borne along through the 
Hudson valley, was mainly diverted through the stronger glacial 
current which swept down the Wallkill valley. The approximate coin- 
cidence of the movement of the ice with the course of that valley, as 
well as the low planes—within or beneath the ice—at which the foreign 
boulders were borne or shoved along, have been the two causes which 
appear to me to have permitted little or none of this northern material 
to cross the Shawangunk range, even through its lowest gaps. 
DISCUSSION. 
Prof. D. S. MARTIN gave some account of the glaciation observed 
by him during a visit to Lake Mohonk, near the northern end of the 
range. At this point the cap of Oneida conglomerate is not less than 
three hundred feet in thickness. The hotel rests upon it, at the shore 
of the lake, which is 1,200 feet above the sea level, and it forms a 
continuous mass extending up to the summit of Sky-Top (altitude, 1,500 
feet). He had observed the same form of bright red weathering at 
this locality. Near the lake, the fresh horizontal surfaces of the white 
quartzyte are polished like a slippery floor, which is even difficult to 
walk upon. He had obtained specimens of the conglomerate, showing 
pebbles sliced off by the glacial action. 
Mr. C. VAN BRUNT stated that the modified till was universally 
distributed, with boulders, over the area on the west of the range up 
to its northern termination. At that point particularly he had observed 
the shoulders of the ridges to be remarkably ground and scratched. 
He inquired whether the great masses of the conglomerate, loosened 
or detached along the escarpment, might not have been pushed away 
by the pressure of the ice. 
Dr. N. L. BRITTON stated that he had visited the southern exten- 
sion of the range, at High Point, which has an altitude of 1,700 to 
1,800 feet. There also a small pond occurs, which is extremely shal- 
low. The glacial strie ran very nearly tothe southwest. Nota single 
boulder of extraneous material was observed in the vicinity, except a 
small flat pebble of Helderberg limestone, which was found at a point 
about 300 feet below the summit. 
Prof. O. P. HUBBARD inquired how the deep excavation of Lake 
Mohonk had been probably effected. 
Dr. JULIEN replied that, judging from the general accounts of the 
