LAKE PASSAIC. 561 
with Millington:—(a@) the size of the stream is greater at 
Stanley ; (0) its gradient is slightly greater; and (c) the material 
in which it has cut is very much more easily eroded. If, under 
these circumstances, the post-glacial cutting at Stanley has been 
no more than the figure cited above, the amount of post- 
lacustrine erosion at Millington gorge must have been much less. 
Before being lowered by erosion, the drift dam at Stanley 
nad anvelevation of about 230 feet. Aitter the ace treed the 
Little Falls-Paterson outlet, a long, narrow lake must have hada 
temporary existence behind this barrier, in the valley between 
Second mountain and Long Hill. Its greatest depth could 
hardly have exceeded twenty feet. All the lacustrine clay 
between Long Hill and Second mountain lies below this level, 
and furthermore most of the surface below this level is clay- 
covered. There is little doubt that such a lake existed for a 
time after the great body of the water of Lake Passaic had 
drained away. It was lowered as the Stanley gorge was cut 
down, and disappeared when the outlet was cut to the level of 
its bottom. 
The Little Falls outlet—Where it is crossed by the Passaic 
river at Little Falls, Second mountain is broken by a gap more 
than two miles wide. The bottom of this gap is nearly flat, and 
is covered with a coating of till, clay and fine sand, not exceed- 
ing ten feet in depth, where now cut through by the river. It is 
certain that the level of the outlet which Lake Passaic tound via 
Little Falls after the retreat of the ice, had an altitude of not 
more than 190 feet, and not less than 175. 
At West Paterson, the Passaic river crosses First mountain 
through a gap two miles wide. When the ice had melted back 
so far as to open this outlet, the river must have crossed this 
ridge at an elevation of not more than 150 feet, and not less than 
125 feet. Since this height is at least 12 feet lower than the 
height of the lowest swamps in the lake basin, this rocky barrier 
could not have caused subordinate lakes within the Passaic 
basin. 
Great Notch.—-Three miles south of Paterson, First mountain 
