128 — W. M. Dawis—Gorges and Waterfalls. 
three hundred feet thick. The explanation of the new course 
of the Raymondskill is equally conclusive. Professor White 
suggests that the several other high cascades over the Hamilton 
bluffs along the Delaware in this part of its course, such as 
those on Adam’s, Dingman, Hornbeck and Little Bushkill 
Creeks owe their origin to a diversion from their old channels 
by drift-dams ; but no detailed study of their topography was 
made.* 
Other illustrations of our topic described by the same author,t — 
are found on the hi 
Harvey’s lake is a long, narrow, irregularly shaped body of 
water, occupying an old buried valley to a depth of ninety 
feet. T 
ighlands northwest of Wyoming Valley: a 
outlet is closed by drift; the new line of over AS 
flow has already lowered the lake over one hundred feet by — 
* Geol. Penn., G6, Pike and Munroe Counties, 1882, 57-62... 
+ Geol. Penn., Gi, Wyoming, etc. Counties, 1883, 171, 131, 133. 
