Geology and Mineralogy. 983 
It crosses the Conewango River seven miles north of Warren, 
forming immense accumulations i the valley of the river. Then, 
after another, and forms a line separating not only the glaciated 
from the non-glaciated regions, but also the cultivated from t 
uncultivated and densely wooded regions.” After crossing caw 
ord, Venango and Butler Counties, the southeast corner of 
thus leaves Parga ibgren: at precisely y the latitude at which it 
entered the Stat 
“The total “se of the moraine is about 400 miles. It 
and the Be 
(225 feet above ore ’ Erie) ; ie upon the high lands of eter! 
County it rests on ground nearly 2600 feet above tide and i 
surface must have been about 3000 feet 
he thickness of the vey is stated to vary from a mere sprinkling 
of bowlders to 100 feet or more; it is even 200 feet deep in many 
parts of peta abe Pennsylvania, while in eastern, it is gen- 
erall ab 
7 s gives for the usual limit of transport of bowlders in 
aectndivanik 10 to 20 miles. The thickness of the ice at the 
terminal edge in some valleys is estimated at about 700 feet, and 
ve miles back 1000 feet; but where the edge of the re was 
t. Lewis’s report, Professor 2 males mes the height over the 
_ tain, one of enty feet in le ona. a class of facts known 
to be well illustrated by bowlders on Katahdin in Maine, and 
Others carried from Canaan into Goshen, Connecticut ; showin 
Upper surface of the glacier rising to a higher level to the north- 
ward, ae d up the encountered slope carrying its gathered load 
sto 
The / Sirection of the glacial strie over the eastern ice-region of 
Pennsylvania is described as southwesterly, while the same over 
the northwestern, is southeasterly. 
The most remarkable feature brought out by the investigations 
is the bending of the moraine northwestward in crossing the 
