872 BR. P. Stevens—Glaciers of the Glacial Eva in Virginia. 
gravel reposing upon them. Similar observations were madeall 
the way up to Lewis Tunnel, or the passage of the railroad into 
the valley of the Green River. 
he Jackson branch has its source on the east flank of the 
east front of the Alleghany Mts., in Highland Co., Va. The 
Green River rises on the west side of the same mountains, in 
Pocohontas County. 
. You may remember, that some time since I wrote you, that 
I had found Canadian boulders on the summit of the West 
Front Mts., or Back Bone Mts., in Tucker Co., at the sources 
of the N. W. branch of the Potomac River. Bearing this in 
mind, I was on the alert to find signs of glaciers, also, in 
the Green Briar Valley. 
No sooner had the tunnel been passed, and the valley en- 
tered, when great masses of true boulder drift were found 
massed on slates and limestones of the Subcarboniferous group. 
Ascending to the table land in Fayette Co., S.W. from ne 
: , to 
Guayandotte Ri i i eet i 
y tte Rivers, did I find any signs of gl nae highlands in 
these southern latitudes and remained stationary on the! er 
then, perhaps, and most probably more extensive table 9 
than at present, and only moved along the water courses W 
slopes obtained to give descent to the sea? 
New York, Sept. 25, 1873. 
