318 R. Brown on the supposed absence of the 
I have done, and have thus developed at least any value it may 
ess. It certainly presented an interesting problem and the 
pleasure afforded in its solution has repaid me for the consid- 
erable labor which it required. 
S. Bethlehem, Pa., July 15, 1870. 
ArT. XXX.—On the supposed absence of the Northern Drift from 
the Pacific Slope of the Rocky Mountains; by Dr. ROBERT 
Browy, M.A., F.R.G.S., etc., Edinburgh, Scotland. 
In so 
Academy 
in their ‘ Proceedings’ for that year (vol. li, pp. 271, 272), Pro- 
always to be accumulated at the base of the mountains. Fur- 
remarks that “it would appear that no evidences of a North- 
ee RS ON yl eee ee Pe te te ae 
: 
