1873.] 381 [Mann. 
the fact that it covered nearly all elevations. But the Alpine gla- 
ciers now obtain most of their freight from the extensive and precip- 
itous bare, or half clad slopes, where frost and avalanches, not 
glaciers, carve out the rock and shape the peaks. 
If, therefore, the valleys were not formed by glaciers, how were 
they produced? Iam not a believer in the old fracture-theory, but 
in all the steep lateral valleys of the Alps the observer may see tor- 
rents of water cutting deep gorges in the rock; the frost breaks up 
the rocks at the sides, and the process of deepening and widening, 
or of valley excavation, may there be seen and studied. I believe 
it was so in the past, and that the valleys, in which the glaciers now 
are, were not formed by them, but rather that they received their 
courses and limits from the valleys. 
April 16, 1878. 
The President in the chair. Twenty-four persons present. 
Mr. Wm. T. Brigham exhibited a fine collection of photo- 
graphs, taken by Prof. Hayden’s surveying party, of the 
Yellowstone Park country, and described the scenes thus 
illustrated. 
Mr. Bouvé exhibited a fine Japanese crystal ball presented 
by Thomas Gaffield, Esq., to the Society. 
Section of Entomology. April 23, 1873. 
Mr. E. P. Austin in the chair. 
The following paper was read : — 
ANISOPTERYX VERNATA DISTINGUISHED FROM A. POMETARIA. 
By B. Pickman Mann. 
The question of the difference between Anisopteryx vernata and 
Anisopteryx pometaria having been raised, I have looked over my 
notes, and made some new observations, with the results contained in 
this paper. 
