Meeting of I he American A.saociation. — Uplmm. 213 
sometimes embracing the latter poikilitieally, much resembling 
the devitrified groundniass of ancient acid lavas from this 
locality. The feldspar grains are altered and much filled with 
calcite and sericite, and these two minerals, together with 
secondary quartz and chlorite, are in the interstices between 
the grains. But the most striking feature of the rock is the 
presence of a number of larger roughlj'- angular grains which 
are similar to some of the smaller rounded ones and which 
appear to be composed of the products of devitrification; and 
what is still more confirmatory of this idea is that some of 
these grains still show very clearly the remains of a perlitic 
parting common to glassy rocks. This perlitic parting has 
been found in great perfection in some of the devitrified acid 
lavas of the north shore of lake Superior and is similar to 
that described from the aporhyolytes of South Mountain in 
Maryland and Virginia.* 
The two rock samples just mentioned are perhaps the most 
characteristic of a number of similar rocks from the north 
shore of lake Superior but mostly from the vicinity of Du- 
luth. There seems to be no other interpretation of their 
characters possible than to refer these rocks to volcanic ash 
deposits. While remains of fragmental volcanic material are 
not known to be abundant, still such deposits do occur in 
rocks which are usually considered as Keweenawan in age. 
No craters have been located, but it seems quite probable that 
future careful investigations may enable us to locate exactl}'^ 
some of the vents where explosive volcanic action occurred. 
BUFFALO MEETINGS OF THE GEOLOGICAL SOCI- 
ETY AND THE AMERICAN ASSOCIATION. 
By Warren Upham, St. Paul, Minn. 
The forty-fifth meeting of the American Association for the 
Advancement of Science was held in Buffalo, N. Y., under the 
presidency of Prof. Edward D. Cope, August 22-29, 1896, this 
being the fourth meeting of the Association in Buffalo, with 
intervals of ten years. The enrolled attendance was 330, 
from a total membership (including fellows) of about two 
thousand. At this meeting 110 new members were elected; 
*G. H. Williaius: Amer. Jour. Sci., 3, vol. 44, p. 486; Dee., 1892. 
F. Bascom: Jour, of Geol., vol. 1, p. 821; Nov. -Dec, 1893. 
