1881. 49 Trans. N. Y. Ac. Sci. 
Dec. 5, 1881. 
REGULAR BUSINESS MEETING. 
The President, Dr. J. S. NEWBERRY, in the Chair. 
Twenty six persons present. 
Dr. NEWBERRY exhibited an ancient perforated stone axe from 
Europe, consisting of dioryte, and remarked that the aboriginal 
tribes of America never attained to the degree of skill required in 
the perforation of stone implements for the insertion of wooden 
handles. 
The following paper was read by Dr. ALExis A. JULIEN. 
THE VOLCANIC TUFFS OF CHALLIS, IDAHO, AND OTHER WEST- 
ERN LOCALITIES. 
(Abstract). 
In a paper recently read before the Academy it was shown that a 
certain compact white almost structureless rock, often porcellanous in 
texture, occuring abundantly in the Western ‘Territories, and variously 
styled ‘“trachyte,” “rhyolyte,” “porphyry,” etc., (e. g., at Leadville, 
Colorado, in the Black Hills of Dakota, etc.), is a sedimentary form of 
a highly silicious volcanic tuff, probably derived from the finest detritus 
of trachytes, rhyolytes, and quartz-porphyries. A series of specimens 
collected by Prof. NEWBERRY, during the last and previous summers, 
and kindly put in the author’s hands for lithological examination, has 
furnished the material for the following additional notes on this inter- 
esting but neglected group of widespread American rocks. 
1. Coarse pumice-tuff of Challis, Idaho. 
The rock is quite compact, schistose, of a gray color with duli white 
spots. The latter consist of pumice in finely fibrous grains, from 1 
to 5 mm. in length. Quartz and feldspar are seen in small angular 
flakes, sometimes reaching 0.5 mm. in length: hornblende commonly 
in fibrous black fragments, about I mm. in diameter: and much 
biotite, brownish-green, sometimes brownish-black, with greasy lustre, 
in hexagonal scales, often up to 2 to 3 mm. in size. 
The thin sections present under the microscope numerous grains, 
generally angular, of several minerals, varying in size up to 3 or 4 mm.: 
pumice in rounded to sub-angular fawn-colored fragments lying at all 
angles, commonly made up of straight or curved fibres, and often in- 
cluding glassy lenses filled with crystallites: a triclinic feldspar, in clear 
grains, sometimes including minute globules of glass, and possessing 
fine lamellation, beautifully striated in polarized light, the remaining 
traces of crystalline outlines indicating that these grains are all of frag- 
mentary, never of indigenous formation: quartz, in water-clear angular 
