1883. i Trans. N. Vi Ac. Sci. 
The specimens of the deposits of the geysers and hot springs of 
the Park, exhibited by Mrs. Smiru, are of two kinds ; one, silicious 
(geyserite), from the geysers; the other, calcareous, from the 
‘‘ Mammoth Hot Springs.” The first kind was produced by the 
action of hot water on a silicious volcanic rock (rhyolyte) ; the sec- 
ond, on limestone, which underlies the northwest corner of the 
Park. A third kind of deposit is seen in the “ paint pots” and 
“mud geyser” of the Norris basin, a pink or white clay, appar- 
ently derived from the feldspathic portion of the decomposed rhy- 
olyte, the quartz having been dissolved out. ‘The clay in the paint 
pots is sometimes highly colored, forming a pasty or semi-fluid 
inass in a state of constant ebullition from escaping steam. The 
deposit of calcareous tufa, from the Mammoth Hot Springs, is 
quite rapid, coating objects, like the horse shoes and other things 
shown, with a film an eighth of an inch thick, when they are im- 
mersed in the water for two or three days. 
The PresipENT exhibited specimens of brilliant anthracite, 
sent by Mr. M. C. Reap, Corresponding Member of the Academy, 
residing at Hudson, Ohio. They are reported to come from 
Hastings Co., Canada, a region underlain by Laurentian rocks. 
If this report is correct, they are probably the residue of the spon- 
taneous distillations of petroleum, like the asphaltic anthracite of 
the Calciferous sandrock of Herkimer, in New York, and of the 
Utica shale at Canajoharie. 
Mrs, JAMES WELD exhibited some peculiar crystals of carbon- 
ate of lime from Fort Laramie, Wyoming Ter. ; hexagonal prisms, 
I to 2 inches wide, + to 4 inch in length, with bevelled edges ; the 
form of aragonite, with minute and partial internal rhombic 
cleavage of calc-spar—probably aragonite changing to calcite. 
Mr. N. H. Darron read a paper 
ON THE STRATA OF INDURATED SHALES BETWEEN BERGEN HILL 
AND THE PALISADES, N. J. 
Prot. DanreL S. MartIN then spoke on the subject of 
THE TRENTON (N. J.) GRAVELS, AND THEIR CONTAINED IMPLE- 
MENTS, AS BEARING ON THE ANTIQUITY OF MAN. 
(Abstract.) 
After reviewing the general facts regarding prehistoric archeology 
abroad, as to the differences between palzolithic and neolithic imple- 
