Foreign Notices in Mineralogy, &c. 243 
ihe red sandstone and conglomerate, disrupting the rock in 
a narrow dyke: no possible supposition of aqueous agency 
could have caused this appearance. T: 
Look at the same volume, p. 134, for the localities of a- 
gate, Chalcedony, Zeolyte, Titanium, Prehnite, &c. they 
amount to proofs of the volcanic character of the country 
from Deerfield to East-Haven and Woodbury :* for all these 
substances are thus found as the indubitable accompany- 
ments of rocks whose igneous origin is undisputed (Iceland, 
Ferro, &c.) and are never thus found in rocks of undisputed 
aqueous origin. : 2 TC. 
‘P.S. Since writing the above; I have been induced to 
consider as the source of volcanic fire, the caloric of tem-. 
perature given out by the condensation of a column of at- 
mospheric air, reaching from the surface below the old 
Granite. On the same principle as the common condensing 
tube for firing punk. It appears that the temperature of 
mines increases about 12 or 14° of Fahrenheit gradually at 
the depth of one thousand feet. I have not yet had time. 
to give sufficient consideration to the subject, to state any ra- 
tio of compression (other than Cotes’s) or the quantum of 
precipitated Caloric by the condensation of the lowest part 
ofthe column. I therefore throw out the idea only for con- 
sideration, ~~ 4 LH OF 
Arr. H.—Foreign Notices in Mineralogy, Geology, ancient. 
Arts, &c. ; communicated by Dr. J. W. Wensrer. 
: : Boston, Nov. 25th, 1821. 
To Pror. Siniiman, 
Dear Sir, 
From 'Thomson’s Annals of Philosophy, I extract the 
results of an analysis of a substance that occurs in the Lime- 
stone of Pargas, (by P. A. V. Bondsdorf, Ph. Dr. of Abo.) 
This substance * occurs in Limestone in a white, radiated 
form 5 it was long considered Tremolite—it is accompanied 
* Woodbury is an isolated basin of trap surrounded by primitive and sepa- 
rated by many miles of primitive from the great trap region of New- 
England. Vid. Vol. Il. pa. 231 of this Journal.—En. ; 5a) 
