30 J. D, Dana— Geological Relations of the 
(3.) Serpentine and other Hydrous Minerals. 
The limestone areas, at several widely distant points, are 
associated with or contain serpentine, with sometimes also tale 
and hydrous anthophyllite. It is embedded in small masses 
in the northwestern limestone area, or that of Canopus Hollow, 
at a quarry two and one-half miles north-northeast of Peeks- 
“is (as has eee been iia) the chief constituent of large beds 
near New Rochelle and Rye, at both of which places the area 
is embraced, like the or limestone belts, between conform- 
s of micaceous enei 
The Rew Rochelle serpin area is on Davenport’s Neck, a 
western portion of the peninsula, and near the middle of the 
northern shore. At the eastern end of the last mentioned expo- 
sure, the rock is mostly crystalline limestone ; but the thickness 
of the limestone portion of the belt is uncertain because earth 
covers the next two hundred yards, and then succeeds the 
gneiss. In Rye, the serpentine area commences one mile north 
of the i radivendl station at Rye, and extends northward for 
over a mile and a half. The rock contains some limestone dis- 
translucent, resembling retinalite and deweylite. The fibrous 
variety, ¢ rysotile, i is also met with. e rock is much rifted, 
and impure with disseminated magnetite, tale, “‘ hydrous antho- 
phyllite,” and other materials. 
The propriety of classing these serpentine areas with those of 
limestone is sustained by the following’ considerations : “) 
The pigs lena position accords with this view; 
presence of dolomite, disseminated through the ser oak ie 
rock or associated with it, favors it; and (8) the fact that the 
7 Mather’s N. Y. Report, 
8 For the facts 2 to the aieniinaoal opengl os the meg ge areas and the 
adjoining schists, see the ete eee on the areas, Nos. 5 spe 
er oor he in his N. Y. Report (p. 461), the occurre serpent 
three og four miles southeast of White Plains. I have Tooked’ "for Fie Prcality 
witho 
