32 J. D. Dana—Limestone Belts of Westchester County, N. Y. 
Oo ser- 
entine pseudomorphs at the Brewster (Tilly Foster) Iron 
Mine in Putnam County, New York.’ 
In view of the facts with regard to the character of the Jime- 
of Rye, limonite has resulted from the alteration of the serpen- 
tine rock, and the bed has been opened, though not with good 
prospects of profit. The limonite in this case has come chiefly 
from the oxidation of the iron of the ferriferous dolomite asso- 
ciated with the serpentine, and that of the disseminated mag- 
. 
netite. 
* See the author’s memoir on the serpentine pseudomorphs of the Tilly Foster 
Iron Mine, in this Journal, ILI, viii, pages 454, 455, 1874, 
[To be continued. ] 
