eisai nates 
SEER Ee SHES S 
On some Reactions of the Salts of Lime and Magnesia, 365 
Art. XL.—On some Reactions of the Salts of Lime and Magne- 
sia, and on the Formation of Gypsums and Magnesian Rocks ; 
by T. Srerry Hunt, F.R.S., of the Geol. Survey of Canada, 
(Continued from this vol., p. 187.) 
I¥; 
Facts in the history of Gypsums, Dolomites, Magnesites and Lime- 
stones. 
43. The gypsums found in nature may be divided into two 
classes, those directly deposited from water, and those produced 
by the alteration of beds of limestone. To the latter division 
belong the gypsums found in the vicinity of solfataras, where, 
as 
2], vil, 175; 
dus de V Acad., 1855, xl, 1848. 5 
These acid waters which make their appease in an almost 
undisturbed region, I conceive to have their origin in d 
. Waters containin piney ae acid or ferric or alumin- 
ous sulphate, may by fowitis into basins where carbonate of 
lime is present, give rise to solutions of renga of lime, a 
the evaporation of these, of sea-water or other gypseous solu- 
tions pet give ia to deposits of sulphate of lime, which will 
