36 Geology and Mineralogy of a part of Massachusetts, &c. 
“11. Marl. 
Var. 1. Earthy Calcareous. 
In beds in Pittsfield and Lenox—seems to be chiefly car- 
bonate of lime, often containing many decayed snail shells.. 
A large bed in Sand Lake. Eaton. 
Var. 2. Earthy Argillaceous. 
It abounds at Hudson—has the appearance of clay, effer- 
vesces rapidly with acids, and is said to contain Sulphate of 
Magnesia. 
Schistose marl or argillaceous limestone, containing forty 
per cent of lime, and disintegrating on exposure, is found at 
Schaghticoke. Eaton. 
4, PHOSPHATE OF LIME. 
In Chester, disseminated in granite; also, the var. apa- 
tite in yellowish green crystals, and granular masses— 
phosphoresces on hot iron with a pale yellow light. Also 
in mica-slate, in roundish masses ; its powder digested in 
water changes vegetable blue to green; its colour is green- 
ish. Emmons. 
5. SULPHATE OF LIME. 
In the hard waters that issue all along the range of 
limestone. In small crystals near Hudson in clay ? 
6, SULPHATE OF ALUMINE AND POTASH. Alum. 
Effloresces on the aluminous slate at Pownal. Found 
in abundance at New Lebanon, in the same slate. Eaton. 
