52 Geology and Mineralogy of apart of Massachusetts, &c. 
29. CHLORITE. 
eep a distinctly foliated. Middlefield and 
Chester, in small m sses, and also mica-slate. Emmons. 
Among the older Srisices rocks, chlorite seems to be 
composed of more distinct folia. Also, in the vallies on 
both sides of the Taconick ae of mountains, e com- 
mon var. is very abundant in , associated with 
quartz. Itis found along the Hudson also. 
Chiorite Slate. Abundant in Williamstown and oa 
burgh. Also in Pownal, Great Barrington, and in various 
places i in -Pepssolacr and Columbia Counties. 
30. GIBBSITE.* 4 
Discovered by Dr. E, Emmons in an iron mine in Rich- 
mond. It occurs in incrustations and stalactical and ma- 
millary forms, partially crystallized. In Lenox, small 
mammillary bodies upon brown hematite. Most of it seems 
to be com hs, of radiating fibres. It is also diffused 
through disintegrating quartz. Besides these forms, it is 
found compact and earthy, eee an indurated clay, in 
the same mine in Richmon 
31. ARGILLACEOUS SLATE. 
[See the preceding Geol, Sketch. | 
The var. A/uminous Slate occurs in Pownal in argillite. 
Also in New Lebanon and Troy ; Eaton. 
-Grapinc Slate, in small quantity with argillite in Lanes- 
borough and Williamstown. Abundant at Bennington in a 
hill of argillite. See the Geol. Sketch. When this mine- 
ral is thrown into melted nitre, carbonic acid is rapidly ex- 
tricated, as from charcoal or plumbago in a similar situa- 
4 n. + 
Glazed Slate. Troy, &c. Eaton.—See the preceding 
Geology. 
not those minerals, which are composed of the nearly pure earths, 
with patie be arranged in a separate class. 
