Geology and Mineralogy of a part of Massachusetts, &c. 55 
or spheroidal masses, with radiations from the centre, and 
the masses often divide by a natural seam into equal por- 
tions. It is sometimes capillary. . 
Hepatic sulphuret of iron in mica slate, Williamstown. 
In Chester, this mineral yields abundance of sulphuretted 
hydrogen by the action of sulphuric acid. In Hancock, 
Richmond, and Petersburgh, the crystals of the sulphuret, 
are often more than an inch onaside. In Lee, it is in 
compact masses. If my informant is to be credited, this 
mineral is occasionally thrown out of the side of a hill in 
Pewnal——he brought some of the crystals. The action of 
the water in forming, with the mineral, sn]phuretted hydro- 
gen, which was suddenly evolved or expended, would ac- 
count for the fact. May we not in this way account for 
those fires which are reported to have been seen in various, 
though not numerous, places? One has been reported to 
me on the most credible authority. The gas took fire and 
burnt vegetables or scorched them, near where it issued. 
The place, abounds in sulphuret of iron. Much money 
has formerly been expended in digging for imaginary sil- 
ver ore, in Williamstown, Adams, and Savoy, where noth- 
ing but sulphuret of iron occurred or was to be expected. 
2. MAGNETIC OXIDE OF IRON. 
In mica slate and chlorite slate, and in serpentine, gene- 
rally of the primitive form. It is sometimes massive, weigh- 
ing some pounds. Emmons. Also, at Somerset, with do- 
lomite. 
3. SPECULAR OXIDE OF IRON. 
In large folia, cemented with serpentine. ‘The micaceous 
oxide, abundant and beautiful, at Hawley. 
4. BROWN OXIDE OF IRON. 
This is the principal ore of iron at the several beds men- 
tioned in the preceding Geol. Sketch. The varieties are 
the Hematiiic in allits various forms; the Compact ; and the 
