52 Geology of Massachusetts. 
ton; as in North Brookfield and Southbridge, although the rocks 
do not appear as highly impregnated with pyrites in any place as in 
Hubbardston. 
The decomposition of pyrites, in large quantities, often produces 
a considerable degree of heat; and sometimes pieces of rocks are 
driven off with explosion. This is one of the sources of those numer- 
ous stories which one hears in the country, concerning noises heard, 
and lights with smoke, seen in the mountains. Such occurrences 
excite the belief of the existence of valuable mines in the vicini- 
ty ; but they evince the existence of nothing more than iron pyrites. 
Magnetic oxide of Iron. 
This is a valuable ore, affording from 50 to 90 per cent, of iron. 
It exists in several places in Massachusetts, and on the borders of 
the state. 
Hawley Iron Mine. 
The principal ore here, is the magnetic oxide, which is very good, 
and the bed is favorably situated for exploration. ‘The ore does not 
seem to be abundant, the bed being rarely more than one or two feet 
wide. It has been wrought to some extent; but the operations are 
at present suspended. It belongs to Hon. Samuel C. Allen. Mica- 
ceous oxide of iron occurs at the same bed. 
The same bed of ore makes its appearance a mile or two south 
of the excavation; and, also as I have been told, two or three miles 
north, in Charlemont. 
In Bernardston. 
As already remarked in the postscript to limestone, this forms a 
bed several feet thick in limestone, dipping at a moderate angle to the 
south east. When the ore was formerly worked, some complaint was 
made, as if it did not produce the best of iron. But probably the 
trials then made were very imperfect. The ore is doubtless very 
abundant, and I should think well worthy the attention of the iron 
manufacturer. 
In Somerset, Vt. 
This bed is similarly situated to that in Hawley, and in the same 
range of talcose slate, although twenty miles north of the north line 
of Massachusetts. The ore, yielding 78 per cent of iron, is of the 
