Geology and Mineralogy of a part of Massachusetts, &c. 31 
sides of this line of iron ore has been for many years to the 
west of north. Even if beds of iron ore exiend to the 
north pole upon a great circle of the earth of which this 
line is a part, the north magnetic pole would, from the dis- 
coveries of Capt. Parry, be about thirty degrees west of 
this circle or line of iron ore. The variation of the needle ap- 
pears, in this part of the country, to be decreasing, and from 
observations made by surveyors is about the same as it 
was fifty years ago. 
The beds of iron ore in Somerset Vt., the well known 
bed of Hawley distinguished for its beautiful micaceous ox- 
ide of iron, the specular cre of some‘of the towns south of 
Hawley, and the coarse iron ore of Middlefield, seem to 
me to be ina linevery distinctly separated from the other, as 
well by the nature of the ore as by its geographical position. 
MINERAL SPRINGS. 
The principal is the well known spring at New Lebanon, 
very near the boundary of Mass. Only a small quantity of 
solid matter is contained in its waters, according to the 
analysis of Dr. Meade. In Williamstown isa spring, pos- 
sessing similar properties. The gas which issues from it is 
common atmospheric air. It contains a small quantity of 
carbonate of soda. 
Hepatic waters, or springs containing sulphuretted hydro- 
gen, are not uncommon along the Hudson. The one at 
Bath, opposite Albany, attracted some attention a few 
years since. At Adams, Pittsfield and Great Barrington, are 
springs, whose waters have a favourable influence upon many 
cutaneous diseases. At Hinsdale is a hepatic spring, around 
which the earth is covered with sulphur in dry and settled 
weather, from the decomposition of the sulphuretted hy- 
drogen which rises from it. 
Springs from which nitrogen gas issues in some quanti- 
ties are found in the S. E. part of the town of Hoosick, 
Geol. and Ag. Survey of Rensselaer county, p. 29. 
SIMPLE MINERALS. 
This section contains a great variety of interesting mine- 
rals, some of which are rarely found in our country. The 
