312 
[Assembly 
those of Essex, Clinton, Franklin and Warren counties ; a difference 
for which it is not easy to account. The specular ore, which is a per- 
oxide of iron and always gives a red powder, though black in itself, is pe- 
culiar to the former counties, while the magnetic, which is a combina- 
tion of the protoxide and peroxide, belongs to the latter. There are no 
instances of the occurrence of the specular ore on the eastern side of the 
Adirondack mountains. There are, however, veins of the altered mag- 
netic oxide ; for instance, there is a collection of ore in Crown-Point, 
known as the Saxe ore bed, in which the ore has probably been changed 
from the magnetic to the hydrous per-oxide of iron ; and again, the 
Arnold vein, without doubt, has been so far changed as to give a decid- 
ed red powder ; though the structure and crystalline form remains as 
in the magnetic oxide. In the Saxe ore bed the structure has become 
fibrous, and resembles the Limonite of Authors. The specular ore 
belongs to a formation in which the primary limestone forms a large 
part. This is the only geological condition in which the rocks in the 
two districts differ. Both species of ore belong, strictly speaking, to a 
primary formation ; but the limestone of the St. Lawrence exceeds that 
on the Champlain side ; and, moreover, the specular appears to have 
a more or less intimate connexion with limestone. It is, perhaps, suf 
ficient to state the fact, without entering upon the speculation how the 
limestone can have produced the change. In regard to the geological 
position of the two species of ore, it is evident that the hypersthene rock, 
that which constitutes the central portion of mountains of the northern 
part of the State, is the true location for the magnetic oxide. In this 
it is developed to the greatest amount ; though it is not confined to it, it 
will be seen, however, on comparing the amount of ore in the hyper- 
sethene rock, and the ordinary granite and gneiss, that a single vein in 
the former equals all the veins of the latter rocks put together. 
The specular oxide may be found in two geological positions ; in the 
first it is associated with primary limestone ; in the second with gneiss 
or some other primary rock beneath, and the Potsdam sandstone above. 
Examples of the first geological position are furnished by several col- 
lections of ore in Edwards ; and of the second by the Kearny and Pa- 
rish ore beds in Governeur. In addition to the limestone, serpentine 
is a common associate. It is sometimes in pure, separate masses, and 
then in others, it is in intimate mixture and combination ; giving in the 
first instance a spotted, and in the last a mottled appearance to the 
rock. The character of the beds or veins of specular ore is now well 
