300 [Assembly 
In the second place, there are often seen branches extending off from 
the main vein, which are similar to those which granite sends off la- 
terally, or obliquely, from a great mass. 
Again, there are many instances both on a large and small scale, in 
which the mass widens as it proceeds downwards. Such is the case 
with the great mass of ore at Lake Sandford. 
In searching for changes of structure, in parts of the rock adjacent to 
a mass of ore which would bear the appearance of heat, we do not dis- 
cover that evidence which presents itself, when an igneous rock comes 
in contact with one of aqueous origin. We, however, discover a change 
of a different kind, which we are disposed to attribute to the agency of 
a mass. of melted matter on the rock ; it is the conversion of rock into 
garnet, a change, which requires only the chemical union of iron with 
the earthy matters composing the labradorite ; and a change of this 
kind appears possible, while the materials are in a melted state. This 
view of the subject, is sustained by the fact, that garnet does not occur 
in the rock, except in proximity with the ferruginous masses. 
Without pretending to establish the doctrine of the igneous origin of 
the veins of the magnetic oxide, I have only to remark that all the facts 
which have been observed, favor the doctrine expressed above ; but a 
greater number of observations and facts are required, to establish it, 
and place it on the same ground, as that of the igneous origin of granite 
and basalt. 
SECTION XXXL 
Face of the Country^ Lakes, Timber, <^c. 
The face of the country, is both hilly and mountainous. To the 
northeast of the Adirondack Iron Works, at the distance of about 15 
miles, is Mount Marcy, the highest mountain* in the State. Surround- 
ing it in all directions, are other peaks of lesser elevation. In the im- 
mediate vicinity of the works, the mountains are comparatively low, 
and the valleys between them of considerable extent. The arrange- 
ment of the mountains, and the connexion of the valleys, are such, that 
* The height of this mountain is 5^67 feet. Mr. Johnson, however, gives the height 
as much less, and he has made an elaborate statement in Silliman's Journal to prove that 
his measurement was right and mine was wrong. This was quite natural. Proof has 
been furnished since his report, that he is in error only a little over 400 feet. 
