No. 161. J 21 
grains of ore sparingly dissenfiinated through it, the mineral often 
predominates, and it not unfrequently indeed exists in large masses 
and even in beds. In general, the ore does not possess the purity 
of that from some of the mines previously described. It appears, 
however, from the excavations which are every where observed, 
that large quantities of it have been removed. 
The associates of the ore at this locality are similar to those no- 
ticed at the other beds, viz: quartz, feldspar and mica. Horn- 
blende also occurs, and occasionally the ore contains a small por- 
4ion of sulphuret of iron, which renders more caution necessa- 
ry in its reduction than would otherwise be required. 
Before leaving this interesting region, I feel it a duty to present 
my acknowledgments to the Messrs. Pearson of Rockland county, 
and to Messrs. Whitney and Pearson, the agents of the Stirling 
company, for the assistance which they afforded me in its exami- 
tion. 
Following the course of the Highlands, the magnetic oxide of 
iron occurs in various localities. Thus the granulated variety 
abounds in the gneiss rock of the mountiiins near West-Point, 
which is said to contain small crystals of phosphate of lime and 
carburet of iron; while the common magnetic oxide is found on 
Constitution' Island. At Phillipstown in Putnam county, there is 
also abundance of the same ore, and the magnetic iron sand is not 
unfrequently met with on the shores of the Hudson near this place.* 
In proceeding from this range in a northern direction, I am not 
aware that any large deposites of magnetic iron are known to ex- 
ist, until we reach the head waters of the Hudson, in Warren coun- 
ty; although, according to Dr. Steel, two varieties of this ore are 
found in the county of Saratoga. 
At Warrensburgh, in the county of Warren, near the East river, 
twelve miles from the village of Caldwell, this mineral occurs in 
beds of considerable extent, and has there been worked by the 
bloomery process, to be hereafter noticed. I received specimens 
from Mr. Roberts, of Caldwell, possessing characters which ren- 
dered their minute examination a matter of some interest. The 
* See Mr. Mather's paper on the geology of the Highlands, in Silliman's Journal, 
XXI. 97. 
