48 
[Assembly 
and seams of mica, forming gneiss. While in the comity of Franldin 
the rocks contain much more hornblende, which is frequently observed 
in crystalline masses in the walls of the beds and among the ore.* 
The ore in these counties is in almost all cases, in what are usually 
termed beds, or deposits of variable widths and unknown depths run- 
ning parallel to the direction of the stratification, when-the rock is stra- 
tified. The general direction of these beds is North-northeast and 
South-southwest, but when subject to local variations the course is 
iNorth and South or Northeast and Southwest. Sometimes, however, 
this ore occurs in large masses in the rock without any regular paral- 
lelism of the sides, as is the case in Essex county. And lastly, it is 
sometimes disseminated in particles in the rock, apparently without 
any connexion with a bed or vein. 
Southern Counties. — In Orange county, the most abundant ore of 
iron is the magnetic oxide. It is generally found in that species of pri- 
mitive rock so common in the highlands of this county, and often called 
granitic gneiss or gneissoid granite. It lies in beds and layers in this 
rock, and has the same line of bearing and dip. Where it exists in 
layers, they are from one inch to twenty feet in thickness, and in some 
places the layers of the ore alternate several times with those of the 
rock. Where the ore occurs m masses, the magnitude of the largest 
has never been ascertained.! 
The magnetic iron ore is also found in the gneiss and hornblendic 
gneiss rocks in Putnam county. " They form" according to Professor 
Mather, masses which by casual examination would be called beds ; 
but after a careful investigation of the facts, I think they may be called 
veins. Their course is parallel to the line of bearing of the strata and 
they lie parallel to the layers of rock, but by a close examination, it is 
found that in several instances, after continuing with this parallelism 
for a certain distance, the ore crosses a stratum of rock and then re- 
sumes its parallelism, then crosses obliquely another and so on. In 
other places, where a great bed of the ore occurs at some depth, only 
a few small stripes of ore penetrate through the superincumbent mass 
to the surface, as if the rocks had been cracked asunder, and these 
small seams of ore had been filled up from the main mass below. The 
* See the Reports of Dr. Emmons and Mr. Hall. 
t Dr. Horton's Report on the Geology and Mineralogy of Orange county.— Geolo, 
gical Reports, 1839. 
