30 l'li< American Geologist. Jvfy, mm 
of N. J. in two respects. In the first place a great bulk of 
these ores are what is known as ••shut ore." This is too well 
known to Deed special description. The N. J. ores arc usually 
hard and compact though thoroughly crystalline. In the sec- 
ond place, while the N. J. deposits have never yielded any 
good crystals, the Barton Hill or "Lover's Hole" mine is prin- 
cipally made up of perfect crystals of magnetite, often of 
greal size and of remarkable purity. The form is of the un- 
modified and modified octahedron. In the mine great crys- 
talline masses of ore two and three feet in diameter l>re;ik up 
Lntocleavage pieces, and often perfect octahedrons are cleaved 
from the mass. 
Shot ores are not common in the New Jersey mines in great 
quantities. Yet at the Dickerson, Hurdtown and Richards 
mine they form no inconsiderable proportion of the ore mined. 
These ores occur in many other mines, hut not in such quantities. 
In the Adirondack region the larger number of magnetite 
deposits are not especially remarkable for their size, certainly 
not averaging greater than the New .Jersey mines. The depos- 
its at Mineville, however, eclipse all. They are among the 
largest of worked deposits so faras known. The country rock 
of these mines is not to be distinguished lithologieally from 
the Mt. Hope rock described by the writer. The extent of this 
rock was not traced beyond the immediate vicinity of the 
mines where it showed abundantly and unmistakably. A rock 
which corresponded closely to the Oxford type was also found 
and in the same relative position. No graphite gneiss was ob- 
served. 
As to the identity in age of theMt. Hope and Oxford types 
of rock found from the Durham Furnace in Pennsylvania to 
the Hudson river at West Point, there can be but little doubt. 
These rocks can be traced almost continuously between these 
two points and in their distinct ridges, presenting practi- 
cally a continuous outcrop. At least these rocks have been 
traced from the Delaware river into New York near the point 
mentioned. 
If the above inference is correct it naturally follows that 
the ore bodies enclosed in these rocks are of the same age. At 
least the weight of opinion is in favor of their being cotempo- 
raneously bedded deposits. 
