Iron-Bearing Rocks of the AdirondacJcs. — Ncison. 29 
Near Natural Bridge, east of the white limestone, there are 
also outcrops of lean magnetic ore having the same general 
resemblance to the Little River deposits but of much more 
limited extent. What was nor distinctly observed at the 
Little River mines was noticed here, extensive outcrops of a 
rock of the Mt. Hope type. Near by, but with contacts, if 
such existed, covered with soil, was the peculiar graphite 
gneiss found so abundantly in New Jersey. 
At St. Regis Falls on the Northern Adirondack R. R. a rock 
cut in the railroad was made through a rock lithologically 
identical with the Nit. Hope rock. At this point the rock 
was interbedded with a dark hornblende-feldspar rock so 
often noted in New Jersey.* 
No graphite rock was found near by. This may exist, how- 
ever, as no extended search for it was made. Beyond this 
point to Paul Smith station rocks when exposed were princi- 
pally of the labradorite type. 
At the Mt. Lyon magnetite mines on the Chateaugay R. R. 
the country rock was also lithologically identical with the 
Mt. Hope type. Neither the Oxford rock nor graphite gneiss 
was observed here, though search was as limited as at the 
other localities. Careful examination was made of the ores 
and mine rock, however. These in all the important details 
agreed very closely with the magnetic ores and mine rock of 
New Jersey. 
At the Mineville iron deposits, however, the most striking 
resemblances were found. In many of the mines phosphate 
of lime or apatite was observed in grains included in the ore. 
Crystals were rarely observed. In the Port Henry ore bed 
this mineral occurs in layers in which the iron is in a less 
quantity than the apatite. Many of the ores are Bessemer, 
and in this respect they differ from the New Jersey deposits, 
though in New Jersey some Bessemer ores are found in parts of 
a vein while the greater part of the vein is non-Bessemer. Like 
the New Jersey ores, these of the Mineville region are remark- 
ably free from titanic acid. Molybdenite was not observed by 
the writer, though it is reported to be sparingly found. 
The ore of these deposits i- somewhat unlike the magnetites 
* For a description of a similar rock in the Mt. Hope type see Ann 
Rep., State Geologist of N. J., 1890, p. 76. 
