108 NEW YORK STATE MUSEUM 
doned prior to 1880 (although according to Putnam *’® 15 tons of 
ore were hoisted from the mine in April 1880) is situated about one- 
half of a mile southeast of the east shore of Round pond and about 
1% miles south of Monroe. 
All the openings were made through a thin cover of drift which 
veneers a low hill of gneiss. There are numerous shallow pits, partly 
filled with caved-in drift and in some cases containing water, a large 
open cut about 4oo feet long and possibly 200 feet wide, full of 
water, and a narrow cut about 150 feet long which widens out at 
the end and leads into an inclined shaft or tunnel of unknown depth, 
which is also water-filled, so that the old workings are inaccessible 
and of unknown extent. 
The rocks seen along the walls of the narrow cut leading into the 
drowned slope are massive igneous types without well-defined 
structure, except where they are cut by a small crush-zone, not more 
than a foot wide; here they are badly crushed and decayed. 
On the southeast wall of the cut (hanging wall?) appears a very 
coarse, massive hornblendite, while on the opposite wall (the foot- 
wall?) the rock is a massive pyroxenite (see plate 1, figure 1) 
associated with highly quartzose granite (see plate 2, figure 4), all 
facies of the Pochuck. 
The ore (see plate 11, figure 4) is a massive, rather coarse 
magnetite with considerable interstitial pyrite and pyrrhotite. 
There is a great variety of different sorts of very coarse-textured, 
massive, basic rock on the dumps; the magnetite appears to be 
associated with the coarse, dark biotite masses. During the replace- 
ment process the ferromagnesian minerals of these rocks were 
changed by deuteric action to fine flaky talc, chlorite and secondary 
magnetite (see plate 1, figure 2), all late magmatic end-stage prod- 
ucts and possibly just preceding the ultimate replacement by the 
magnetite. 
There are no available data descriptive of the extent, character, 
form or size of the ore body, except the comment of Horton,’ who 
in his report to Mather states that the mine had then (1839) been 
“open many years,’ and that the ore was a “compact and granular 
shot-ore,’ with more or less disseminated pyrite. It is also stated 
that the ore alternates with rock, occurring in streaks and bands from 
a few inches to a maximum of 4 feet in thickness. It apparently 
was necessary to mine considerable lean ore and rock in order to 
150 Putnam B. T. Tenth Census Report, 1880. 
151 Appendix, 3d Annual Rep’t Geol. Surv., N. Y. 1830. 
