76 NEW YORK STATE MUSEUM 
it was made and delivered in 6 weeks.*?* The Daughters of the 
Revolution have erected a tablet on this historic spot to commemo- 
rate the ruins of Sterling furnace. (See plate 13.) 
The ore in the Sterling mine was stripped from the surface, and 
followed under Sterling lake at an approximate angle of 28° meas- 
ured on the average inclination of the slope. 
The mine, which was closed about 1902, is now inaccessible; it 
has been stated that the slope (inclined shaft) of this mine was 
down 1000 feet, a figure which is probably approximately correct 
judging from a map kindly furnished by the Ramapo Ore Company 
(see fig. 6). From this map it would appear as though the two 
mines, Lake and Sterling, were separated by an interval of 250 to 
400 feet. This interval has been called a “ pinch,” but this should 
not be understood to imply an actual squeezing apart of a single 
ore body by dynamic forces. 
According to Putnam ’*™ the ore varies in thickness from 10 to 
30 feet, owing to the rolls in the walls. The character and origin 
of the rolls have already been discussed (see plate 12). 
Putnam (op. cit.) states that the ore is a granular magnetite carry- 
ing more or less apatite, and gives the following analysis of a sample 
taken from a pile of 250 tons: 
1S aerate ERNE lr, EPRI Ar ROIS SLM NR A 61.01 
SLUICE NARRATE A ARL, SHemi ai NaunVarrae aS, oer, Baltealnat era O275 
PG EH ie co TIVES, OPAL RI EL Ae RE SE A DN 0.284 
It is certain that the same general conditions as to the character of 
the walls, the rolls, and the general geologic relations prevail in the 
Sterling mine as in the Lake mine and that a discussion of the 
latter will apply as well to the former. 
The Lake mine. This mine is equipped with an electric hoist, a 
Ball-Norton magnetic concentrating mill with a capacity of 50 tons 
an hour, and dryers. The mine is nearly dry, although it lies wholly 
under Sterling lake; the little water that enters is taken care of by 
three pumps; one at the bottom of the mine of 7.5 horse power, a 
larger one on the 1600-foot level of 35 horse power, and another of 
15 horse power, at the surface. 
The ore body, about 500 feet in width, lies on the gently dipping 
western limb of what appears to be an asymmetric syncline (see 
fig. 6); it is a long, relatively narrow and thin, corrugated and 
123 Appendix to the Third Annual Report of the First Geological District, 
1839. The report of Doctor Horton to W. W. Mather on the Geology of 
Orange County. 
124 Tenth Census Report, 1880, p. 91. 
