572 
GEOLOGY OF THE FIRST DISTRICT. 
hematite locality, and not more altered from the calciferous rock of the Champlain division, 
than the limestone near the Copake ore bed, or that on the eastern side of the Amenia ore 
bed. 
Granite and gneiss, and some sienite, occur still farther to the west, and southwest of the 
Clove mine. The limestone above referred to, is like that of the valley of the western 
branch of the Ramapo that flows from Long pond, and like that in the vicinity of the village 
of Warwick, and on the western side of Bellevale mountain. 
“ About one mile southeast of the Clove mine, in a straight line, is the O’Neil mine, or, 
as it is commonly called in the vicinity, the Nail mine. This is a vast bed of magnetic oxide 
of iron. It is often in the seams, beautifully crystallized in octohedrons and cubes; the lat¬ 
ter are rare. It also contains pyrites, and requires the roasting process. Magnetic pyrites 
are also occasionally found in this mine; the ore is very hard and compact, the most so of 
any of our standard ores. This ore is very much esteemed. It makes a good iron, which 
is of the red short description. This mine is the property of Gouverneur Kemble, esquire. 
Large quantities of this ore are used. The bed is now open one hundred and fifty by five 
hundred feet. A wall is partially exposed on the southeast side, but no appearance of limit 
is any where else visible. One dyke has been crossed, which is several feet thick, cutting 
the bed perpendicularly and nearly east and west. The immediate associates of the ore in 
this mine are calcareous spar (white and abundant), rose colored garnet, green coccolite, dark 
colored sahlite and hornblende (massive), arragonite (the flosferri variety), amianthus, and 
serpentine.”* 
The O’Neil mine, like the Clove mine, seems an immense mass of ore without any easily 
traced connection with the adjacent rocks. On the southeastern side, the same kind of gra¬ 
nitic gneiss is seen as at the Clove mine. A mass of sienite or felspar rock projects into the 
mine on the southwest, but it is more than half surrounded by ore, which lies partly on op¬ 
posite sides of it. The ore lies very irregularly, in some places very pure, in others more or 
less mixed with hornblende, serpentine, limestone (as calcareous spar, rhombic spar, verd 
antique, etc.), and various aggregates of these with each other and with other minerals. 
Some of the ore contains much common pyrites and magnetic pyrites. Slight traces of copper 
ores were observed in some of the fragments. Much of the ore seems to be an intimate 
union of magnetic oxide of iron and serpentine, so that it has much the aspect and color of 
the dark green serpentine; much seems also intimately blended with greenish hornblende. 
This mine is a place of great interest to the mineralogist. Many very well characterized 
and beautiful minerals occur here. The crystallized magnetic ore makes the most brilliant 
and beautiful specimens of that mineral, of any locality I have ever seen. Many of them in 
brilliancy, beauty, and richness of color, vie with the richest specimens of the specular iron 
ore from the Island of Elba. The following minerals were observed at this mine, viz ; 
Dr. Horton’s Report: Third Annual Geological Report of New-York, 1839, p. 162. 
