560 
GEOLOGY OF THE FIRST DISTRICT. 
Local Details. 
A bed of magnetic oxide of iron has been opened on Breakneck mountain, and several tons 
taken from it. The extent of the bed is not kno-wn, and the ore has not, it is believed, been 
smelted. 
Another bed has been opened on the northeast part of Constitution island, opposite the 
West-Point foundry. 
Another was opened in the middle of the island. The ore occurs disseminated in granite 
near the redoubt, above the Target rock on Constitution island. Magnetic oxide of iron is 
thickly disseminated in limestone, near Phillips’s mill, one and a quarter miles east of West- 
Point ; and it is found in that stratum of limestone in many places, from the above locality to 
near half a mile south of the “ Cotton rock,” a distance of three miles. 
It also occurs in the granite rock that is associated with the augite and limestone rocks 
near the old “ Silver mine,” three-quarters of a mile southeast of Conshook island, and one 
mile northeast of Anthony’s Nose mountain. 
A bed was opened many years ago on Anthony’s Nose mountain, but it contained much 
pyrites and crystallized phosphate of lime, both of which injure the ore for the manufacture 
of iron. 
The brown spar at the “ White mine,” about one mile east of the western summit of 
Anthony’s Nose, contains magnetic oxide of iron disseminated. 
A locality of magnetic oxide of iron occurs on Mr. Tilly Foster’s farm, two and a half 
miles southeast from Putnam court-house. The ore forms a large part of a hill about one 
hundred yards long, ten to forty feet broad, and elevated twenty to thirty feet above the ground 
adjoining. Some hundreds, perhaps thousands of tons of ore can be easily procured at this 
place, without digging below the level of the hill. It is associated with serpentine, with 
limestone containing brucite or boltonite, and with green mica. The mass of ore is bounded 
by gneiss on the east; and serpentine, limestone and verd antique seem to form its western 
boundary. It was thought that some cliromated oxide of iron was observed here, but no 
examination has been made to ascertain that point. Prof. Beck has probably analyzed the 
ore, and detected chromiunf if it exists in it. 
Another ore bed was discovered some years ago about half a mile southwest of the pre¬ 
ceding, on land belonging to the Misses Fowler. Some tons were dug out, but I do not know 
whether any has been smelted. The ore is here mixed with manganesian garnet, augite and 
hornblende. 
The Simewog vein passes through Simewog hill, and was traced one and a half miles south- 
southwest on Mr. Jedediah Wood’s farm ; and it is supposed to continue still farther south- 
southwest, as ore has been dug in that direction about one mile south-southwest from Mr. 
Wood’s house. The variation of the compass at this place has been described at page 117 
of this volume. This vein was formerly extensively worked at Simewog hill, and the mine 
is called Townsend’s mine. 
