** : * * > a 
Geological Survey of the State of New York. 81 
Prof. Emmons presents in his report a notice of much interest, 
in relation to the iron ores of his district. Those of Essex county, 
at McIntyre, o = in vast abundance in the hypersthene rock ; 
i“. are also fo in the other primary rocks. They belong to 
in. variety, the octahedral or magnetic oxide, and occur in veins 
“of great extent. r 
The peculiar connexion of trap dikes with these veins suggests 
to Prof. Emmons an i igneous hypothesis as to the origin of the ore. 
These veins in Arnold Hill, are crossed by a greenstone dike, 
ten feet wide, which Hiclocated one of them four feet, and they 
ran north and south, making an angle with the direction of the 
rock and red granite, which is northeast and southwest. The 
Palmer vein is cut by four dikes; one of them is fourteen feet 
wide, and is traceable on the surface half a mile. This dike be- 
ing pierced, a vein of.ore thirty five feet wide was found, in close 
contact with the dike and cleaving readily from it. 
The Winter ore has been cut through by nine dikes. 
* The amount of the several veins in the vicinity of Clintonville 
is one hundred and thirty six feet. The ores in the Sandford 
mine, town of Newcomb, ‘are in the hypersthene rock, and it 
would appear, from the minute survey and description given, that 
this ore is very superior, and the locality possesses advantages that 
tender it more available than any other works of the country. 
These ores have been wrought, and the iron made has been 
submitted to com parative experiments by Prof. Johnson* of Phil- 
adelphia, and found to be equal in strength to the best English 
iron and surpassed only by the Russian. 
Prof. Emmons contrasts the position of the specular oxide of 
iron of Jefferson and St. Lawrence counties, with the magnetic 
oxide of Fissex, and describes the association of the former as 
follows: “'The specular oxide may be (is) found in two geolo- 
gical positions,—in the first it is associated with primary limestone 
—in the second with gneiss, or some other primary rock beneath, 
= the Potsdam sandstone above. In addition to the limestone, 
ntine is a common associate. It is sometimes in pure sepa- 
asses, and in others, it is in intimate mixture and somes 
ton—giving in the first instance a spotted, and in the last a mot- 
tled appearance to the rock.” ‘ 
Ni Ng a ae a a one 
# — Pais Vol. xxxvi, p. 94. 
Vol. x1, No. 1.—Oct.-Dec. 1 1 
