68 NEW YORK STATE MUSEUM 



furous magnetite is at all events closely involved with them. 

 Crystalline limestones occur abundantly in the 225 teet or 1<sO'»oi 

 rocks that overlie the Cheever ore body in the deepest part , of its 

 basin. The limestones and their associated strata appear on the 

 surface, but the wall rock of the ore is a syenitic gneiss of the usual 

 mineralogy. The Pilfershire ores occur in almost exactly the same 

 relationship. The limestones are near and above but the ore is 

 really in a syenitic gneiss. Between the Cheever and the Pilfer- 

 shire there intervene nearly 2 miles of mountainous ridges of 

 syenitic gneisses rising a thousand feet above the former, and 

 while one may remark the similarity of position, it is rash to go 

 further. 



The Grenville series is thus closely associated with at least three 

 of the ore bodies, but the latter are not actually in undoubted 

 sediments. 



Description of the mines 



Following the map [pi. 2] the ore deposits will be briefly outlined 

 in order from south to north. 



No. 1. This pit now abandoned was opened by Butler and 

 Gillette and continued under the name of the Essex Mining Co. 

 The work was based upon a band of ore now represented by an 

 excavation 40 feet long and 8 to 10 feet high, sloping at an angle 

 of about 6o° and striking approximately n. 12 w. magnetic. 

 The dump alone reveals a rather lean ore with much hornblende 

 and feldspar intermingled. The walls are reddish granitic gneiss. 

 No analyses of the ore are available nor were any samples taken 

 or notes recorded by B. T. Putnam for the Tenth Census. 



No. 2. Lee mine. This opening is just in the outskirts of Port 

 Henry and in a little hillock with abrupt north and east sides 

 which rises from a valley covered with sand. The nearest rocks 

 both to the east and west are the Grenville limestones and their 

 associates, but faults quite certainly intervene between them and 

 the mine. Its wall rock is a granitic gneiss, whose dark silicate 

 is biotite. It is reddish in color and somewhat different both in 

 minerals and appearance from the greenish syenitic wall rocks, 

 elsewhere met with the ores. The ore strikes n. 20 w. and dips 

 about 1 9 westward into the hill at the more northern slope, 

 but swings around to the southeast and steepens to a 30 dip 

 on the south. B. T. Putnam visited it in 1880, for the Tenth 

 Census [XV: 115], and has left a plan and sections. The mine is 

 cut off on the north by a trap dike with an east and west strike. 

 The dike can be traced across the hills to the eastward. 



