96 . NEW YORK STATE MUSEUM 



The ore bodies are tabular in form, though showing at times rather 

 marked modifications. The walls pinch and swell along the strike 

 and on the dip, and when the irregularities become pronounced the 

 ore bodies assume the shape of lenticular masses arranged in suc- 

 cessive order. The narrowing of the walls seldom cuts off the ore 

 entirely between the lenses. The dip is northwest at a high angle. 



An interesting geologic feature in connection with the deposits 

 is the existence of frequent displacements which were first noted 

 and commented upon by Emmons. So far as observed the fault- 

 ing always takes place across the strike, producing a lateral offset 

 in the line of outcrop. The displacements are small, usually not 

 more than 20 feet, and do not seriously affect operations. At the 

 Sucker mine a thin diabase dike has been intruded along the plane 

 of such a fault. 



The Nelson Bush mine is opened by two shafts 500 feet apart, 

 apparently on the same outcrop, although not connected under- 

 ground. Both shafts are driven on an angle along the course of the 

 deposit. The northern shaft is down 900 feet on the incline which 

 varies from 60° to 30°, while the southern is down 300 feet with 

 an angle of from 42° to 35°. The ore body ranges from 10 to 25 

 feet thick, the maximum being reached at the north end. As a 

 rule the walls are formed of a reddish augite gneiss that has the 

 mineralogic composition of syenite. Near the ore, however, there 

 is much darker gneiss containing hornblende. The latter variety 

 is found to a greater or less extent all through the deposit, usually 

 as bands of variable thickness alternating with the magnetite. 



Although the entire mine output at present is concentrated, a fair 

 proportion contains sufficient iron to be classed as furnace ore. 

 Yet concentration exercises a beneficial influence upon the quality 

 of the product, specially as it reduces the phosphorus content. In 

 some of the richer material apatite shows very prominently. In 

 the concentrating ore the magnetite occurs in aggregates rather 

 than as disseminated particles, so that coarse crushing serves to 

 release most of it. On the average a little less than 2 tons of crude 

 ore is required to produce i ton of concentrates carrying 65 per 

 cent iron. 



The Arnold mine adjoins the Nelson Bush on the south. It has 

 been a large 'producer in the past and there is some prospect of its 

 being reopened. The deepest workings are about 800 feet. It 

 is said that the ore bodies narrowed in depth and showed evidences 

 of pinching out, but this point can hardly be regarded as established 

 in view of the little exploration that has been made. It seems 



