104 NEW YORK STATE MUSEUM 



pits. The Cheever at the southern end is, however, the chief one. 

 These workings, now being revived after years of idleness, dip 

 down steeply, at 50° or 60°, then flatten at somewhat over 200 feet 

 vertically from the surface and run westward until cut off by a 

 fault. Their relations are shown on the accompanying section 

 reproduced and reduced from the bulletin of the Geological 

 Society of America 1894, volume 6, page 251. The only point of 

 revision lies in the fact that our recent fuller knowledge of the 

 basic syenite gneisses, makes the occurrence of unbroken gabbro 



y K >c x> X ■<. X X <^ 

 xxxxyxxxxx 

 Xx^ ^^y Kx X >( 



SYENITE Of R £ N V t L LE STRAIA SYEM»Te 



Fig. 18 Cross section at the Cheever mine, in a direction n. 60° e. 



on the east doubtful. Field observations the past summer led to 

 the conclusion that much of the black hornblendic gneiss, formerly 

 taken for gabbro, is basic syenite gneiss, but massive gabbro does 

 occur mingled with it. The ore is a band in the syenitic gneiss, 

 here quite quartzose, and about 150 feet from the undoubted Gren- 

 ville. Below the ore 50 feet of similar gneiss appears before the 

 basic rocks take its place. As the ore bed is followed north the 

 dip appears to flatten and in an old working about half a mile from 

 the Cheever slopes, the strike is north and south and the dip 20° 

 west. The same wall rocks, however, appear. 



Another outcrop of ore appears along the present highway a 

 quarter of a mile north of the old Cheever engine house. It strikes 

 northeast and dips southeast. It has limestone not over 15 feet 

 above it and while thus apparently stratigraphically higher or 

 nearer the limestone than the position of the western end of the 

 Cheever, if we consider it the same bed, it suggests a synclinal 

 basin for the ore, with a pitch of the fold to the south. There can 

 be no doubt that a north and south fault on the west beneath a 

 meadow cuts ofif both the ore and the Grenville series in this 

 direction. 



The Cheever ore resembles very closely the Old Bed variety at 

 Mineville. It is not quite so rich in phosphorus, but is still rather 

 high in this element. Mr Putnam for the Tenth Census [15: 114] 

 took six samples, four underground and two from stock piles on 

 the surface, which showed the following percentages : 



Iron 



Phosphorus 



65-33 



63-5 



63-86 



64.42 



64-77 



6308 



0.643 



. 603 



0.689 



0.452 



0.673 



0-573 



