ADIRONDACK MAGNETIC IRON ORES 



133 



is only from 50 to 100 feet above the river and it continues 

 practically at the same level for a distance of 500 feet or so to» 

 the north. 



The strike of the ore is here about n. 6o° e. West of the pits the 

 deposit follows that course nearly in a straight line for a distance of 

 1000 feet; it then turns quite abruptly toward the northwest, at 

 nearly right angles to its former direction, and ascends the ridge. 

 It apparently dies out or disappears in a swampy tract about a 

 mile west of the railroad station. The outcrop is concealed over 

 considerable intervals, but the magnetic determinations serve to 

 fix its course with reasonable accuracy. North of the pit the con- 

 tinuation of the ore can be traced across the highway and brook. 

 There is some uncertainty as to the further extent of the deposit 

 owing to the heavy covering of drift, though the magnetic surveys 

 indicate that it wedges out or grades into the country rock within 

 a few hundred feet north of the brook. The strike in this part is 

 nearly due north. 



Gneiss Ore GraniTe Gneiss ( 



Ac.U. at F«C 



£_ if. ' >•• 



Fig. 22 Benson Mines. Section across the ore bodies, near middle of quarry 



Observations of the dip of the ore and inclosing strata show a 

 monoclinal arrangement for the central and northern parts of the 

 ore belt. The gneiss on top of the ridge lies nearly flat. Passing 

 across the strike to the southeast the dip increases gradually until 

 at the pits it is about 45 southeast. This inclination is main- 

 tained with little variation for 1000 feet along the outcrop of the 

 ore to the southwest. At the bend or fold in the deposit where it 

 swings toward the northwest, the dip is 6o° southeast. Beyond 

 the bend there is a flattening of the dip, and over the remaining 

 distance in which the ore can be traced the outcrops show, the 

 strata lying nearly horizontal or slightly inclined to the northwest. 

 The change in the dip takes place within an interval of 100 feet and 

 would seem to indicate a structural break, though there has been 

 no discernible displacement of the ore by faulting. 



Besides the deposit described, there are indications of another 



