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of the formation, they evidently compose, Uke the chain to the 

 southeast, one general belt of axes of elevation, inasmuch as they 

 all lie within a narrow zone and nearly in the prolongation of 

 each other. The limestone which encircles them, usually dips 

 from their flanks, apparently in consequence of an upheaving action 

 near a central line traversing each hill longitudinally. 



Proceeding with our detailed delineation of the boundaries of 

 these primary tracts, we first meet, tov^^ards the northeast, the 

 Pochuck Mountain. This ridge, in which the gneiss has evidently 

 an anticlinal arrangement, though a somewhat irregular one, com- 

 mences in New York, about a mile northeast of the State line, 

 and terminates near the village of Hamburg, having a length of 

 about eight miles, and a breadth ranging between one and two 

 miles. 



At its southeastern base, the primary rocks disappear beneath 

 the limestone of the Hamburg, or Black Creek Valley ; while 

 along the northwestern side they are overlapped by the same 

 formation, a little east of the Meadows of the Wallkill. This 

 ridge is interesting from its having, towards its southwest termi- 

 nation, a valuable deposit of hrowii hematitic iron ore, to be here- 

 after described. 



The next ridge of importance is Pimple Hill, which, together 

 with a spur which it throws ofi' towards Sparta, extends from 

 near that place to Franklin. On the southeast flank of this 

 ridge of primary, is the much celebrated Sterling Mine, consist- 

 ing of zinc ore and Franklinite. 



From Sparta there extends, towards the southwest, another 

 elongated narrow belt of the primary to within a mile and a half 

 of Andover village, while, about a mile to the northwest of this 

 belt, which is bounded by the limestone of a highly crystalline 

 and altered aspect, there lies a small oval hill of the gneiss, also 

 similarly encompassed. Next, in our progress to the southwest, 

 we encounter two other low and detached hills of the primary, both 

 of them lying a little east of the turnpike which joins Stanhope 

 and Andover. Immediately west of this road, we meet with a 

 larger tract of the primary, which extends continuously almost 

 to the road which unites the villages of Hacketstown and Vienna. 

 Its southeastern boundary passes Lockwood and the old Andover 

 Forge, thence along the western side of the Hacketstown Valley 



