70 



and varied crystalline nainerals found connected with the changes 

 effected in tlie limestone. 



At the summit of the ridge there is a seam of quartz rock, pre- 

 senting some indications of its occurring as a vein in the white 

 limestone. Its nature and origin cannot be proved, for it may be 

 a vein of mineral matter strictly intrusive, or one of the beds 

 of cliert, so common in the limestone, or a portion of Forma- 

 tion I., completely fused by contact with the intensely heated 

 metalliferous vein. The confused arrangement and varied aggre- 

 gation of the altering and altered materials at this place, render it 

 next to impossible to trace the true relationship subsisting between 

 some of the parts comprised in this curiously heterogeneous belt of 

 mineral matter. The vein, in its course to the southwest, under- 

 goes a considerable change in its character. About two hundred 

 yards southwest from the place already mentioned, it appears to 

 consist almost wholly of garnet rock and Jeffersonile, some of the 

 latter occurring in enormous crystals, projecting from the face of 

 the rock, but so fissured and readily broken as to render it diffi- 

 cult to procure them entire. 



Further still to the southwest, and nearly opposite the Old 

 Forge, are considerable excavations made in former times for 

 iron ore. The ore was far from pure, abounding in Franklinite ; 

 which by the manganese and zinc contained in it seriously inter- 

 fered with the conversion of the ore into iron. This ore includes, 

 moreover, a considerable proportion of the red oxide of zinc, in 

 some places remarkably pure, being finely lamellated and un- 

 associated with any of the Franklinite that generally accompanies 

 it, and which interferes effectually with its reduction into metallic 

 zinc on the large scale. 



Could this pure red oxide be obtained in sufficient quantity, it 

 would probably be better adapted for smelting into zinc than the 

 mixed ore of the Sterling Mine, three miles further to the south- 

 west. This somewhat rare ore of zinc, the crystallized red oxide, 

 occupies, in company with the crystallized Franklinite, a metal- 

 liferous vein, or more probably a line of nearly continuous veins, 

 in the crystallized carbonate of lime, extending, with occasional 

 interruptions the whole distance from Franklin to a little beyond 

 Sparta, a total length of more than eight miles. 



