544 TRANSACTIONS OF THE 



4. Limestone, light blue, silica,. 65 feet. 



8. Limestone, dark blue, 120 do 



2. Limestone, dark blue, crystalline, 30 do 



485 

 1. Gneiss, as seen, 20 do 



Total thicknesss of strata, 505 do 



The limestone dips 20° to 25'^ to the N. W.; gneiss, unconformable, dips 

 seven deg. to S. E , accompanied with quartz, feldspar, and silica. 



The ledge of altered limestone extends from Sparta with a N. E. and S. 

 W. trend to Eden, in Orange co.. New York, and contains the following 

 minerals, most of which are found within a few rods of each other : 



Franklinite, octohedral, beveled edges; garnets of every shade of hue; 

 willemite ; manganese ; calcite, white, salmon-colored and striated ; zinc- 

 iferous calcite; blend, opaque, black, heavy, yellow; fiuor spar; galena; 

 cerutite : chalcopyrite ; malchatite ; azurite ; quartz ; jasper ; magnetite ; 

 talc; mica; hematite; pyrites; calamine ; hornblende; apatite; ephodite ; 

 feldspar. 



Mr. Pomeroy wished to know what had been analyzed ; metal made 

 directly from the ore, or from the residuum of the furnaces in which zinc is 

 prepared ? 



Mr. Curtiss. — There were some "pigs made from the residuum of the zinc 

 manufacture. We have had several analyses made by Dr. Jackson, of 

 Boston, and Dr. Ha3^s. The ore has never shown a trace of sulphur or 

 phosphorus. When analyzed by Dr. Hays, the zinc has been found to take 

 off the sulphur and phosphorus to the top of the chimney where they parted. 

 The residuum sometimes contains three or two and one-half per cent, of 

 zinc, and this is enough to take off all sulphur and phosphorus. 



Mr. Stetson wished to know if there was any reason why metal from the 

 residuum should differ from that from the ore direct. ? 



Dr. Stevens considered that the greater amount of heat required by the 

 residuum would be the only cause of difference. It is a remarkable ore, 

 not containing any impurities, such as silica or alumina. If the pig were 

 made from the ore with charcoal, there would be more per cent, of zino 

 than if made from the residuum ', there would be, also, more manganese- 

 Mr. Pomeroy thinks it of great importance to settle that point, as its 

 commercial value would be affected by the amount of impurities ; for, if 

 used for iron alone, twenty to thirty per cent, of franklinite with a rich 

 iron ore would be useful. The pig would be white and crystallized if from 

 the ore pure. The residuum may show a trace of silicium, derived from 

 the ground upon which it lay ; but the amount of zinc must be exceedingly 

 email, for, as said by Mr. Seeley, there cannot be an alloy of zinc and iron, 

 but the zinc is of great value for taking up the sulphur, oxygen, &c. 



Mr. Tillman. — It is immaterial whether the metal be made from the 

 residuum or ore, for the iron will not fuse until at a higher temperature by 

 2,000° than zinc; therefore, in any case, the zinc will be driven off. 



