270 KEMP'S ORE DEPOSITS. 



gneisses and schists as described for pyrite. They are known at 

 various places in the East. Openings have been made at Lowell, 

 Mass., Chatham and Torrington, Conn., and Anthony's Nose, 

 N. Y., the last in search of pyrite for sulphuric acid. Nickel ap- 

 pears up to 3# of the ore, but these mines have never amounted to 

 much. 1 



2.15.07. Example IQd. Gap Mine, Lancaster County, Penn- 

 sylvania. A great wedge or lense of hornblende rock appears to 

 be inclosed in mica schists. For a space of from 6 to 30 feet of 

 its outer portion it is impregnated with millerite, chalcopyrite, 

 siderite, etc. The millerite occurs as a coating, lining cracks. 

 Nickeliferous pyrrhotite is also found. A great trap dike is near. 

 The mine is not at present worked. It presents some important 

 analogies with the Sudbury deposits. 2 



2.15.08. Example 16c. Sudbury District, Ontario. Breccia of 

 diorit.e, cemented by nickeliferous pyrrhotite and chalcopyrite, form- 

 ing large but more or less irregular deposits; also deposits of purer 

 sulphides, apparently in great veins. An extensive area of Huro- 

 nian schistose rocks runs northwesterly from the juncture of Lakes 

 Superior and Huron. It contains some Archaean inliers, and two 

 great belts of diorite whose strike is northeast, parallel with the 

 schists. These latter include a great variety of rocks and dip at 

 a high angle. The diorites are crossed in places by diabase dikes, 

 which seem to exert an enriching influence. Also, where the dio- 

 rite belt pinches in, ore bodies are found near gneiss and quartz 

 syenite. Where the breccia structure is developed they clearly lie 

 in lines of dynamic disturbances which are parallel with the gen- 

 eral strike. The purer deposits, as in the Stobie mine, present a 

 great thickness of pyrrhotite. In the instance cited it is 160 feet 

 across; but even in this, horses of diorite and more or less angular 

 inclusions occur. The chalcopyrite is in pockety masses in the 

 pyrrhotite. The deposits extend seventy miles in a northwest di- 

 rection, and over a maximum breadth of fifty miles. They pro- 

 duce far more nickel than any other region. The interesting plati- 



1 H. Credner, "Anthony's Nose," B. und H. Zeit., 1866, p. 17. W. E. 

 C. Eustis, "The Nickel Ores of Orford, Quebec," M. E., VI. 208. Engi- 

 neering and Mining Journal, March 16, 1878. 



2 W. P. Blake, Mineral Resources, 1882, p. 399. J. Eyerman, Miner- 

 alogy of Penn. P. Fraser, Rep. CCC, Second Penn. Survey, p. 163. Whar- 

 ton, "Analyses of Nickel Ore from the Gap Mine," Phil. Acad. Sci., 1870, 

 p. 6. 



