732 THE GEOLOGY OP MINNESOTA. 



[Quartz, pyrite, etc. Black schist. 



[NOTE. Nos. 1457 to 1500, inclusive, were collected north of Gunflint lake, 

 outside of Minnesota territory, and there are no sections of them. They are not 

 here described, but brief field notes concerning them can be found in the Sixteenth 

 Annual Report, pages 75, 76, 127-129.) 



No. 1501. QUARTZ, PYKITE, ETC. (Vein material, ) 



West side of East Eagle Nest lake ; N. E. }4 N. E. y sec. 34, T. G2-H W. 



Kef Annual Report, xviii, pages 13, 21, ">'.(; Annual Keport, xix, pages 125, 127; see, also, Annual Report, 

 xv, pages 32 :. 



Met], Vein material composed largely of quartz, with considerable pyrite, some 

 calcite and also apparently chalcopyrite. An assay was made of this specimen for 

 gold and silver. A trace of gold was found, but no silver. No section. 



Aye. Archeau (Keewatin). u. s. G. 



No. 1502. QUARTZ. 



At the mines at Tower. Embraced in considerable masses in immediate proximity to the so-called chal- 

 cedonic silica in the green schist. 



Ref. Annual Report, xviii, page 59. 



Meg. Vitreous quartz. 



Mir. The individual orientations extend parallel (roughly) with each other, 

 showing a coarse fibrous structure. Each individual is united to its neighbors by a 

 granular border, each extending into the other, as evinced by the orientations; at 

 the same time a shadowy extinction goes over each grain. One section. 



Age. Archean (Keewatin). N. H. w. 



No. 1503. QUARTZ. 



Vein one-half inch wide, running transverse to the green schist at Tower. 



A//. Oranular. 



Mic. This has not the fineness of the jaspilitic silica, although it interlocks in 

 the same way. The size, however, of the grains varies, some being not more than a 

 hundredth part the size of others. One section. 



Age. Archean (Keewatin). N. H. w. 



No. 1508. BLACK SCHIST (wWi /<///-/fV nodules). 



From pits north of Chester peak, near Soudan. 

 Ref. Annual Report, xviii, pages 11, 59. 



Mr;/. Dark, heavy schist, which is apparently carbonaceous. In the schist is 

 scattered some pyrite and there are also pyrite nodules, elongated and spherical. 

 The largest spherical nodule of pyrite in the specimens collected is two and a quarter 

 inches in diameter. It has a central mass half an inch in diameter, of granular 



