PETROGRAPHIO GEOLOGY AND DESCRIPTIONS. 307 



Quartzyte. Taconyte.] 



No. 302. QUARTZ AND QUARTZINE. ( Vein matter. ) 



From the Baker shaft on the White Rose vein near Arrow lake (in Canada). 

 Ref. Annual Report, vii, page 17; Annual Report, ix, page 78. 



Mic. Consists largely of quartz and quartzine, the latter differing from chalcedony 

 only in having its fibres elongated parallel with ?i g instead of n f . The fibres are 

 coarse and readily pass into pyramidal quartz. 



There is, besides this siliceous element, apparently a large amount of altered rock 

 material. Pyrite is visible macroscopically. The colored ingredients are hornblende, 

 alteration of augite, biotite, magentite, and a few isolated grains of titanite. 



Four sections. 



Aye. Vein in the Animikie rocks. N. H. w. 



No. 303. QUARTZYTE. ( Vein material. ) 



Apparently auriferous quartzyte from the large quartz vein near the north shore of Pine lake; S. E. ^ 

 sec. 31, T. 65-2 E. 



Ref. Annual Report, vii, page 21; Annual Report, ix, page 79. 



Meg. A gray, cherty mass, holding small fragments of a darker material. There 

 is also some pyrite in the rock. 



Mic. The section, which is very thick, shows finely crystallized quartz and much 

 of an opaque gray substance. 



One section. 



Age. Vein in Animikie rocks. u. s. G. 



No. 304. TACONYTE. 



Point in North lake; N. E. % sec. 16, T. 65-2 W. 

 Ref. Annual Report, ix, pages 80, 81. 



Meg. A cherty rock which varies in color from gray to greenish and to pinkish. 

 A few small spots of finely crystallized quartz are seen; also some small dark spots 

 which have a little pyrite on their peripheries. 



Mic. The section shows numerous small rhombs of siderite in a cherty ground- 

 mass. The section is too thick to enable the exact nature of this groundmass to be 

 determined, but it is probably made up of a very finely crystallized mass of quartz 

 grains. 



One section. 



Age. Animikie. 



Remarks. This rock is similar to those described as sideritic cherts, by Irving 

 and Van Hise, in Monograph xix, U. 'S. Geol. Survey. For a full discussion of these 

 rocks, see that work, and also "The Mesabi Iron Bearing Rocks" (Bulletin x, 

 Geological and Natural History Survey of Minnesota), by J. E. Spurr. 



