PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 691 



Taconyte. Quartzyte.] 



No. 1319. TACONYTE. 



North side of the point that lies north of Animikie bay, Gunflint lake. 

 Ref. Annual Report, xvi, pages 77, 121. (Compare No. 437.) 



Meg. Fine, siliceous. 



Mic. Taconyte. The rock is mostly quartz, but it is stained with iron and other 

 substances so as to show the peculiar globular structure of taconyte. These globules 

 are not heavily charged with iron, but in the main are translucent, though some- 

 times entirely opaque. Some of the finest-grained ones, which suggest a possible 

 derivation from devitrification of volcanic glass, are crowded with feathery tufts of 

 fibres (or trichites?), which are exceedingly fine. It is evident, however, that these 

 fibres are of later date than the deposition of these grains in this rock, since they 

 extend beyond the borders of the grains into the surrounding interlocking matrix 

 of quartz. If these grains are of original volcanic glass, their devitrification was 

 probably effected about the time of the deposition of the interlocking quartz. One 

 section. 



Age. Animikie. N. H. w. 



No. 1320. TACONYTE. (Banded.; 



A condition of No. 1319. (Compare No. 1277.) 

 Ref. Annual Report, xvi, pages 77, 121. 



Meg. The rock appears " streamed." In the field said to be a condition of rock 

 No. 1319. 



Mic. The whole rock consists of quartz and magnetite, in a rhyolitic( ?) structure, 

 the magnetite being in cubes and the quartz in interlocked, very fine grains. The 

 structure is the same as that of the rhyolitic fragment mentioned in No. 1310, but 

 much coarser. One section. 



Age. Animikie. 



Remark. It is in keeping with the intimations that precede, that a rhyolitic 

 rock should be found in place, and this may be that rock. It is at or near the 

 bottom of the Animikie. This seems to be the rock that supplied the supposed 

 grains of volcanic glass seen in No. 1319. N. H. w. 



No. 1322. QUARTZYTE. 



North side of the same point. In fallen, at least transported, masses ; the original beds not seen. 



Ref. Annual Report, xvi, pages 78, 85, 88, 121 ; Annual Report, xviii, page 62 ; Bulletin vi, pages 117, 422. 



Meg. Granular, firm, gray quartzyte. 



Mic. The forms of the original rounded grains are distinctly outlined by the 

 curving bands of colored impurities, outside and inside of which extinction is simul- 

 taneous for the same grain. The secondary growths have formed an interlocking 

 granular quartzyte. Besides the quartz grains there are a few of feldspar and one 



