PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 919 



Quartzyte. Conglomerate.] 



No. 256H. QUARTZYTE. 



Pokegama falls. 



Ref. Annual Report, xvi, pages 438, 473. 



Meg. Gray quartzyte, weathering red. 



Mic. Quartz only composes this rock. The original clastic round grains are 

 grown out to till the angular interstices, making a dense quartz rock. Nearly all 

 the original grains are unique, /. e., simple, having one orientation, but two or three 

 in the slide are compound, the parts being interlocked in the fashion of secondary 

 quartz. They all have lines of inclusions. One section. 



Age. Pokegama (at the base of the Animikie). N. H. w. 



No. -257H. QUARTZYTE. 



Pokegama falls. 



Ref. Annual Report, xvi, pages 438, 473. 



Meg. Rusty quartzyte. 



Mic. Same kind of rock as No. 256H, but having some rustiness in the planes 

 separating the individual grains. One section. 



Aye. Animikie, basal member. N. H. w. 



No. 261 H. QUARTZYTE. 



Foot of the lower falls of Prairie river. 

 Ref. Annual Report, xvi, page 473. 



Meg. Quartzyte. 



Mic. Same as No. 257H, but shows also a few grains of triclinic feldspar, and 

 one of hornblende. One section. 



Age. Animikie, basal member. N. H. w. 



No. 265H. QUARTZYTE. 



Upper end of the lower falls of Prairie river. 

 Ref. Annual Report, xvi, pages 441, 473. 



Meg. Quartzyte. 



Mic. Quite like No. 257H, but finer, less cemented by secondary quartz, and 

 more coated by an opaque oxide; also, apparently, has some garnet(?) One section. 

 Age. Animikie, the basal member. N. H. w. 



No. 364H. CONGLOMERATE. 



From a boulder seen east of Iron lake, N. W. ^ sec. 24, T. 60-13. 

 Ref. Annual Report, xvii, pages 83, 136. 



Meg. Rounded quartz pebbles, three to ten times as large as mustard seeds, are 

 the most conspicuous element. They lie in a matrix of ferro-magnesian debris, and 

 are associated with some feldspathic detritus. 



Mic. Quartz and labradorite( ?), (extinction 58 on n p in the obtuse angle), are 



