PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 751 



Artinolite, magnetite scliist.] 

 State. Quartzyte. 



Ili'iiiurl-. It appears from all the microscopic examinations made on these 

 bombs that their interiors and the surrounding amygdaloidal scales are of igneous 

 structure, the feldspars being arranged as if consolidated at the second stage of cooling, 

 while the rock filling interstices between the bombs is destitute of igneous structure, 

 but similar to some of the greenstone itself where no agglomeratic structure is seen, 

 and may liave been originally a volcanic ash or a basic detrital debris. N. H. w. 



No. 1628. ACTINOLITE, MAGNETITE SCHIST. 



No. 2 of the drill at Wicks', sec. 27, T. 60-13, one mile south of the granite. 



Ref. Annual Report, xxi, pages 82, 153 ; Annual Report, xxii, page 161 ; vol. iv, page 391. 



Mry. Black and gray, fine, banded rock, with magnetite. 



Mir. There is much fi/iim>/itr in fine needles which pierce the section in all 

 directions. Besides maynetite there is apparently only a feldspar which proves to be 

 <>/i(/tir/<ixr-ti}l>ite, by extinction of 84 on ,, taken on a twinning line, the acute optic 

 angle being apparently that which contains -,... The actinolite fibres are frequently 

 placed at an angle of about 90 with each other over considerable areas, suggesting 

 that they are arranged in an obliterated feldspar crystal in the directions of the 

 principal cleavages, since in all cases the actinolite penetrates the feldspars with 

 great freedom. Two sections. 



Age. Animikie. N. H. w. 



No. 1629. SLATE. f Ferruginous. ) 



No. 3 of the drill at Wicks', sec. 27, T. 60-13. 



Ref. Annual Report, xxi, pages 82, 153; Annual Report, xxii, page 161 ; vol. iv, page 391. 



Meg. Collected under the name "black slate." 



Mil-. The rock consists chiefly of maynetite, but this is evidently mingled with 

 ffl'/xjxir and artinolitc as in No. 1628. The section is too thick to separate them 

 optically. One section. 



Age. Animikie. N. H. w. 



No. 1630. QUARTZYTE. (Gray, jaspilitic, magnetic.} 



No. 4 of the drill at Wicks'. 



Ref. Annual Report, xxi, pages 82, 153; Annual Report, xxii, page 161 : vol. iv, page 391. 



Mr;/. Gray quartzyte, sometimes porous, sometimes non-homogeneous, with 

 angular and rounded masses. 



Mir. The qttdtiz is all secondary and interlocking, varying much in coarseness. 

 It is very fine within the rounded pebbles. It is clouded by gray and dirty powder 

 which in high power seems to be resolvable into fine in<iynrfitr. One section has 

 strictly the taconyte structure and is illustrated by figure 11, plate III. Two sections. 



Age. Animikie. N. H. w. 



