PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 7'21 



( ; reenwsu'ki'. Esterellyt e. Dioryte.] 



No. 1413. GREENWACKE. 



The same, near the water. 



Ref. Annual Report, xvi, pages 103, 105, 125. 



Meg. With hard, lenticular sheets. 



Mic. The section is cut perpendicular to the structure. The rock consists of 

 the same elements as the above, but is banded by variations in fineness and by the 

 occurrence of some fragments of feldspar in the coarser bands, which are not visible 

 in the finer. One section. 



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



No. 1414. ESTERELLYTE. 



Near the south side of sec. 35, T. 65-7. In a low bluff at the shore of Kekequabic lake. 

 Ref. Annual Report, .xvi, pages 103, 125. 



Mey. Different forms of porphyry. 



Mic. Only one section has been made. The slide shows a rock identical with 

 the porphyry at the narrows of the lake (No. 1094, etc.). The old feldspars are 

 encroached on at their corners, and all about their margins, by the micro-granulitic 

 quartz and feldspar, and in some cases the same substance appears within the feld- 

 spars. Some grains, indeed, are almost destroyed by such encroachment. These 

 feldspars are not zoned, but much twinned. One part of the slide shows a rock not 

 porphyritic, but largely hornblendic (with some globular pyroxene ?} with biotite and 

 remnants of the old feldspars, being rather a quartz dioryte, but finer grained than 

 that at the summit of the small island (No. 1410). One section. 



At/c. Archean (Keewatin). N. H. w. 



No. 1415. DlOUYTK (or (ini/i/ii/Hi/i/fc). 



Same place as No. 1414. 



Ref. Annual Report, xvi, pages 103, l'2'i. 



Underlying No. 1414; greenish, massive. 



Mic. With much hornblende, some (cgyrine-augite and a little actinolite is much 

 feldspar, these together making up the rock, so that there is very little of the fine, 

 granular, interlocking matrix seen in the greenwackes in general. The aegyrine is 

 included in the feldspars and appears to have maintained its composition more easily 

 in such position, since generally only hornblende is seen in the rock. One section. 



Age. Archean (Keewatin). 



Remark. If a granular disintegration should permeate the feldspars of this rock 

 it would be like some of the green schists of the region, and especially if at the same 

 time the aegyrine were all converted to hornblende. N. H. w. 



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