PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 725 



Green wacke. Diabase.] 



of the rock (aside from calcitc, and actinolite) is composed of a coarse reticulated mosaic 

 of new feldspar (with little or no quartz). One section. 



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



No. 1423. GREENWACKE. (Knotty. ) 



At the head of the bay, on the town line, west end of Kekequabic lake. 

 Ref. Annual Report, xvi, pages 106, 125. 



J/T//. Ureenish, schistose conglomerate, apparently decayed. 



Mic. This rock is similar to No. 1419, with the exception that all original parts 

 are finer, and the distinctions all fade out to a more uniform rock, into which also is 

 introduced much calcitc. There is also a larger proportion of crystals, as compared 

 with pebbles of glass. There appears to be also some epidote, and there is one 

 remarkable group of crystals of iron ore which are black and apparently rhom- 

 bohedric, like ilmenite, in accord with the presence of some leucoxene. One section. 



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



No. 1424. GREENWACKE. 



Same place as the last. 



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



Meg. Knotty projections in No. 1423. 



Mic, In this section the structure and nearly the composition of No. 1423 

 are presented, but the old crystals are still larger and more abundant; the augite is 

 converted to a uralite, preserving, however, the angular form of the augite. At the 

 same time the feldspars are dim by the introduction of chlorite and calcite and by 

 a general breaking down of the grains so that they do not show any enlargements 

 nor any clear and unique extinction. Notwithstanding these deformities they are 

 perfectly evident as feldspars. The surrounding fine matrix is almost entirely feld- 

 spathic; whether of fragmental debris or of secondary growth is not apparent. But 

 amongst the coarser elements is occasionally an angular quartz. One section. 



Aye. Archean (Keewatin). N. H. w. 



No. 1425. DIABASE. 



Dike on the north shore of the bay at the west end of Kekequabic lake ; E. % S. W. % sec. 34, T. 65-7 W. 

 Ref. Annual Report, xvi, pages 106, 125. 



Mey. A rather fine-grained, fresh, black diabase. No section. 



Age. Perhaps Cabotian. u. s. o. 



No. 1426. GREENWACKE. 



S E. J4 sec. 34, T. 64-7, near the head of the broad, shallow bay, Kekequabic lake. 

 Ref. Annual Report, xvi, pages 107, 12.">. 



Meij. Geenish and fine grained, with evident hornblendes. 



