PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 713 



Flint. Conglomerate.] 



The other section having the same number is a dark flint, composed of debris 

 from the basic rocks, similar to No. 1391, but less acid. Two sections. 



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



No. 1394. FLINT. 



In the same subordinate series of low hills as No. 1392. 

 Ref. Annual Report, xvi, pages 100, 124. 



Meg. Flinty, often greenish or grayish, several samples, closely related and 

 banded together in a gritty greenstone (No. 1393). 



Mic. Two sections have this number. They both show a thinly banded rock. 

 In one the bands consist of coarser and finer granulitic quartz, accompanied by belts 

 of actinolite needles. In the other the banding is caused by greater and less amounts 

 of calcite accompanied by fine actinolite needles. In this also the interlocking of 

 the quartzes is less evident. Indeed, some of the quartz is angular and coarser and 

 sharp like fragmental non-detrital debris. Two sections. 



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



No. 1395. CONGLOMERATE. (Greenstone.) 



In the same series of subordinate hills as No. 1392. 

 Ref. Annual Report, xvi, pages 100, 124. 



Meg. Conglomeratic, green, showing some sedimentary structure; a widely 

 disseminated rock. 



Mic. The rock contains some large feldspars, but more ragged than in No. 

 1392, and somewhat more permeated byproducts of alteration, still perfectly evident 

 as feldspars with twinned lamellae. A large part of the rock is of hornblende, which 

 exists as patches and as scattered fibres and cleavage-plates. The differences in the 

 appearance of the rock, whether in hand specimen or under the objective, are due 

 in part to the differences in the manner of distribution of the larger elements, feld- 

 spar and hornblende. There are pebble-like areas in which these crystals are not 

 present, but which consist of granulitic quartz and feldspar, and there are others 

 of pure quartz with a single orientation. There are others still in which there is 

 much fine hornblende in spicules, with fine feldspars and. magnetite. In most cases 

 these parts are distinctly separable from the general rock mass, but it is evident 

 that in the rock mass all these parts are more finely commingled to make the general 

 matrix. One section. 



Age. Archean (Keewatin). 



Remark. These differences of grain are explicable on the assumption that the 

 rock is a conglomerate, a part of the Ogishke conglomerate, but were the differences 

 somewhat less marked, the rock would be similar to several that have been called 

 amphibolyte and dioryte, and others whose origin has been uncertain and which 



