PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 655 



Pebble. Conglomerate. Flint. Tuff.] 



No. 1079A. PEBBLE (from No. 1070). 



Same place as No. 1079, i. e., one-third of a mile north of Ogishke Muncie lake, sec. 23, T. 65-6. 

 Ref. Annual Report, xv, pages 375, 397. 



Meg. Gray, fine-grained pebble. 



Mic. The section shows a rock in all respects like the porphyry at the narrows 

 of Kekequabic lake, and like the pebbles in that porphyry,, having along with 

 crystals of feldspar and altered augite, some large quartzes. These lie isolated in a 

 very fine matrix of feldspar and quartz, in which still are seen some finer fragments , 

 of the same kind of crystals. 



A section of another pebble from the same shows essentially the same kind of 

 rock, but in this the matrix is considerably coarser, and more calcite is disseminated. 

 The feldspars show their original zoning, but the hornblendes are not apparently of 

 two periods of growth, but are much chloritized. Two sections. 



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



No. 1080. CONGLOMERATE. ( " Poi-phyritic." ) 



Northeast corner of S. E. y sec. 22, T. 65-6, north of Ogishke Muncie lake. 

 Ref. Annual Report, xv, pages 375, 397. 



Meg. Evidently a fragments! rock with scattered crystals of large size of some 

 feldspar. 



Mic. There is jasper, quattz, hornblende, feldspar, diabase, and many pebbles 

 like the matrix of the Kekequabic lake porphyroids. These constitute the coarser 

 elements, but they graduate in size downward into the matrix. The whole rock might 

 be considered a product of destructive friction on rocks of the Kekequabic lake series 

 (No. 1061), or a non-metamorphic conglomerate of the same kind and age. One section. 



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



No. 1081. FLINT. (Made.) 



N. E. % sec. 22, T. 65-6, north of Ogishke Muncio lake. 

 Ref. Annual Report, xv, pages 375, 397. 



Meg. Black slate. 



Mic. Very fine-grained mixture of angular quartz and feldspar and probably 

 debris of ferromagnesian elements, with secondary generation of quartz, sometimes in 

 small veins. In convergent light, and on lowering the lower nicol there come to 

 sight many isolated fine granules of what appear to be zoisite or epidote and a 

 network of what appears to be fine spicules and fragments of nrtitm/i/c. One section. 



Age. Archean (I'pper Keewatin). N. H. w. 



No. 1082. TUFF, (lftir/1, (]<), M>, dark.) 



Eighty rods northwest of the last. 



Ref. Annual Report, xv, pages 375, 376, 397. 



Meg. Thicker bedded and arenaceous, sometimes greenish. 



