STRUCTURAL GEOLOGY. 5 



Conglomerates and graywackes.] 



5. Aside from the twisted and confused condition there is nothing further 

 worthy of note in the southern belt, which is about thirty feet across. 



On the south the rock, while plainly a part of a fragments] series, is a coarse 

 irregular green schist containing much vitreous quartz in veins, running with the 

 schist. This is visible only .at the west end of the ridge. There is also some such 

 quartz in irregular deposits throughout this conglomerate. 



6. On the north side, while the conglomerate is continued in that direction, 

 yet it consists wholly of greenstone debris, and is so consolidated that it looks like 

 the massive greenstone of the lower formation. In some places it is so fine-grained 

 and apparently siliceous, that it looks like the agglomeratic greenstone, although 

 without the characteristic agglomeratic masses. It appears massive and uniform 

 (No. 1821). There is another belt of jaspilyte further north, thirty or forty feet wide, 

 and another further south about thirty feet wide, making a total thickness of about 

 100 feet of jaspilyte in 600 feet of conglomerate. 



Conglomerates inn/ graywackes. As already stated, this volcanic material grades 

 imperceptibly into coarser, more siliceous and more detrital rock, forming slates, 

 graywackes and conglomerates, whose stratification is perfectly evident. These 

 detrital rocks are also very extensive, especially in the form of conglomerate. In 

 these beds are fragments, well rounded, of many kinds of rocks, depending on the 

 geographic position and the stratigraphic horizon. Probably the Ogishke and the 

 Stuntz conglomerates are the most remarkable of these coarser beds, but between 

 the localities denoted by these names, and especially in a wide belt at Moose lake 

 and in the environs of Snowbank and Disappointment lakes, this conglomeratic 

 terrane is very conspicuous and extensive. The color and composition depend on 

 the nature of the underlying rock capable of furnishing an abundant detritus. The 

 Stuntz conglomerate, at Vermilion lake and eastward, consists almost wholly of a 

 gray quartz-porphyry, some of the rounded masses being a foot or more in diameter, 

 whose source was unquestionably in some dikes of such rock which cut the older 

 rocks of the vicinity. Eastward further this conglomerate is composed largely of 

 greenstone debris, such as is seen on some of the islands in the southwestern part of 

 Long lake. About Moose lake, especially on the south side, it is still coarse, but is 

 partly of volcanic ejectanienta. The Ogishke conglomerate, which at Ogishke Muncie 

 lake lies on the older greenstones, is largely composed of basic debris, and about 

 Kekequabic lake embraces volcanic tuffs. Toward Saganaga lake this conglomerate 



* 



changes to graywackes and slates, and at its immediate superposition on the Saganaga 

 granite it is composed of debris from that granite, making a rock which, when firmly 

 compacted, closely resembles the granite itself, but is distinguishable from the granite 



