WAVY LAKE GNEISS AND QUARTZITE. 321 



the quartzite. The contact between the two is sharp, but ragged, and portions of 

 the clastic rock are seen to have been incorporated in the granite. The granite 

 itself is'a coarse, angular aggregate of'orthoclase and quartz, with extremely little 

 of the ferro-magnesian constituent. There is a certain amount of finer base in the 

 granite, of which it is difficult to say whether it is simply a later and more rapid 

 consolidation of the magma about the larger constituents or whether it isaportion 

 of the clastic rock, which has been incorporated without fusion in the granite.'' 



Other Localities. 



Il'.l VY LAKE. 



Direction oj the Contact. — The contact was next seen on the western 

 shore of Wavy lake about six miles in a direction X. in° E. from the 

 place where it was examined east of Lake Panache. 



Character and Relation of the Gneiss and Quartzite. — In the southern 

 part of Wavy lake the gneissic foliation has a northeasterly trend, which, 

 in coining north, gradually curves around to an almost easterly direction. 

 In the northern portion of the lake the strike bends around very abruptly 

 from a northeast to a southeast direction, and the change is further con- 

 tinued till in the eastern part of the lake the lamination of these two 

 areas of gneiss converges in a common strike of N. 70° E. A funnel- 

 shaped trough is thus formed in the western part of the lake, which is 

 occupied by a tongue of highly inclined Huronian quartzites. At the 

 southern edge of this trough the quartzites abut on the gneiss as on an 

 irrnptive mass, the strike of the former being X. 65° W. ; dip, S. 25° \Y. 

 <50°, while the foliation of the gneiss is X. E. ; dip, S. E. <75°. At 

 the northern edge of the trough the stratification of the quartzites cor- 

 responds in direction with the lamination of the gneiss. Both rocks 

 strike S. 38° E., although their declination is in opposite directions; the 

 quartzites dipping S. 52° W. <80°, while the gneiss dips X. 52° E. <8()°. 

 The quartzites near the line of junction on Wavy lake are not so highly 

 altered as on Lake Panache, yet the proportion of mica in these rocks is 

 seen to increase as the gneiss is approached. 



Microscopic Examination of tin Gneiss. — Dr Lawson thus speaks of a 

 thin slice of this gneiss which was examined by him : 



"A reddish, highly feldspathic granite, with occasional shear planes traversing it. 

 Under the microscope the rock is a. granular aggregate of orthoclase, quart/,, 

 plagioclase and biotite, in which crush phenomena are to a limited extent appar- 

 ent. The orthoclase is very much kaolinized in its central portion, but quite fresh 

 in the peripheral zone. The plagioclase is, as a rule, fresh. The biotite is very 

 sparingly represented and is almost entirely altered to chlorite. There is present 

 also a little iron oxide. The effect of secondary pressure is seen in the occasional 

 dislocation of the plagioclase and in cataclastic structure which has, to a limited 

 extent, been developed in portions of the section." 



XLVIII— Hum,. Geoi,. Soc. Am., Vol. I L892. 



