OF CENTRAL CANADA PART V. 305 



and the Muskoka lakes, lie within its area ; and an almost continu- 

 ous chain of these extends along its southern border. As a rule, 

 the country is of a broken, hilly character : vast masses of gneissoid 

 rock standing in many places high above the ground. The entire 

 district, however, is more or less densely wooded. 



Gneissoid, Laurentian rocks underlie the district generally. These 

 consist for the greater part of ordinary and hornblendic gneisses, 

 traversed by numerous granite veins, and interstratitied with subor- 

 dinate beds of dark-green pyroxenic rock, crystalline limestone, 

 quartzite, and siliceous slate, some beds of conglomerate appearing 

 in places near the upper part of the series. The green pyroxenic 

 bands are mostly associated with deposits of iron ore. In some parts 

 of the district, long rugged belts of red syenitic granite (as seen in 

 the Huckleberry Hills near Marmora, and elsewhere) traverse the 

 country in a general N.E. and S.W. direction, and produce a syn- 

 clinal structure in the intervening tracts. At many spots, as around 

 Stoney Lake and elsewhere, the gneiss is almost free from mica ; 

 and where it is traversed by granite veins, the latter are usually very 

 feldspathic and more coarsely granular than the gneiss. Good 

 exposures occur more cr less all over the district, especially on the 

 lake shores and islands, and along the high ridges which traverse the 

 district generally. The beds at most spots are tilted at high angles, 

 and are frequently much corrugated and contorted, as shewn in the 

 annexed sketch. 



Outliers: The Laurentian rocks 

 of this district are overlaid here and 

 there by outlying patches of Lower 

 Silurian strata. On the Bonnechere 

 River in Renfrew, and in the vicin- 

 ity of Pembroke, outliers of this F ^ 2 43. 



kind, Composed of light-Coloured Portion of a granite vein traversing con- 

 ~, j TI i r>- torted micaceous-gneiss. Vicinity of Hali- 



Chazy sandstones and .Black Kiver burton, Ontario, 

 limestones, rest directly on the Laurentian gneiss. Several outliers 

 of Black River and Trenton limestone (see under the Lake Ontario 

 District) cover detached areas of considerable extent in the gneissoid 

 country inwnediately north of Madoc in the county of Hastings. 



Drift deposits : Over many portions of the district, unstratified 

 clays with boulders of gneissoid rock, and higher or post-glacial 

 20 



