PART V. 



SYSTEMATIC OUTLINE OF THE GEOLOGY OF CEN- 

 TRAL CANADA, COMPRISING THE PROVINCES 

 OF ONTARIO AND QUEBEC. 



As explained in preceding sections of this work, the various rock- 

 formations which make up the outer portion or so-called crust of the 

 earth do not form a single unbroken series, but belong to various 

 epochs of formation. These epochs comprise five primary divisions 

 or ages : determined partly by the superposition of their rocks, and 

 partly by the fossilized organic bodies which many of these rocks 

 contain. The ages fchus recognized are as follows : 



5. The Present or Existing Age. 



4. The Cainozoic Age. 



0. The Mesozoic Age. 

 2. The Palaeozoic Age. 



1. The Archaean Age. 



These ages, although distinct in the main, offer, as in all historic 

 periods, a gradual passage from their older into their newer epochs. 

 The rocks by which they are made known to us are of three princi- 

 pal kinds : Sedimentary or Stratified rocks, represented by ordinary 

 sandstones and limestones, clay-slates, clays, sands, &c., many of 

 which contain the fossilized remains of plants and animals living on 

 the earth when the rocks in question were formed ; Foliated or 

 Stratiform-crystalline rocks, represented by gneiss, mica-schist, crys- 

 talline limestone, &c.; Eruptive rocks partly crystalline, as granites 

 and syenites ; partly compact or aphanitic in texture, as ordinary 

 traps and basalts ; partly scoriaceous, as ordinary lavas ; and partly 

 vitreous, as obsidian. 



In the Dominion of Canada, viewed in its entirety, examples occur 

 of all these rocks, and each of the five great geological ages is repre- 

 sented by rock-formations ; but in the separate Provinces of the 

 Dominion, the rock-representatives of some of the geological ages are 

 unknown. Thus within the boundaries of Ontario and Quebec there 

 are no known rock-formations of Mesozoic or Cainozoic age. Viewed 



