206 MINERALS AND GEOLOGY 



its close. Mesozoic strata, although occurring in other parts of the- 

 Dominion, are unknown within the limits of Ontario and Quebec.* 



(8). The organic remains entombed in Cainozoic strata present, 

 collectively, a marked resemblance to those of the existing epoch. 

 Angiosperms, except under local conditions, evidently formed, as 

 now, the prevailing vegetation of the age ; but among the dicoty- 

 ledonous types, gamopetala, as compared with polype tala and apetala, 

 were apparently less numerous than at present. In the animal world, 

 the crinoids, brachiopods, chambered cephalopods, ganoid fishes and 

 other types eminently characteristic of Mesozoic and Palaeozoic 

 periods were no longer predominating forms, but were reduced to a 

 few comparatively unimportant representatives. The reptilian char- 

 acteristics of the Mesozoic age had also given place to higher modifi- 

 cations of vertebrate structure and organization. Placental mammals 

 formed the leading or more characteristic types, and were abundantly 

 represented. All Cainozoic orders still offer representatives; but 

 many Cainozoic genera, and practically all the species, have become 

 extinct ; and two orders, at least, the Edentata and Proboscidea, 

 exhibit marked decadency. Cainozoic strata underlie an immense 

 extent of country throughout the north-western portions of the 

 Dominion, but have not been recognized in Ontario or Quebec. 



(9). During the Palaeozoic and Mesozoic ages, and the earlier 

 epochs of the Cainozoic age, the entire surface of the globe appears to 

 have possessed a warm and comparatively uniform temperature, re- 

 sembling that which now prevails in intertropical regions. This 

 view is amply sustained by fossil evidence. The remarkable plant 

 remains, so abundant in the middle or higher Palaeozoic strata, ex- 

 hibit in widely separated regions the same aspect and character. 

 Those of Mesozoic formations, and also the characteristic reptilian 

 and other types of the Mesozoic periods, exhibit the same law. The 

 broad distinctions, due to geographical position, which now prevail, 

 were absent also throughout the greater portion of the Cainozoic age, 

 or only became indicated towards its close. Not only do we find, 

 for example, in the Cainozoic strata of Northern Europe, and other 

 comparatively high latitudes, the shells of conularise, nautili and 



* Certain marls and sandstones associated with the trappean overflows of Thunder Bay and 

 the Nipigon district, Lake Superior, have been thought by some observers to represent Triassic 

 strata, but the weight of evidence is opposed to that view. 



