84 



THE POST-PLIOCENE PERIOD. 



Fig. 23. — Femur of Mastodon (reduced). 



Fig. 24. — Molar of Mastodon (reduced). 



In conclusion of this part of the subject, we may view the Drift 

 period as the close of the great Tertiary era of geologists. In that 

 era there was much dry land in the northern hemisphere, and 

 multitudes of large animals now extinct inhabited it, apparently under 

 a climate milder than at present. Great changes, however, took place 

 in the relative positions of land and water, inducing very important 

 changes of climate, which finally became of an almost Arctic char- 

 acter over all the present temperate regions. The greater part of 

 northern Europe and Asia appear to have subsided beneath the 

 waters of the boulder-bearing semi-arctic ocean, until raised again 

 by successive stages to be the abode of man and the animals of 

 the modern earth. This final elevation, marked by the superficial 

 gravels, appears to have fixed the present contour of the country, 

 though the extinction of the mastodon and the phenomena of sub- 

 merged forests show that important changes both in inorganic and 

 organic nature have occurred subsequently. We have thus, in tracing 

 back the geological history of Acadia observed first, certain modern 

 formations now in progress, and depending wholly on the present 

 condition of the country. We have seen in connexion with these, 





