CASTOROLOGIA. 23 



clous, as a passing study of the age will show. Dana says : " America 

 in the Quaternary era was inferior to Europe in the number of 

 its Carnivores, but exhibited the gigantic feature of the life of 

 its time in its species. In North America the mammals in- 

 cluded an elephant {E!ephas Aincn'canics) as large as the European, 

 besides the Asiatic, {Elcphas Primcgeiiius) in the more northern 

 latitudes ; a mastodon (^Mastodon Aynericanus) of still greater mag- 

 nitude ; horses much larger than the modern ; species of ox, bison, 

 tapir, gigantic beavers, etc." 



In the " Handbook of Canadian Geology," Sir William Dawson 

 divides the Quaternary into Pleistocene and Modern ; and the latter 

 is again divided into two periods and treated as follows : — 



" I. Tl:c Post Glacial. The climate was temperate but some- 

 what extreme. All the modern mammals, including man, seem to 

 have been in existence, but several others now extinct, as the Mam- 

 moth, the Tichorhine Rhinoceros and the Cave Bear, lived in the 

 Northern Hemisphere, .... This period was terminated by a 

 submergence or a series of submergences which with their accom- 

 panying phj'sical changes proved fatal to many species of animals 

 and to the oldest races of men, and left the continents at a lower 

 level than at present, from which they have risen in the recent 

 period . 



"2. The Recent or Historic Period. This dates from the settle- 

 ment of our continents at the present levels after the Post-Glacial 

 subsidence. 



" I have called this the Historic Period, becau.se in some regions 

 history and tradition extend back to its beginnings. The historical 

 deluge is in all likelihood identical with the movements of the land 

 above referred to, by which this age was inaugurated ; though in 

 certain localities, as in America, the beginning of the historic period 

 is ver)^ recent. In this age man co-exists w^holly with existing 

 species of mammals, and the races of men are the same which still 

 survive. The whole forms geologically one period, and the distinc- 



