374 LOCAL CHANGES IN VEGETATION, ETC. chap. xix. 



olimute of those Post-plioccno ages, when Man was a denizen 

 of the northwest of France and of southern and central 

 England, appears to have been much more severe in winter 

 than it is now in the same region, though far less cold than 

 in the glacial period which immediatel}' j)receded. 



We may presume that the time demanded for the gradual 

 dying out or extirpation'of a large number of wild beasts 

 which figure in the Post-pliocene strata, and are mis.sing in 

 the Eecent fauna, was of protracted duration, for we know 

 how tedious a task it is in our own times, even with the aid 

 of fii*e-arms, to exterminate a noxious quadruped, a wolf, for 

 example, in any region comprising within it an extensive 

 forest or a mountain-chain. In many villages in the north 

 of Bengal, the tiger still occasionally carries off its human 

 victims, and the abandonment of late yeai'S by the natives 

 of a part of the Sunderbunds or lower delta of the Ganges, 

 which they once peopled, is attributed chiefly to the ravages 

 of the tiger. It is probable that causes more general and 

 powerful than the agency of Man, alterations in climate, 

 variations in the range of nian}^ species of animals, verte- 

 brate and invertebrate, and of plants, geographical changes 

 in the height, depth, and extent of land and sea, some or all 

 of these combined, have given rise, in a vast series of years, 

 ta the annihilation, not only of many large mammalia, but 

 to the disappearance of the Cyrena fluminalis, once common 

 in the rivers of Europe, and to the different range or relative 

 abundance of other shells which we find in the European 

 drifts. 



That the growing jjower of Man may have lent its aid as 

 the destroying cause of many Post-pliocene species, must, 

 however, be granted; yet, before the introduction of fire- 

 arms, or even the use of improved weapons of stone, it seems 

 more wonderful that the aborigines were able to hold their 

 own against the cave-lion, hyena, and wild bull, and to cope 



