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



climate of those Post-pliocene ages, when Man was a 

 denizen of the north-west of France and of southern and cen 

 tral 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 immediately preceded. 



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 missing 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 fire-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 years by the natives of 

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

 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 many species of animals, vertebrate 

 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, to 

 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 power 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 wonder 

 ful that the aborigines were able to hold their own against 

 the cave-lion, hyaena, and wild bull, and to cope with such 



