CURRENT ERA. 169 



through the instrumentality of men, becomes a little more 

 decided and apparent. The mammoth and mastodon, the 

 Irish deer and urus, the cave-bear and hyaena, that seem to 

 have roamed over Europe during the dawn of the post- 



Megaceros Hiberuicus, or Gigantic Irisla De 



tertiary period, become extinct, though their congeners still 

 flourish in Asia and Africa. As we ascend to later deposits, 

 species, or, it may be, merely varieties of horse, ass, ox, deer, 

 goat, sheep, bear, wild boar, wolf, and fox become the more 

 frequent forms ; and ultimately, in the more recent accumu- 

 lations, the bones, whether of mammals, birds, reptiles, or 

 fishes, become indistinguishable, even in variety, from those 

 that are now our associates in the scheme of vitalit} r . 



And it is just in this palpable approach to existing nature 

 that we begin to detect the earliest traces of the human 

 species. First, and far back among the river-silts and 

 peat-bogs and cave-earths, we discover his rude stone-im- 

 plements and weapons, his tree- canoes, and the embers of 

 the fires which he alone of all animals can either kindle or 

 sustain. Side by side with these remains, occasionally lie 



