26 Geological Age of Man. 



ference of the position of land and sea tends rapidly to dimi- 

 nish our chances of learning what mollusca or mammalia 

 may then have inhabited the land. 



Geological Age of Man. 



Yet, small as may be the progress hitherto made in deci- 

 phering the records of the tertiary periods, we seem entitled 

 to declare that, during several great revolutions in the mam- 

 malia, probably not less than five, there has been no step 

 whatever made in advance, no elevation in the scale of being ; 

 so that had man been created in the lower eocene era, he 

 would not have constituted a greater innovation on the state 

 of the animate creation previously established, than now, 

 when we believe him to have begun to exist at the close of 

 the pliocene. 



Antecedently to investigation, we might reasonably have 

 anticipated that the vestiges of man would have been traced 

 back at least as far as those modern strata in which all the 

 testacea and a certain number of the mammalia are of exist- 

 ing species, for of all the mammalia the human species is the 

 most cosmopolite, and perhaps more capable than any other 

 of surviving considerable vicissitudes in climate and in the 

 physical geography of the globe. How far the interior of 

 Asia, the supposed cradle of our race, may hereafter afford 

 geological evidence of higher antiquity than can be deduced 

 from European monuments, we have yet to learn. The ob- 

 servations recently made by Dr Abich on the changes of level 

 going on in the Caspian ; the periodical oscillations of level 

 in that sea, due principally to subterranean movements ; the 

 shifting of the position of its waters, partly by the encroach- 

 ment of deltas on one side and the overflowing of the land in 

 other directions ; the buildings now seen under water while 

 others are above the sea-level, and yet, like the temple of Se- 

 rapis, having been drilled by perforating mollusks, bear the 

 marks of former submergence — these proofs of recent changes, 

 coupled with the evidence obtained by MM. Murchison and 

 De Verneuil, of the vast extent of a marine or brackish-water 

 Aralo-Caspian limestone hundreds of feet above the level of 

 the Mediterranean, may encourage us to hope that we may 

 hereafter be able to find a geological date for the origin of 



