92 NATURAL HISTORY OF 



ages of his presence on earth. Though particular points 

 in the changes here alluded to may be doubted or de- 

 nied, still sufficient will remain to substantiate the 

 influence they must have exercised upon human distri- 

 bution, upon man's earliest wanderings ; and they will 

 finally establish, we think, the fact of his coexistence 

 with the latter period of the great Pachydermous era. 

 We have, in fact, both sacred and profane authority 

 for diluvian convulsions of great magnitude, when the 

 earth was inhabited by human families, in quarters very 

 distant from each other, and when many genera of, 

 animals may have perished. If, in the opinion of geo- 

 logists, more than due importance has been ascribed to 

 the action of volcanoes, the answer is, that the violence 

 of subterrene fires was unquestionably much greater, 

 and its presence much more generally manifested than 

 in succeeding ages ; since it can be shown, that scarcely 

 one fortieth of existing craters is now in activity, 01 

 about one hundred in four thousand ; and yet, that there 

 are still about two thousand eruptions in a century, or 

 about twenty per annum ; moreover, Iceland offers a 

 comparatively recent example to what extent a vol- 

 canic eruption may ruin a great region of fertile 

 country. Since this was written, another devastation 

 has taken place in the same island. 



