270 EOCEXE PERIOD. [Ch. XIX. 



same may be said of those of Velay. Until the bones of men 

 or articles of human workmanship are found buried under 

 some of their lavas, instead of the remains of extinct animals, 

 which alone have hitherto been met with, we shall consider it 

 probable, as we before hinted, that the latest of the volcanic 

 eruptions may have occurred during the Miocene period. 



Supposed effects of the Flood. 



They who have used the terms antc-diluvian and post- 

 diluvian in the manner above adverted to, proceed on the 

 assumption that there arc clear and unequivocal marks of the 

 passage of a general flood over all parts of the surface of the 

 globe. It had long been a question among the learned, even 

 before the commencement of geological researches, whether the 

 deluge of the Scriptures was universal in reference to the whole 

 surface of the globe, or only so with respect to that portion of 

 it which was then inhabited by man. If the latter interpreta- 

 tion be admissible, the reader will have seen, in former parts of 

 this work, that there are two classes of phenomena in the con- 

 figuration of the earth's surface, which might enable us to 

 account for such an event. First, extensive lakes elevated above 

 the level of the ocean ; secondly, large tracts of dry land de- 

 pressed below that level. When there is an immense lake, having 

 its surface, like Lake Superior, raised GOO feet above the level 

 of the sea, the waters may be suddenly let loose by the rend- 

 ing or sinking down of the barrier during earthquakes, and 

 hercbv a region as extensive as the valley of the Mississippi, 

 inhabited by a population of several millions, might be de- 

 luged *. On the other hand, there may be a country placed 

 beneath the mean level of the ocean, as we have shown to be the 

 case with part of Asiaf, and such a region must be entirely laid 

 under water should the tract which separates it from the ocean 



* See vol. i. p. {;!. and Second Ediiion, p. 101. 

 f \ ul. ii. p. 1G;J ; and Sccund Edition, p. IG'J. 



