Ch. XIX.] AGE OF AUVERONE VOLCANOS. 2G9 



those of ante-diluvian and those of post-diluvian origin. To 

 the former they attribute such hills of sand and scoriae as 

 exhibit on their surface evident signs of aqueous denudation ; 

 to the fetter, such as betray no marks of having been exposed 

 to such aqueous action. According to this classification almost 

 all the minor cones of Central France must be called post- 

 diluvian 5 although, if we receive this term in its ordinary 

 acceptation as denoting posteriority of date to the Noachian 

 deluge., we are forced to suppose that all the volcanic eruptions 

 occurred within a period of little more than twenty centuries, 

 or between the era of the flood, which happened about 4000 

 years ago, and the earliest historical records handed down 

 to us respecting the former state of Central France. Dr. 

 Daubeny has justly observed, that had any of these French 

 volcanos been in a state of activity in the age of Julius Caesar, 

 that general, who encamped upon the plains of Auvergne, and 

 laid siege to its principal city, (Gergovia, near Clermont,) 

 could hardly have failed to notice them. Had there been 

 even any record of their existence in the time of Pliny or 

 Sidonius Apollinaris,, the one would scarcely have omitted 

 to make mention of it in his Natural History, nor the other to 

 introduce some allusion to it among the descriptions of this 

 his native province. This poet's residence was on the borders 

 of the Lake Aidat, which owed its very existence to the dam- 

 ming up of a river by one of the most modern lava cur- 

 rents*. 



The ruins of several Roman bridges and of the Roman 

 baths at Royat confirm the conclusion that no sensible 

 alteration has taken place in the physical geography of the 

 district, not even in the chasms excavated through the newest 

 lavas since ages historically remote. We have no data at 

 present for presuming that any one of the Auvergne cones has 

 been produced within the last 4000 or 5000 years; and the 



* Daubeny on Volcanos ; p. 14. 



