and on the Origin of ilie Wdlnjfi cf Auvergne. 535 



Hence it is evident, that the level of the bottom of the J«ke 

 would be gmdunlly rising, so that the lavas of latest ejection 

 would naturally occupy an higher position than the rest, and a 

 body of water, which should have swept away in certain cases 

 the upper l)eds, whilst it spared them in others, would produce 

 precisely that irregularity of level, which is adduced as a de- 

 cided objection to the possibility of a deluge. 



With regard to the post-diluvial lavas, I am not aware of 

 any case which lends support to Mr Scrope''s position. It is 

 true that they have not in every instance descended to the 

 lowest level of the valley in which they are situated; but this 

 circumstance may l>e seen explained by Messrs Murchison and 

 I.yell, in their judicious remarks on the Cheires of Auvergne *, 

 and may have very naturally arisen 'frotn- the cooling of the 

 lava having been completed, before it had time to continue its 

 sluggish course to the extreme point. In a considerable num- 

 ber of instances, however, where any stream lay in the direction 

 they took, they have actually reached its bed, and in these 

 cases, as we have seen, the depth to which the river has since 

 worked its way is an index of the amount of destructipo effected 

 since that remote period. joj ui aoi/ix/iq oj m aiMtn \o - 



The other arguments of Ml" Scmpe, whfch app^r to have 

 the same drift, need not perhaps detain us so long. Thus, he 

 states, that the strips of the fresh water formation, which rise 

 from the plain of Limagne in long tabular hills, owe their pre- 

 servation from denuding forces to the cappings of basalt they 

 possess. Now, such a capping, he contends, although it might 

 defend the subjacent stratum from rains, frost, &c. would form 

 a very insufficient protection against the force of any violent 

 deluge or general current of water. 



•<» But this argument, if of any force, is applicable in an equal 

 degree to all other countries in which basaltic or other compact 

 rocks occur, and comes therefore under the consideration of 

 those who take up the question generally, rather than of those 

 who limit themselves to the phenomena of Auvergne. 



The existence of a crater in a tolerable state of integrity, es- 

 pecially when composed of loose scorise, is, I am ready to admit, 



• Edinburgh Journal, July lf29. 



