46 Messrs Lyell and Murchison nn the 



ages were violently broken up, and carried, without the least re- 

 ference to existing levels, to vast distances, often across deep 

 ravines, and spacious intervening valleys. 



Are there not, however, some other signs, we shall be asked, 

 upon those older basaltic plateaus of Dor and Cantal, which are 

 unquestionably more ancient than the great valleys of the same 

 district (by whatever theory the origin of those valleys be ex- 

 plained), — are there not some decided proofs of a violent flood, 

 which transported thither fragments of foreign rocks from dis- 

 tant regions? We answer there are none. The Coiron has not 

 sent its quartzose grits and calcareous rocks of Jura limestone 

 formation to the Vivarals or Velay, nor has the zone of second- 

 ary rocks encircling Auvergne lent its debris to cover the gra- 

 nitic and volcanic regions of Dor, or the Puy de Dome. In a 

 word, the repeated investigations of the ablest observers have 

 been unable to discover a single fragment of any rock inclosing 

 marine remains, mixed up with the alluvions of the primary, 

 tertiary, and volcanic districts of Central France. 



The succession of events which have taken place in Auvergne 

 since the tertiary lakes were in existence, indicate an incalculable 

 period of time ; yet it must not be forgotten that even these la- 

 custrine deposites are modern in geology ; and still more modern 

 is the surface last given to the country by some of the eruptions 

 of Mont Dor, which, nevertheless, preceded the excavation of 

 most of the present valleys. We ought not, therefore, to won- 

 der that Central France presents no mysterious and wholly in- 

 explicable phenomena, in the distribution of its superficial debris, 

 merely because frequent difficulties occur in explaining the older 

 alluvions, and the waste caused by floods in other parts of Eu- 

 rope, where the comparative antiquity of the surface may, for 

 aught we know, be infinitely greater. 



Let but the convulsions and changes which have affected 

 Auvergne and Cantal, since the lacustrine strata were formed, 

 be multiplied several times over, and the imagination will be 

 baffled in all its efforts to restore the successive states of the 

 country, the former relative levels of its several parts, and of 

 the adjoining mountain districts. The solution of every local 

 problem will then be impossible ; and however unphilosophical, 

 even under such circumstances, may be an appeal to preter- 



