CHAPTER XIX. 



Volcanic rocks of the Eocene period Auvergne Igneous formations associated 

 with lacustrine strata Hill of Gergovia Eruptions in Central France at suc- 

 cessive periods Mont Dor an extinct volcano Velay Plomb du Cantal 

 Train of minor volcanos stretching from Auvergne to the Vivarais Monts 

 Domes Puy de Come Puy Rouge Ravines excavated through lava Cur- 

 rents of lava at different heights Subjacent alluviums of distinct ages The 

 more modern lavas of Central France may belong to the Miocene period The 

 integrity of the cones not inconsistent with this opinion No eruptions during 

 the historical era Division of volcanos into ante-diluvian and post-diluvian in- 

 admissible Theories respecting the effects of the Flood considered Hypo- 

 thesis of a partial flood Of a universal deluge Theory of Dr. Buckland as 

 controverted by Dr. Fleming Recapitulation. 



EOCENE VOLCANIC ROCKS. 



WHEN we treated in the seventeenth chapter of the lacustrine 

 deposits of Central France, we purposely omitted to give a 

 detailed account of the associated volcanic rocks, to which we 

 now recall the attention of the reader. (See the Map, p. 226.) 



We stated that, in the arenaceous and pebbly group of the 

 lacustrine basins of Auvergne, Cantal, and Velay, no volcanic 

 pebbles had ever been detected, although massive piles of 

 igneous rocks are now found in the immediate vicinity. As 

 this observation has been confirmed by minute research, we are 

 warranted in inferring, as we before explained, that the volcanic 

 eruptions had not commenced when the older subdivisions of 

 the fresh-water groups originated. 



In Cantal and Velay we believe no decisive proofs have yet 

 been brought to light that any of the igneous out-bursts hap- 

 pened during the deposition of the fresh-water strata ; but there 

 can be no doubt that in Auvergne some volcanic explosions 

 took place before the drainage of the lakes, and at a time when 

 the Eocene species of animals and plants still flourished. We 

 shall first advert to these proofs as relating to the history 



VOL. III. S 



