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—PIomb 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 Prance, 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 
