86S Dr Daubehy on the Volcanoes of Auvergne. 
the modern volcanoes of Auvergne must all have been posterior 
to the latter event. 
Another important characteristic of the modern volcanoes, of 
frequent, though not of universal occurrence, is the existence in 
them of craters. That of the Puy Pariou, near Clermont, is as 
perfect as any of those belonging to volcanoes now in activity ; 
others, though less complete, retain sufficient indications of their 
origin ; whilst a third class might perhaps be hardly known as 
such, unless viewed in connection with those contiguous. 
Such are the principal circumstances which mark the first or- 
der of volcanoes ; the characters of the second we shall defer, un- 
til we come to describe the mountains in which they are princi- 
pally found, proceeding at present to some details respecting 
the rocks in the neighbourhood of Clermont, where the modern 
class of volcanoes are chiefly, though not exclusively found. 
Modern Volcanoes. 
The town of Clermont, the capital of the ci-devant province 
of Auvergne, and of the present department of the Puy de 
Dome, is situated in the plain of Limagne, one of the most fer- 
tile I believe in France. The peculiar richness of the soil may 
perhaps be attributed to the character of the substratum, com- 
posed of an alternation of calcareous and sandy beds, which are 
referred to the same formation with those which cover the chalk 
near Paris ; and in our own country in the neighbourhood of 
London and the Isle of Wight. 
The extensive distribution of these beds in the valleys 
throughout France, might afford an excellent field for the sci- 
entific traveller ; but it would be foreign to the present purpose 
to enter further into their detail, as we may have something to 
say respecting them when speaking of the neighbourhood of 
Aurillac in Cantal, where they likewise occur. These beds are 
deposited in a granite bason, which constitutes the hills bound- 
ing either side of the plain of Limagne, and rises particularly in 
a striking manner to the north-west of Clermont, where it forms 
the chain of hills on the road to Limoges, seen so conspicuously 
from the town, and on which repose the volcanic rocks which it 
will be our object to describe. 
