204 On the Antiquity of the Volcanos of Auvergne. [April, 
diluvial gravel, and to other phenomena, as attesting the action of 
an universal deluge. 
And such was the influence upon the scientific world which he 
commanded by the zeal, eloquence, and research which he displayed 
in carrying out his favourite hypothesis, that diluvial action, diluvial 
gravel, diluvial pebbles, diluvial detritus, and the like were for many 
years received amongst the household words of geologists both im 
England and on the Continent. 
It is true, that the scientific evidence by which he supported the 
notion of an universal deluge broke down upon further inquiry, and 
thus an early lesson was afforded us of the imprudence of pressing 
hastily into the defence of religion even the most plausible inferences 
deducible from the facts of science. The risk of thus prejudicing 
the cause which it was intended to uphold, by the re-action pro- 
duced upon the mind from the subsequent exposure of the fallacies 
involved in the argument advanced, has been lately pointed out by 
Dr. Pusey in his discourse on ‘ The Relation of Science to Religion,’ 
delivered at the Norwich Church Congress, and will, I believe, meet 
with general assent amongst men of science as well as theologians 
of all parties. 
Still at the time I first visited Auvergne, the position that the 
valleys had been excavated by the action of the Noachian deluge 
reigned undisputed; and thus I began my explorations in that 
district with a mind prepossessed, not only with the doctrine of the 
aqueous origin of trap which I had derived from my Edinburgh - 
preceptor, but also with the idea that the valleys in every country 
were the results of this supposed catastrophe. 
It did not require more than a few days’ sojourn in Auvergne 
to disabuse my mind of the former opinion, for the association of 
rocks undistinguishable from the traps and porphyries of Scotland, 
with craters, lava streams, and heaps of scorize, which plainly attested 
the operation of volcanic heat, soon convinced me that the Wernerian 
doctrine as regarded the origin of basalt was untenable. 
But the theoretical views which I imbibed from my Oxford in- 
structor were not so easily got rid of; for the phenomena presented 
by the volcanos of Auvergne proved of a nature to afford an ap- 
parent confirmation of the distinction which Dr. Buckland had set 
up between rocks formed before and after the Noachian deluge, or, 
according to his nomenclature, those of ante-diluvial and _post- 
diluvial origin. 
The volcanic rocks which we observe in this part of Central 
France may be separated into two classes, both by the difference in 
their external characters, and also by their position with reference to 
the surrounding strata. 
The first class consists of those which have been cut through by 
the existing valleys like the other rocks of the district; the second, 
of those which follow the equalities of the surface, so as to prove 
