Dr Daubeny on the Volcanoes of Auvergne, 95 
as it were, of basalt, which stretches, vertically, towards the 
summit of the hill, but does not penetrate the limestone above. 
There appeared to be a transition from the tuffaceous rock 
into the basalt, although I would not be understood to speak 
confidently on that point ; and must therefore leave it for others 
to determine, whether the imbedded mass is to be considered in 
the relation of a Vein, or merely as composed of a modification 
of the tuff in which it is found, 
I should observe, however, while on this point, that I saw at 
Brives, a little village within a league of the town of Puy en 
Velay, columnar basalt, so enclosed in the midst of beds of 
slaggy lava, and other decided volcanic products, collected into 
a sort of tuff, that we are compelled to admit the origin of both 
to be, in this instance, the same. Thus, too, at St Pierre Eyriac, 
near the same place, the basalt and tuff alternate with each 
other ; and to prove their identity of origin still further, both 
rocks equally have their fine drusy cavities filled with olivine 
and hornblende, which have somewhere been called, by the 
French geologists, Peridote rock. But to return : — -Underneath 
this bed of trap-tuff, if such it be, is the limestone, similar to 
what occurs generally over the plain of Limagne, so that we 
have here two alternations of trap, with the most recent lime- 
stone beds, — a fact analogous to what has been observed by Spal- 
lanzani in Sicily, and, if I recollect right, among the Euganean 
I-Iills. 
These instances are sufficient to prove, that Trap-rocks, (for 
it would be assuming too much at present, to style them by 
any other name,) are found near Clermont, which cannot, by 
possibility, be referred to the modern order of volcanoes. We 
may now proceed to mention one or two, the era of which ap- 
pears more dubious. 
A mile or two south of Clermont, near the road to Brionde, 
we observe, close together, two eminences, one of them consti- 
tuting a little knoll, hardly perceptible until we are close to it;, 
the other attaining a considerable height, and remarkable for 
the abruptness with which it rises out of the midst of so level a 
plain. The first of these is called the Puy de la Peye, or Puy 
de la Poix ; the other, or larger one, the Puy Cronelle. The 
Puy de la Peye, consists entirely of a species of trap, strongly 
