t towards the north and directly east of Clermont it forms a high
ridge traversed by the railway to St. Etienne and Lyons, and descending
towards the east into the valley of the Loire. No more impressive view
is to be obtained of the volcanic region than that from the summit of
this second ridge, on arriving there towards evening from the city of
Lyons. At your feet lies the richly-cultivated plain of Clermont, dotted
with towns, villages, and hamlets, and decorated with pastures,
orchards, vineyards, and numerous trees; while beyond rises the granitic
plateau, breaking off abruptly along the margin of the plain, and deeply
indented by the valleys and gorges along which the streams descend to
join the Allier. But the chief point of interest is the chain of
volcanic crater-cones and dome-shaped eminences which rise from the
plateau, amongst which the Puy de Dome towers supreme. Their individual
forms stand out in clear and sharp relief against the western sky, and
gradually fade away towards the south into the serried masses of Mont
Dore and Cantal, around whose summits the evening mists are gathering.
Except the first view of the Mont Blanc range from the crest of the
Jura, there is no scene perhaps which is calculated to impress itself
more vividly on the memory than that here faintly described.[3]

[Illustration: Fig. 18.--Transverse view of the Puy de Dome and
neighbouring volcanoes from the Puy de Chopine.--(After Scrope.)]

(_b._) _The Vale of Clermont._--The plain upon which we look down was
once the floor of an extensive lake, for it is composed of various
strata of sand, clay, marl, and limestone, containing various genera and
species of fresh-water shells. These strata are of great thickness,
perhaps a thousand feet in some places; and along with such shells as
_Paludina_, _Planorbis_, and _Limnaea_ are also found remains of various
other animals, such as fish, serpents, batrachians, crocodiles,
ruminants, and those of huge pachyderms, as _Rhinoceros_, _Dinotherium_,
and _Caenotherium_. This great lake, occupying a hollow in the old
granitic platform of Central France, must have been in existence for an
extensive period, which MM. Pomel, Aymard, and Lyell all unite in
referring to that of the Lower Miocene. But what is to us of special
interest is the fact that, in the deposits of this lake of the Haute
Loire, with the exception of the very latest, there is no intermixture
of volcanic products such as might hav