have reached the bed of the river Sioule, a league and a half higher up than they would naturally have done.

Compelled however to flow in a direction contrary to the slope of the country, a large portion of the waters constantly stagnates in its channel, and has formed a swamp which goes by the name of the "Etang de Fung.'

A somewhat similar circumstance has happened in the case of the lake Aidat, which seems to have been originally formed by a stream of lava now stretching across it. In this case, however, a still greater impediment existing to the escape of the waters by any other outlet, they have in process of time succeeded in cutting themselves channels through the parapet of lava thrown across them, the projecting portions of which appear like islands in the midst.

The stream of lava that has occasioned this impediment appears to have been furnished by one of three mountains, all of which have given out coulées flowing in the same direction, and therefore intermixed one with the other. The most considerable of these mountains is called the Puy de la Vache, the whole of which is composed of scoriaceous lava very different from that of Volvic, as it contains much iron in the state of magnetic, as well as in that of specular iron ore, the oxydation of which imparts a general redness to the rock, and likewise occasional crystals of augite and olivine. There would seem to have been formerly a crater on the summit, three sides of which are now standing, whilst the fourth was perhaps broken away by the stream of lava which descended from that quarter. The Coulée is easily followed with the eye along the valley as far as the lake, in consequence of the irregularities of its surface, and the ridge which it forms above the level plain.

The most perfect crater, however, which exists in Auvergne is that of the Puy Pariou, north of the town of Clermont. It is perfectly round, and according to M. Ramond, more than 250 feet in depth. Its structure is simple enough, consisting wholly of loose masses of slaggy

This is very well laid down in Desmarest's Map of Auvergne, Paris 1823.

lava, sufficiently decomposed to allow of the growth of turf. It has given off a stream of lava which may be traced southward to the place called "les Barraques," where it divides into two branches, descending the slope of the gra nitic hills between that spot and Clermont.

Of the modern Volcanos, however, in this neighbourhood, there is probably none more interesting than the Puy Graveneire. This mountain, which lies within two miles of Clermont, seems, as we approach its summit, to consist of an entire mass of cinders, so that we may in some degree comprehend the origin of a ludicrous opinion ascribed to a professor of the Academy of Clermont, when the volcanic nature of the rocks of Auvergne was first asserted, and maintained by an appeal to the structure of this particular mountain, who, it is said, accounted for the scoriæ found on its surface, by gravely remarking that he had heard of iron-founderies having formerly been established on the spot. Notwithstanding such strong indications of its having been in a state of ignition at a comparatively recent era, no trace of its crater can be detected, nor has it that abrupt and conical form characteristic of volcanic hills, being rather a long, round-backed eminence, rising abruptly indeed on two of its sides, but to the north connected with the chain of the Puy de Dôme, and to the south reaching into the plain of Limagne. In spite of the absence of a crater, two streams of lava appear to have pierced the sides of this mountain, and to have descended into the valley, one on the side of the village of Royat, the other on that of the Puy Montaudoux. These coulées display a singular intermixture of compact and cellular lava, the former generally occupying the centre, and surrounded by the latter variety, but without any marked line of demarcation between the two. The compact rock is a basalt, remarkable for its large distinct crystals of augite and olivine, and its being seen in connection with a lava of so cellular and vitreous an aspect affords, in common with the facts I shall detail, with respect to the German. volcanos, a sufficient

proof, that pressure is not always necessary for the formation of such products.

I shall not stop to particularize any larger number of the more recent class of volcanos, as they are much the same in their characters with those already enumerated, and differ very little from such as are at present in activity in other parts of the world. Indeed even the streams of lava which they have given out, are often so little decomposed, so partially covered with vegetation, that we not only readily admit their post-diluvial origin, but even imagine they must have been formed within the limits of authentic history. The records nevertheless of their eruption are no where to be found, and the evidence we are in quest of can only, it would seem, be collected from the volume of nature, which in this instance speaks a language so intelligible; for with regard to the popular names of certain of the mountains and vallies, to which some have referred as indications of a remote tradition, it seems more probable that they were applied to the places they designate, in consequence of the ideas which their appearances were calculated to suggest to the minds of their first inhabitants, than from the latter having been themselves eye-witnesses of the events which occasioned them.

*

The high antiquity of the most modern of these volcanos is indeed sufficiently obvious. Had any of them been in a state of activity in the age of Julius Cæsar, that general, who encamped upon the plains of Auvergne, and laid siege to its principal city,† could hardly have failed to notice them. Had there been even any record of their existence in the time of Pliny or Sidonius Apollinaris, the one would scarcely have omitted to make mention of it in his Natural History, nor the other to introduce some allusion to it among his descriptions of this his native province.

Such are Montbrul, Vallée d'Enfer; and perhaps the very name of the province may be derived from certain appearances that might have reminded its first settlers of the lake Avernus near Naples.

+ Gergovia, near Clermont.

The case is even stronger, when we recollect that the poet's residence was on the borders of the Lake Aidat, which owed its very existence to one of the most modern volcanos; and that he was aware of the nature of such phænomena, appears from a letter extant of his addressed to the Bishop of Vienne,* in which, under the apprehension of an attack from the Goths, he informs him that he is going to enjoin public prayers, similar to those which the bishop had established, at the time when earthquakes demolished the walls of Vienne, when the mountains opened and vomited forth torrents of inflamed materials, and the wild beasts, driven from the woods by fire and terror, retired into the towns, where they made great ravages.

A passage of this kind, though it may be brought forward as an argument in favour of the modern date of some of the volcanos in the neighbouring province of Vivarais, affords I think strong negative evidence of the antiquity of those in Auvergne, and disposes us to assign to them an æra as remote, as is consistent with the fact of their posteriority to the formation of the vallies,

Let us now proceed to the consideration of another description of rocks found in the same neighbourhood, the nature and origin of which appear to be somewhat more problematical, and less in harmony with the phænomena of volcanos at present in activity.

The department of which Clermont is the capital, has received its name from a mountain, which as the highest in the province, and occurring in some degree detached from the rest, has acquired more importance than it might in other situations have obtained, although indeed its height is considerable, exceeding 4000 feet. The Puy de Dôme, the hill to which I allude, is of a conical form, and remark able for the distinctness of its outline, rising abruptly from the midst of a sort of amphitheatre of volcanic rocks, which it considerably overtops, but which by a little stretch of the

* See Sidon. Apoll. Lib. 7. Epist. 1. ad Mamertum.

imagination might be supposed to have constituted the crater from whence this great central mass was projected.

However this may be, the mineralogical characters of the mountain are such, as differ entirely from those of the hills on either side of it. The Puy de Dôme seems to consist almost entirely of a rock with a felspar base, allied as it would seem to trachyte, but of a more earthy character, and containing more rarely crystals of glassy felspar. These however do occur even in the most pulverulent part of the rock, and are common in the more compact portions, where indeed the resemblance to trachyte is often so perfect, as to leave us in little doubt with respect to the real nature of the rock in general. The term Domite therefore, which was originally assigned to it from its occurring in the Puy de Dôme, must be considered as expressive merely of a variety or subspecies of trachyte, marked by the earthy character of its basis, and by its whitish or greyish colour. It contains numerous plates of mica disseminated, as well as of specular iron, which also forms a thin superficial coating on the stone between its crevices.

It also contains occasionally quartz, grains of which are sometimes so disseminated as to give an arenaceous character to the rock.

The most remarkable circumstance relating to this substance, is that it is confined to this hill, and two or three in its immediate vicinity; which, though they all present some modifications of aspect, still possess sufficient of a common character to be referable to the same class.

They are all conical, all detached, and have surrounding them hills of a volcanic nature, which bear not the slightest analogy to them in appearance. I shall refer to M. Montlozier, and the other writers who have described them, for an account of the Grand and Petit Cliersou and the Sarcouy, and shall confine myself to some remarks on the Puy Chopine, the most extraordinary certainly for the assemblage of rocks of which it is made up.