222 SUCCESSION OF CHANGES IN AUVERGNE. [Qm XIY. 



followed by showers of sand and scorise, — deep valleys have been sub- 

 sequently furrowed out through masses of lacustrine and volcanic origin, 

 — at a still later date, new cones have 'been thrown up in these valleys, — 

 new lakes have been formed by the damming up of rivers, — and more 

 than one creation of quadrupeds, birds, and plants, Eocene, Miocene, and 

 Pliocene, have followed in succession ; yet the region has preserved from 

 first to last its geographical identity ; and we can still recall to our 

 thoughts its external condition and physical structure before these 

 wonderful vicissitudes began, or while a part only of the whole had 

 been completed. There was first a period when the spacious lakes, ot 

 which we still may trace the boundaries, lay at the foot of mountains ot 

 moderate elevation, unbroken by the bold peaks and precipices of Mont 

 Dor, and unadorned by the picturesque outline of the Puy de Dome, or 

 of the volcanic cones and craters now covering the granitic platform. 

 During this earlier scene of repose deltas were slowly formed ; beds of 

 marl and sand, several hundred feet thick, deposited ; siliceous and cal- 

 careous rocks precipitated from the waters of mineral springs ; shells and 

 insects imbedded, together with the remains of the crocodile ,and tor- 

 toise, the eggs and bones of water birds, and the skeletons of quadru- 

 peds, some of them belonging to the same genera as those entombed in 

 the Eocene gypsum of Paris. To this tranquil condition of the surface 

 succeeded the era of volcanic eruptions, when the lakes were drained, 

 and when the fertility of the mountainous district was probably enhanced 

 by the igneous matter ejected from below, and poured down upon the 

 more sterile granite. During these eruptions, which appear to have 

 taken place after the disappearance of the upper Eocene fauna, and partly 

 in the Miocene epoch, the mastodon, rhinoceros, elephant, tapir, hippo- 

 potamus, together with the ox, various kinds of deer, the bear, hyaena, 

 and many beasts of prey, ranged the forest, or pastured on the plain, and 

 were occasionally overtaken by a fall of burning cinders, or buried in 

 flows of mud, such as accompany volcanic eruptions. Lastly, these 

 quadrupeds became extinct, and gave place in their turn to the species 

 now existing. There are no signs, during the whole time required for 

 this, series of events, of the sea having intervened, nor of any denuda- 

 tion which may not have been accomplished by currents in the differ- 

 ent lakes, or by rivers and floods accompanying repeated earthquakes, 

 or subterranean movements, during which the levels of the district 

 have in some places been materially modified, and perhaps the whole 

 upraised relatively to the surrounding parts of France. 



Auvergne. — The most northern of the freshwater groups is situated 

 in the valley-plain of the Allier, lying in the department of the Puy de 

 Dome, being the tract which went by the name of the Limagne d' Au- 

 vergne. It is enclosed by two parallel mountain ranges, — that of 

 the Forez, which divides the waters of the Loire and Allier on the 

 east ; and that of the Monts Domes, which separates the Allier from the 

 Sioule on the west.* The average breadth of this tract is about twenty 



* Scrope, Geology of Central France, p. 15. 



