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CONTENT S.

CHAPTER I.

Page

SKETCH OF THE GEOLOGY OF CENTRAL FRANCE

CHAPTER II.

TERTIARY LACUSTRINE FORMATIONS .. .. .. .. .. .. ..

1. Limagne d'Auvergne. 2. Cantal. 3. Haute Loire. 4. Montbrison.

CHAPTER III.

INTRODUCTORY ACCOUNT OF THE NOTICES WHICH HAVE BEEN

HITHERTO PUBLISHED CONCERNING THE VOLCANIC REMAINS OF
THE INTERIOR OF FRANCE .. .. .. .. .. .. .. ..

CHAPTER IV.

GENERAL ACCOUNT OF THE VOLCANIC FORMATION3 OCCURRING

UPON THE ELEVATED GRANITIC PLATFORM OF CENTRAL FRANCE

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CHAPTER V.

FIRST VOLCANIC REGION. — MONTS DOME AND THE LIMAGNE
D'AUVERGNE .. .. .. .. .. .. .. .. .. .. ..

1. Chain of Puys. 2. Products of earlier Eruptions.

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CHAPTER VI.

114

REGION II.-THE MONT DORE .. .. .. .. .. .. .. ..

§ 1. The Volcanic Mountain-Its general Outline--Conglomerates.
§ 2. Structure ---- Central Peaks -- Trachytic Plateaux — ('linkstone

and Basalt. $ 3. Recent Eruptions.

LIST OF ILLUSTRATIONS.

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Plate.

VI. Valley of Villar and Plateau of Prudelle .. .. .. VIII. Clinkstone Rocks, Tuilière and Sanadoire, from the Puy

Gros (Mont Dore) .. .. .. .. .. .. .. X. Montagne de Bonnevie (a cluster of Basaltic Columns),

above the Town of Murat (Cantal) ..... .. XII. Basaltic Plateaux of the Coiron (Ardêche), from the

South .. .. .. .. .. .. .. .. .. XIV. Valley of Montpezat (Ardêche) .. .. .. .. ..

XV. La Coupe d'Ayzac (Ardêche) .. .. .. .. .. XVII. Profiles and Sections, &c. .. .. ..

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163 187 194

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XIII. Volcanic Cone and Basaltic Lava-current of Jaujac

(Ardêche) .. .. .. .. .. .. .. ..

Frontispiece.

I. Panoramic View from the Puy Girou, 6 miles South

of Clermont (Puy de Dôme) .. .. .. .. .. At the end of the Volume. II. General View of the Chain of Puys, from the West,

above the Valley of the Sioule, near Pont Gibaud .. III. Transversal View of the Monts Dôme, from the summit

of the Puy Chopine .. .. .. .. .. .. .. IV. Eastern View of Monts Dôme, from the Croix de

Pirobot, between Volvic and Channat .. .. ..
V. The Southern Chain of Puys, from the Puy de la Rodde
VII. Valley of the Dordogne and Mont Dore, from the Puy

Gros on the North .. .. .. .. .. .. ..
IX, The Valley of Chambon and the Mont Dore from the East
XI. Panoramic Sketch of the Basin of Le Puy (Haute Loire)

and of the Mont Mezen, taken from the Mont d'Ours XVI. Sections of Granitic Plateau from East to West and

from N.N.E. to S.S.W... .. .. .. .. ..

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GEOLOGY AND EXTINCT VOLCANOS

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CENTRAL FRANCE.

CHAPTER I.

GRANITIC PLATEAU AND MARINE STRATIFIED FORMATIONS.

The parallel of 46-30, passing near the towns of Châteauroux and Châlons-sur-Saône, will be found to divide France into two nearly equal portions, of which the northern may be considered as a vast plain, whose waters flow gently towards the north and west through the Seine and the lower Loire. South of this line the surface continues to rise with a gradual slope, so as to form an inclined plane, which progressively acquires an elevation of more than 3000 feet above the sea in the Auvergne and Forèz, and a still greater in the Gevaudan and Vivarais, where it reaches the height of 5500 feet. Here it is abruptly cut down by the deep valley of the Rhone, which, running nearly due north and south, separates it from the ranges east of that river, in the departments Drôme, Isère, and Hautes Alpes. On the south - west also this high ground rapidly descends through broken and irregular embranchments to the basin of the Gironde. It may, in fact, be considered as a triangular

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