DESCRIPTION OF PLATE II. 



EXTINCT VOLCANOES OF AUVERGNE. 



I. Profile of Mont Dore, as seen from a distance; with a plan of the crater of the 

 mountain : see nage 271. 



II. Part of these n chain of Puys; exhibiting the broken craters of Chau- 



mont, each with a current of lava issuing from its base : Mont Dome is seen 

 in the distance : see page 268. 



IJI. View of the Environs of Clermont, from the Puy Girou. 



In the foreground is a basaltic peak, on the summit of which is the 

 Castle of Montrognon. The town of Clermont is seen in the valley imme- 

 diately beyond ; and Montferrand in the plain on the right. 



The dark horizontal lines indicate the basaltic platform which caps the 

 summits of the hills of fresh-water limestone. These beds of basalt are 

 between 300 and 400 feet in thickness, and are spread over limestone 

 strata, which, together with the basalt, were once continuous, but have I 

 since been eroded, and the detritus carried away by alluvial action; see 

 page 276. 



The remote distance is the granitic escarpment, forming part of the boundary 

 of the plain of Auvergne ; see page 270. 



