Miss M. S. Johnston — Geological Notes on Central France. 63 



The peak of the Puy Mary is capped by an andesite, with 

 ■porphyritic felspars and horublende, overlying a band of porphy- 

 roidal basalt, which is situated on a mass of breccia; the whole 

 three deposits being dyked by phonolite, basalt, and andesite. 

 From the top of this Puy a fine view of the crater of the Cantal 

 is obtained. The Cantal massif was formed by one crater, the 

 remains of which may be traced from the Puy Mary ; its ring 

 is eight miles in diameter, the highest points being the Plomb 

 <le Cantal, the Pay Mary, and the Puy Chavaroche. In the centre 

 of the crater are several cone-shaped hills of phonolite, the Puy 

 Orion being the highest. These are weathered dykes, phonolite 

 having the peculiarity of weathering into cones, as will be observed 

 in PI. Ill, Fig. 4 of the phonolite hills of the Megal district. 



The order of deposition in the Cantal region is — Miocene basalt, 

 trachyte, and phonolite ; andesitic breccia ; andesitic and phonolitic 

 flows ; and finally, the plateau basalt. 



On leaving the Cantal district and proceeding by train to Le Puy, 

 another volcanic area may be studied, that of Velay. The chief 

 points to be noticed along the line are the union of Quaternary 

 moraines from the valleys of the Allagnon and AUange at 

 Neussargues, and at Mei'dogne a remarkable basaltic rock over- 

 spreading cinerites, containing Miocene flora ; at this point also the 

 valley casts off its glacial character, and narrows itself between walls 

 of gneiss, often amphibolic. At Leuipdes the plain of the Limagne 

 is reached, but soon the line turns to the south, and after Arvant 

 it passes over some part of the Oligocene plain and then on to the 

 gneiss again. At Darsac is to be seen a characteristic view of 

 the plains of basalt, with the scoriaceous cones of the axis of the 

 Velay chain in the distance. 



The plain in whicli Le Puy is situated bears striking evidence 

 of tlie wearing away of volcanoes. In the centre are two isolated 

 rocks of breccia, the Roches Cornel lie and Aguilhac, surrounded 

 by Oligocene deposits. From the Roche Corneille is seen the plain, 

 whose edges rise on all sides in terraces and hills, first of ravined 

 'Oligocene deposits, tlien of volcanic remains. Over the hills to the 

 south and east are the Mezen and Megal peaks. On the north, 

 in the middle distance, is a small volcano which has been cut in 

 half; the crater pipe and outer slopes can still be clearly traced. 

 The hills of Polignac and Denise are both of interest. At Denise 

 the hill is composed of a pipe of scoria, often containing granite, and 

 two varieties of breccia, one of Middle Pliocene age, the other of 

 the age of Elephns meridionalis : in the latter was found the ' Man 

 of Denise,' but how he got there is still a vexed question ; his 

 skeleton has been placed in the Le Puy Museum. 



The Loire flows along to the east of Le Puy, but in early 

 Quaternary times the principal river flowed away to the west 

 on the south of the town. 



The Megal and Mezen district is one of the most interesting 

 round Le Puy. This region is the oldest volcanic area of the Velay, 

 and is composed almost entirely of basalt and phonolite ; indeed, the 



