'62 Miss M. S. Johnston — Geological Notes on Central France. 



of very regular columns and overlies a Pliocene river bed, situated 

 some hundred feet above the valley of the Goul. The basalt is 

 Itreached in places; the largest, as seen in PI. II, Fig. 2, has 

 caused the andesitic breccia below to be seen. 



After leaving Carlat the road takes a sharp turn to the south, 

 and a section of cinerite, with loose felspar crystals, is found near 

 ihe top of a hill overlain by concretionary Miocene sand. 



Tlie I'oad now continues around the southern spurs of the Cantal, 

 which presents new vistas of beauty at every turn, and on reaching 

 Cui'ebourse a magnificent panorama of the valley of the Cere is 

 obtained. At a short distance from Curebourse and above Vic-sur- 

 Cere is the celebrated section of Mougudo of compact cinerite, 

 containing fossil plants. About twenty-two species of plants have 

 been found there, in the shape of leaves, twigs, trunks, and 

 wood opal. 



The road now follows the valley of the Cere, where there is an 

 abundance of volcanic breccia, mostly capped by columns of basalt. 

 At Thiezac, near St. Jacut, is a noticeable section across the valley 

 and one which may be easily distinguished at sight. On the north- 

 -west side the highest rocks are of andesite, then a band of 

 porphyritic basalt, beneath this a mass of breccia, with dykes of 

 andesite and labradorite overlying the mica-schists. The formation 

 ■of the small hill, on which stands a white statue of the Virgin, is 

 a dyked breccia, while on the south-east side of the Cere rises 

 a dome of trachyte and phonolite, tilting the breccia containing 

 andesite and cinerite dykes, and capped by andesite and Oligocene 

 basalt. 



The two most striking features now in the landscape are the peak 

 of the Puy Grion, a w^eathered phonolite dyke on the left, and the 

 Plomb du Cantal, the highest summit in this region, and situated on 

 the edge of the crater ring on the right. The lateral ravines and 

 the flanks of the cirques are riddled with dykes, as are also the cliffs 

 along the valley of the Allagnon, which is reached by the tunnel 

 -of Lioran, three-quarters of a mile long. 



At a waterfall not far from Lioran a trachyte called the ' roche 

 de deuil ' is to be found, and at Laveissiere, a short distance further 

 on, the base of an ancient volcano may be seen resting on 

 Oligocene limestone. The Rocher de Bonnevie rises in successive 

 tiers of basaltic columns above the town of Murat, and there is also 

 a fine example of columns, showing various directions of contact 

 cooling in the hill below Bredon church. In the village of Bredon 

 aTe cave dwellings, which were inhabited as late as fifteen years ago. 



From Murat a good excursion can be made to the Puy Mary 

 (PI. Ill, Fig. 3). The road leads up the valley of the Chevade to the 

 "Gol d'Entremont, where there is a large exposure of augitic andesite, 

 with haiiyne, which is used for tiles. Many of the specimens are 

 good sounding clinkstones. At this point the road descends and 

 crosses the valley of the Dienne, which has its origin at the foot 

 of the Puy Mary, and is a good example of a glacially and aerially 

 denuded valley. 



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