AMONG THE VOLCANOS AND GLACIERS OF AUVERGNE. IT 
must have occupied a long period of volcanic activity ; and 
secondly, that the destruction of its original shape must have 
been caused by long ages of quiescence. Had the volcano con- 
tinued in action, the effects of erosion would soon have been 
obliterated ; while the deep valleys and gorges tell of long con- 
tinued denudation since the last outbursts from the Mont Dore 
crater. 
Our route to the Tranteine valley passed over the Col be- 
tween the Pic de Sancy and Puy Ferrand, and our guide was 
Guillaume Pierre, of the Hotel Chabory ainee, whom we can re- 
commend, and to whom I pointed out various phenomena in 
the Tranteine gorge which I commend to others who have 
time at their disposal for examination. 
The head of the Mont Dore valley is a semicircle of pre- 
cipitous mountains, buttressed with jagged dykes of hard 
trachyte and columnar basalt, and intrusive masses of felstone 
porphyry. Looking northwards we behold the deep valley and 
amphitheatre of the Dordogne, and huge pinnacles of rock which 
shoot up from the lateral Gorge d’Enfer. Far and wide the eye 
beholds volcanic hills, many so bare of vegetation as to give the 
distant view an aspect of sterility. At one point you see the 
modem volcanos of the Monts Dome ; at another you look upon 
the older volcano of the Cantal, glistening with snow as if to 
assert its more hoary longevity as a patriarch of other days. 
The gorge of Chaudefour opens out to the north-west, below 
Puy Ferrand, and we look down on bristling rocks, sheets of 
basalt, the valley of Chambon, the old castle of Murol, and the 
modem volcano of the Puy de Tartaret, with the lake of Cham- 
bon dammed up by its lava current. The Tranteine valley 
runs due south, and faces the country of the Cantal. High 
above its northern gorge rises the Pic de Sancy surmounted 
by a cross. The Pic itself owes its shape and preservation to 
the slow weathering of a hard felstone porphyry, which Mr. 
Scrope calls a 44 porphyritic trachyte,” and which is important 
to bear in mind as a good local rock to mark for evidence 
as respects transportation, like the granite erratics of Mont 
Blanc. 
The transported rock masses sketched by Dr. Hooker in 
44 Nature ” are distant a mile and a-half from the summit of the 
Pic de Sancy, and I took the guide from the Col at the head 
of the pass down the gorge. Nearly in the centre of the 
gorge we came upon a roche moutonnee , close by which flows 
a rivulet ; and on both sides the hills, as they slope downwards 
towards the south, are studded with perched blocks resting on 
masses, in situ , of different mineral composition, and of which 
the only way of accounting for the distribution, save that of a 
glacier, is that they may have been shot out of the volcano and,. 
NEW SERIES VOL. I. NO. I. C 
