16 
POPULAR SCIENCE REVIEW. 
granitic rocks of the Monts Dome had made us all, perhaps, 
over careful, and we were none of us the least inclined to make 
lateral moraines of mere local debris or roches moutonnees of 
weathered granite. 
The valley of the Dordogne was yellow with the flowers of 
Primula elatior , and the bright blue blossoms of Gentiana verna 
were glistening on the slopes of the Cascade side by side with 
Thlaspi alpestre and purple pansies ( Viola tricolor) ; but the 
heights of Puy Ferrand and the Pic de Sancy were white with 
snow, from which a thousand streamlets poured, laden with 
detritus, and affording an excellent illustration of the power of 
melting snow in carrying detritus from mountain slopes to a 
lower level. In fact, the valley of the Dordogne is now every 
spring-time everywhere percolated through and through by 
running water, and if there was a glacier there, in days long 
ago, the numerous streamlets produced by the melting snows 
and rains must have long ago sorted the glacial debris and 
rolled and washed the materials. 
The masses of rock known as “ Les Trois Diables ” appear to 
be fallen masses, and the bristling pinnacles of the Gorge 
d’Enfer called “ Les Cheminees du Diable ” are about soon to 
follow their example and hurtle downwards into the abyss below. 
The wind was bitterly cold at the Gorge d’Enfer, and the snow 
lay deep in its gullies. Here and there the rosy blossoms of 
Androsace carnea looked like blood-spots among the snow, on 
which we picked up a dead Brambling finch ( Fringilla monti- 
fringilla ), which had succumbed to the cold. Passing over a 
coulee of snow, I ascended to the basaltic platform above, and 
there saw masses of trachyte and felstone resting on basalt, which 
could hardly be fallen debris , and I was thus led to believe 
that a glacier had passed over the higher platforms of basalt 
before the erosion of the valley. I also called the attention of 
my companions to what I think is moraine matter, and trans- 
ported rock masses of trachyte resting on basalt, on the road 
between Mont Dore les Bains and La Cour,. as on the basaltic 
platform below the Rochers de Beauzac. 
Above the entrance of the valley of La Cour we cross the 
Dordogne and wind up the zigzag towards the Pic de Sancy. 
Opposite to the “ Vallee de la Cour ” is a deep gorge, dividing 
the Cacadogne and the Roc du Cuzau, and from this gorge 
rises the ££ Roc Barbu,” a mass of columnar basalt which is in- 
teresting, as it was believed by Scrope to occupy nearly the site of 
the great crater of the ancient miocene volcano. No one can 
examine into these inner recesses, and afterwards explore the 
volcano round its base, and observe the enormous masses of 
volcanic materials spread forth from a common centre, without 
becoming convinced, first, that the formation of the volcano 
