VOLCANOS OF THE HAUTE LOIRE AND THE ARDECHE. 341 
of Coiron flowed over a great plain of secondary rocks, which 
abutted against the granite, and protected it from denuda- 
tion. Since that period great valleys have been excavated, 
and the configuration of the country has been entirely 
changed. We saw in several places the excavations of the rail- 
way from Montelimar and gathered on the limestone Centau- 
area ccerulescens and aspera , JEchinops libro , and Campanula 
media. Leaving on our right the ancient city of the Helvii, 
Aps, our last view of volcanic rocks was the Roche Maure, 
which in 1751 led MM. Gruettard and Malesherbes to the dis- 
covery of the volcanos of Auvergne. What changes have 
happened since those days ; what progress in geological know- 
ledge ! The “ Principles of Geology ” had not been penned, 
and the tertiary shells of the Apennines were supposed to be 
the scallops of the pilgrim. It was dangerous to doubt the 
fact of a universal deluge, or that the world was more ancient 
than some 6,000 years. The older rocks were but a chaos, and 
no Lyell, Sedgwick, or Murchison had appeared to throw the 
vigour of a lifetime into a labour of love. Yet the investiga- 
tions of the geologist are inexhaustible ; and among hills and 
valleys the most romantic, in beautiful southern France, where 
the wild rose blossoms on the red cinder of the volcanos, and 
chestnut forests cluster at their base, there are problems to be 
solved, and shrouded fossils to be disinterred, which shall yet 
throw light upon the extinct volcanos of the Ardeche. 
