Oh. XIV.] 
VOLCANOS OF THE EIFEL. 
quakes, nor subjected to the action of any great transient flood 
since their origin. 
East of Olot, on the Catalonian coast, marine tertiary strata 
occur, which, near Barcelona, attain the height of about 500 
feet. It appears probable, from a small number of shells which 
I collected, that these strata may correspond with the Sub- 
apennine beds, so that if the volcanic district had extended 
thus far, we might be able to determine the age of the igneous 
products, by observing their relation to these older Pliocene 
formations *. 
Sardinian volcanos. — The line of extinct volcanos in Sar- 
dinia, described by Captain Smyth f, is also of uncertain date, 
as, notwithstanding the freshness of some of the cones and lavas, 
they may be of high antiquity. They rest, however, on a ter- 
tiary formation, supposed by some to correspond to the Sub- 
apennine strata, but of which the fossil remains have not been 
fully described. 
VOLCANIC ROCKS OF THE EIFEL. 
The volcanos of the Lower Rhine and the Eifel are of no less 
uncertain date than those of Catalonia ; but we are desirous of 
pointing out some of their peculiar characters, and shall, 
therefore, treat of them in this chapter, trusting that future 
investigations will determine their chronological relations more 
accurately. 
For the geographical details of this volcanic region, we refer 
the reader to the annexed map, for which I am indebted to 
Mr. Leonard Horner, whose residence in the country has 
enabled him to verify the maps of MM. Noeggerath and Von 
Oyenhausen, from which that now given has been principally 
compiled. 
* For some account of the Olot volcanos see ' Noticia de Los Estinguidos 
Volcanes de la Villa de Olot,' by Francisco Bolos. Barcelona. No date,— but the 
observations, I am told, preceded those of Dr. Maclure. 
f Present state of Sardinia, &c, pp. 69, 70. 
Vol. Ill, 0 
