158 
OLDER PLIOCENE PERIOD. 
[Ch. XII. 
larly stratified. He seems to have been misled by Brocchi's 
description, who contrasts the more crystalline and solid texture 
of the older secondary rocks of the Apennines with the loose 
and incoherent nature of the Subapennine beds, which resemble, 
he says, the mud and sand now deposited by the sea. 
We have endeavoured, in the last chapter, to restrict within 
definite limits the meaning of the term alluvium ; but if the 
Subapennine beds are to be designated « marine alluvia,' the 
same name might, with equal propriety, be applied not only to 
the argillaceous and sandy groups of the London and Hamp- 
shire basins, but to a very great portion of our secondary series 
where the marls, clays, and sands are as imperfectly consoli- 
dated as the tertiary strata of Italy in general. 
They who have been inclined to associate the idea of the more 
stony texture of stratified deposits with a comparatively higher 
antiquity, should consider how dissimilar, in this respect, are 
the tertiary groups of London and Paris, although ad- 
mitted to be of contemporaneous date, or they should visit 
Sicily and behold a soft brown marl, identical in mineral cha- 
racter with that of the Subapennine beds, underlying a mass of 
solid and regularly- stratified limestone, rivalling the chalk of 
England in thickness. This Sicilian marl is older than the 
superincumbent limestone, but newer than tlWSubapennine marl 
of the north of Italy ; for in the latter the extinct shells rather 
predominate over the recent, in the former the recent pre- 
dominate almost to the exclusion of the extinct. 
We shall now consider more particularly the characters of 
those Subapennine beds which we refer to the older Pliocene 
period. 
Subapennine maris. — The most important member of the 
Subapennine formation is a marl which varies in colour from 
greyish brown to blue. It is very aluminous, and usually 
contains much calcareous matter and scales of mica. It 
often exhibits no lines of division throughout a considerable 
thickness, but in other places it is thinly laminated. Near 
Parma, for example, I have counted thirty distinct lamina? in 
