20 On the Geology of the Paduan, 
volcanic superstratum, the fissile limestone loses its extraordi- 
nary characters, and is replaced by the common limestone, 
with few or no organic remains, which forms the base and 
nucleus of this mountain, and the mass of those around. When, 
in addition to this, we recollect that the extraordinary attitudes 
of some of the Bolca fish prove them to have been enyeloped in a 
calcareous sediment by some instantaneous catastrophe, it will be 
difficult not to conclude that they owe their death and wonderful 
preservation to some violent explosion of the sub-marine volcano, 
whose products overlie the very rock in which they occur. 
The fishermen of Stromboli assured me, that after any un- 
usually severe eruption of the voleano of their island, such as 
sometimes takes place in the stormy season, they have found 
the whole beach on one side of the island strewed with innume- 
rable fish in a half-boiled state. The fossil fish of Bolea may 
be imagined to have perished in this manner, or rather to have 
been overwhelmed by thick clouds of loose, unconsolidated, 
calcareous sediment, cast up from the bottom of the sea by the 
volcanic explosions, and which subsiding quickly again, carried 
down the fish it had enveloped, and was in turn overwhelmed 
by the ejected lava. The heat, thus communicated, operating 
its sudden induration, was probably the cause of its highly 
fissile structure, as well as of the singularly perfect state of the 
imbedded fossils. The quantity of animal matter, afforded by 
the numerous fish thus enclosed, sufficiently accounts for the 
peculiar smell this stone gives out on friction, 
It seems to me that the interest which has always been 
attached to the fish of Monte Bolca, from their excessive pre- 
servation, and the variety of their species, must assume a cha- 
racter of much deeper importance to the geologist on their 
being recognised as the inhabitants of that ancient ocean, 
which deposited the earliest secondary or horizontal limestone. 
I observe that Brieslak, in a note to his Institutions Géolo- 
giques, § 533, mentions it to be the opinion of some naturalists, 
that the Bolca fish were enveloped in the ashes of a volcanic 
eruption; an opinion from which he justly dissents, on the 
ground of their being found in a bituminous limestone, which 
