Dr Daubeny on the Geology of Sicily. 239 
covered with a very different kind of material, which would 
appear to have been at one time of considerable thickness, as 
it constitutes hills, which, though they offer no comparison in 
point of elevation with those consisting of the compact lime- 
stone, are yet some hundred feet in height. 
The line of demarcation between this and the preceding 
rock, is very distinctly marked by the character of the vege- 
tation. The compact limestone, like that of the Appenines, 
or of Nismes in the south of France, is chiefly adapted for 
the olive, and affords but a scanty pasturage, vegetation being 
obstructed by the fragments of chert, which cover the surface 
here, as in many portions of the limestone district in Derby- 
shire; whereas, the formation now about to be described, 
affords the finest crops of corn, and is distinguished, even 
where uncultivated, by the luxuriance of the plamts that grow 
every where upon it. 
This formation consists either of a coarse puddingstone, 
containing rolled and angular fragments of quartz, and of the 
compact limestone on which it rests, or of a calcareous brec- 
cia, in which sand is also present, though limestone be the 
predominating ingredient. 
Wherever the latter variety is found, shells are very abun- 
dant, so that we may be led to attribute the presence of cal- 
careous matter in this instance, principally to the accumula- 
tion of decayed organic bodies. 
The genera of shells commonly most frequent in this rock, 
are the Pecten, Ostrea, and Venus; but in that variety of it 
which occurs at the foot of Mount Pelegrino, and is only dis- 
tinguished from the former by its greater freedom from sandy 
matter, and the consequent wh'teness of the rock, Serpule, 
Dentalia, and Venericardie, may be distinguished along with 
those already mentioned. 
I may remark once for all, that a breccia of this kind, re- 
plete with shells, not far, if at all, removed from existing 
species, seems to fill up the hollows in most of the older 
rocks of Sicily. Thus, a formation of this kind exists, as I 
am informed, at Messina, though, being at that time occupied 
on other subjects, | did not observe it. ‘The same formation 
occurs at Syracuse, and along the coast upwards towards 
Catonia, where it must not be confounded with the calcareous 
rock afterwards to’ be deseribed, which alternates with vol- 
