S3 Oil certain Newer Deposits in Sicily, 



arrangement in the particles of limestone. I have seen these bodies 

 more than a foot long ; they are always smooth on their outer 

 surface, of the same thickness throughout their whole length, 

 seldom bent, and have never any branches or any other appear- 

 ance of a vegetable structure. 



The same formation extends the whole way to the village 

 gf Pachino, a few miles from Cape Passero, where I found a few 

 shells, and among others a small terebratule, and one resembling a 

 gryphaea, but which I suppose to be the Ostrea anomalis. Ano- 

 ther formation is now met with, having different mineralogical 

 characters, and containing different fossils from those already de- 

 scribed, viz. the hippurite limestone, which extends from the vil- 

 lage of Pachino to the sea, occupies the upper part of the island 

 of Cape Passero, extends round the most southerly point of Sicily, 

 and forms the base of the small island named the Isola delle 

 Conenti. It consists of beds of different coloured hard compact 

 limestones, containing great numbers of hippurites, nummulites, 

 and casts of various other shells, the characters of which cannot 

 be easily determined, on account of the hard nature of the rock. 

 The most common colour of the limestone is white, with which 

 grey is often intermixed in the same stratum, and red and white 

 sometimes occur in the same mass, giving it a brecciated appear- 

 ance. A yellowish limestone is also met with along the south 

 coast, and in the Isola delle Conenti. These beds are all hori- 

 zontal, are quite conformable in stratification to the white creta- 

 ceous and straw-coloured limestone which are above them, and 

 rest upon beds of trap-tuff and basalt. The trap-rocks ex- 

 tend from the neighbourhood of Pachino along the valley to 

 the south of that place, as far as the sea, and are only seen be- 

 low the limestone beds, there being no appearance of alterna- 

 tions, at least as far as my observations extended. They are 

 seen very distinctly in the island of Cape Passero, and on the 

 neighbouring coast, with the hippurite limestone resting upon 

 them in horizontal strata. They are lost near Porto Palo, and do 

 not again make their appearance along the coast so far as the Isola 

 delle Conenti, which was the extent of my excursion. They consist 

 of a black compact basalt, containing grains of pyroxene and 

 olivine, a grey basalt, without any disseminated minerals, and 

 different kinds of trap-tuff containing a good deal of lime. 



