CHAPTER IX. 
Origin of the newer Pliocene strata of Sicily — Growth of submarine formations 
gradual — Rise of the same above the level of the sea probably caused by sub- 
terranean lava — Igneous newer Pliocene rocks, formed at great depths, exceed 
in volume the lavas of Etna — Probable structure of these recent subterranean 
rocks — Changes which they may have superinduced upon strata in contact- 
Alterations of the surface during and since the emergence of the newer Pliocene 
strata — Forms of the Sicilian valleys — Sea cliffs — Proofs of successive eleva- 
tion — Why the valleys in the newer Pliocene districts correspond in form to 
those in regions of higher antiquity — Migrations of animals and plants since 
the emergence of the newer Pliocene strata — Some species newer than the 
stations they inhabit Recapitulation. 
ORIGIN OF THE NEWER PLIOCENE STRATA OF SICILY. 
Having- in the last two chapters described the tertiary forma- 
tions of the Val di Noto and Valdemone, both igneous and 
aqueous, we shall now proceed more fully to consider their 
origin, and the manner in which they may be supposed to have 
assumed their present position. The consideration of this 
subject may be naturally divided into three parts : first, we 
shall inquire in what manner the submarine formations were 
accumulated beneath the waters ; secondly, whether they 
emerged slowly or suddenly, and what modifications in the 
earth's crust, at considerable depths below the surface, may be 
indicated by their rise ; thirdly, the mutations which the sur- 
face and its inhabitants have undergone during and since the 
period of emergence. 
Growth of Submarine formations. — First, then, we are to 
inquire in what manner the subaqueous masses, whether vol- 
canic or sedimentary, may have been formed. On this subject 
we have but few observations to make, for by reference to our 
former volumes, the reader will learn how a single stratum, 
whether of sand, clay, or limestone, may be thrown down at the 
bottom of the sea, and how shells and other organic remains 
