CONTENTS. 
xxi 
PAGE 
Submarine lavas of the bay of Trezza not currents from Etna — Internal 
structure of the cone of Etna — Val di Calami a — Val del Bove not an ancient 
crater — Its precipices intersected by countless dike-s — Scenery of the Val del 
Bove— Form, composition, and origin of the dikes — Lavas and breccias 
intersected by them .... 75 
CHAPTER VIII. 
Speculations on the origin of the Val del Bove on Etna — Subsidences — 
Antiquity of the cone of Etna — Mode of computing the age of volcanos— 
Their growth analogous to that of exogenous trees — Period required for the 
production of the lateral cones of Etna — Whether signs of Diluvial Waves 
are observable on Etna . . . . , .95 
CHAPTER IX. 
Origin of the newer Pliocene strata of Sicily — Growth of submarine for- 
mations gradual — Rise of the same above the level of the sea probably caused 
by subterranean lava — Igneous newer Pliocene rocks formed at great depths, 
exceed in volume the lavas of Etna — Probable structure of these recent sub- 
terranean 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 elevation — Why the valleys in the newer Pliocene districts cor- 
respond in form to those in regions of higher antiquity — Migrations of 
animals and plants since the emergence of the newer Pliocene strata — Some 
species older than the stations they inhabit — Recapitulation , 103 
CHAPTER X. 
Tertiary formations of Campania — Comparison of the recorded changes in 
this region with those commemorated by geological monuments — Differences 
in the composition of Somma and Vesuvius — Dikes of Somma, their origin 
— Cause of the parallelism of their opposite sides — Why coarser grained in 
the centre — Minor cones of the Phlegrsean Fields — Age of the volcanic and 
associated rocks of Campania — Organic remains — External configuration of 
the country, how produced — No signs of diluvial waves — Marine Newer 
Pliocene strata visible only in countries of earthquakes — Illustrations from 
Chili' — 'Peru — Parallel roads of Coquimbo — West-Indian archipelago — 
Honduras — East-Indian archipelago — Red Sea . , . 118 
CHAPTER XI. 
Newer Pliocene fresh-water formations — Valley of the Elsa — Travertins of 
Rome — Osseous breccias — Sicily — Caves near Palermo— Extinct animals 
