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CHAPTER VII. 
Marine and volcanic formations at the base of Etna — Their connexion with the 
strata of the Val di Noto — Bay of Trezza — Cyclopian isles — Fossil shells of 
recent species — Basalt and altered rocks in the Isle of Cyclops — Submarine 
lavas of the Bay of Trezza not currents from Etna— Internal structure of the 
cone of Etna — Val di Calanna — Val del Bove not an ancient crater — Its preci- 
pices intersected by countless dikes — Scenery of the Val del Bove — Form, 
composition, and origin of the dikes — Lavas and breccias intersected by them. 
MARINE AND VOLCANIC FORMATIONS AT THE BASE OF 
ETNA, 
The phenomena considered in the last chapter suggest many 
theoretical views of the highest interest in Geology ; but before 
we enter upon these topics we are desirous of describing some 
formations in Valdemone, which are analogous to those of the 
Val di Noto, and to point out the relation of such rocks to the 
modern lavas of Etna. 
If the traveller passes along the table-land, formed by the 
great limestone of the Val di Noto, until it terminates suddenly 
near Primosole, he there sees the plain of Catania at his feet, 
No. 11. 
View of Etna from the summit of the limestone platform of Primosole. 
a, Highest cone, b, Montagnuola. c, Monte Minardo, with smaller lateral 
cones above, d, Town of Licodia dei Mouaci. e, Marine formation called creta, 
argillaceous and sandy beds with a few shells, and associated volcanic rocks. 
/, Escarpment of stratified subaqueous volcanic tuff, Sec, north-west of Catania. 
ff, Town of Catania, h, i, Dotted line expressing the highest boundary along 
which the marine strata are occasionally seen, k, Plain of Catania. /, Lime- 
stone platform of Primosole of the newer Pliocene, m. La Motta di Catania. 
