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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. 



HLMiuardo 

 h 



View of Etna from the summit of the limestone platform of Primosole, 



a, Highest cone. , Montagnuola. c, Monte Minardo, with smaller lateral 

 cones above. d } Town of Licodiadei Monaci. e, Marine formation called creta, 

 argillaceous and sandy beds with a few shells, and associated volcanic rocks. 

 /, Escarpment of stratified subaqueous volcanic tuff, &c., north-west of Catania. 

 g, Town of Catania, k, 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. 



