CHAPTER X. 



Tertiary formations of Campania Comparison of the recorded changes in this 

 region with those commemorated hy geological monuments Differences in the 

 composition of Somma and Vesuvius Dikes of Sonima, 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. 



TERTIARY FORMATIONS OF CAMPANIA. 



Comparison of recorded changes with those commemorated 

 bij geological monuments. IN the first volume we traced the 

 various changes which the volcanic region of Naples is known 

 to have undergone during the last 2000 years, and, imperfect 

 as are our historical records, the aggregate effect of igneous 

 and aqueous agency, during that period, was shown to be far 

 from insignificant. The rise of the modern cone of Vesuvius, 

 since the year 79, was the most memorable event during those 

 twenty centuries ; but in addition to this remarkable pheno- 

 menon, we enumerated the production of several new minor 

 cones in Ischia, and of the Monte Nuovo, in the year 1538. 

 We described the flowing of lava-currents upon the land and 

 along the bottom of the sea, the showering down of volcanic 

 sand, pumice, and scoriae, in such abundance that whole cities 

 were buried, the filling up or shoaling of certain tracts of the 

 sea, and the transportation of tufaceous sediment by rivers and 

 land-floods. We also explained the evidence in proof of a 

 permanent alteration of the relative levels of the land and sea 

 in several localities, and of the same tract having, near Puz- 

 zuoli, been alternately upheaved, and depressed, to the amount 

 of more than 20 feet. In connexion with these convulsions, 



