Ch. IX>] PROOFS OF SUCCESSIVE ELEVATION. 113 



destroyed, and every trace of the successive rise of the land will 

 be obliterated. 



We have been led into these observations, in order to show 

 that the principal features in the physical geography of Sicily 

 are by no means inconsistent with the hypothesis of the succes- 

 sive elevation of the country by the intermittent action of 

 ordinary earthquakes *. On the other hand, we consider the^ 

 magnitude of the valleys, and their correspondence in form with 

 those of other parts of the globe, to lend countenance to the 

 theory of the slow and gradual rise of subaqueous strata. 



We have remarked in the first volume f, that the excavation 

 of valleys must always proceed with the greatest rapidity when 

 the levels of a country are undergoing alteration from time to 

 time by earthquakes, and that it is principally when a country 

 is rising or sinking by successive movements, that the power of 

 aqueous causes, such as tides, currents, rivers, and land-floods, 

 is exerted with the fullest energy. 



In order to explain the present appearance of the surface, 

 we must first go back to the time when the Sicilian forma- 

 tions were mere shoals at the bottom of the sea, in which the 

 currents may have scooped out channels here and there. We 

 must next suppose these shoals to have become small islands of 

 which the cliffs were thrown down from time to time, as were 

 those of Gian Greco, in Calabria, during the earthquake of 

 1783. The waves and currents would then continue their 

 denuding action during the emergence of these islands, until 

 at length, when the intervening channels were laid dry, and 

 rivers began to flow, the deepening and widening of the val- 



* Since writing the above I have read the excellent memoir of M. Boblaye, on 

 the alterations produced by the sea on calcareous rocks on the shores of Greece. 

 By examining the line of littoral caverns worn by the waves in cliffs composed of 

 the harder limestones, together with the modes of decomposition of the rock, acted 

 upon by the spray and sea air, as well as lithodomous perforations, and other 

 markings, he has proved that there are four or five distinct ranges of ancient sea 

 cliffs, one above the other, at various elevations in the Morea, which attest as 

 many successive elevations of the country. Journal de Geologie, No. 10. Feb. 

 1831. 



t Chan. xxiv. 



VOL. III. I 



