SUB-APENNINE STRATA. 



245 



The range of mountains in Italy, called the Apennines, that rise 

 in some parts to the height of from six to eight thousand feet, and 

 extend north and south from the borders of Piedmont to Calabria, 

 are accompanied, both on the Adriatic and Mediterranean flanks, by- 

 ranges of lower hills, which have, from their position, received the 

 name of sub-Apennine. The sub-Apennine hills rise to the height of 

 from one to two thousand feet ; they are composed of tertiary beds 

 of marl, sand, clay, and calcareous tufa, and abound in marine shells, 

 many of which are identical with existing species in the Mediterra- 

 nean sea, or with other existing species of tropical climates. It is 

 observed that the upper beds contain the greatest proportion of spe- 

 cies similar to what exist in the neigbouring seas. The sub-Apennine 

 beds rest unconformably upon the inclined beds of the Apennine 

 range. It has been ascertained by dredging the bed of the Adriatic 

 sea, that there are beds now forming at the bottom, which closely re- 

 semble beds in the sub-Apennine hills, more than a thousand feet 

 high. There can be no doubt that these sub-Apennine beds have 

 once formed the bottom of an ancient sea, and have been raised to 

 their present elevation by subterranean action. The occurrence of 

 numerous volcanic vents, in the whole of that part of Italy, can 

 leave litde doubt respecting the agent by which this elevation has 

 been effected. 



In the third ediuon of this work, I had, on the authority of M. 

 Brongniart, referred a great part of the sub-Apennine beds to the up- 

 per marine sandstone of the Paris basin, above the gypseous marl. 

 Whether any portion of the sub-Apennine strata belong to the same 

 epoch as the upper strata in the Paris basin, may be doubtful ; but 

 we may safely infer, both from their organic remains and position, 

 that the superior sub-Apennine beds, belong to a far more recent 

 epoch than that in which the tertiary strata round Paris and in Eng- 

 land were deposited. Mr. Lyell, who has recently examined this in- 

 teresdng range of tertiary hills, and from whom geologists may ex- 

 pect much valuable information respecting them, has extended his 

 researches into Sicily, where he found that "there were many places 

 in which the extinct species had nearly disappeared ; and that amid 

 vast accumulations of marine shells, entering into the composition of 

 mountains of no inconsiderable altitude, nearly all w^ere rpecifically 

 identical with those now inhabiting the adjoining sea." According to 

 the principles of M. Deshayes, these Sicilian beds must be more re- 

 cent than the sub-Appennine. 



One thousand species of shells have been collected by Signor 

 Guidotto from the sub-Apennine beds ; and if the rules laid down by 

 M. Deshayes, respecting this formation, can be relied upon, the 

 greater number of the species of shells belong to existing species^ 

 and of these ihe greater proportion belong not only to existing spe- 

 cies, but to species inhabidng the neighbouring sea. In Sicily, how- 

 ever, we approach much nearer to the present state of things, as 

 nemigall the shells in the tertiary strata are identical with living spe- 



