S6 On certain Newer Deposits m Sicily, 



not be so easily determined, and their magnitude was not equal 

 to those which formed the most marked features of the scene. 



On the north side of the chain we have scarcely any means of 

 coming to a positive conclusion regarding the epoch of its eleva- 

 tion ; but when we get to its south side, we see the recent ter- 

 tiary rocks heaved up to several thousand feet above the level 

 of the sea, and in lines parallel to the general direction of the 

 chain. Thus we have a proof of the elevation of these mountains 

 after the formation of the tertiary rocks ; but this is not suffi- 

 cient to make it correspond with the epoch of elevation along the 

 principal chain of the Alps, which took place at a still later pe- 

 riod, viz. after the formation of the great deposit of pebbles and 

 clay which occupies the valley of the Isere, and the plain of 

 L'Abresse, (the terrain de transport ancien of Elie de Beau-- 

 mont). At first, therefore, I was inclined to suppose that the 

 recent tertiary beds containing shells of existing Mediterranean 

 species, might be the equivalent of the deposit of the plain of 

 L'Abresse, and be entitled to the term of a quaternary forma- 

 tion ; but the discovery of a deposit newer than these beds, and 

 most distinctly corresponding to that of L'Abresse, made me 

 abandon this hasty opinion. The deposit to which I allude, is 

 that which I have described under the name of old conglome- 

 rate. It has somewhat different characters in different situa- 

 tions, according to the nature of the rocks from which it has 

 been derived ; but the following are the general results which 

 will be obtained from studying it in a variety of situations, viz. 

 on the north coast, in the valleys to the south of the great 

 chain, particularly in that of the Simethus, between Palermo and 

 Catania, and to the south of Syracuse, it is composed of rolled 

 pieces of a great variety of rocks, some of which have been'de- 

 rived from a great distance, and it was therefore produced by 

 some great general disturbing cause. Since it contains frag- 

 ments of tertiary rocks it was of posterior formation to these. 

 In some places it has a cement of lime which contains sea shells, 

 shewing that in such situations it was formed under the sea, and 

 being sometimes found perforated by lithodomi it must have con- 

 tinued long under the waves before its elevation. We may 

 therefore fairly conclude that it is of the same age as the deposit 



