Ch.XL] 



BRECCIAS IN SICILIAN CAVES. 139 



of testacea. At a subsequent period, volcanic eruptions oc- 

 curred, and tuffs were superimposed. The marine formation 

 then emerged from the deep, and supported lakes wherein the 

 fresh-water groups above described slowly accumulated, at a 

 time when the mammoth abounded in the country. The 

 valley of the Tiber was afterwards excavated, and the adjoin- 

 ing hills assumed their present shape, and then a long interval 

 may, perhaps, have elapsed before the first human settlers 

 arrived. Thus we have evidence of a chain of events all re- 

 garded as extremely recent by the geologist, but which, never- 

 theless, may have preceded, for an immense series of ages, a 

 very remote era in the history of nations. 



OSSEOUS BRECCIAS. 



Sicily. The breccias recently found in several caves in 

 Sicily belong evidently to the period under consideration. We 

 have shown, in the sixth chapter,, that the cavernous limestone 

 of the Val di Noto is of very modern date, as it contains a 

 great abundance of fossil shells of recent species. But if any 

 breccias are found in the caverns of this rock they must be of 

 still later origin. 



We are informed by M. Hoffmann, that the bones of the 

 mammoth, and of an extinct species of hippopotamus, have 

 been discovered in the stalactite of caves near Sortino, of which 

 the situation is represented in the annexed diagram at b. The 



No. 26. 



1} fr, Debits in caves, } containi f '<* quadrupeds. 

 C, Limestone containing remains of recent shells. 



same author also describes a breccia, containing the bones of 



