ON THE ELEVATED SUBMARINE ALLUVIA. 303 



that they have not been brought from a distance, or 

 that these are not transported alluvia. The terrestrial 

 remains generally occur a few feet beneath the surface, 

 and are therefore commonly in the sand or gravel, or 

 in the upper bed; but as that bed is occasionally 

 absent, they are also found in the marl. They consist of 

 the bones of the Rhinoceros, Elephant, Hippopotamus, 

 Mastodon, Urus, and Elk, together with the horns 

 of Stags; and to these must be added vegetable re- 

 mains, consisting of trunks and fragments of trees, to- 

 gether with leaves often little altered, fresh water 

 shells, and lastly, fragments of travertino, or alluvial 

 rocks, with vegetable calcareous incrustations resem- 

 bling those which are daily formed in situations where 

 solutions of carbonat of lime flow. 



Besides these two remarkable beds, many parts of 

 Italy present superficial strata, some of which are 

 peculiar to itself, while one is common to all coun- 

 tries. This last is the ordinary alluvium of rivers; 

 such as that of the Po and Adige to the northward 

 of the Apennine, and that of the Tiber to the south- 

 ward. Those which are peculiar to it, are the solid cal- 

 careous alluvial rock called Travertino, loose tufaceous 

 matters of the same nature, and volcanic tufas. The 

 plain of Sarteano, the Maremma of Tuscany, the 

 Solfatara, and the vicinity of Rome, offer examples 

 of these strata. The calcareous substances sometimes 

 contain fresh water shells and vegetables; nor are 

 these always absent, even from the volcanic tufas. 



Hence arises a confusion which requires to be ex- 

 plained, because it has very much obscured this sub- 

 ject. And the chief source of this consists in the 

 transportation of the volcanic substances, and in their 

 cementation by means of the calcareous waters which 

 flow from the Apennine. In consequence of this, 



