304 ON THE ELEVATED SUBMARINE ALLUVIA. 



they sometimes contain matters, the presence of which 

 would otherwise be unaccountable, such as vegetables, 

 and land or river shells. In the same way, they al- 

 ternate, or are strangely and irregularly intermixed 

 with the travertine and the loose alluvia of the rivers ; 

 while they are also found in places far from the vici- 

 nity of recent volcanoes, or from even the suspicion 



of antient ones. 







It is easy to comprehend the fallacies that must 

 have arisen from misapprehending the real nature of 

 these appearances. When also an opinion of their 

 unintelligible derangement had once been adopted, 

 much more confusion than was actually present was 

 supposed to exist, though a little attention would 

 have solved all the imagined difficulties. Had Brocchi 

 originally proceeded on a proper theory, it is probable 

 that he would have found every thing easy, and have 

 rendered it equally so to his readers. 



Though it is said that similar shells are sometimes 

 found in both the alluvial beds, and that the more 

 conspicuous marine remains occur in both, it is de- 

 cidedly stated that these are far more numerous in the 

 marl bed than in the arenaceous one. As I have un- 

 dertaken to prove that the lower or marl bed, at least, 

 is a marine alluvium, and the upper probably a ter- 

 restrial one, it is necessary to try to reconcile these 

 anomalies, as well as that which consists in the con- 

 fusion among the volcanic tufas and the alluvial sub- 

 stances. The entire absence of all organic remains 

 requires no explanation. 



Where the terrestrial alluvia are wanting the organic 

 substances that would otherwise be found in them, 

 must necessarily appear to lie in the marine or lower 

 stratum, however slightly covered or truly superficial 

 they may be. If even found somewhat deeper, it is 



