ON THE ELEVATED SUBMARINE ALLUVIA. 307 



In the present case, we see the germs of these very 

 submarine strata, exposed before their consolidation, 

 and probably presenting the appearances which they 

 do, merely because they are of more recent date. And 

 instead of being compelled to seek for causes by a 

 circuitous and analogical road, we find these at hand 

 in the general volcanic nature of the country under 

 review; while, in some places, we can almost trace 

 the very cause itself in action. 



In different places, and in Italy very particularly, 

 it has been observed that the relative level of the sea 

 arid land is subject to change, and that it has, in past 

 times, undergone frequent alterations. The present 

 case may be considered an extreme one of that nature; 

 in consequence of which the bottom of the sea, to- 

 gether with its consolidated alluvia, has been raised 

 above the surface of the water, so as to have become 

 dry land. Thus it is easy to account for the presence 

 of marine remains, as well as for their existence in 

 that singularly undisturbed state which has been de- 

 scribed. 



It is equally easy to account for the proximity of 

 the marine and the terrestrial remains, as also for that 

 of the alluvia which respectively enclose each. What- 

 ever cause or causes generated the usual terrestrial 

 alluvia that occur all over the world, these are thought 

 to have been deposited, in most cases, upon naked 

 rock. In this particular one, they have settled on a 

 previous alluvium of a different character, and, as far 

 as our present imperfect observations go, solitary. 

 The apparent interference of the two classes of organic 

 remains, follows of course. If that interference is 

 ever greater, so as to amount to a real mixture or 

 alternation, it is explained by a variety of circum- 

 stances, consisting in more recent changes from the 



