170 LYELL'S ELEMENTS OF GEOLOGY. 



Recent and Newer Pliocene Strata. 



what manner shall we define the limits between this group and 

 those fossiliferous deposits which are now in progress, or which 

 have accumulated under water since the globe was inhabited by 

 man? The strata last mentioned, namely, those of the human 

 period, I shall call Recent, distinguishing them from the most 

 modern tertiary formations. Strata may be proved to belong to 

 the Recent period by our finding in them the bones of man in a 

 fossil state, that is to say, imbedded in them by natural causes ; 

 or we may recognize them by their containing articles fabricated 

 by the hands of man, or by showing that such deposits did not 

 exist in the place where we now observe them at a given period 

 of the past when man existed, so that they must be of subsequent 

 origin. In general all recent formations lie hidden from our sight 

 beneath the waters of lakes and seas ; but we may examine them 

 wherever these lakes or seas have been partially converted into 

 land, as in the deltas of rivers, or where the submerged ground 

 has been heaved up by subterranean movements, and laid dry. 



Thus at Puzzuoli, near Naples, marine strata are seen contain- 

 ing fragments of sculpture, pottery, and the remains of buildings, 

 together with innumerable shells retaining in part their colour, 

 and of the same species as those now inhabiting the Mediterranean. 

 The uppermost of these beds is about twenty feet above the level 

 of the sea. Their emergence can be proved to have taken place 

 since the beginning of the sixteenth century.* But the hills at 

 the base of which these strata have been deposited, and those of 

 the interior of the adjacent country round Naples, some of which 

 rise to the height of 1500 feet above the sea, are formed of hori- 

 zontal strata of the Newer Pliocene period ; that is to say, the 

 marine shells observed in them are of living species, and yet are 

 not accompanied by any remains of man or his works. Had 

 such been discovered, it would have afforded to the antiquary 

 and geologist matter of great surprise, since it would have shown 

 that man was an inhabitant of that" part of the globe, while the 

 materials composing the present hills and plains of Campania 

 were still in the progress of deposition at the bottom of the sea ; 

 whereas we know that for nearly 3000 years, or from the times 

 of the earliest Greek colonists, no extensive revolution in the 

 physical geography of that part of Italy has occurred. 



In Sweden, analogous phenomena have been observed. Near 

 Stockholm, for example, when the canal of Sodertelje was dug, 

 horizontal beds of sand, loam, and marl were passed through, in 

 some of which the same peculiar assemblage of testacea which 

 now live in the Baltic were found. Mingled with these, at different 



* See Principles of Geology, Index, " Serapis." 



