158 THE RECENT. 



rivalling orbitoidal masses of the New World, are almost 

 entirely the work of these many-celled foraminifera ; while 

 thick and extensive strata of tripoli, and other siliceous 

 earths, are wholly made up of the moulted shields of 

 the minuter diatoms and infusoria. There is nothing 

 more wonderful in nature than the magnitude of the 

 stony masses elaborated by the lowest of animated 

 creatures the diatoms, foraminifers, corals, and other mi- 

 croscopic organisms. It seems as if an ordinance, that the 

 nearer the vital approaches the physical, the less the organic 

 is elevated above the inorganic, the more nearly they should 

 resemble each other in the bulk and character of their 

 lithological operations. And yet the elaboration of, lime- 

 stone from marine waters, by the merest vitalised speck of 

 gelatinous matter, is a result that can never be mistaken 

 for that of mechanical or chemical, agency. The two things 

 may approximate ; they can never be confounded. 



Exuberant as the aspect of eocene life may appear, the 

 march of creation is still ever forward. The physical agen- 

 cies of nature are ever slowly but surely at work. Here 

 the eocene sea is being gradually elevated into shoals and 

 islands ; there the fresh- water lake is submerged, and its 

 sediments overlaid by those of marine origin ; and here 

 again volcanic energy gives birth to new mountain-chains, 

 which interrupt the former currents of the air and ocean, 

 and new external influences begin to prevail. The eocene 

 gradually merges into the miocene, and the miocene into the 

 pliocene. Old forms drop away, new ones begin to take 

 their places, and a flora and fauna indicative of a more tem- 

 perate climate begin to establish themselves over the lati- 

 tudes that now constitute the middle regions of Europe, 

 Asia, and North America. And just as we approach ex- 

 isting nature in time, so in space the flora and fauna begin 



