MODERN DEPOSITS OF ORGANIC REMAINS. 337 



where the prevaihng currents cause the deposits to lie here 

 of mud, aud there of calcareous matter, it is proved that 

 difierent species of co-existing shells are being buried in 

 these respective formations. On our own coasts, the ma- 

 rine remains found a few miles from shore, in banks where 

 fish congregate, are difierent from those found close to the 

 shore, where only littoral species flourish. A large propor- 

 tion of aquatic creatures have structures that do not admit 

 of fossilization ; while of the rest, the great majority are 

 destroyed, when dead, by the various kinds of scavengers 

 that creep among the rocks and weeds. So that no one 

 deposit near our shores can contain anything like a true 

 re^^resentation of the Fauna of the surrounding sea ; much 

 less of the co-existing Faunas of other seas in the same lat- 

 itude ; and still less of the Faunas of seas in distant lati- 

 tudes. Were it not that the assertion seems needful, it 

 would be almost absurd to say, that the organic remains 

 now being buried in the Dogger Bank, can tell us next 

 to nothing about the fish, crustaceans, mollusks, and corals 

 that are being buried in the Bay of Bengal. 



Still stronger is the argument in the case of terrestrial 

 life. With more numerous and greater contrasts between 

 the plants and animals of remote places, there is a far more 

 imperfect registry of them. Schouw marks out on the Earth 

 more than twenty botanical regions, occupied by groups of 

 forms so far distinct from each other, that, if fossilized, geo- 

 logists would scarcely be disposed to refer them all to the 

 same period. Of Faunas, the Arctic difiers from the Tem- 

 perate ; the Temperate from the Tropical ; and the South 

 Temperate from the North Temperate. Nay, in the South 

 Temperate Zone itself, the two regions of South Africa and 

 South America are unlike in their mammals, birds, reptiles, 

 fishes, mollusks, insects. The shells and bones now lying at 

 the bottoms of lakes and estuaries in these several regions, 

 have certainly not that similarity which is asually looked 

 15 



