88 Selections from Huxley 



organisms, imbedded in granular matter. Here and there, 

 however, this hardened mud of the ancient sea reveals the 

 remains of higher animals which have lived and died, 

 and left their hard parts in the mud, just as the oysters 



5 die and leave their shells behind them, in the mud of the 

 present seas. 



There are, at the present day, certain groups of animals 

 which are never found in fresh waters, being unable to 

 live anywhere but in the sea. Such are the corals; those 



10 corallines which are called Polyzoa; those creatures which 

 fabricate the lamp-shells, and are called Brachiopoda; the 

 pearly Nautilus, and all animals allied to it; and all the 

 forms of sea-urchins and star-fishes. 



Not only are all these creatures confined to salt water 



15 at the present day ; but, so far as our records of the past 

 go, the conditions of their existence have been the same: 

 hence, their occurrence in any deposit is as strong evi- 

 dence as can be obtained, that that deposit was formed in 

 the sea. Now the remains of animals of all the kinds 



20 which have been enumerated, occur in the chalk, in greater 

 or less abundance; while not one of those forms of shell- 

 fish which are characteristic of fresh water has yet been 

 observed in it. 



When we consider that the remains of more than three 



25 thousand distinct species of aquatic animals have been 

 discovered among the fossils of the chalk, that the great 

 majority of them are of such forms as are now met with 

 only in the sea, and that there is no reason to believe 

 that any one of them inhabited fresh water the collateral 



30 evidence that the chalk represents an ancient sea-bottom 

 acquires as great force as the proof derived from the 

 nature of the chalk itself. I think you will now allow 

 that I did not overstate my case when I asserted that 

 we have as strong grounds for believing that all the vast 



