16 ON A PIECE OF CHALK i 



that deep-water Globigerince are larger than those 

 which live in shallower parts of the sea ; and such 

 facts negative the supposition that these organisms 

 have been swept by currents from the shallows 

 into the deeps of the Atlantic. It therefore seems 

 to be hardly doubtful that these wonderful 

 creatures live and die at the depths in which they 

 are found. 1 



However, the important points for us are, that 

 the living Globigerince are exclusively marine 

 animals, the skeletons of which abound at the 

 bottom of deep seas; and that there is not a 

 shadow of reason for believing that the habits of 

 the Globigerince of the chalk differed from those 

 of the existing species. But if this be true, there 

 is no escaping the conclusion that the chalk itself 

 is the dried mud of an ancient deep sea. 



In working over the soundings collected by 

 Captain Dayman, I was surprised to find that 

 many of what I have called the " granules " of that 

 mud were not, as one might have been tempted 



1 During the cruise of H.M.S. Bulldog, commanded by Sir 

 Leopold M'Clintock, in 1860, living star-fish were brought up, 

 clinging to the lowest part of the sounding-line, from a depth 

 of 1,260 fathoms, midway between Cape Farewell, in Green- 

 land, and the Rockall banks. Dr. Wallich ascertained that 

 the sea-bottom at this point consisted of the ordinary Globi- 

 gerina ooze, and that the stomachs of the star-fishes were full 

 of Globigerince. This discovery removes all objections to the 

 existence of living Globigerince at great depths, which are based 

 upon the supposed difficulty of maintaining animal life under 

 such conditions ; and it throws the burden of proof upon those 

 who object to the supposition that the Globigerince live and 

 die where they are found. 



