II THE PROBLEMS OF THE DEEP SEA 55 



epoch was doubtless the newer Pliocene or Glacial Era, when the 

 Mya truncata and other northern forms now extinct in the 

 Mediterranean, and found fossil in the Sicilian tertiaries, 

 ranged into that sea. The changes which there destroyed the 

 shallow water glacial forms, did not affect those living in the 

 depths, and which still survive.&quot; * 



The conception that the inhabitants of local 

 depressions of the sea bottom might be a remnant 

 of the ancient population of the area, which had 

 held their own in these deep fastnesses against an 

 invading Fauna, as Britons and Gaels have held 

 out in Wales and in Scotland against encroaching 

 Teutons, thus broached by Forbes, received a 

 wider application than Forbes had dreamed of 

 when the sounding machine first brought up 

 specimens of the mud of the deep sea. As I have 

 pointed out elsewhere, 2 it at once became obvious 

 that the calcareous sticky mud of the Atlantic 

 was made up, in the main, of shells of Globigcrina 

 and other Foraminifcra, identical with those of 

 which the true chalk is composed, and the identity 

 extended even to the presence of those singular 

 bodies, the Coccoliths and Coccospheres, the true 

 nature of which is not yet made out. Here then 

 were organisms, as old as the cretaceous epoch, 

 still alive, and doing their work of rock -making at 

 the bottom of existing seas. What if Globigerina 



1 Memoirs of the Geological Survey of Great Britain, Vol. i. 

 p. 390. 



2 See above, &quot;On a Piece of Chalk,&quot; p. 13. 



