72 SELECTED ESSAYS FROM LAY SERMONS 



As I have mentioned, the soundings from the great Atlan- 

 tic plain are almost entirely made up of GlohigerincB, with the 

 granules which have been mentioned, and some few other 

 calcareous shells; but a small percentage of the chalky mud — 

 perhaps at most some five per cent, of it — is of a different 

 nature, and consists of shells and skeletons composed of 

 silex, or pure flint. These silicious bodies belong partly to 

 the lowly vegetable organisms which are called Diatomacece , 

 and partly to the minute, and extremely simple, animals, 

 termed Radiolaria. It is quite certain that these creatures 

 do not live at the bottom of the ocean, but at its surface — 

 where they may be obtained in prodigious numbers by the 

 use of a properly constructed net. Hence it follows that 

 these silicious organisms, though they are not heavier 

 than the lightest dust, must have fallen, in some cases, 

 through fifteen thousand feet of water, before they reached 

 their final resting-place on the ocean floor. And considering 

 how large a surface these bodies expose in proportion to 

 their weight, it is probable that they occupy a great length 

 of time in making their burial journey from the surface of 

 the Atlantic to the bottom. 



But if the Radiolaria and Diatoms are thus rained upon 

 the bottom of the sea, from the superficial layer of its waters 

 in which they pass their lives, it is obviously possible that 

 the Globigerincc may be similarly derived; and if they were 

 so, it would be much more easy to understand how they 

 obtain their supply of food than it is at present. Neverthe- 

 less, the positive and negative evidence all points the other 

 way. The skeletons of the full-grown, deep-sea Globigerince 

 are so remarkably solid and heavy in proportion to their 

 surface as to seem little fitted for floating; and, as a matter 

 of fact, they are not to be found along with the Diatoms 

 and Radiolaria in the uppermost stratum of the open ocean. 



