76 EXPEDITION OF THE " CHALLENGER " ni 



tion of such multitudes must form sedimentary deposits, propor- 

 tionate in their extent to the length and exposure of the coast 

 against which they are washed, in thickness to the power of 

 such agents as the winds, currents, and sea, which sweep 

 them more energetically to certain positions, and in purity, to 

 the depth of the water and nature of the bottom. Hence we 

 detected their remains along every icebound shore, in the depths 

 of the adjacent ocean, between 80 and 400 fathoms. Off 

 Victoria Barrier (a perpendicular wall of ice between one and 

 two hundred feet above the level of the sea) the bottom of the 

 ocean was covered with a stratum of pure white or green mud, 

 composed principally of the silicious shells of the Diatomacece. 

 These, on being put into water, rendered it cloudy like milk, 

 and took many hours to subside. In the very deep water off 

 Victoria and Graham's Land, this mud was particularly pure and 

 fine ; but towards the shallow shores there existed a greater or 

 less admixture of disintegrated rock and sand ; so that the 

 organic compounds of the bottom frequently bore but a small 

 proportion to the inorganic." . . . 



" The universal existence of such an invisible vegetation as 

 that of the Antarctic Ocean, is a truly wonderful fact, and the 

 more from its not being accompanied by plants of a high order. 

 During the years we spent there, I had been accustomed to 

 regard the phenomena of life as differing totally from what obtains 

 throughout all other latitudes, for everything living appeared 

 to be of animal origin. The ocean swarmed with Mollusca, and 

 particularly entomostracous Crustacea, small whales, and por- 

 poises ; the sea abounded with penguins and seals, and the air 

 with birds ; the animal kingdom was ever present, the larger 

 creatures preying on the smaller, and these again on smaller 

 still ; all seemed carnivorous. The herbivorous were not recog- 

 nised, because feeding on a microscopic herbage, of whose true 

 nature I had formed an erroneous impression. It is, therefore, 

 with no little satisfaction that I now class the Diatomacece with 

 plants, probably maintaining in the South Polar Ocean that 

 balance between the vegetable and the animal kingdoms which 

 prevails over the surface of our globe. Nor is the sustenance 

 and nutrition of the animal kingdom the only function these 



