II THE PROBLEMS OF THE DEEP SEA 49 



prove that the shells have been transported into 

 the position in which they are found ; while, on 

 the other hand, the absence of shells in a deposit 

 will not justify the conclusion that the waters in 

 which it was formed were devoid of animal in- 

 habitants, inasmuch as they might have been only 

 too deep for habitation. 



The new line of investigation thus opened by 

 the French naturalists was followed up by the 

 Norwegian, Sars, in 1835, by Edward Forbes, in 

 our own country, in 1840,^ and by (Ersted, in 

 Denmark, a few years later. The genius of 

 Forbes, combined wdth his extensive knowledge of 

 botany, invertebrate zoology, and geology, enabled 

 him to do more than any of his compeers, in 

 bringing the importance of distribution in depth 

 into notice ; and his researches in the iEgean Sea, 



^ In the paper in the Memoirs of the Survey cited further on, 

 Forbes writes : — 



"In an essay 'On the Association of Mollusca on the 

 British Coasts, considered with reference to Pleistocene 

 Geology,' printed in [the Edinhurcfh Academic Anvuciliox] 1840, 

 I described the mollusca, as distributed on our shores and seas, 

 in four great zones or regions, usually denominated ' The Lit- 

 toral Zone,' 'The region of Laminarine,' ' The region of Coral- 

 lines,' and 'The region of Corals.' An extensive series of 

 re earches, chiefly conducted by the members of the committee 

 appointed by the British Association to investigate the nsarine 

 geology of Britain by means of the dredge, have not invalidati-d 

 this classification, and the researches of Professor Loven, in the 

 Norwegian and Lapland seas, have borne out their correctness. 

 The first two of the regions above mentioned had been previ- 

 ously noticed by Lamouroux, in his account of the distribution 

 (vertically) of sea-weeds, by Audouin and Milne Edwards in • 

 their ObiiervcUions on the Natural History of the coast of France^ 

 ami by Sai's in the preface to his Bcskriielssr og Jagttajelser.'* 



190 



