THE PROBLEMS OF THE DEEP SEA. 457 



region they distinguish a fifth, which is never uncovered, and is in- 

 habited by oysters, scallops, and large starfishes and other animals. 

 Beyond this they seem to think that animal life is absent. 1 



Audouin and Milne Edwards were the first to see the importance 

 of the bearing of a knowledge of the manner in which marine ani- 

 mals are distributed in depth, on geology. They suggest that, by this 

 means, it will be possible to judge whether a fossiliferous stratum 

 was formed upon the shore of an ancient sea, and even to determine 

 whether it was deposited in shallower or deeper water on that shore ; 

 the association of shells or animals which live in different zones of 

 depth will prove that the shells have been transported into the posi- 

 tion 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 inhabitants, inasmuch as 

 they might have been only too deep for habitation. 



The new line of investigation thus opened by the French natural- 

 ists was followed up by the Norwegian, Sars, in 1835, by Edward 

 Forbes, in our own country, in 1840," and by CErsted, in Denmark, a 

 few years later. The genius of Forbes, combined with 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, and still more his remarkable paper "On the Geological Rela- 

 tions of the Existing Fauna and Flora of the British Isles," published 

 in 1846, in the first volume of the "Memoirs of the Geological Survey 

 of Great Britain," attracted universal attention. 



On the coasts of the British Islands, Forbes distinguishes four 

 zones or regions, the Littoral (between tide-marks), the Laminarian 

 (between low-water mark and 15 fathoms), the Coralline (from 15 to 50 

 fathoms), and the Deep sea or Coral region (from 50 fathoms to beyond 

 100 fathoms). But, in the deeper waters of the ^Egean Sea, between 

 the shore and a depth of 300 fathoms, Forbes was able to make out 



1 " Enfin plus bas encore, c'est-a-dire alors loin des cotes, le fond des eaux ne paraifc 

 plus 6tre habite, du moins dans nos mers, par aucun de ces animaux" (1. c, tome i., p. 

 237). The "ces animaux" leaves the meaning of the authors doubtful. 



2 In the paper in the "Memoirs of the Survey" cited farther on, Forbes writes : 



" In an essay ' On the Association of Mollusca on the British Coasts, considered with 

 reference to Pleistocene Geology,' printed in the Edinburgh Academic Annual for 1840, I 

 described the mollusca, as distributed on our shores and seas, in four great zones or re- 

 gions, usually denominated ' The Littoral Zone,' ' The region of Laminariae,' ' The region 

 of Corallines,' and ' The region of Corals.' An extensive series of researches, chiefly 

 conducted by the members of the committee appointed by the British Association to in- 

 vestigate the marine geology of Britain by means of the dredge, have not invalidated this 

 classification, and the researches of Prof. Loven, in the Norwegian and Lapland Seas, 

 have borne out their correctness. The first two of the regions above mentioned had 

 been previously noticed by Lamouroux, in his account of the distribution (vertically) of 

 sea-weeds, by Audouin and Milne Edwards in their ' Observations on the Natural History 

 of the Coast of France,' and by Sars in the prefaoe to his ' Beskrivelser og Jagttagelser.' " 



