SEA-FISHERIES LABORATORY. 343 



porarily scarce, or that the organisms forming the unusual 

 food were, for the time, very abundant. It is also suggested 

 that the movements of fish in the Irish Sea may be accounted 

 for, to a certain degree at any rate, by the movements or 

 migrations of their food. 



The second part of my work, which includes the examina- 

 tion and general distribution of the bottom-deposits of the 

 Irish Sea, has also been touched on, to some extent, by previous 

 observers. In the Eighth Annual Keport of the Liverpool 

 Marine Biology Committee (1894-95), Professor Herdman gave 

 a preliminary account of the submarine deposits of the Irish 

 Sea. In this report a general outline was given of the contour 

 of the bottom of that part of the Irish Sea lying between the 

 Isle of Man and England. It was found that the Isle of 

 Man and Lancashire were connected by a plateau, which 

 except at a few places was never more than 14-16 fathoms 

 below the surface of the sea. The surface of this plateau 

 consisted for the most part of sand (siliceous) out to a depth of 

 10 fathoms, but further out, between the 10 and 20 fathom 

 line, this sand was mixed to a certain extent with mud, and 

 was much diversified by gravelly and shelly patches, while 

 local muddy tracts, due to eddies and currents, were not 

 uncommon. The effect of certain types of deposits upon the 

 distribution of the bottom fauna was also discussed, and it was 

 found that undoubtedly the fauna varied from place to place 

 with the nature of the sea-floor. Samples of the bottom were 

 sent, at Sir Archibald Geikie's request, to the museum of the 

 Geological Survey in London, and the report of the Geological 

 expert (Mr. Clement Reid) upon the origin of these deposits is 

 contained in this and in the Ninth Annual Report of the 

 L.M.B.C. (1895-96). 



In this Ninth Report the second article on the Submarine 

 Deposits is chiefly devoted to giving reasons for modifying the 

 " Challenger " classification of submarine deposits (Terrigenous 



