SEA-FISHERIES LABORATORY. 345 



remains of plants and animals living in the sea. Many 

 deposits are analysed in a most detailed manner, but as the 

 great majority of them were obtained from the West of the 

 Isle of Man, or in the vicinity of that island, their work and 

 mine do not overlap to any extent. 



Finally, I might just refer to the most interesting and 

 important work on bottom-deposits, recently published by 

 C. G. Joh. Petersen and P. Boyson Jensen, in the Keport of 

 the Danish Biological Station, Copenhagen, for the year 1911. 

 In this paper the sources of the organic matter in the sea, 

 and in the sea-water, are fully discussed, as well as the 

 deposits of organic matter on the sea bottom. Many new 

 methods have been adopted, with great success, in their in- 

 vestigation, and some of them will, no doubt, be made use 

 of in future researches of this type in the Irish Sea. 



Bottom Deposits. 



The samples which I have been able to collect and examine 

 were all obtained in the portion of the Irish Sea lying North 

 of Wales and between the Isle of Man and England. They 

 are as follows : — 



I. [la.] 18/2/13. 25 miles W.N.W. of Piel Gas Buoy. 



This deposit consists, for the most part, of small stones, 

 very fine quartz sand, and comminuted molluscan shells. 

 On the whole it is fairly coarse. The stones vary greatly in 

 size — ranging from the most minute particle up to one weighing 

 2-4 grms. They are all well-rounded and smoothed, and the 

 larger ones are encrusted with polyzoa and serpulids. A rough 

 idea of the proportion of stones in the sample may be obtained 

 from the statement that out of a total weight of 27-723 gnus. 

 the stones accounted for 10 grms. The composition of these 

 stones varies so much that it is impossible to suggest with any 

 accuracy their origin. Pieces of pure quartz are found along- 



