MAEINE BIOLOGICAL STATION AT POET EEIN. 



63 



the deposits, and I do not mind much whether they are 

 called Neritic or Benthonic so long as the category is 

 recognised as distinct from terrigenous. 



Dr. C. Kohn has kindly analysed for me a series of fair 

 samples of deposits from different parts of the Irish Sea, 

 with the following results : — 







NERITIC. 





TERRIGENOUS. 





A.* 



B.t 



C. 



D. 



E. 



F. 



G. 



H. 



Silica. SiO 2 . 



16-83 



46-65 



54-84 



23-41 



84-62 



83-06 



77-10 



78-92 



Cal. Carbonate. 

 CaC03. 



79-27 



38-45 



39 71 



59-66 



6-38 



9-18 



9-20 



8-59 



Residue (other 

 than Silica). 



3-90 



14-90 



6-45 



19-93 



9-00 



13-70 



1370 



12-69 





100-00 



ioo-oo 



ioo-oo 



ioo-oo 



100-00 



ioo-oo 



100-00 



ioo-oo 



The localities and particulars are, — 



A. 1 mile off Spanish Head, 16 faths., shell fragments. 



B. 1 mile off Calf of Man, 20 faths., shells and spines. 

 G. 1 mile off Calf of Man, 18 faths., shell sand, spines. 



D. 2 miles off Dalby, 15 faths., nullipores. 



E. Liverpool Bar, 3 faths., sand. 



F. Bahama Bank, 13 faths., muddy sand. 



G. King William Bank, 5 faths., coarse sand. 

 H. North end of " Hole," 28 faths., mud. 



It will be noticed that the four terrigenous deposits (sands 

 and muds) all show less than 10 % of calcium carbonate ; 

 while the four neritic have all more than 38 % — well over a 

 third — of calcium carbonate, and one (A.) has over 79 %. 

 The silica in these neritic deposits may be less than 17 %, 



* Shelly deposit. Contained 1-09 % of small stones not included in 

 analysis. 



t Contained 4 -82 % of magnesium carbonate, in addition to calcium 

 carbonate. 



