154 JOURNAL OF CONCHOLOGY, VOL. l6, NO. 5, JANUARY, I92I, 



the boundary of coastal and Atlantic waters, inasmuch as it forms 

 approximately the limit of private dredging by hand ; but on further 

 consideration I found the hundred fathom line in every way a more 

 suitable limit. Guided by physical features of the sea and coast, and 

 by the known distribution of species, I have for the most part con- 

 ventionalized the dividing lines into meridians and parallels. 



My own experience includes dredging in eleven of the proposed 

 areas, chiefly North Sea and Channel, where I think the limits will 

 prove fairly satisfactory. Area I, the largest, might be again divided 

 by 60° N. west of and 59°i5'N. east of i°5o'W., thus separating 

 Shetland from Orkney by the Fair Isle Channel, but from my own 

 limited experience the two areas coastally though very different 

 geologically are very similar in species, while the whole Shetland 

 sea as far as the Long Forties seems to be a good single area. 



The Whole British Area as Defined by the Conchological 

 Society, September, 1901. 



Areas. 

 shallow seas. 



I. Shetland, Orkney, and 

 Scotland N.E. .. 



II. Scotland, East . . 



III. England, North-East. 



IV. East Coast 



v. Channel, Eastern Area 



VI. Channel, Middle Area 



VII. Channel Isles .. 



VIII. Channel, Western Area 



IX. Bristol Channel and 

 South Wales 



X. Liverpool Bay & S. of Man 



XI. Irish Sea 



XII. Clyde and Argyll .. 



XIII. Hebrides and Minch 



XIV. Ireland N.W. 



XV. Ireland S.W 



XVI. Nymphe Bank 



XVII. Scilly 



DEEP SEAS. 



XVIII. Porcupine Bank . 



XIX. Rockall Deep 



XX. Rockall Bank 



Limits. 



50W(CapeWrath) ; s70 3o'N(Buchan Ness) 



NE from Berwick, then 56° N 



54°N 



Line, Dover to Griz Nez 



20 W (St. Alban's Head) 



30 40' W (Start Point) 



Sofm. line, north of Hurd Deep 



50 50' W ; parallel of C. Cornwall ; 50 fm. line 



5050'W ; 52O 45' N (Bardsey) 



50 W = approx. 30 fm. line . . 



52045'N ; soW ; ssoN 



7025'W (Malim Head) ; thence 50 fm. line, 

 round Hawes Bank to Ardnamurchan 



50 W ; 100 fm. line ; 56ON 



100 fm. line ; 53O25' N (Slyne Head) 



100 fm. line ; 51° N ; 90 W (Galley Head) 



Si°N; 5050'W 



TOO fm. line ; 51° ; 5== 50' W and 50 fm. line 



Inside 1, 000 fm., south of S5°N 

 All waters deeper than 1,000 fm. 

 Inside 1,000 fm., north of 55° N 



SUBAREAS. 



Shetland ; Orkney ; Scotch coast 



Aberdeen ; Firth of Forth 



Northumberland (Limit 55° = S. 

 Shields) ; Tees and Yorkshire ; 

 Dogger (Limit 20 fm. line). 



Wash and Humber to 52° 30' N ; 



Thames. 

 East of o°3o' W ; west of o°3o'W 

 Weymouth Bay ; Lyme Bay 



N. Cornwall ; Bristol Channel ; 

 Cardigan Bay 



Clyde ; Argyle ; Ulster 



