THE PLIOCENE BEDS OF ST. ERTH. 207 



Recent seas. Several of these may be called, prevailing shells, for 

 example Buccinum Dalei. The absence of such shells in a locality 

 only 100 miles further south is to us quite inexplicable on any hy- 

 pothesis which takes the physical features and distribution of land 

 and water in Western Europe as they now are. Mr. Wood, in his 

 paper, alluded to the difference observable between the Eastern and 

 Western Pliocene faunas, and considered that the existence of a land- 

 barrier which stretched across the eastern end of the English 

 Channel would explain this, as the communication between the 

 St. Erth Sea and that portion of the North Sea in which our Crag 

 beds were deposited would then be round the north of Scotland, 

 which is 9° of latitude from St. Erth. 



This explanation would be satisfactory as accounting for an 

 absence of southern species in the East Anglian area, which, how- 

 ever, we do not observe, while it wholly fails to account for the 

 arrest of the south-westerly migration of shells of northern habitat. 



We think that the facts at present before us point to the con- 

 clusion that, at the period of which we are writing, no channel of 

 direct communication existed between the North Sea and the 

 Atlantic Ocean, the Straits of Dover in the south being closed, 

 while on the north-west the Tertiary Yolcanic chain threw a barrier 

 across from the north of Scotland to Greenland by way of the Shet- 

 land and Earoe Islands and Iceland. 



The study of the present configuration of the North Atlantic sea- 

 bottom is strongly confirmatory of this opinion. The 100-fathom 

 line encloses the Orkneys and Shetlands, while a long submerged 

 ridge with deep water upon each side extends from the Hebrides to 

 the Eardes and, as has been so fully explained by the late Dr. Jeffreys, 

 has had a great influence in preventing the intermingling of the 

 marine faunas upon each side of it. 



The component islets of the Faroe group are separated by deep 

 narrow straits with very precipitous sides, which might almost be 

 called fiords, and are clear indications of considerable subsidence. 



Erom the Earoes to Iceland an undulating bottom exists, reaching 

 a depth of 368 fathoms, whence a plunge takes place to 686 

 fathoms, and within 30 miles recovers to 350 fathoms. 



Across the Denmark Straits, between Iceland and Egede's Land 

 (Eastern Greenland), the depth nowhere reaches 500 fathoms, though 

 both N. and S. much more profound depths are recorded. 



Erom the south-western angle of Iceland a great submarine pro- 

 montory runs down far into the Atlantic, carrying the 500 and 1000 

 fathom lines in a great sweep many degrees to the south, and upon 

 this is situated the spot marked on the old charts as the " Sunken 

 land of Buss." This region is mentioned by some Venetian navi- 

 gators of the 14th century, who state that they found there a well- 

 populated land, which they called West Eriesland. In later records 

 mention is made of the " Sunken land of Buss ;" and even so late 

 as 1777, charts indicated the existence of a dangerous shoal in the 

 vicinity. Sir John Ross sounded over the spot in 1818, but found 

 no bottom with 180 fathoms of line. To the S.W. of this point, in 



