416 Professor D'Arcy W. Thompson [March 22, 



some 150 miles long. Let oiir upheaval proceed some 10 fathoms 

 more, or 30 fathoms in all, and now from the Yorkshire coast straight 

 across to the most northerly point of Denmark the new shore line 

 appears ; and all to the south of it, an area of some 70,000 square 

 miles, is now dry land, save for a few small lakes, chief among which 

 are the celebrated Silver Pits, where nowadays the soles congregate. 

 Once more let the bottom of the North Sea rise up 50 fathoms, or 

 ?>00 feet (not yet near the height of St. Paul's), and the new coast 

 line now runs round the Orkney Islands, and then from somewhere 

 about Peterhead through the Skagerack to Sweden, with one con- 

 spicuous dip or bend, that under the conditions we have imagined 

 would form a sort of new Zuyder Zee. Northward, far beyond the 

 50-fathom line, and away to the north of Shetland, the comparatively 

 shallow bottom of the North Sea slopes downwards to the north, until 

 we reach the 100-fatliom line a little to the north of Shetland. But 

 some 60 miles from the Norwegian coast this 100-fathom line bends 

 southward, until it, like our other contour lines, enters the Skagerack. 

 The deep groove that surrounds the Norwegian coast, and cuts off 

 from it the comparatively shallow plateau of the North Sea, is a 

 geographical feature of great importance, whose meaning and history 

 has not yet been fully told. The 100-fathom line is succeeded to the 

 northward at no great distance by the 200-fathom line, and beyond 

 this the depths increase rapidly, for we are now at the edge of the 

 Continental shelf, and the old abyss of ocean is but a stone's throw 

 away. Elevate, then, in imagination, the bottom of the North Sea 

 by, say 150 or 200 fathoms (rather less or rather more than the 

 length of Albemarle Street), and all the North Sea to beyond the 

 Shetlands and all the British Islands and the British seas become 

 part of the Continent ; all that remains of the North Sea is a large 

 lake, immensely deep, that occupies the greater part of the present 

 Skagerack, and continues the chain of great deep cold lakes, wdth 

 their ancient faunas, still showing traces of their origin from the 

 sea, that are so conspicuous a feature of the geography of Sweden. 



Of all these physical features the greatest is that which is repre- 

 sented, or approximately represented, by the 100-fathom line. The 

 geographer traces it along all the western coasts of the Old World, 

 from the north of Norway to southern Africa. It encircles our own 

 islands, it broadens here and there, it is the edge of our continental 

 area, and beyond it the Continent plunges into the abyss of ocean. 

 The geologist sees in it, in all probability, the actual coast line of 

 early Tertiary times after the great changes that had raised part of 

 the bed of the cretaceous ocean into dry land : the coast line of an 

 age when broad plains or chalky downs stretched over the North Sea. 

 And now that subsequent and successive changes, in which again 

 subsidence and upheaval have alternated, and the great ice sheet has 

 scraped and scooped the North Sea and filled its bed to unknown 

 depths with its drift and clay, now over the shallow slopes and levels 



