414 Joshua Wilson — On the Glacial Epoch. 



upheaval, of about 20 to 25 feet, took place after tliis island was 

 inhabited and probably covered with forests, showing the ameliora- 

 tion of the climate, as several canoes have been found imbedded in 

 it, which have been hollowed out from large trees. 



In order to show that the alteration of the set of the Gulf-stream 

 occurred subsequently to the elevation of the 40 feet beach, I may 

 remark that it is situated on the west coast of Scotland, where it 

 fronts the Atlantic Ocean, and that if the Gulf-stream had impinged 

 on that shore previous to the elevation of this beach, as it now does, 

 nearly at a right angle, it would have been by its off-set under- 

 current swept away into the depths of the ocean. To explain my 

 position, I may refer to what I term the offshore current of the onshore 

 gale. It is a well-ascertained fact that the effect of an onshore gale 

 is to give a sea- beach a seaward direction ; the cause of this move- 

 ment we need not go far to seek. If I am not mistaken, Mr. Coode 

 mentions, in his account of the Cliesil Bank, that in a heavy south- 

 west gale the level of the water in front of it will be raised three feet 

 above that of the Fleet behind it. This is the result of the friction 

 of the wind on the surface of the water, causing an inshore upper 

 current. This inshore drift must be counterbalanced by an under- 

 current in an opposite direction, a movement similar to a web pass- 

 ing horizontally over two rollers inshore above offshore below. 

 Although this offshore current may not have sufficient velocity to 

 move sand or shingle when at rest upon the beach, yet in unison 

 with the back sweep of the wave it will give a preponderating di- 

 rection seaward to the beach : hence the millions of tons washed 

 down from that bank in a south-west gale, to be returned again next 

 day when the wind has changed to say west-north-west, the Atlantic 

 swell still continuing. An ocean current impinging on a coast at an 

 angle approaching to a right angle will have a similar effect, with 

 this difference — that this action will be constant ; hence we must not 

 be surprised that under the influence of the impinging action of the 

 Gulf-stream, the sea-beach is absent. As, for example, we can trace 

 the action of the Gulf-stream from the neighbourhood of Brest to 

 the south-west 6oast of England as far north as the Bay of Carnarvon 

 in Wales, the south-west and west coasts of Ireland, the west coast 

 of Scotland, to the north of Ireland, the Orkney and Shetland 

 Islands, etc., and the coast of Norway to the north of the latitude of 

 Scotland, as far as the North Cape. It is to be remarked that in 

 Norway to the south of the latitude of Scotland the land is not so 

 deeply indented as to the north, while the warmth of the Gulf- 

 stream is not felt at Christiania ; for the winters are colder there than 

 at Bergen, which is so much further north. I may remark how 

 much the west coast of England is incumbered by sands to the 

 north of Anglesea, and also that the shores of the Bay of Biscay are 

 quite sandy in the neighbourhood of Bordeaux, although exposed to 

 the full Atlantic swell. To this action of the Gulf-stream may we 

 not attribute the encroachments of the sea, of which there exist so 

 many traditions as having occurred from the coast of Brittany to the 

 Bay of Carnarvon ? I may remark that the west coast of Patagonia 



