MR DAVID MILNE HOME ON THE BOULDER-CLAY OF EUROPE. 691 



the land was submerged, would be pushed out, and moraines would be formed at 

 the mouths of these valleys. 



By this time the general climate was improved, owing possibly to a rise in 

 South America, whereby the Gulf Stream was made to take its present course. 



Forests of pine, beach, and oak, again appeared in the British islands. 

 Remains of these, under the present level of the sea, have been found round all 

 our coasts. In the estuary of the Tay the submarine forest and peat-beds are 

 situated on a blue clay. In the Firth of Forth, Dr Brown has pointed out that at 

 Elie, the submarine forest lies above the Arctic shell-bed* 



(4.) The land again sunk, though probably not to the extent to which it was 

 previously submerged— perhaps not more than to about 1000 feet above the 

 present sea-level. 



It was probably during this period that the submarine banks and spits of 

 gravel and sand, called /minis in Scotland, were formed. Some of these are at a 

 height of 750 feet above the sea (Berwickshire, Mid-Lothian, &c.) 



The forests previously existing below that level would, of course, be destroyed, 

 and be covered over with sediment. On the Tay, the submarine forest and peat- 

 beds are covered with beds of clay and sand containing various species of sea- 

 shells of the existing species. f The submarine forest in the Firth of Forth, 

 according to Dr Brown's account of it, underlies a bed of clay full of the 

 Scrdbicularia.% 



During this submergence, any moraines formed by glaciers, situated in the 

 submerged parts of the country, would probably be levelled by submarine cur- 

 rents. The only mounds I have seen in Scotland, which I thought were moraines, 

 are at Loch Skeen, at a height of about 1700 feet above the sea. 



(5.) The land again emerged from the sea, with intervals of suspension, when 

 the old beach lines were formed, described by Dr Robert Chambers in 

 " Ancient Sea Margins." 



* Trans. Roy. Soc. Edin. vol. xxiv. p. 633 

 f Newer Pliocene Geology, by Smith, p. 35. 

 + Roy. Soc. Tr. vol. xxiv. pp. 619 and 633. 



VOL. XXV. PART II. 8 R 



