on the Bocks in the Environs of Edinburgh. 317 



and erratic blocks. Having reached the extremities of the 

 gulfs and deep bays which disrupt the coast, as do the friths 

 of Scotland and the fiords of Norway, they advance beneath 

 the sea, and let fall to the bottom of the water the angular 

 blocks, the mud, and the striated pebbles. These sink into 

 this glacier mud, and, as the sea is tranquil at the bottom of 

 these bays, they are not rolled by the waves, and maintain 

 their streaked marks, especially if the sea is deep.* But the 

 present seas of Spitzbergen are not inanimate ; and there are 

 found numerous mollusca, even in the neighbourhood of the 

 glaciers. On the death of the animal the calcareous enve- 

 lopes are deposited in the glacier mud which, on the shore, 

 forms the bottom of the sea. Suppose, then, that the coast 

 sinks somewhat, the glacier will recede, and we shall then 

 have precisely what now exists in the lowlands of Scotland, 

 namely, polished and striated rocks, covered with glacier 

 mud, containing striated pebbles and arctic shells. 



The elevation of Scotland since the termination of the glacial 

 epoch is not a gratuitous hypothesis, since its coast is fringed 

 with sea-beaches covered with shells, which belong to existing 

 species in the neighbouring seas, and the shells of which Mr 

 Prestwich has found near Glasgow at an elevation of 320 

 feet above the ocean. It is since these observations were 

 repeated by Mr J. Smith, that it has been found that these 

 shell-banks are always placed above the clay and the arctic 

 shells. 



In recapitulation, I remark, that the glacier traces in the 

 neighbourhood of Edinburgh appear explicable by the fol- 

 lowing succession of phenomena. \st. By the ancient exist- 

 ence of glaciers, which descended from the mountains to the 

 sea-shore.f 2d. The partial immersion of the country during 

 the glacial epoch, ^d. The subsequent emersion at the close 

 of this epoch. Hence the existence of striated rocks, of 



• This depth of the sea, previous to the advance of the glaciers, is not a simple 

 supposition. Near the terminal escarpments of those of Bell Sound and Mag- 

 dalena Bay, I have found a depth reaching from 100 to 360 feet. 



t I am delighted to find that, as it respects the turning point of this expla- 

 nation, I am supported by the authority of Professors Agassi z and Bucklaud, 

 and also by Sir Charles Lyell, who stated their views some ten years ago. 



