Reviews — Dr. James Geikie* s^G-reat Ice Age. 31 



changes which he considers them to indicate. There is, first, the 

 Lower Till or Boulder-clay, the ground-moraine of a mer -de -glace, 

 which covered all Scotland to a height of 3500 feet. This ice-sheet 

 united with the inland ice of Scandinavia on the bed of the North 

 Sea, and the united masses swept even across the Orkney and 

 Shetland Islands. (2) The mer-de-glace melted away, and an 

 extensive land-surface was laid bare, on which a flora and fauna 

 of a temperate character flourished. In many places there are 

 fresh-water and marine deposits of this period which rest on the 

 Lower Boulder-clay, and are covered up by an Upper Boulder-clay. 

 Then depression of the land commenced ; the submergence may 

 have amounted to 500 feet, and it was accompanied by an Arctic 

 climate. (8) Another mer-de-glace, probably less extensive than the 

 first, spread over the country and produced the Upper Till or 

 Boulder-clay. (4) During the melting of this second mer-de-glace 

 the Kames and asar may have been formed, and probably some of 

 the glacial lakes of the Southern uplands. (5) The melting of the 

 second mer-de-glace seems to have been followed by a prolonged 

 interval of milder climate, but the evidence for this depends rather 

 upon some of the continental deposits than upon anything preserved 

 in Scotland. (6) A third period of glaciation set in, but this time 

 the ice only formed district sheets and valley glaciers. There was 

 a contemporaneous submergence to the extent of 100 feet, shown by 

 the Arctic flora in the Marine Clays. The glacial lakes of Lochaber 

 are attributed to this period, and the high-level gravel terraces of 

 the larger river- valleys. (7) The land was again elevated ; the 

 climate became milder, and Scotland was covered with forests and 

 inhabited by a temperate Mammalian fauna. (8) The Estuarine 

 Deposits and the Raised Beaches of about 50 feet above the present 

 sea-level, covered as they are in places by the terminal moraines of 

 valley glaciers, indicate that the Forest period was succeeded by a 

 colder and wetter climate, which was favourable to the growth of 

 peat. (9) An Upper Buried Forest seems to show that the country 

 had been again raised, and that there was a drier climate, and 

 another period of forest growth. (10) A colder climate and a slight 

 submergence of 25 to 30 feet is shown by another deposit of peat 

 covering the upper buried forest, and by raised beaches. (11) The 

 present period, in which the land is slightly higher again, and the 

 climate probably drier. 



As compared with the glacial succession in Scotland, given in the 

 preceding edition, the above summary indicates with considerable 

 confidence not only a greater number of climatic changes in which 

 Arctic conditions alternate with temperate, but also a very regular 

 series of depressions and elevations of the land, and the association 

 of the Arctic climate in each case with the period of submergence 

 and the genial climate with the period of elevation. 



Passing on to the description of the glacial phenomena of 

 England, the author treats first of the beds exposed on the Norfolk 

 coast, at and near Cromer, from which had been obtained the only 

 reliable evidence as to the kind of plants and animals that flourished 



