524 Revieivs — W. B. Wright's Quaternary Ice Age. 



I. — The Quateknaky Ice Age. By "W. B. Wright, of the Geological 

 Survey of Ireland, pp. xxiv + 464, with 23 plates and 155 

 text-illustrations. London: Macmillan, 1914. Price 17s. 



THE literature of glacial geology, hoth European and American, 

 has of late years attained enormous proportions, and much of it 

 is very inaccessible. The author has set himself the task of giving 

 a summary of the latest conclusions in this interesting field, and it 

 must be said that in this he has admirably succeeded. The book 

 is evidently the result of a vast amount of reading, much of which 

 must have been of monumental dullness, and the author's intimate 

 acquaintance in the field with the Quaternary geology of the British 

 Isles adds very greatly to its value and interest. 



The whole forms an admirable summary of modernist views of 

 glaciation and of the general geology of the Quaternary period in 

 Britain, Scandinavia, the Alps, and North America, and the latest 

 results of prehistoric archaeology are freely utilized. It is becoming 

 abundantly clear that in the study of human remains lies the best 

 chance of solving the problem of the correlation of the British drifts 

 with those of other areas, especially with regard to the occurrence 

 of interglacial periods in this country. 



To the majority of readers the most interesting portion of the book 

 will be that dealing with the glaciation of Great Britain and especially 

 of eastern England, as to which there is still much controversy. 

 The author has here contented himself with an exposition of the 

 land-ice theory in its most complete form. It should, however, 

 have been made clear that the land-ice theory is not proven. The 

 mechanical difficulties involved are very great. Even on the most 

 favourable assumptions the possible angle of slope of the ice from the 

 Scandinavian centre of glaciation to the Yorkshire coast is under 1°, 

 and it is difficult to see how such an angle of inclination could 

 produce sufficient driving force to bring about the tremendous effects 

 postulated by the Yorkshire school of glacialists. Many of these 

 difficulties have been effectivelj^ stated by Professor Bonney in his 

 presidential address to the British Association at Sheffield. On this 

 subject it is at any rate necessary to preserve an open mind, since 

 with our present knowledge the problem seems to be insoluble. At 

 any rate it is scarcely sufficient to dismiss the " Great Submergence " 

 in four lines as a " geological fiction ", as is done by the author. 



Special attention is paid to the connexion between raised beaches 

 and glaciation, and here comes the most original part of the book. 

 According to the theory suggested the vai-iations in the relative levels 

 of land and sea are due to a combination of two causes : firstly, the 

 actual lowering of the sea-level owing to accumulation of water on 

 land in the form of snow and ice, and secondly, a slow isostatic rise 

 of the land after removal of the heavy ice-cap which had previously 

 led to depression of the region. This theory is worked out in a very 

 convincing way with reference to the raised beaches of Scotland and 

 the known variations of the Baltic which have been so ably studied 

 by the Scandinavian geologists. It is argued that the pre-glacial 



