This volume deals with the general aspects of glacier study and glacial geology. A brief history of the study of glaciers and the development of the science of glaciology precedes an account of the distribution of present day glaciers in terms of the alimentation-ablation balance. The remainder of the first chapter is devoted to the classification of glaciers mainly from the point of view of the geomorphologist. The second chapter outlines the methods available for the determination of the age of Quaternary glacial deposits and summarizes the chronology and extent of Quaternary and earlier glaciations. The final part of this chapter briefly describes the hypotheses developed to explain the climatic changes of the Quaternary period.
The second part of the book (Chapter III) is more directly concerned with the study of snow and ice. The changes that occur in the transformation of snow to ice are described, but little attempt is made to explain the mechanism of the process. By way of introduction to the mechanism of glacier movement, numerous observations on the velocity of glaciers (mostly temperate) are given, and brief mention is made of the properties of ice as determined in the laboratory. The authors note that some 80 theories have been evolved to explain the movement of glaciers, but consider that most are marred by two serious errors:
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The extrapolation of laboratory results without sufficient understanding of natural conditions.
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Incorrect extrapolation from oversimplified hypotheses.
The hypotheses of Demorest, Nye, Finsterwalder and Haefeli are outlined, but without comment. This part of the book is completed by a review of the theories of glacial erosion and their modification in relation to the development. of land forms. The “ultra-glacial” theory, developed towards the end of the nineteenth century, claimed that moving ice was a sufficiently powerful erosive agent for the ultimate land form to be independent of the pre-glacial one. At the opposite extreme was the “anti-glacial” theory developed by Heim, Freshfield and others, that the glaciers acted as protective agents and prevented erosion. A more modern form of this extreme view has supposed that glaciers were capable of acting in the manner of a bulldozer and removing loose surface material. Current morphological opinion would seem to steer a moderate course between these extremes.
The third and largest part (Chaps. IV, V & VI) of this volume deals with the development of those land forms attributable to the action of snow and ice. The problem of cirque formation is dealt with at some length, the older ideas being dismissed in favour of those of W. V. Lewis.
While of considerable interest to the geologist and the geomorphologist the bulk of this part and the whole of the last part (Chaps. VII & VIII), which deals with the indirect consequences of glaciation, would seem to be beyond the scope of glaciology.
The authors have covered a great deal in a comparatively small space and have succeeded in putting forward many points of view, albeit somewhat briefly. The bibliography of some 500 references appears to be well chosen and provides ample material for further study.
It is unfortunate that the quality of production of this book is so poor; line drawings of photographs have suffered especially.
