This book is one of a series devoted to various aspects of geomorphology, written by two of the leading French workers in this field. Snow and ice produce very distinctive modifications of the landscape, which are discussed in detail in the book. The first section deals with glaciological data, beginning with the nature of snow and its distribution, and going on to discuss different types of glaciers. Throughout the book the emphasis is on the geomorpho-logical significance of ice and snow. The study of present-day ice cover is followed by a discussion of past ice ages and a short section on Pleistocene chronology and stratigraphy. The second part deals with the dynamics of ice movement and stresses the paucity of data concerning the flow of ice at depth. Most of the recent views on glacier flow are mentioned, and a fair assessment of the present state of knowledge in this field is given, although it is not always related to the morphological forms that glacier flow produces and which are described in the rest of the work. The discussion of glacier flow is followed by an account of the theories of glacial erosion. In the third section the processes operating to erode typical glacial landforms, such as cirques and glacial troughs, are considered in detail, following a valuable section on the geomorphological significance of avalanches. The section ends with a discussion of the processes operating on the margin of the ice, in which deposition plays a significant part and melt water becomes one of the dominant forces in operation. The morphological effect of a sequence of glacial stages is discussed in the last section; the featuresdue to advance are differentiated from those formed during retreat and stagnation. The book ends with an account of the indirect effects of glaciation, including changes of sea-level resulting from eustatic and isostatic movements of sea and land, and biogeographical influences.
Both authors are familiar with present ice masses and have travelled widely in previously glaciated areas, so that they describe many of the features at first hand. They have not only relied on their own work, as the very long and detailed bibliographies show. These are arranged at the end of each chapter or section, subdivided according to the subject matter to which they refer. The book is a well documented and scholarly work, which stresses the processes operating, or which have operated in the past, to form the very distinctive glaciated landscapes. The illustrations, however, are not as satisfactory as the text; the drawings rarely reveal so clearly the features they portray as good photographs would have done, and some of the figures lack units and maps occasionally have no scale. One figure is missing and another repeated.
The geomorphological effects of ice sheets and local glaciers are differentiated from each other and from the influence of snow. These differences are important in that, although local glaciers are now generally studied more intensively, ice sheets have in the past been much more widespread in their influence on the landscape. The book can be strongly recommended to anyone who wishes to read a full account of the various theories that have been put forward to explain glacial phenomena in terms of the processes which operate in a region covered by snow and ice.
