Revieivs — Professor Bouney — Building of the Alps. 565 



words, of slate wherein mica is so abundant as to give the rock 

 a peculiar silky lustre. 



Ordovieian strata are the oldest representatives of the Palaeozoic 

 series that have been identified in the Alps, and of these and succeeding 

 formations the author gives brief descriptions. It was not, however, 

 until the end of the Eocene, or quite early in the Oligocene period, 

 that the making of the Alps began, and the process was continued 

 towards the close of the Miocene and into the Pliocene period. 



In the course of his chapter on the Materials of the Alps the author 

 discusses the 'difficult question' of certain reported examples of 

 crystalline schists of Silurian, Carboniferous, Triassic, and Jurassic 

 ages. While in certain instances, as he admits, the evidence is incon- 

 clusive, yet in others the facts are capable of explanation, and can 

 be attributed to intense folding and overthrust faulting, or to the 

 derivation from older crystalline rocks of mica, garnets, and stauro- 

 lites. The supposed fossil plants observed in gneiss are now regarded 

 as pseudo-organisms. 



In dealing with the great flexures and thrusts which have affected 

 the Alps, we are not surprised to learn that he hesitates to accept all 

 the disturbances "on a scale so gigantic as is demanded by certain 

 enthusiastic advocates of the overthrusting process" . 



The relations between different types of rock and mountain forms 

 are discussed in an interesting chapter in which the work of Ruskin 

 receives appropriate commendation.' The subject too is well illustrated 

 by many of the photographic views and by figures in the text. 



Nearly one-third of the volume is occupied by descriptions and 

 discussions concerning the snowfields and glaciers, topics that had 

 been considered by the author in 1865 in a work entitled Outline 

 Sketches in the Sigh Alps of Dmiphine, and three years later in The 

 Alpine Regions of Switzerland and the neighhouring countries, as well as 

 in separate papers on Cirques, Lakes, and Glacier-Erosion, etc. Here, 

 and also in the descriptions of the rock features, we feel the want of 

 maps, the only important omission among the illustrations in this book. 



The making and movement of glaciers and their extension in 

 ancient and modern times are subjects less controversial than those 

 dealing with the sculpturing of the land, the shaping of peaks and 

 valleys, corries or cirques, and the excavation of lake-basins. The 

 author's early conclusions are not modified, namely, " that the work 

 of glaciers is, as a rule, not more than ahrasive, and is erosive only 

 under special circumstances." Nevertheless, wliile the volume is 

 intended to embody the results of his personal observations and 

 researches, he has indicated throughout fairly, and perhaps with more 

 suavity than of old, where different conclusions are held. 



There are chapters on Alpine Meteorology, on the Yegetation, and 

 on the Wild Animals of the Alps, and it is interesting to know that 

 the brown bear, wolf, and lynx survive in certain areas. Interesting 

 also is the account of the Alps in relation to Man. It is remarked 

 that the Palaeolithic hunter may have wandered into the mountains 

 in pursuit of game, but though he has left a few relics of his presence 



^ See Euskin, " Shape and Structure of the Alps" : Geol. Mag., 1865, 

 pp. 49 and 193. 



