38 Revieios — DicJcens's Dictionary of the Thamea. 



constructed by Waltershausen himself. The work is also embellished 

 by 14 large copper-plate engravings, giving striking views of iEtna, 

 and its sections, besides numerous smaller woodcuts illustrating 

 various topics connected with the subject. A portrait of Walters- 

 bausen forms an appropriate frontispiece to the volume. We feel 

 sure that all students of Vulcanicity will welcome a work which, 

 after Vesuvius, deals in an exhaustive manner with the most re- 

 markable volcano in Eui'ope. 



Since the above was in type the second volume has come to hand — 

 not less elaborate than the first. In this the authors deal with the 

 geological structure of the region around ^tna, beginning with the 

 old gneissose rocks which are the foundation for all the others, and 

 then pass on to the consideration of those of Jurassic, Cretaceous, 

 Tertiary and Quaternary age. The gradual unfolding of the 

 volcanic history of the region, from the time of the oldest basalts 

 which break through the Cretaceous beds, down to the most recent 

 lavas, is descinbed and illustrated by drawings, and maps. Chapters 

 on the mineral products of j3l3tna form an appropriate conclusion to 

 the volume. The map of the Valle del Bove on a scale of -xt^-qs is 

 an admirable example of topographical portraiture. E. H. 



11. — ■Dickens's Dictionaky of thk Thames. London, 1880. 

 16mo. pp. 268. Price Is. 



TO this "unconventional handbook," Mr. Whitaker has contributed 

 an essay on the Geology of the Valley of the l^hames, which 

 occupies a little over four pages of closely printed type. Dividing 

 the area (for convenience of description) into three parts, he first 

 gives an account of the formations exposed along the course of the 

 river, and then points out the leading features in the geology of 

 (1) the Upper Thames, to a little below Wallingford ; (2) the Middle 

 Thames, from near Wallingford to Richmond ; and (3) of the Lower 

 Thames, below Richmond. The influence of the geology on the 

 scenery is noted by the way. Thus the several divisions of the 

 Oolites, of the Cretaceous Series, of Older Tertiaries, Drift and 

 Alluvium, are described. Only in connexion with the Drift of 

 Glacial age do we meet with matters of dispute among geologists ; 

 but concerning this there is great variety of opinion, and some ex- 

 tensive patches of gravel in the area are left as of uncertain age. 

 Speculations on the origin of the Boulder-clay are alluded to, but 

 Mr. Whitaker contents himself with mentioning them without lend- 

 ing the weight of his own opinion to any particular explanation. 

 The great deposits of brickearth and gravel which in the Lower 

 Thames Valle}'^, more particularly, have yielded so many remains of 

 large mammalia, are classed as Post-Glacial, in the sense of their 

 being newer than the Boulder-clay (usually known as the Chalky 

 Boulder-clay), which is only found on the heights bordering the 

 northern margin of the valley, and not in it. 



As pointed out by Mr. Whitaker, these Post-Glacial beds constitute 

 the most important division of the drift, as far as the Thames Valley 

 is concerned, and he gives an interestine: sketch of their method of 



