Reviews — Barrande's Silurian of Bohemia. 369 



The travelling of shingle and the influence of shingle in the 

 destruction of the cliffs by the breakers are dealt with, but we 

 question the statement (p. 199) that " the greatest amount of erosion 

 is off the points, where not only the waves are largest, but their 

 transported load of debris is heavier and more powerful as an erosive 

 factor ". The author remarks that there the water is deepest. 

 Mr. Reid in his evidence given before the Royal Commission (before 

 noted) explains that in the case of some Cornish headlands the points 

 may remain after the harder rock, which was the cause of the 

 headland, had disappeared, as such points descend into deep water, 

 which in stormy times would not be charged with the sand and 

 pebbles that occur in the bays. Nor can we agree with the author 

 (p. 36) that the waters of the Bristol Channel " have naturally little 

 power of erosion even in times of storm ". A visit to the coast near 

 Watchet would not support this view. Nevertheless, we may fully 

 agree with him that along the hard rocky coasts which he describes 

 the changes that have taken place "within the memory of the oldest 

 generation " are for the most part inappreciable. If, however, the 

 destruction along the coast is not so serious as that along the borders 

 of our eastern counties, the infinite variety of rock-structures, the 

 grand scenery described with enthusiasm by the author, and the 

 various processes of erosion now in action, form a far more interesting 

 field of study. 



II. — Barrande's Silurian System of Bohemia. 

 Systeme Silurien do Centre de la Boheme. Par Joachim Barrande. 

 l e partie : Recherches Paleontologiques. Continuation editee 

 par le Musee Boheme. Yol. IY : Gasteropodes, par le Doct. 

 Jaroslav Perner. Tome III. 1911. Traduit par A. S. Otjdin. 

 Pis. 176-247. 



SOME account of the scope of this great work was given in the 

 Geological IIagazine for March, 1908, together with a brief 

 abstract of the contents of the first two 'tomes', and an explanation 

 of the difficulties encountered and so ably overcome by Dr. Perner. 



Now we have tome iii before us, which maintains in every respect 

 the high standard of its predecessors. Dr. Perner expected that in 

 addition to the material on the Gasteropoda originally collected this 

 volume would also have contained all that has since come to light 

 on the subject, as well as descriptions of the organisms other than 

 Gasteropoda figured on the plates. This he has, however, found 

 impossible, hence there is still a supplement to follow. 



Tome iii contains the descriptions of members of seven families, viz., 

 the Capulidse, Naticidae, Horiostoroidse, Calyptraeidse, Siphonariidse, 

 Atlantidse, and the Pterotracheidse : numerous figures of these are 

 now given in addition to those already published, as well as figures of 

 some fifty forms previously described. It also comprises comprehensive 

 and exhaustive tables showing the distribution of all the forms dealt 

 with, together with remarks on their genetic affinities, the nature of 

 the sediments in which they are embedded, and their representatives 

 in other countries. Yaluable Addenda and Corrigenda to the three 

 ' tomes ' are also given. 



DECADE V. — VOL. VTLT. — NO. VIII. 24 



