38 Reviews — A. de Grossouvre on the Upper Chalk. 



terms, which simply extend the accepted geological scale into more^ 

 minute units of thickness and time. Thus — 



A stage represents an age, 



A zone i-epresents a secule. 



A subzone represents a hemera. 

 Mr. Buckman's use of the term hemera with the specific name of 

 a fossil in front of it may very well be adopted as a shorter phrase 

 than the full expression of the subzone ; thus we may write of the 

 ' concavi-hemera, ' as short for the " hemera of the subzone of 

 Lioceras concaviim," but the stratum containing this Ammonite is 

 a subzone, not a hemera nor a zone. 



S. JB "V I IE ^W S. 



Memoires pour seevir a l'Explication de la carte geologique 



DETAILLEE DE LA FrANCE. (a) EeCHERCHES SUR LA CrAIE 



SuPERiEURE (premiere partie), par A. de Grossouvre, avec (b) une 

 monographie de genre Miorasteb par J. Lambert. 4to ; in two 

 Fasciculi with 1,013 pages, 33 figures and maps, and 3 plates. 

 (Paris, 1901.) 



THOUGH both the fasciculi of this work bear the date 1901 they 

 do not seem to have been distributed until 1902. The scope of 

 the treatise is considerable, for under the title of " Craie Superieure " 

 the author includes the Turonien, Senonien, and Maestrichtien 

 divisions of the Chalk throughout western and central Europe, with 

 chapters on the Chalk of India and the United States. These are 

 followed by an essay on the classification of the Upper Cretaceous 

 Series, and by another on the History of the Earth with especial 

 reference to that of Cretaceous Time. Moreover, some space is 

 devoted to a monograph on the genus Micraster written by M. J. 

 Lambert. 



It is evident, therefore, that in these volumes we have the results 

 of a detailed and comparative study of what has been discovered 

 and written about this portion of the Cretaceous System, not only 

 in France but in many other countries. The work does indeed 

 furnish the reader with an enormous amount of information, the 

 greater part of which is a careful compilation from the most 

 authoritative sources available at the time of writing ; each chapter 

 contains one or more tabular correlations of the strata described 

 therein, and also tabulated lists of the Cephalopoda and Echinoderms- 

 showing the vertical distribution of each species. 



Moreover, in those chapters which call for the exercise of original 

 thought and the critical faculty we are pleased to find that M. de 

 Grossouvre is a careful balancer of evidence, that he seldom takes 

 an extreme view on any debateable question, but generally takea 

 a comprehensive grasp of its several aspects. Consequently his 

 opinions and conclusions deserve serious consideration, whether they 

 happen to fall in with the reader's views or not. 



The treatise will undoubtedly be useful to every student of the 

 Cretaceous System, though of course some portions are of less value 



