134 Rcvieics — Lemoine's Geologie du Bamn de Paris. 



An example may be taken from plate i, in which is figured a species 

 of Plioladidea, the bored crypts of wliich descend from the base of the 

 8andgate Eeds into the Atherfield Clay. Here the pause in deposition 

 is indicated by the absence of the Hythe Beds, as previously noted. 



Interesting lists of fossils are given from various horizons, from the 

 Mammillatus Bed downwards, and comments are made on many species 

 in refei'ence to the vexed subject of nomenclature, on records of species 

 new to this country, and on the limits of formations and epochs. The 

 difficulty of fixing a definite plane of division is felt with the Corallian 

 and overlying and underlying strata, as in Dorset; and so also with 

 the Kimeridge Clay and Portland Beds, the French geologists, in their 

 usage of the name Portlandian, having insufficiently realized the 

 limits in the type-areas of England. 



II. — Geologie du Bassin de Pakis. Par M. Paul Lemoine. 8vo ; 

 pp. ii, 408, witli 9 plates and 136 text-illustrations. Paris, 

 Hermann & Fils ; London, Dulan & Co., 1911. Price 15 fr. 



IN this well-printed and well-illustrated work the author gives 

 a comprehensive account of the stratigraphy, economic products, 

 zonal paliBontology, and physical geography of the Secondary, 

 Tertiary, and Quaternary formations which, in a broad sense, 

 constitute the Paris Basin. 



After some preliminary remarks on general geology, he describes 

 the main structural features of the basin. Then follow a short 

 historical summary of the work of previous geologists, from Cuvier 

 and Brongniart (1810) to the present time, and useful jjarticulars of 

 the geological survey maps, with names of the geologists responsible 

 for them. 



With the aid of palaeographic and other maps and sections, the 

 tectonic structure of the region, the areas of land and water at 

 different periods, and the variations in sedimentary conditions of 

 strata from the Trias onwards are expounded by the author. His 

 objects are to give a faithful account of this interesting and important 

 region from the knowledge scattered in many publications, to verify 

 doubtful points, and where possible to decide differences of opinion. 

 Illumined, as it is, with much additional information derived from 

 the author's own researches, the result may be justly regarded as 

 u standard work for study and reference. 



In giving some account of this volume we propose to deal mainly 

 with such points in the classification, nomenclature, and correlation 

 of formations as may be of interest to our readers. 

 TRIAS. This system is divided as follows : — 

 Neotkias. Keuper and Marnes irisees. 

 Mesotkias. Muschelkalk. 

 EoTEiAS. Gres bigarre. 

 EHETIAN" (or Pvhsetic Beds). These are placed independently as 

 Passage Beds, and consist of arkoses, grits, sands, marls, and 

 limestone, with the zonal Avicida contorta, also A. infra- 

 liasiana, Leda Beffiieri, Mytilus minutus, MyopJioria, Psammohia, 



