278 Bevieus — A. J. Jukes-Browne — Upper Chalk of England, 



generally been defined as all that part of the Chalk which overlies 

 that rock wherever it can be identified. Mr. Whitaker's Chalk 

 Kock, which possesses a typical structure and is characterised by 

 a peculiar fauna, occurs towards the upper part of the Holaster 

 planus zone, but in this memoir the whole of this zone is included 

 in the ' Upper ' Chalk. Other hard beds, similar in lithological 

 aspect to the Chalk Rock but devoid of the peculiar fauna, occur, 

 especially in the zone of Terebratulina gracilis of the Dorset coast. 

 Precise limits to the various zones have been defined in the series 

 of papers recently published by Dr. Eowe, by means of the dis- 

 tribution of the fauna ; and generous recognition of the work of 

 that author and his colleague, Mr. Sherborn, has been accorded by 

 the authors themselves, as well as by the Director, Mr. Teall, in 

 his prefatory remarks. 



We need therefore merely remark on the new zone of Ostrea 

 lunata, which is founded on the admirable paper published by 

 Mr. Brydone, and on the unpublished researches of Mr. Clement 

 Eeid, on the Trimingham area in Norfolk. This small but interesting 

 area consists of beds of Chalk, lying upon the strata of the miicronata- 

 zone, and characterised by a fauna comparable in many respects with 

 that of the Chalk of Riigen and Maestricht. The occurrence of 

 a small oyster in great profusion has led to the adoption of Ostrea 

 lunata as the distinguishing name for the zone. Personal observation, 

 however, would have shown that the oysters occur only in one of 

 the beds. 



After defining the various zones the authors discuss the typical 

 fossils, special attention being called to the forms of the genus 

 Micraster, whose value, first pointed out by Mr. C. J. A. Meyer, was 

 fully worked out by Dr. Rowe. Condensed diagnoses of these 

 forms and rough sketches of the ambulacral areas and of the labral 

 plates are supplied. 



Chapters iii to xx deal with the description of the beds proper, 

 and contain a vast amount of valuable material concerning the 

 various exposures from Devon to Yorkshire, especially with regard 

 to the inland areas, not yet subjected in many cases to critical zonal 

 division by means of their fossils. It is unfortunate that Dr. Rowe's 

 paper on the Yorkshire coast was not published in time for quotation, 

 the Yorkshire chapter being the poorest in the volume. 



A sketch of the " Upper Chalk in France " occupies chapter xxi, 

 and allows of easy comparison with the corresponding beds in 

 England. Some interesting remarks communicated to the authors by 

 M. Grossouvre, who has zoned the Chalk of France with reference 

 to the Cephalopod fauna, are quoted. M. Grossouvre writes: "The 

 classification established by the evolution of the Ammonite-faunaa 

 represents, in my opinion, the ideal theoretical classification or 

 standard for comparative purposes, to which all regional classi- 

 fications should be referred for the purpose of correlating and 



synchronising the strata of difi"erent countries On the 



other hand, for the practical purpose of establishing the stratigraphy 

 of the Cretaceous series of any given country, we shall be obliged ta 



