518 Reviews — Handbook of Bedfordshire. 



The account of Heteranginm and the associated seed Sphcerostoma 

 follows that of Lyginopteris, after which is a chapter on Medullosese 

 and the Trigonocarpus seed-type. The Lyginopterideae and Medul- 

 loseae are regarded as offshoots of a common stock, the latter 

 occupying a position farther removed from the filicinean ancestry 

 than the former. 



Under the heading Cycadofilices is a description of several types 

 represented by stems, but which in the absence of definite informa- 

 tion with regard to the reproductive organs cannot be assigned to the 

 Pteridosperms, including among others Megaloxylon, Cycadoxylon, 

 Calamopitys, Cladoxylon, and Protopitys ; their structure is well 

 illustrated by photographic reproductions of sections and diagram- 

 matic figures. 



The two following chapters are devoted to the Cordaitales under 

 the headings Poroxyleae, comprising Poroxylon, Cordaiteee, including 

 Cordaitex proper with some allied or imperfectly known genera, and 

 Pityese, including the large petrified stems known as Pitys and other 

 genera founded on stems of comparable structure. A chapter on 

 Palaeozoic gymnospermous seeds forms a useful comparative study of 

 selected examples illustrating the remarkable variety in details of 

 external form and internal structure associated with certain funda- 

 mental features which they have in common. Here, again, the 

 illustrations are most helpful. 



The concluding chapters deal with the fossil Cycadophyta. These 

 are represented by the important class Bennettitales and include 

 Cycadeoidea (more generally known as Bennettites), TPtlliamsonia, 

 the recently described WilliamHoniella, and other less perfectly known 

 genera ; these forms are fully and carefully described. A chapter 

 follows dealing (1) with Cycadean stems other than Cycadeoidea, the 

 best known of which are those assigned to Bucklandia, and (2) with 

 reproductive organs of fossil Cycadean plants which cannot be 

 assigned to Bennettitales. Some of these, which have been described 

 by various authors as Carpolithus, agree in external features with the 

 seeds of modern Cycads, but in the absence of anatomical details 

 their position must remain doubtful. 



The last chapter, Cycadophytan fronds, contains a description of 

 a number of genera founded on detached leaves which are believed 

 to be Cycadean. 



A list of works referred to in the text (including vols, iii and iv), 

 arranged alphabetically under the author's name, occupies nearly 

 fifty pages. 



A. B. Rendle. 



II. — Cambridge Cot/ntt Handbooks. 

 Bedfordshire. By C. Gore Chambers. Cambridge County Hand- 

 books, pp. x + 195. Cambridge University Press. 1917. 

 ALTHOUGH Bedfordshire is one of the smallest of the English 

 counties, nevertheless it shows a surprising diversity of natural 

 features and productions. This diversity is closely correlated with 

 the geological structure of the district. From this point of view the 

 county may be divided into three sections ; firstly, the Jurassic clays 



