474 Reviews — The Cretaceous Flora. 



I. — Catalogue of the Mesozoic Plants in the British Museum 

 (Natural History). The Cretaceous Flora: Part II. Lower 

 Greensand (Aptian) Plants of Britain. By Marie C. Stopes, 

 D.Sc, Ph.D. 8vo; pp. xxxvi -f- 360, with 112 text-figures and 

 32 plates. Trustees of British Museum. London : Dulau & Co., 

 37 Soho Square, W., 1915. Price 21s. 



WE heartily congratulate the author of the volume, and the 

 Department of Geology which is responsible for its publica- 

 tion, on the appearance of this second instalment of the Catalogue of 

 the Cretaceous Flora. Dr. Stopes is well qualified for the task of in- 

 vestigating the often unpromising fragments upon the study of which 

 a knowledge of this flora is based, and the book is a record of careful 

 painstaking research. It appeals essentially to the botanist, who 

 will examine with admiration the photographs, and more especially 

 the line drawings, in which Dr. Stopes illustrates the histological 

 structure of the species she is describing. In preservation of detail 

 many of these Lower Greensand species are equal to the remarkable 

 specimens with which we have become familiar in the Coal-measure 

 petrifactions. As the author reminds us, the plants of the Lower 

 Greensand in this country are found under very favourable conditions, 

 occurring in a well-defined and well-known marine deposit. The 

 principal localities are the coasts of the Isle of Wight, the quarries of 

 North Kent near Maidstone and Ightham, near Woburn and Potton 

 in Bedfordshire, and near Leighton Buzzard in Bucks. Forty-five 

 forms are described, comprising one Thallophyte ( Chondrites Targionii), 

 two Ferns, nine Cycadophyta, twenty-seven Conifers, and five Angio- 

 sperms. As compared with other Mesozoic floras the list is remarkable 

 for the scarcity of Ferns and the great preponderance of Conifers. In 

 the Wealden flora, on the other hand, the Ferns head the list and the 

 Conifers are relatively few, while Angiosperms are unrepresented. 

 The Aptian flora is characterized by absence of leaf-structures, and is 

 composed mainly of woody stems with a fair sprinkling of gymno- 

 spermic cones. These characters are explained by the nature of the 

 deposits, which represent " a narrow arm of the sea in which a coarse 

 marine detritus was being laid down at no great distance from land". 

 The plant remains must have drifted for some time before they were 

 entombed, and this resulted in the elimination of all the soft leaves. 

 The only well-preserved leaf is that of a twig of Sequoia which had 

 become sheltered in the stem of a larger plant. Hence the absence 

 of herbaceous plants does not imply their non-existence in the flora, 

 and, as the author points out, does not support the view that the 

 woody tree is the primitive type of Angiosperm. The five genera of 

 Angiosperms described are the earliest Dicotyledons recorded for the 

 North of Europe, and the earliest specimens of which the anatomy is 

 known from any part of the world, but Dr. Stopes wisely refrains 

 from adding to the burden of the discussion of the origin of 

 Angiosperms. The species studied " were woody plants of a highly 

 advanced and differentiated character, and there is nothing in their 

 anatomy to indicate any more clearly their phylogenetie origin than 



