CURRENT. LITERATURE 
BOOK REVIEWS 
Cretaceous plants 
The second part of the British Museum Catalogue of Cretaceous plants, by 
STOPES,’ treats of the flora of the so-called Lower Greensand, which is known 
on the Continent as the Aptian stage of the Lower Cretaceous. The beds of 
this age which have escaped erosion and are available for study are nearly all 
typically marine deposits, with only such traces of terrestrial vegetation as 
withstood the maceration and trituration of the sea. Consequently, the flora 
of the Lower Greensand has hitherto been supposed to have been essentially 
the same as that of the older and better known Wealden deposits. Thus, with 
the exception of the classic Bennettites Gibsonianus of CARRUTHERS and a 
few cones, the plant remains consist almost entirely of pieces of ayes _ 
By a careful study of the latter, Sropss is enabled to list 45 plant forms, com- 
prising 1 thallophyte, 2 Filicales (Weichselia and Tempskya), 9 cya 
27 conifers, and 5 angiosperms. Notable features are the presence of angi- 
osperms, the preponderance of conifers, and the scarcity of ferns. Angiosperms 
have been sparingly represented by leaf impressions in deposits of this age or 
slightly older, but these have been few in number and vague in character, while 
ese forms of the Lower Greensand, although vague in their affinities, are 
well characterized. 
The proportions of the different groups represented, upon which STOPES 
lays considerable stress in emphasizing the differences between this flora and 
other floras of the Lower Cretaceous, is due almost entirely, I believe, to the 
methods of preservation; that is to say, to differences in the physical conditions 
of deposition of the sediments. Coniferous remains usually predominate and 
ferns are scarcely represented in coarse marine deposits. Thus, in the Trinity 
beds of Texas, which are about the same age as the Lower Greensand, there 
is but one fern, while there are 8 cycadophytes and 11 conifers. On the other 
hand, in the Lakota beds of the Black Hills, which are continental deposits 
partially synchronous with the marine Trinity, there are 13 ferns and only 8 
conifers 
The two features of the present work which are of greatest botanical inter- 
est are the interpretation of the coniferous woods and the careful description 
of the wood structure of five indubitable angiosperms of a relatively high degree 
* Stopes, Marie C., Catalogue of the mesozoic plants in the British Museum. 
The cretaceous flora. Par t II. London. 1 5. 
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