926 REPORT—1899. 
7. The Jurassic Flora of Britain. By A. C. Snwarp, F.R.S. 
The Lower Oolite rocks exposed in the cliff-section between Whitby and a few 
miles south of Scarborough have long been famous as affording rich collections of 
fossil plants, which enable us to form a fairly accurate idea of the chief charac- 
teristics of the Jurassic Flora. Plants from the Yorkshire coast are abundantly 
represented in most of the English museums as well as in Continental collections. 
The Ferns and Cycadean genera constituted a large proportion of the vegetation, 
with an abundance of one or two species of Eguisetites and a few conifers; no 
trace of undoubted Angiosperms has so far been discovered. 
The account of the flora includes a description of the more important types, a 
general comparison of the English species with recent plants, and remarks on the 
characteristics and distribution of the Lower Oolite floras. 
TUESDAY, SEPTEMBER 19. 
The following Papers were read :-— 
1. A new Genus of Paleozoic Plants. By A. C. Sewarp, 2. B.S. 
The description of this genus, which represents a new type of Cycadofilices, is 
founded on a single specimen in the Binney Collection of Coal-measure Plants 
(presented in 1892 to the Woodwardian Museum, Cambridge),: The specimen 
consists of a small piece of stem, unfortunately without the cortical tissues, with 
the structure of the primary and secondary wood very clearly preserved. A strand 
of primary xylem, 1-9 cm. in diameter, occupies the axial region; this consists of 
large isodiametric or slightly elongated tracheids with multiseriate bordered pits 
on their walls, associated with parenchymatous tissue; the narrow and spirally 
thickened protoxylem elements occur at the margin of the primary stele, which 
is, therefore, of exarch structure. Surrounding the primary stele there is a broad 
cylinder of secondary wood exhibiting anatomical features characteristic of 
Cycadean stems. Leaf-traces are given off from the periphery of the primary 
strand; these consist of long tracheids intermixed with parenchyma. 
The features of most interest in the anatomy of this stem are (1) the manner 
of origin and behaviour of the leaf-traces; (2) the exarch structure of the primary 
system; and (3) the structure of the large primary tracheids. 
The genus is placed among the Cycadofilices, and compared with Heteranyium 
and other Paleozoic genera, also with Zygodium and other recent plants. 
2. On the Structure of a Stem of a Ribbed Sigillaria. 
By Professor C. Ec. Berrranp (Lille). 
The specimen described was obtained by M. Breton from a colliery in the 
Hardinghem district, Pas de Calais ; it presents external features similar to those of 
Sigillaria elongata, and the structure of the wood is well preserved. The fragment 
of stem measures 100 x60 mm. and the surface is traversed by 72 ribs. The 
primary system (corona) is in places perfectly preserved; it agrees with that of a 
Diploxylon stem and forms a continuous centripetally developed ring. Exteriorly 
the primary wood is succeeded by a continuous zone of centrifugal secondary wood, 
but the cambial and phloeum regions have not been preserved. The continuou 
corona consists of 10-13 rows of large scalariform tracheids; its external surface is 
characterised by the very prominent teeth which form ridges separated by sinuses. 
The narrowest xylem elements are situated in the projecting teeth. ‘The leaf- 
traces arise as separate strands from the external face of the primary wood, and 
each is detached from the middle of a sinus; the arrangement of the leaf-traces 
suggests an almost regularly yerticillate disposition of the appendices. Each leaf- 
