518 Notices of Memoirs — A. C. Seward — Lyginodendron. 



had been proved in the boring at Wytham, near Oxford ; l and 

 Mr. H. B. Woodward has classed with the Inferior Oolite Series 

 30 feet of strata proved in a boring at Witney. 2 These correlations 

 were inferential, but the facts now brought forward give them 

 support. 



VI. — A New Cycad from the Isle of Portland. By A. C. Seward, 



M.A., F.G.S. 



R. WOODWARD lately obtained an exceedingly fine specimen 

 of a cycadean stem from the Purbeck Beds of Portland, which 

 is now in the fossil plant gallery of the British Museum. The stem, 

 which is probably the largest known, has a height of 1 m. 18 - o cm., 

 and measures 1 m. 7 cm. in girth at the broadest part. A striking 

 feature of the specimen is the conical apical bud enclosed by tapered 

 bud-scales, bearing numerous ra mental outgrowths on the exposed 

 surface. The surface of the stem presents the appearance of a 

 prominent reticulum of pi'ojecting ridges, of which the meshes were 

 originally occupied by the persistent petiole bases. The substance 

 of the leaf-stalks has for the most part disappeared, while the inter- 

 petiolar ramental tissue has been mineralized and so preserved as 

 a projecting framework. In structure the ramenta are practically 

 identical with those of Bennettites, as described by Carruthers and 

 other writers. The petiole bases also agree very closely with 

 those of Bennettites, consisting of a mass of parenchymatous tissue 

 traversed by numerous vascular bundles and secretory canals, with 

 a distinct band of cork at the periphery. No trace of any 

 inflorescence has been found. It is proposed to name the plant 

 Cycadeoidea gigantea. 



VII. — Note on a Large Specimen of Lyginodendron, By A. C. 

 Seward, M.A., F.G.S. 



THE specimens on which this description is based are in the 

 Botanical Department of the British Museum and in the 

 recently acquired Williamson Collection. The block, from which 

 several sections have been prepared, is a striking example of the 

 preservation of the minute structure of a Coal-measure plant on 

 a large scale ; it consists of a mass of wood at least 6 cm. thick in 

 a radial direction, and a pith about 3 cm. in diameter, but without 

 any trace of cortical tissue. Sections obtained from this block, and 

 included in the Williamson Collection, were described at some 

 length in the recently published memoir by Williamson and Scott 

 on Lyginodendron and Eeteranyium. The examination of additional 

 specimens has led to a somewhat fuller diagnosis of the structure 

 and a more detailed comparison with Lyginodendron Oldhantiiou and 

 other plants. The main mass of the wood possesses a structure 

 practically identical with that of Lyginodendron Oldhamiunt and 

 recent cycadean stems ; internal to the centrifugally developed 



1 Geol. Mag. 1876, p. 238. 



2 " Jurassic Rocks of Britain," vol. v, 1895, p. 42. 



