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XXXIV. — On the Structure and Affinities of a Lepidodendroid Stem from the 

 Calciferous Sandstone of ' Dalmeny, Scotland, possibly identical with Lepidophloios 

 Harcourtii (Witham). By A. C. Seward, M.A., F.K.S., University Lecturer in 

 Botany, and A. W. Hill, B.A., University Demonstrator in Botany. Cambridge. 

 (With Plates I.-IV.) 



(Read June 19, 1899.) 



Introductory.* 



The unusually fine stem which forms the subject of this paper was found by Mr 

 T. Kerr, of Edinburgh, in rocks of Calciferous sandstone age exposed in a railway 

 cutting at Dalmeny, Linlithgowshire. Mr James Bennie, of the Geological Survey 

 of Scotland, called the attention of Mr Kidston to the fossil, and the latter 

 very generously placed part of the specimen in the hands of one of us for in- 

 vestigation. 



The photograph reproduced in PI. I. fig. 1, for which we are indebted to the kind- 

 ness of Mr J. J. H. Teall, was taken from a polished slab of the stem in the Museum 

 of Practical Geology, Jermyn Street. A similar specimen is in the Geological Museum, 

 Edinburgh, and the remaining portions of the fossil are in Mr Kidston's possession 

 and in the Botanical Laboratory Collection, Cambridge. A preliminary note on the 

 structure and affinities of this Carboniferous plant was contributed to the Cambridge 

 Philosophical Society in November 1898,t but no detailed account of the fossil has 

 been published. A reference to the state of preservation of the tissues has also been 

 made by one of us in a text-book published last year.J 



The specimen consists of a fairly thick piece of a stem, 33 cm. in diameter, and a 

 polished transverse section of the block presents the appearance shown in PL I. fig. 1. 

 The peripheral portion consists of a band of unequal thickness of partially disorganised 

 bark ; internal to this there is a light-coloured matrix of volcanic ash filling up the 

 hollow trunk, and the detached central cylinder of wood and pith occupies an eccentric 

 position close to the thicker part of the shell of bark. The marked contrast between 

 the dark silicified plant tissues and the buff-coloured volcanic ash renders the specimen 

 one of the most striking examples of a Palaeozoic tree that has so far been discovered. 

 The position of the larger angular fragments in the ash and of the central cylinder, point 



* The numbers in brackets after the authors' names in the footnotes refer to the year of publication of the works 

 given in the bibliography on page 928 ; e.g., (99) means that the paper was published in 1899. 



t Seward and Hill (99). % Seward (98), figs. 14, A, B, and 15, p. 83. 



VOL. XXXIX. PART IV. (NO. 34). 7 A 



