810 MR ROBERT KIDSTON ON THE FOSSIL PLANTS OF 



scar placed very slightly above the centre of the cushion — almost central — and 

 occupying rather more than three-fifths of its width, rhomboidal or diamond-shaped, with 

 upper angle rounded, lower angle sharp, lateral angles rounded or pointed, and from 

 which two lines frequently descend ; cicatricules three, punctiform, slightly below the 

 centre of the scar. 



Description of Specimens : — 



Plate II. fig. 17 is a photograph, natural size, of a plaster of Paris cast from 

 an impression from the " Coal Measures near Halifax, Yorkshire," in the collection of 

 the Geological Department of the British Museum. An outline of a cushion is given at 

 fig. 18. 



This specimen is uncompressed , and the contiguous leaf cushions rise up towards the 

 leaf scar, above which the cushions are rather more raised than below it, as the leaf scar 

 slopes slightly downwards. The lower part of the cushion is slightly keeled with 

 transverse notches, the upper portion of the cushion is smooth, without a keel. The 

 leaf scar is almost central, rounded above and sharply pointed below, with lateral angles 

 which are not very prominent, and from which extend two downward lines. The leaf 

 scar sometimes appears as if very sharp-pointed on its lower margin, but this appearance 

 is partly caused in the uncompressed condition by the central keel rising up to meet 

 the lower angle of the leaf scar. The leaf cushions are straight, or if the points are 

 twisted, the bend is so slight that it is scarcely observable. 



My thanks are due to Dr A. Smith Woodward for permission to figure this 

 example. 



Plate III. fig. 25 shows a younger condition of the plant from Jockie's Syke, 

 Cumberland, and a portion is enlarged two times at fig. 22, while a leaf cushion and 

 leaf scar are seen at figs. 23 and 24. 



The contiguous keeled leaf cushions have straight sides with slightly rounded 

 lateral angles, and about their centre they bear a relatively large rhomboidal leaf scar. 



Remarks. — This species, which was first figured by Martin in 1809 under the name 

 of Phxjtolitlius cancellatus, has been confused with other species of Lepidodendra, but 

 especially with Lepidodendron rimosum, Sternb., but from Lepidodendron fusiforme, 

 Lepidodendron rimosum differs in the leaf cushions being distant, more narrowly fusiform, 

 with long tail-like prolongations from the ends of the cushions, which often unite with 

 the neighbouring cushions of the same series ; the leaf scar is also smaller in proportion 

 to the width of the cushion, only occupying about one-third of the width, and the 

 interfoliar cortex is ornamented with wavy lines crossed obliquely by fine striae. 



Lepidodendron simplex, Lesqx., appears to me to be referable to Lepidodendron 

 fusiforme. His figure shows the leaf cushions united in spiral series, and the same 

 character is seen in the specimen figured by Martin. 



Lepidodendron fusiforme is not common in Britain, though it extends throughout 

 the whole of the Coal Measures. 

 Locality B. 



