THE FOSSIL FLORA OF THE YORKSHIRE COAL FIELD. 57 



scar, and Hanked by two very slightly outward-directed oval cicatricules. Immediately 

 above the leaf-scar is a small transversely elongated little cicatricule, above which is a 

 short transverse lunate depression, which is again surmounted by a larger straight or 

 slightly lunate hollow, from each extremity of which arises a bent band of slightly curved 

 oblong depressions, decreasing in size as they reach the centre of the rib, where the two 

 halves of the semicircle meet. Outer surface of ribs otherwise smooth. 



Remarks. — PI. iii. fig. 6 shows the fossil natural size ; and at fig. 6a one of the leaf- 

 scars and the surmounting ornamentation is shown in outline, also natural size. 



This specimen I received in 1888 from Mr C. Bradshaw, Sheffield, to whom my thanks 

 are due. The species is evidently very rare, as I have not again met with the plant. 



Middle Coal Measures. 



Locality. — Kilnhurst Pit, Eotherham, Yorkshire. 

 Horizon. — Barnsley Thick Coal. 



Sigillaria semipulvinata, Kidston, n. sp. 



PI. III. figs. 1-5. 



Description. — Leaf-cushions almost contiguous, transversely rhomboidal, hexagonal 

 or longer than broad ; in transversely rhomboidal forms, lateral angles prominent, acute ; 

 in others, generally rounded. Lower margin rounded or truncate ; extreme upper 

 portion occupied by the leaf-scar. Leaf -scar occupying the entire apex of the cushion, 

 rhomboidal, or transversely rhomboidal, lateral angles prominent ; upper margin flatly 

 arched or slightly notched ; lower margin rounded, or rounded with slightly concave 

 sides ; cicatricules placed slightly above the centre, central punctiform, the two lateral 

 oblong and slightly directed outwards. On the leaf-cushion are occasionally seen two 

 faint rows of transverse lines, which descend obliquely from the base of the leaf-scar. 

 Subcortical layer striated longitudinally. 



Remarks. — Though this species varies in the proportional size of the leaf-cushion to 

 the size of the leaf-scar, and in the cushion and leaf-scar being sometimes transversely 

 expanded, or in the cushion being longer than broad, a definite character runs through 

 all these variations which at once connect them as different conditions of the same 

 species, — forms whose existence depends entirely on circumstances of growth, as shown 

 by these variations sometimes occurring on the same individual. 



Description of Specimens. 



PI. III. fig. 1. 

 This illustrates what I regard as the typical form of the species. A few of the leaf- 

 scars and cushions are given in outline, natural size, at fig. la. This example shows a 



VOL. XXXIX. PART I. <N0. 5). L 



