714 DR R. KIDSTON. 



At figs. 6 and 7 two small portions of the outer surface of a compressed stem are 

 given, enlarged two times. At fig. 6 the leaf scars are seen to be more pointed 

 below and slightly flattened or emarginate on their upper margin. The smooth 

 cushion here forms a distinct marginal area at the sides and especially below the leaf 

 scar. At fig. 7, which holds the same level on the other side of the stem as fig. 6, 

 the leaf cushion is still further developed below the leaf scar, and on the lowest 

 cushion in the centre row there are indications of two decurrent ridges which descend 

 from the base of the leaf scar. Some of the cushions and leaf scars on this example 

 correspond very closely with some towards the lower end of figs. 5 and 5a. 



Another small specimen is given on PL III, fig. 5, natural size, and enlarged two 

 times at fig. 5a, where the leaf scars and cushions are more transversely elongated. 

 The leaf scars are here placed very close to the upper end of the smooth cushions. 



It was on this example I recorded, in error, the occurrence of Sigillaria Brardii 

 Brongt. from the Lanarkian Series. This species must therefore now be removed 

 from the lists of fossil plants from that horizon. 



Sigillaria incerta is, however, easily distinguished from Sigillaria Brardii Brongt. 

 by the lateral angle of the leaf scar of Sigillaria incerta joining the margin of its 

 cushion some distance above the lateral angle of its cushion, except in those con- 

 ditions where the leaf scar occupies almost the entire cushion. 



If the specimens of Sigillaria incerta be compared with those of Sigillaria elegans 

 Sternb., sp., described in this communication, it will be seen that they possess certain 

 points in common. On the specimen of Sigillaria elegans given on PI. II, figs. 1 and 

 la, it is seen that the lateral angles of the leaf scar and its cushion are on the same 

 level, a condition we also find in the central portion of Sigillaria incerta, PI. II, 

 figs. 5, 5a ; but where the leaf cushions become elongated below the leaf scar, the 

 lateral angle of the leaf. scar is at a higher level than the lateral angle of the cushion. 

 This is seen on some of the cushions of Sigillaria elegans figured on PL II, fig. 3. 

 They also agree in having the cone scars arranged in a single verticillate row. 



They further agree in the lower margin of the leaf scar being occasionally pointed 

 (cf. PL II, fig. 3 and figs. 6, 7). These circumstances have raised a suspicion in my 

 mind that Sigillaria incerta may be an extreme variation of Sigillaria elegans, 

 especially as the fossils occur together. I am, however, unable to satisfy myself that 

 this is really the case, so I have deemed it safer to keep separate the plant given at 

 PL II, figs. 5, 5a, 6, and 7, and PL III, figs. 5, 5a, which is here distinguished as 

 Sigillaria incerta. 



Locality. — Stein's Fireclay Works, f mile north-east of Castlecary Railway 

 Station, Stirlingshire. (PL II, figs. 5-7.) 



Horizon. — Upper part of Millstone Grit, Lanarkian Series. Collected by Mr 

 D. Tait. 



Locality. — East Newton, Wemyss, Fife. (PL III, fig. 5.) 

 Horizon. — Coxtool Coal (=Six-Foot Coal), Lanarkian Scries. 



