FOSSIL FLORA OF THE STAFFORDSHIRE COAL FIELDS. 141 



presence of two short diverging ridges which descend from the base of the elevation 

 of the leaf scar. 



The subepidermal surface of the ribs is longitudinally striated. 



Remarks. —Although the coaly matter has been removed from part of the specimen 

 figured here, and partially fractured at other parts, still many of the leaf scars are 

 beautifully preserved, and show very distinctly the details of their structure. 



Sigillaria trigona Sternb., with its prominent zigzag furrows, belongs to the Favu- 

 laria section of the genus. The pyriform, or what Weiss has well described as " bell- 

 shaped,"' leaf scars, contracted at top, occupy the narrower, and the expanded base the 

 wider, portion of the rib. Bach leaf scar is separated from its neighbour above and 

 below by a transverse furrow which passes across the whole width of the rib. These 

 transverse furrows are sometimes straight as at fig. 3, or semicircular as at fig. 4, both 

 forms occurring on the same specimen as seen on the enlarged portion given at fig. 2<x. 

 The leaf scars are therefore placed in compartments which gradually slope upwards 

 from the top to the base, and thus come to be situated on little sloping brackets. The 

 line following the basal contour of the leaf scars seen on figs. 3 and 4 represents the 

 elevation of the lower margin of the scar ; the cushion on which it sits is smooth, and 

 free from all ornamentation except for the occurrence of two small ridges which are so 

 slight that they can only be observed on well-preserved examples. 



Like many of the older species, owing to imperfect description some doubt has 

 arisen as to the specific position of Sigillaria trigona Sternb. (non Knorr). The original 

 figure shows the specimen to belong distinctly to the Favularia section of Sigillaria, and 

 has " bell-shaped" leaf scars rounded below and somewhat truncate or rounded above. 



Though the upper margins of the leaf scars are mostly truncate on Sternberg's 

 figure, a few are rounded at top like those shown on the figure given by Weiss # 

 and that shown here. It appears to me therefore that these two specimens, and that 

 figured some years ago under the same name by myself,f from the form of their 

 leaf scars, the zigzag furrows, and the raised- up bracket-like shelf that supports the 

 leaf scar, as well as their smooth ribs, refer them without doubt to the Sigillaria 

 trigona Sternb. 



Sigillaria subornata Weiss should, I think, be united to Sigillaria trigona Sternb. 

 The differences are so slight — the leaf scar a little broader in proportion to its length 

 and the lunate part of the cushion below the scar not so wide ; but these differences can 

 scarcely be considered as of specific value. It seems also highly probable that 

 Sigillaria decorata Weiss belongs to the same plant. The occasional occurrence of a 

 few transverse wrinkles on the cushion below the leaf scar, and the slightly greater 

 distance of the leaf scars apart, are surely not sufficient characters for the creation of a 

 "species," even when we add that the leaf scars are a little broader in proportion to 

 their length. 



The specimens assigned to Sigillaria trigona by Feistmantel appear to have been 



* hoc. cit. t hoc. cit. 



