OF LOWEIl GREENSAXD PLANTS. 55 



Exact determinations of the casts are impossible. As described 

 by Saporta, the longitudinally running grooves and ridges form 

 very narrow, vertically placed rhomboidal protuberances in 

 which " Les parties saillantes correspondent evidemmcnt ici 

 a 1'embouchure des prolongements medullaires, et les sillons a 

 1'empreinte des faisceaux ligneux qui circon^crivent la moelle." 



Species of various shapes and sixes have been described (see, 

 for example, Lignier, 1895, p. 133). 



The shape and nature of the lenticular ridges vary so much 

 on the same specimen that it is evident that they alone cannot 

 be used as reliable specific characters. 



This pseudo-generic name is, however, useful if employed in 

 a sense parallel with that of the term " Sternbergia" etc. 



V. 761. A Cycadean pith-cast 22 cm. long, in shape a tapering 

 cylinder 7x6 cm. in diameter, tapering to 5 X 3 cm. 

 in diameter. At the narrower end there are internally 

 some fragments which are suggestive of plant fragments, 

 but the specimen, as a whole, is merely a cast in sand- 

 stone without vegetable tissue. Externally the surface 

 is irregularly ridged by the long narrow lenticular or 

 rhomboidal ridges characteristic of the " genus " ; the 

 ridges vary considerably, ranging from 3x 12 mm. to 

 1-5 x 40mm. Between the ridges which stand out 

 in high relief are finer vertical striations. 



The specimen is much smaller than the pith in 

 B. Allchini, and is probably from another, unknown, 

 species. 



Kentish Kag (Lower Greensand) ; near Maidstone. 

 Presented by F. H. Butler, Esq., 1885. 



Another, and similar specimen, found in the Iguanodon Quarry, 

 is now in the Maidstone Museum. 



Sub-class CONIFERALES. 



Stems much branched, tree-forms preponderating. Leaves 

 simple, generally small, and with " xerophytic '' morphology, 

 principally evergreen. Sporophylls, bearing either seeds or 



