Xl] GEOLOGICAL RANGE. 413 



certain points of contact with Sphenophyllum on the one hand 

 and with Calamites on the other. This important question will 

 be dealt with after we have given an account of Gheirostrobus\ 

 To put the matter shortly, Sphenophyllum agrees with some 

 Lycopodinous plants in its anatomical features; with the 

 Equisetales it is connected by the verticillate disposition of the 

 leaves, and some of the forms of Sphenophyllum strobili present 

 features which also point to Equisetinous affinities. 



In his Presidential address to the Botanical Section at the 

 British Association Meeting of 1896 Scott "^ thus refers to the 

 Sphenophyllums : — " We may hazard the guess that this in- 

 teresting group may have been derived from some unknown 

 form lying at the root of both Calamites and Lycopods. The 

 existence of the Sphenophyllae certainly suggests the proba- 

 bility of a common origin for these two series." The result of 

 the subsequent investigation of the new cone Cheirostrohus 

 amply justifies this opinion as to the position of Sphenophyllum. 



It is probable that Sphenophyllum lived during the 

 Devonian period, but the unsatisfactory specimens on which 

 Dawson has founded a species of this age, S. antiquum^, can 

 hardly be said to afford positive evidence of the Pre-Carboni- 

 ferous existence of the genus. From the Culm rocks and 

 other strata older than the Coal-Measures, we have such species 

 as S. insigne (Will), Sphenophyllostachys Romeri (Solms- 

 Laubach), and Sphenophyllum tener^rimum, Ett.** while S. emar- 

 f/inatum^, Brongn. occurs in the Upper Coal-Measures and in the 

 Transition rocks. S. cuneifolium^ (Stemb.) has been recorded 

 from the Transition, Middle and Lower Coal-Measures. Spheno- 

 phyllum oblongtfolium, Germ.^ is recorded from Lower Permian 

 rocks, as is. also S. Thoni^ Mahr. 



The comparison which has naturally been drawn between 

 Sphenophyllum with its slender stems bearing occasionally 

 dimorphic leaves, and water-plants is not, I believe, supported 

 by the facts of anatomy or external characters. The entire 

 and finely-dissected leaves do not exhibit that regularity of 



1 Scott (97). '^ Scott (OO'), p. 16. 



3 Dawson (61), p. 10, fig. 7. * Kidston (94), p. 260. 



5 Kidston (94), p. 250. « Sterzel (98), p. 148. ' Zeillor (94), p. 179. 



