XLn] DICEANOPHYLLTJM 93 



a thickened lower margin extending horizontally a short distance 

 on either side of the petiole and presenting the appearance of 

 being formed by the bifurcation of the summit of the leaf-stalk 

 at right-angles to its long axis. The lamina is irregularly dissected, 

 but from the pubhshed figures it is difficult to distinguish between 

 original lobing and divisions due to tearing. The dichotomously 

 branched veins spread through the lamina from the centre of the 

 base and are given off at a wide angle from the thick lower edge of 

 the lamina. In Saportaea grandifolia the petiole has a length of 

 10 cm. and the rest of the incomplete leaf is 8 cm. long and 9-5 cm. 

 broad : the second species S. salishwioides is represented by por- 

 tions of similar but smaller leaves with a slender petiole. While 

 comparing these fossils with Ginkgo the authors of the genus call 

 attention to the peculiar features of the lower edge of the lamina 

 and of the venation. The general resemblance in leaf- form between 

 Saportaea and Ginkgo is hardly sufficient to warrant any definite 

 statement as to relationship and this Permian genus must for the 

 present be relegated to the class of Plantae incertae sedis. 



DICRANOPHYLLUM. Grand'Bury. 



This genus was first described by Grand'Eury^ who, before the 

 pubhcation of the full description of the type-species, suggested 

 the substitution of Eotaxites for Dicranophyllum^ the name finally 

 adopted*. The genus is fairly abundant in the Upper Carboniferous 

 rocks of France and occurs also in Portugal, Belgium, and Germany ; 

 it has recently been recorded from England and is represented in 

 the Coal Measures of the United States and Canada. It occurs in 

 Permian strata in Germany but with a few exceptions the genus 

 is characteristic of Stephanian beds. 



The systematic position of Dicranophyllum is far from settled ; 

 by many authors it is considered to be a member of the Ginkgoales 

 and is compared also with the Taxeae. In all probability the 

 genus is allied to the Cordaitales, though, as stated in the case of 

 Trichopitys, it cannot be assigned to a definite position in the 

 Gymnosperms until we possess fuller information with regard to 

 the reproductive organs or the anatomical structure. 



1 Compt. Rend. Vol. lxxx. p. 1021, 1875. ^ SiKpavos, two-pointed. 



3 Grand'Eury (77) A. p. 272, Pis. xiv., xxx. 



