94 CLADOPHLEBIS. 



between this Potomac species and the English specimens is cer- 

 tainly striking ; in the former there seems to be no sign of any 

 denticulate character in the pinnules ; on the whole they ought, 

 I think, as Fontaine has decided, to be kept separate. Finally, 

 C. inclinata, Font., 1 resembles some portions of C. Albertsii fronds. 



It should be remembered that the material included in the 

 British Museum Collection which I have referred to C. Albertsii, 

 under a modified definition, is much more perfect than that at the 

 disposal of previous writers ; it is not surprising, therefore, that 

 some of the species which have been founded on isolated fragments 

 are brought into close connection with one another by the exami- 

 nation of the fronds of the English specimens. 



It would not be difficult to point to various specimens from 

 different parts of the world which can with difficulty be separated 

 from the present species; this applies to such forms as are repre- 

 sented by Cladophlebis Whitbyensis, Brong., and others. The 

 figures given by Oldham and Morris of Pecopteris (Alethopterit) 

 Indica, 0. and M., 2 appear to be very similar indeed to some of our 

 specimens of C. Albertsii', and if such a pinna as the one figured 

 in pi. xxvii. fig. 3 were found in European Wealden rocks I 

 should have no hesitation in referring it to Dunker's species. 

 Oldham and Morris recognized the great difficulty in attempting 

 to separate such forms as Pecopteris Whitbyensis, P. dentata, Go'pp., 

 P. nebbensis, Brong., and several other similar species. 3 Another 

 example of this close resemblance between portions of sterile 

 fronds, which come under the provisional designation Cladophlebis, 

 is afforded by the fragment figured by Saporta 4 as C. Rosserti, 

 Schenk ; this agrees closely with C. Albertsii. Sphenopteris 

 flabellifolia, var. erecta, Ten. -Woods, seems to be very like C. 

 Albertsii, if not identical. A specimen in the British Museum 

 (41417) from the Douglas River Coal-seam in Tasmania is 

 probably identical with this Wealden species of Cladophlebis. 

 Possibly, as suggested in the synonomy, Asplenium nebbense 

 (Brong.), figured by Bartholni from the Jurassic rocks of Born- 

 holm, may be regarded as a fragment of Cladophlebis Albertsii. 



The specimens from the English Wealden beds show no traces 



1 Potomac Flora, p. 76, pi. x. figs. 3-4 ; pi. xx. fig. 7. 



2 Foss. Fl. Gond. vol. i. ser. ii. pt. i. 1863, p. 47, pi. xxvii. 



3 Ibid. p. 48. 



* Pal. Franq. vol. i. 1873, pi. xxxi. fig. 4. 



