138 CLADOPHLEBIS. 



genera and families of recent ferns; an identification of fossil 

 fragments of this type without the evidence of fertile pinnae is- 

 a hopeless task. All that we can do, is to point out what appear 

 to be the most probable cases of identity among the numerous 

 examples of fronds of this type in the English Jurassic strata 

 and in beds of approximately the same age in other countries. 



Zigno includes Pecopteris whitbiensis, L. & EL, as a synonym 

 of P. ligata, Phill. The pinnules as represented in pi. cxxxiv. 

 of the Fossil Flora (P. whitbiensis] have entire margins, but are 

 otherwise identical with those of Neuropteris ligata of Lindley & 

 Hutton. The small portion of a pinna figured in PL XV. Fig. 5 

 of this volume is taken from a fairly large specimen of a frond 

 which is labelled by Bean Pecopteris whitbiensis (No. 39,240), and 

 agrees exactly with the frond illustrated under this name by the 

 authors of the Fossil Flora. I believe that P. denticulata of 

 Brongniart and P. whitbiensis of Lindley & Hutton are specifically 

 identical. 



The specimens figured by Lindley & Hutton as Pecopteris dentata 

 have been incorporated under the species Todites Williamsoni, as 

 a result of the examination of the type-specimens. 



Brongniart' s figure of Pecopteris Phillipsii t drawn from a specimen 

 contributed by Williamson from Cayton, near Scarborough, presents 

 a fairly close agreement with some forms of Cladophlebis denticulata,. 

 and is clearly identical with the example represented in PL XX. 

 Fig. 4 ; this specimen has been labelled by Bean Pecopteris 

 Phillipsii, Brongn. The somewhat narrower form of the pinnules 

 and other slight differences between this form of frond and the 

 more typical C. denticulata are, I believe, of no importance ; they 

 rather suggest that the frond had been exposed to the sun some 

 time and slightly contracted or shrivelled before it was embedded 

 in the mud. 



Enough has been said to indicate the confused state of the 

 synonymy of these Cladophlebis fronds. 



Brongniart's specific name denticulata is adopted as having 

 been published earlier than C. insignis of Lindley & Hutton, and 

 as denoting a type of frond of common occurrence in collections 

 of Yorkshire Oolite plants. To use the specific name whitbiensis 

 would lead to considerable confusion, as different authors have- 

 applied this designation to fern fronds belonging to distinct genera. 

 and different families. 



