138 



CLADOPHLEBIS. 



genera and families of recent ferns; an identification of fossil 

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

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

 to be the most prohable 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 Peeopteris wMtbiensis, L. & H., as a synonym> 

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

 of the Fossil Flora (P. whithiensis) have entire margins, but are- 

 otherwise identical with those of Nev/ropteris ligata of Lindley & 

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

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

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

 agrees exactly with the frond illustrated under this name by the 

 authors of the Fossil Flora. I believe that P. dentioulata of" 

 Brongniart and P. whitliensis 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. 



Brongniaxt's figure of Pecopteris Phillipsii, drawn from a specimen 

 contributed by Williamson from Cayton, near Scarborough, presents 

 a fairly close agreement with some forms of Cladophlehis denticulatUf 

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

 Fig. 4 ; this specimen has been labelled by Bean Pecopteri» 

 Phillipsii, Brongn. The somewhat narrower form of the pinnules 

 and other slight differences between this form of frond and the- 

 more typical C. dentioulata 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 Cladophlelis 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 whithiensis- 

 would lead to considerable confusion, as different authors hav& 

 applied this designation to fern fronds belonging to distinct genera 

 and different families. 



