290 PAGIOPHTLLTJM. 



identical with one of the American forms figured by Fontaine ; the 

 Potomac species Nageiopsis miorophylla, Font., N. descrescens, Font., 

 and others ^ are very similar to the "Whitby fragments. 



Text-fig. 51. Whitby Museum, 'No. 2503. 



This fragment shows clearly the form and disposition of the 

 broadly linear leaves, 1-2-1 -5 cm. in length; the axis of the 

 specimen has a length of 3 cm. 



Another specimen (2377) in the "Whitby Collection consists of 

 several pieces of branches similar to that shown in the figure ; 

 in one fragment the axis of the shoot is branched, as in the 

 "Wealden specimen already referred to. Each leaf is traversed by 

 several parallel veins, which converge slightly towards the point 

 of attachment of the narrow leaf -base. 



PCOMFEE^ IXCEET^ SEDIS. 



Genus PAGIOPHYLLUM, Heer. 



[Secc. Trab. Geol. Portugal, p. 11, 1881.] 



Saporta '' and other authors incline to the view that the species 

 included in Heer's genus should be regarded as members of the 

 Araucarinese, but this opinion is based very largely on a similarity 

 of vegetative structures, which does not receive decisive support 

 from such evidence as is afforded by the more important 

 reproductive structures. While recognizing the possibility of 

 a close relationship between this widespread Mesozoic genus and 

 Arauoaria, it is safer to regard Pagiophyllum as one of the 

 numerous extinct forms which cannot be safely included in any 

 particular family of the ConiferoB. It is difficult to draw 

 a satisfactory line between the genera Pcogiophyllum and Elatides, 

 and perhaps the English Jurassic species, which I have placed 

 in the former genus, should rather be referred to Heer's genus 

 JSlatides, the name under which ISTathorst' has recently included the 

 plant described by Lindley & Hutton as Lyoopodites WilUamsonis. 



' Fontaine (89), pis. Ixxyii., Ixxxvi., etc. 

 ■^ Sapoi-ta (84), p. 373. 

 3 Xathorst (97), p. 34. 



