15 



The specimens which have been named Ptilophyllum oligoneurum 

 are iindoubtedlj" fronds of the Williamsonia j)ecten type, from which 

 it is impossible to distinguish them. 



In the Queensland examples the fronds are pinnate, long and 

 narrow, gradually narrowing towards both base and apex ; they 

 attain a length of as much as 15 cm., and a breadth up to 2 cm. 

 The pinnae are closely set, attached to the rachis at a wide angle 

 and are inserted on the upper surface ; they have a pointed apex 

 and the upper edge is somewhat auriculate near the base ; they 

 reach a length of a little over 1 cm. and are 1*5 to 2 mm. broad. 

 The veins are slightly divergent and few in number, there being about 

 4 on each pinna. 



Etheridge^^ questions whether Tenison-Woods was right in 

 distinguishing this species from P. acutifolium, Morris, to which 

 it had been referred by Kidston. 



All the specimens from Queensland are of the small type of 

 Williarnsonia pecten frond figured by Seward from the Jurassic 

 flora of Yorkshire.-^ 



The majority of the specimens come from a single locality, 

 and in the specimens collected there are no traces of Willimnsonia 

 flowers. 



Locality: — [Walloon Series): Stewart's Ck., Stanwell (F 73). 



Figured sjiecimen : The original of Plate 5, fig. 6, is specimen 

 F 78 in the collection of the Queensland Geological Surve3^ 



CYCADOPHYTA INCERTM SEDIS. 



PTEROPHYLLUM. 



The majority of the cycad remains from the Lower Mesozoic of 

 Queensland seem to be referable to this genus. The separation 

 of Pterophyllum and Nilssonia depends largely on the accurate 

 determination of the manner of attachment of the pinnae to the 

 rachis, this being lateral in Pterophyllum and on the upper surface in 

 Nilssonia. When viewed from the lower side the appearance of the 

 genera is essentially the same, but their appearance on the upper 

 side is quite different. It seems justifiable to be certain that the 

 majority of the Australian forms here referred to are Pterophyllum 

 since a comparatively large number of specimens is available, and 

 it would hardly be expected that they could all be views of the 



" Etheridge (02), p. 382. *' Seward (00), t. 3, fig. 5 ; text-fig. 34. 



