198 



WILLIAMSONIA. 



39,284. PL III. Figs. 4 and 5. 



Fig. 4 represents a small piece of a frond which, occurs out 

 a large slah of rock in association with between thirty and forty 

 other examples, of which the pinna3 vary considerably in size and 

 shape. The upper edge of the base of the long and narrow pinnae 

 shown in Fig. 4 is slightly lobed, but in some of the pinna? the 

 auriculate base is much more evident. The veins are somewhat 

 spreading at the base, and inclined at an oblique angle to the upper 

 margin of the pinnae, but their general course is parallel to the 

 long axis of the segments. Cf. Pterophyllum rigidum as figured 

 by Andrae, 1 and Text-fig. 31. 



FIG. 33. The base of a frond of Williamsoma pecten (Phill.). 

 No. 13,515. (Nat. size.) 



In Fig. 5, PI. III. we have a form of frond similar to that 

 shown in Fig. 1, but this specimen no doubt represents a young 

 leaf which is not fully expanded, and in which the segments 

 are slightly imbricate in their arrangement, as in the fronds of 

 many recent Cycads. Similar examples of young and narrow 

 fronds, showing an imbricate vernation, may be seen in the 

 Museum of Practical Geology, Jermyn Street, London, and in 

 the Newcastle Collection. Some of the fronds associated with 

 the figured specimens are of the type shown in Fig. 2 ; others are 



1 Andrae (53), pi. xi. fig. 1. 



