108 ■\VILLIAMSONIA. 



■without speaking definitely as to its systematic position ; th.e 

 «peoimen of which, a drawing is given in the Fossil Flora 

 (pi. clxxii.) is the same which Sternberg described as Poh/podiolites 

 pectiniformis. 



The original of Phillips' figure (Diag. xxx. fig. 2, Geol. Oxford) 

 is a larger and more perfect specimen than the drawing suggests ; 

 it has been figured also by Sternberg.^ 



In 1823 Brongniart described a Stonesfield fossil as Fucoides 

 {Caulerpa) pennatula;'' in his Histoire (1828)' he says that his 

 original determination was based on a drawing sent to him by 

 Buokland, and adds that an examination of the specimens in the 

 Oxford Museum convinced him that they were Cycadean fronds 

 identical with the example figured by Sternberg as Polypodiolites 

 pectiniformis. The Oxford Collection includes several examples of 

 WilUamsonia peeten from Stonesfield in addition to those already 

 referred to ; one of them is a portion of a frond 22-5 cm. long and 

 about 4 cm. broad, with narrow and contiguous pinnse bearing a 

 very close resemblance to Feistmantel's Indian fronds which it 

 has been customary to include in a distinct genus, Ptilophyllum. 

 I have elsewhere given reasons for uniting some of the Indian 

 species of Ptilophyllum with WilUamsonia peeten.'^ 



Specimens of WilUamsonia peeten from Stonesfield are represented 

 also in the Sedgwick Museum, Cambridge, and in other collections. 



V. 3361, PI. IX. Fig. 6. 



A piece of a frond 9 cm. long and 2*5 cm. broad. The axis is 

 represented by a deep groove. The pinnae are crowded and slightly 

 imbricate, with blunt apices, and traversed by 8-10 parallel veins. 



Stonesfield. Brodie Coll. 



52,868. PI. XII. Fig. 8. 



A portion of a narrow and possibly a young fi'ond, very similar to 

 specimens from the Yorkshire coast.^ 



Stamford (Inferior Oolite). Sharp Coll. 



' Sternberg (23), pi. xxxiii. fig. 1. 



■^ Brongniart (23), p. 313, pi. xxi. fig. 3. 



3 Brongniart (28), p. 49. 



* Seward (00), p. 192 ; (03'-). 



5 Seward (00), pi. iii. fig. 1. 



