588 



CYCADOPHYTAN FRONDS 



[CH. 



the edge of the rachis with a cuneate base slightly decurrent 

 below and a broadly rounded apex; the veins dichotomise once 

 or twice as they diverge from the 

 narrow base (fig. 628). The pinnae 

 resemble the leaflets of Noeggemthia 

 foliosa Sternb. and are similar in shape 

 to those of the Jurassic species Spheno- 

 zamites Geylerianus Zig. 



Sphenozamites Belli Seward. 



This Middle Jurassic species from 

 Stonesfield 1 is founded on detached 

 pinnae possibly identical with a speci- 

 men figured by Buckman as INaiadea 

 obtusa 2 . The pinnae are wedge-shaped, 

 tapering gradually to an acute apex 

 and attached by a narrow base: the 

 leaflet shown in fig. 629 is 9 cm. long 

 and more divergent than in some 

 referred to the genus Podozamites. 



FIG. 628. Sphenozamites Rochei. 

 (After Renault; nat. size.) 



the veins are numerous 

 leaves of similar form 

 With this species may 



FIG. 629. Sphenozamites Belli. (Oxford Museum; nat. size.) 



be compared several Italian Jurassic specimens described by 

 Zigno 3 as four distinct species but more appropriately assigned 

 to a single type S. Geylerianus. An examination of Zigno's 

 fronds in the Padua Museum, which he named S. Rossii, leads 



1 Seward (04) B. p. 119, PL xi. fig. 4, text-fig. 12. 



2 Buckman (45) PI. I. fig. 2. 



3 Zigno (85) Pis. xxxix., XL. 



