456 



GENERA INCERTAE SEDIS 



[CH. 



gradually tapered towards the apex; the veins are slightly more 

 than 1 mm. apart and converge at each 

 end of the lamina. The species re- 

 sembles P. lanceolatus var. latifolius 

 figured by Schenk 1 from China. 



Podozamites Griesbachi' 2 is a Jurassic 

 species from Afghanistan similar in the 

 shape and size of the leaves to the other 

 two species; it has a coarser venation 

 than P. Reinii but the venation is still 

 coarser in P. stones fieldensis . A similar 

 form of leaf is figured by Velenovsky 3 

 from the Lower Cretaceous of Bohemia 

 as P. striatus. 



FIG. 814. Podozamites Reinii. 

 (After Geyler; J nat. size.) 



Podozamites Kidstoni Etheridge. 



In this type 4 , usually represented by detached leaves, the 

 lamina is smaller than in other species, short and broad with a 

 blunt apex and abruptly contracted at the base. The species is 

 recorded from Afghanistan & and similar leaves are figured by 

 Chapman 6 from Jurassic rocks in Victoria, Australia. Etheridge's 

 type-specimen is from the Burrum Coal Measures ('? Triassic) oi 

 Queensland. This form of leaf agrees closely with some of 

 Fontaine's Potomac species of Nageiopsis, e.g. N. obtusa and N. 

 heterophylla 7 , and a similar though not identical form is described 

 by Nathorst 8 from the Khaetic of Sweden as P. ovalis, distinguished 

 by its broadly rounded and mucronate apex. 



NAGEIOPSIS. Fontaine. 



This genus was established 9 for vegetative shoots abundantly 

 represented in the Potomac flora many of which closely resemble 

 Podozamites, though differing in their branched habit and in the 

 veins being less convergent in the apical region of the lamina. 



1 Schenk (83) A. PL XLIX. figs. 4 b, 5. 



2 Seward (12) p. 36, PL iv. fig. 58; PL vi. fig. 79. 



3 Velenovsky (85) B. PL n. fig. 8. 



4 Jack and Etheridge (92) B. p. 317, PL xvm. figs. 6, 7. 



* Seward (12) PL iv. fig. 39. 6 Chapman (09) PL xvm. 



7 Fontaine (89) B. Pis. LXXXIV., LXXXV. 



8 Nathorst (78) B. PL xm. fig. 5. 9 Fontaine (89) B. p. 194. 



.shed 



