362 Systematic Paleontology 



This species is based upon considerable incomplete material from 

 widely separated localities which afforded the basis for two different 

 species of Fontaine, but which seem to be identical and markedly 

 different from the* types to which they were referred. The forms 

 referred to Angiopteridium strictinerve are from Virginia and Cali- 

 fornia while those described as a new species of Sapindopsis, which 

 genus they do not resemble in the remotest degree, are from California. 

 The former are quite different from the type of that species, being 

 smaller and less elongate, with closer, mostly simple veins, and with the 

 rachis prominent below and masked above by the lamina of the frond. 

 The latter correspond with the others in outline and venation, differing 

 in outline, venation, and in the character of the rachis from Sapindopsis. 



The present species, which is confined to the Potomac Group and the 

 Shasta of California, where it occurs in both the Knoxville and the 

 Horsetown beds, is suggestive of the species from the N'eocomian of 

 Japan which Yokoyama ^ identifies as Nilsonia Jolinstrupi Heer. It may 

 also be compared with the rather widespread Wealden species Nilsonia 

 scJiaumburgensis (Dunker) Nathorst, which has also been recorded from 

 Japan and from the Kootanie of Montana. 



Occurrence. — Patuxent Fokmation ( ?) . Chinkapin Hollow, Vir- 

 ginia. 



Collection. — TJ. S. National Museum. 



NiLSOZSTLA. DENSINERVE (Fontaine) Berry- 

 Plates LVII, LVIII 



Platypterigium densinerve Fontaine, 1890, Mon. U. S. Geol. Survey, vol. xv, 



1889, p. 169, pi, XXX, fig. 8; pi. xxxl, figs. 1-4; pi. xxxii, figs. 1, 2; pi. 



xxxiii, fig. 1; pi. xxxiv, fig. 1; pi. xxxv, figs. 1, 2. 

 Platypterigium Rogersianum Fontaine, 1890, Mon. U. S. Geol. Surv., vol. 



XV, 1889, p. 171, pi. xxxi, fig. 2; pi. xxxiii, fig. 2; pi. xxxiv, fig. 2. 

 Platypterygium densinerve Fontaine, 1906, in Ward, Mon. U. S. Geol. 



Survey, vol. xlviii, 1905, p. 521, pi. cxii, fig. 8. 

 Nilsonia densinerve Berry, 1910, Proc. U. S. Natl. Mus., vol. xxxviii, p. 638. 



^Yokoyama, Jour. Imp. Coll. Sci., Japan, vol. vii, 1895, p. 226, pi. xxv, figs. 

 1-4. 



