FLOKA OF THE SHASTA FORMATION. 233 



there is a strong midnerve, which, after the fashion of Pecopteris, is 

 maintained with full strength to near its end. The lateral nerves could 

 not be made out. 



This plant is probably a Gleichenia, a genus that, as Heer has made 

 known, is common in the Kome or Lower Cretaceous of Greenland. 

 Heer has shown that this genus passes up into the Atane or Upper Ci'e- 

 taceous of Greenland. This plant does not seem to be identical with 

 any of the Greenland species. It is more robust and has larger pinnules 

 than any of them. In the absence of fructification it can not be deter- 

 mined with certainty as a Gleichenia, and the generic designation must 

 be left in doubt. Of course, it can not be of much value in determining 

 the age of the strata that contain it. All that can be said of it is that 

 its age might be either Lower or Upper Cretaceous. 



Family MARSILEACEiE. 



Genus SAGENOPTERIS Presl. 



Sagenopteris Mantelli (Dunker) Schenk. 



PI. LXV, Figs. 30-35. 



1846. Cijclojyteris 2fanteUiT)unk.: Monogr. d. Norddeutsch. Wealdenbildung, p. 10, 



pi. ix, figs. 4, 5. 

 1849. Adiantites Mantelli (Dunk.) Brongn.: Tableau, p. 107. 

 1S69. Aneimidium Mantelli (Dunk.) Schimp.: Pal. Veg., Vol. I, p. 486; Atlas, 



pi. xxxi, fig. 13. 

 1871. Sagenopteris Mantelli (Dunk.) Sclienk: Palaeontographica, Vol. XIX, p. 222 



[20], pi. xxxi [x], fig. 5. 

 1894. Glossozamites Klifsteini (Dunk.) Font, in Diller & Stanton: Bull. Geol. Soc. 



Am., Vol. V, p. 4.50. (PI. LXV, Figs. 32, 33.) 

 1894. Sagenopteris Mantelli (Dunk.) Schenk. Font, in Diller & Stanton: Loc. cit. 

 1895 [1896]. Glossozamites Klipsteini (Dunk.) Font, in Stanton: Bull. U. S. Geol. 



Surv., No. 133, p. 15. (PL LXV, Figs. 32, 33.) 

 1895 [1896]. Sagenopteris Mantelli (Dunk.) Schenk. Font, in Stanton: Loc. cit. 



Three imprints of single detached pinnules of a fern were found 

 at locality No. 12." They occur on a fine-grained rock, which pre- 

 serves them well and shows the nervation beautifully. The nervation 

 and shape of the pinnules show that the plant is a Sagenopteris. An 



a One of the specimens from locality No. 9, originally referred by him to Glossozamites Klipsteini, is now 

 placed in this species. It is represented on PI. LXV, Figs. 30-3.5. — L. F. W. 



