66 MESOZOIC FLORAS OF UNITED STATES. 



in position on the compound piiuia to the sterile ones shown in PI. IX, 

 Figs. 3 and ('•>. PI. X, Fig. 5, gives a portion of one of these piiniules magni- 

 fied two diameters to show the sori. PI. X, Fig. (1, represents, with Hke 

 enlargement, a sterile pinnule with crenate margins showing the lateral 

 nerves. PI. X, Fig. 7, gives, enlarged, two diameters, a fertile entii-(^ 

 pinnide, to show the sorus. 



This fossil is not so abundant as Dickso7iia orcgonensis, l^ut it is on(» 

 of the most common fcM'iis, ferns being mucli less connnon than cycads. 

 It occurs most commonly, and in tlie best specimens, at locality No. 19, 

 but is also foiind, not rarely and in good specimens, at locality Xo. IS. 

 It occurs also at localities Xos. 1, 2, 7, and 16. 



Genus CLADOPHLEBIS Brongniart. 

 Cladophlebis vaccexsis Ward n. sp. 

 PI. X, Figs. S-12. 



LS96. CladopJilehis whitbiensis tenuis var. a Heer. Font.: Am. Joiirn. Sci., 4tli 



.ser., Vol. II, p. 274 (nomon.). 

 1900. PladopJtIehis ivhifhienfiis tenuis, var. a Heer? Font.: Twentieth Ann. Kep. 



r. S. Geol. Surv., 1S9S-99, Pt. II, p. .346." 



A fern of the Cladophlebis type of the general form illustrated in 

 Cladophlebis ivhitbiensis, but not identical with the species of Lindley and 

 Hutton, is found sparingly at some of the Oregon localities. It is always 

 in a very fragmental condition, most of the specimens showing only l)its 

 of ultimate pinnae with attac^hed pinnules. Xo fructification was seen. 

 The constant absence of fructification on ferns of this type is a noteworthy 

 feature. The largest specimens obtained give, at most, portions of ulti- 

 mate pinnae so placed as to show that they were once attached to a common 

 rachis. The size of the rachises and tlieir rigid aspect indicate that the 

 plant must have attained considerable size and have been probably sub;ii'- 

 borescent. There is a considerable variation in the pinnules in shajje and 

 textin-e, which may perhaps l)e accounted foi- by different positions on the 

 compound pinna, or different preservation. The forms graduate into 

 one another in such a way that they can not wc^ll be separated. The 

 piniui' aic long and slendei', with a rigid rachis. The pinnules have a 



"Professor KDntiiiiic docs not in his report incnticjii the iHiiincnci' «if lliis I'uirii in tlir Omvillc beds, and 

 he rites a different li^nrc in Ilcci's work, but l>()tli figures refer to Heer's vnriely ii. In rorrespoiulcnce lie 

 admits that the Oroville and Oregon forms are tiie same. — L. F. W. 



