eQ MESOZOIC FLORAS OF UNITED STATES. 



in position on the compound pinna to the sterile ones shown in PL IX, 

 Figs. 3 and 6. PI. X, Fig. 5, gives a portion of one of these pinnules magni- 

 fied two diameters to show the sori. PI. X, Fig. 6, represents, with like 

 enlargement, a sterile pinnule with crenate margins showing the lateral 

 nerves. PI. X, Fig. 7, gives, enlarged, two diameters, a fertile entire 

 pinnule, to show the sorus. 



This fossil is not so abundant as Dicksonia oregonensis, but it is one 

 of the most common ferns, ferns being much less common than cycads. 

 It occurs most commonl}^, and in the best specimens, at locality No. 19, 

 but is also found, not rarely and in good specimens, at locahty No. 18. 

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



Genus CLADOPHLEBIS Brongniart. 

 Cladophlebis vaccensis Ward n. sp. 

 PL X, Figs. 8-12. 



1S96. CladopMehis wMtUensis tenuis var. a Heer. Font.: Am. Journ. ScL, 4th 



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

 1900. Cladophlebis whitbiensis tenuis, var. a Heer? Font.: Twentieth Ann. Rep. 



U. S. Geol. Surv., 1898-99, Pt. II, p. .346.'' 



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

 Cladophlebis xiiMibiensis, 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 bits 

 of ultimate pinnae with attached pinnules. No 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 pinnse so placed as to show that they were once attached to a common 

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

 plant must have attained considerable size and have been probably subar- 

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

 texture, which may perhaps be accounted for by different positions on the 

 compound pinna, or different preservation. The forms graduate into 

 one another in such a way that they can not well be separated. The 

 pinnae are long and slender, with a rigid rachis. The pinnules have a 



n Professor Fontaine does not in his report mention the occurrence of this form in the Oroville beds, and 

 he cites a different figure in Heer's work, but both figures refer to Heer's variety a. In correspondence he 

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



