JURASSIC FLORA OF DOUGLAS COUNTY, OREG. 71 



PL XI, Fig. 1, shows the most complete specimen, which is a frag- 

 ment of an ultimate pinna having several pinnules. These are distorted 

 and slickensided. The production of slickensides is not an uncommon 

 feature in the Oregon plants whenever they have a firm resisting texture. 

 The creep of the rock seems often to have taken place along the surface 

 of the plant, polishing it and obliterating the nerves. Fig. 2 shows an 

 enlarged pinnule of this. Fig. 3 depicts a fragment of an ultimate pinna, 

 having one entire pinnule that shows indications of denticulation toward 

 its tip. This pinnule is shown enlarged in Fig. 4. Fig. 5 gives a small 

 fragment of an ultimate pinna with several pinnules of the more slender 

 kind. Fig. 6 shows two fragments of ultimate pinna? with mutilated 

 pinnules that occur toward the termination of the pinna?. Fig. 7 gives 

 a pinnule enlarged to show the nerves. 



The plant is most common, but still rare, at locahty No. 19, and is 

 found also at localities Nos. 1, 2, 7, 9, 12, 14, 17, and 18. 



Cladophlebis haibuenensis (Lindley & Hutton) Brongniart ? 



PI. XI, Figs. 8-10. 



1836. Pecopteris haiburnensis L. & H.: Foss. Fl. Gt. Brit., Vol. Ill, p. 97, pi. 



clxxxviii. 

 1849. Cladophlebis haiburnensis (L. & H.) Brongn.: Tableau, p. 105. 

 1865. Pteris haiburnensis (L. & H.) Ett.: Farnkriiuter der Jetztwelt, p. 114. 

 1869. Aleihopteris haiburnensis (L. & H.) Schimp.: Pal. Veg., Vol. I, p. 565. 

 1890. Thinnjeldia haiburnensis (L. & H.) Rac: Bull. Int. Acad. Sci. de Cracovie, 



Janvier, 1890, p. -32. 

 A single specimen of a fern of marked Cladophlebis type was found 

 at locality No. 1. It seems different from any of the other Cladophlebis 

 of the Oregon Jurassic. The specimen shows only a fragment of an ulti- 

 mate pinna carrying several pinnules. These agree so well with the fern 

 called by Lindley and Hutton Pecopteris haiburnensis " that it is most 

 probably the same species. The English fern is clearly a Cladophlebis 

 and not a Pecopteris. The amount of material, however, is not sufficient 

 to justify a positive identification. It may possibly be an abnormal form of 

 Cladophlebis vaccensis, but the entire aspect of the plant is different from 

 that fern. The rachis is slender. The pinnules are slightly falcate and 

 attached by the entire, somewhat widened base. They are in form 



«Foss. Fl. Gt. Brit., Vol. HI, pp. 97-98, pi. clxxxviii. 



