70 MKSOZOIC i^LORAS OF UNITED STATES. 



less than usual of the Cladophelns charactei'. Tlic lateral nerves are 

 strong and veiy distinct. They ai'e given off at an angle of about 45°, 

 and fork neai' their insertion. The hranehes divei'ge strongly, then become 

 parallel and turn outward to meet the margin under a large angle. One 

 of the Ijranches may fork again, l:)ut they are mostly single. Some of the 

 pinnules appear denticulate near their tips, but this may be due to lacera- 

 tion and imperfect preservation. The larger pinnules are about 24 mm. 

 long and (i mm. wide. 



This fine fern seems identical with the Pecopteris insignis of Lindley 

 and Hutton." The larger pinnules are exactly like the form given bj^ 

 Phillips for this species. '' Seward, in his paper on the Jurassic Plants in 

 the Manchester IMuseum, identifies this and a number of other species 

 with Cladophlebis denticulata (Brongn.) Nath., and on pi. iv he gives a 

 figure of C. denticulata that agrees well with the Oregon plant. The pin- 

 nules of this plant resemble so much those of the fine Danceopsis Storrsii, 

 described farther on, that I am inclined to think that they are the sterile 

 forms of that fossil. 



Lindley and Hutton described from the Yorkshire Oolite a fertile 

 fern under the name Pecopteris undans,'^ giving a fructification like that 

 of Dameopsis Storrsii. Seward, in the paper above quoted, p. 19, states 

 that Xathorst had suggested that Pecopteris undans may be the fertile 

 pinna of CUidophlehis denticidata, and further that an examination of sev- 

 eral examples of Pecopteris undans enabled him to confirm Nathorst's 

 opinion. The fructification, as given by Lindley and Hutton in the figure 

 of f . undans, is strikingly like that of Danceopsis Storrsii and would make 

 the plant a Dana^opsis. Seward gives no reason foi' connecting Clado- 

 phlebis denticulata with this plant. There is no connection between 

 Danceopsis Storrsii and the Oregon form referred to Cladopldchis denticu- 

 lata, hence the latter nmst remain in the genus Cladophlebis. It is, 

 however, significant to find that in both these cases the idea is suggested 

 that the fructification of this Cladophlebis is that of Danseopsis. It 

 should l)e stated that Seward does not in his remarks indicate the res(>m- 

 blance of the fructification of Pecopteris undans to that of Danaeopsis. 



"Foss. Fl. Gt. Brit., Vol. II, p. 09, pi. cvi. 



'' PliiUips, (ii'()l()<;y i)f Yorkshire, .3tl ed., p. 2()(), li{;ii. 17 



<Foss. Fl. Gt. IJrit., Vol. II, pp. 10.3-104, pi. cx.\. 



