JURASSIC FLORA OF DOUGLAS COUNTY, OREO. 97 



strength from near their bases to their ends. The.y are distinctl}" defined, 

 but slender. 



PL XVIII, Fig. 1, shows the largest specimen seen, in which the 

 leaflets are considerably distorted, none being entire. The narrowing 

 above the bases of the leaflets, due to distortion, causes the bases to 

 appear too wide. Fig. 2 gives leaflets of the smallest size, they being 

 shown on only one side of the rachis. Fig. 3 shows four of the seg- 

 ments enlarged. Fig. 4 gives a fragment of a leaf with the longest 

 leaflets seen. Fig. 6 is an enlargement of one of them. Most of them 

 are narrower than common and are distorted in width from pressure, 

 but some seem originally to have been wider than the rest. Fig. 5 

 gives parts of some of the widest leaflets in which the base and apex 

 are not preserved. 



The plant occurs rarely at locahties Nos. 2, 7, and 19. 



Genus PTEROPHYLLUM Brongniart. 



Pterophyllum Nathorsti Schenk. 



PI. XIX, Figs. 1-6. 



1883. Pterophyllum Nathorsti Schenk: Pflanliche Versteinerungen aus Richthofen's 

 Clrna, Vol. IV, p. 261, pi. liii, figs. 5, 7. 



Schenk has described with the name Pterophyllum Nathorsti a 

 fossil from the Jurassic of China that agrees closely with an important 

 plant in the Oregon beds. The plant is exceedingly abundant at some 

 of the localities and the large number of specimens obtained give a 

 good idea of its character. The leaf was evidently quite long in propor- 

 tion to its width, but in all cases it was small. Most of the Oregon forms 

 are rather smaller than the two given by Schenk, but specimens can 

 be selected that equal these in size. The leaves were linear elliptical 

 in shape, wider in the central portion, and, from the shortening of the 

 segments, narrowing toward the base and apex. The longest fragment 

 seen is 85 mm. long, without showing the base and tip. In this the 

 longest segments are in the upper end, showing that this was near the 

 middle of the leaf. These segments are about 7 mm. long, so that the 

 entire leaf was about 17 cm. long and 15 mm. wide in its middle portion. 

 The leaves apparently had a petiole. The leaf substance was pretty 



MON XL VIII — 05 7 



