JURASSIC FLORA OF DOUGLAS COUNTY, OREG. 79 



In the description of this species given in the Twentieth Annual Report 

 of the United States Geological Survey, Pt. II (p. 348), the statement, 

 by misprint, is made that "the fronds vary in length from 1-4 cm." 

 For "length" read width. The fragments seen indicate that some of 

 the Oregon leaves may have reached the width of 5 cm. 



PI. XII, Fig. 12, shows the upper part of one of the larger leaves, 

 and Fig. 13 a portion of this enlarged. Fig. 14 represents the basal 

 portion of one of the narrower leaves that was evidently quite long. 

 It is distorted by pressure. Fig. 15 gives the middle portion of one 

 of the leaves of medium size. This, too, is distorted. Fig. 16 shows 

 a leaf nearly entire, and Fig. 17 a portion of this enlarged. 



The plant is most common at locality No. 2, where it is quite abun- 

 dant. It is also found at localities Nos. 1, 7, 14, and 19. 

 TiENioPTERis MAJOR Liiidlej and Hutton. 

 PI. XIII, Figs. 1-3. 



1833. Tieniopteris major L. & H.: Foss. Fl. Gt. Brit., Vol. II, p. 31, pi. xcii. 



1836. Aspidites Williamsonis Gopp.: Syst. Fil. Foss., p. 353. 



1843. Pterozamites major (L. & H.) Fr. Br. in Minister: Beitr. z. Petrefacten-Kunde, 



Vol. II, Heft VI, p. 29. 

 1865. Txniopteris Williamsonis (Gopp.) Zign.: Osserv. sulle Felci Foss. dell' Oolite, 



p. 39. 

 1869. Macrotasniopteris major (L. & H.) Schimp.: Pal. Veg., Vol. I, p. 610. 



Lindley and Hutton have described with the name Tceniopteris 

 major " a fern that agrees so well with one found in the Oregon Jurassic 

 that there can be no doubt that it is the same. The dimensions of 

 the leaf and the size of the midrib in the two are the same, but there 

 is some difference in the lateral nerves. In the figure given by Lindley 

 and Hutton of the English plant these nerves are represented as very 

 slender, and not varying in thickness from their insertions to their 

 ends. They are also given as forking very copiously, especially at 

 the margin of the leaves. In the Oregon fossil the lateral nerves are 

 decidedly stronger near their bases, where they are attached to the 

 midrib, than they are near the margin of the leaf. Owing to the great 

 thickness of the leaf substance, and the fact that the plant is generally 

 slickensided, it is difficult to see them distinctly. This is especially 

 true of the parts near the margin of the leaves, for they have suffered 



a Foss. Fl. Gt. Brit., Vol. II, pp. 31-32, pi. xcii. 



