61' MKSOZOIC FLOKAS OF FNTTFI) STATES. 



1838. Polystichifts M urraijana (Bronjin.) Prcsl in Sternberg: Flora dcr Vorwclt, 



Vol. II, p. 117. 

 1849. Coniopteris Murrayana Brougii.: Tableau, p. 21!. 

 1S56. Hymenophyllites Murrayana (Brongn.) Zign.: Fl. Foss. Form. Oolitb., Vol. 



I, p. 92. 

 1S6.5. Sphenopteriy Munvi/aiia (Brongn.) Zign.: (Xs.serv. sulle Felci Foss. (IcH'Oolitp, 



p. 20. 

 1876. Thyrsopteris Murrayana (Brongn.) Heer: Fl. Foss. Arct., Vol. IV, Pt. II 



(.Tura-Fl. Ostsibiriens), p. 30, pi. i, figs. 4. 41). 4c: ]il. ii, figs. 1, 2a, .) (left 



side of fig.), 4, 4b; pi. viii, fig. lib. 



There are among the Oregon fossils certain imprints that have the 

 aspect of Sphenopteris. They are mostly small and ^•ery poorly pre- 

 served, so that their trne character can not always l.)e made out. The 

 leaf texture seems to have been very thin, so that the imprints of the 

 pinnules are generally faint. The forms agree veiy well with the fern 

 described by Heer as Thyrsopteris Murrayana,'^ and I identify the plant 

 with that species. The pinnules are narrowed at l)ase very much, so 

 as to give them a marked sphenopterid liabit. Above the narrowed 

 base the larger ones are oval or oblong, with oljtuse lobes or teeth that 

 are very obliquely placed. The nerves of these were not seen. The 

 .smaller pinnules, from higher up on the compound pinna, are sutn'hom- 

 boid or subtriangular, with crenate or undulate margins. Their nerves 

 consist of a flexuous midnerve sending off mostly single nerves. The 

 lower anterior one may be forked. No fructification was found. 



PI. VIII, Fig. 4, gives the terminal portion of an ultimate pinna 

 from probably low down on the compound pinna, carrying the larger 

 sized pinnules. Figs. 5 and 6 show magnified pinnules of this. Fig. 7 

 represents the largest specimen found. It shows the rachis quite well, 

 but the pinnules are indistinct. Fig. 8 is an enlarged portion of Fig. 7. 

 Fig. 9 shows fragments of ultimate pinna", probably from high up on 

 the compound pinna, and Figs. 10 and 11 two enlarged j)innules. 

 This plant is quite variable in the form of its pinnules, if indeed all the 

 specimens show forms belonging to the same species. In some cases 

 a portion of the pinnules resembles the lower pinnules of Heer's 

 Dicksonia ardica,'' with undulate margins. Others could l)e selected 

 that resemble more the i)innules of Thyrsopteris Maakiana" of the same 



oFl. Foss. Arct., Vol. IV, Pt. II, pp. 30-31, pi. ii, figs. 1-4. 



fcOp. cil., VmI. V, Pi. H (Bi'itr. z. Foss. Fl. Sibiricns), pp. 12-13, pi. iii, figs. I- 



cOp. cit., Vol. IV, I't. II, pp. 31-32, pi. i, figs. 1-3: pi. ii, figs. ,5, 6. 



