240 MESOZOIC FLORAS OF FMTED STATES. 



close, apparently luibranched, and at right angles with tlio midril). It 

 seems to have been rather abundant. 



This plant, in the narrow rigid iiiiinules, looks a good deal like 

 Angiopteridium auricuMum Font., of the Lower Potomac of Virginia." 

 Init the nervation is entirely different, while the base of the pinnules nar- 

 rows and is not auriculate. 



PI. LXVI, Fig. 1, gives the terminal portion of one of the narrowest 

 pinnules. Fig. 2 repi-esents a portion, apparently the middle part, of a 

 pinnule. Fig. 3 gives the basal portion, txit not the exact base, of a 

 pinnule. Fig. 4 represents the specimen that was formerh' I'cferred to 

 .4.. nervosum with doubt. 



The plant now in question occurs at localities Nos. 7, 9, 13. 19, and 22. 



Angiopteridium strictixehve Fontaine. 



PI. LXVL Figs. 5-7. 



1889. Angiopteridium sfricfinerve Font.: Potonuu- Flora (Monogr. l-. S. Geol. Surv., 

 Vol. XV), p. 116, pi. xxix, figs. S, 8a, 9. 



Numerous specimens of fragments of pinnules occur at several locali- 

 ties that seem to belong to Angiopteridium strict i nerve Font., of the Lower 

 Potomac formation of Virginia. Some of the specimens are well enough 

 preserved to show their character fairly well, l)ut many are too imperfect 

 to pei-mit positive identification. Those showing recognizable characters 

 are too near the Potomac plant to allow their separation into a species 

 distinct from it. The specimens figured will give a good idea of the best 

 preserved of these forms. The impressions occur only in the form of frag- 

 ments of detached pinnules, none of which are well enough preserved to 

 show the dimensions of the pinnules. It is possible that these various 

 forms, which, in this paper, I have regarded as Angiopteridium, may 

 belong to Nilsonia. They show, however, more of the character of 

 Angiopteridium than of Nilsonia, and no trace of the division of the 

 lamimc of the pinnules into lacinia? was ever seen. The specimens from 

 the Shasta group are not better preserved than those of the Potomac, and 

 do not add anything to our knowledge of this plant. The nervation is 

 rarely visible, as the leaf substance of the pinnules seems to have been 

 thick and coriaceous. The lateral nerves, in the only specimen which 



Monogr. U. S. Geol. Surv., Vol. XV, p. 11.3, pi. vii, figs. 8-11 : pi. xxviii, fi<;. 1. 



