240 MESOZOIC FLORAS OF UNITED STATES. 



close, apparently unbranched, and at right angles with the midrib. It 

 seems to have been rather abundant. 



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

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

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

 rows and is not auriculate. 



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

 pinnules. Fig. 2 represents a portion, apparently the middle part, of a 

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

 pinnule. Fig. 4 represents the specimen that was formerly referred to 

 A. nervosum with doubt. 



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



Angiopteridium strictinerve Fontaine. 



PL LXVI, Figs. 5-7. 



1889. Angiopteridiu7n strictinerve Font.: Potomac Flora (Monogr. U. S. Geol. Surv., 

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



Numerous specimens of fragments of pinnules occur at several locali- 

 ties that seem to belong to Angiopteridium strictinerve 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 permit 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 

 laminae of the pinnules into lacinite 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. 113, pi. vii, figs. 8-11; pi. xxviii, fig. 1. 



