LEBQUEREUx.j REVIEW OF CRETACEOUS FLORA. 331 



under the primary ones and in right angle to the midrib, they represent a 

 species of Protophyllum; but the border base of the leaves is truncate, 

 not subpeltate, and by this difference the leaves are rather referable to 

 Credneria, from which, however, they differ by the veins all craspedo- 

 drome as well as their divisions, and by the truncate, not cordate, base 

 of the leaves. I have formerly published a short description of these 

 leaves under the name of Credneria f microphylla. It now seems that 

 by their evident relation to Protophyllum quadratum, they have to be 

 admitted in the generic division, an opinion which may be put at naught 

 by the discovery of specimens pointing to another reference for these 

 leaves. 



We have, also, an addition of three new species to the group of Cre- 

 taceous plants described under the genericuame of Menispermites. In this 

 case, however, there is no difficulty whatever in conformably uniting into 

 a definite group the characters of the leaves which, round, ovate, or oval, 

 with borders entire or undulate, have a common generic affinity, indi- 

 cated by their nervation. In order to more clearly bring into view 

 the relation of the undulate-lobed forms of leaves described in Cret. 

 Flora, PI. XX, figs. 1-4, and PI. XXV, fig. 1, I have represented, PL 

 VII, fig. 3, of this paper, a finely and wholly preserved leaf of Menisper- 

 mites obtusiloba, which, though small, is easily identified with the large 

 one of PL XXV, fig. 1. Now, comparing it to figs. 3 and 4 of the 

 present PL V, the identity of nervation is defined by the five basilar 

 veins, with a thin pair of marginal veinlets underneath ; and by the up- 

 ward direction of the internal lateral veins, which, in fig. 3 of PL VII, 

 ascend to above the middle, pass still higher in the short oval leaf, 

 PL V, fig. 3, and reach nearly to the obtuse point in fig. 4. The subdi- 

 vision of the tertiary veins is in all the leaves of the same type, and the 

 shape of the leaves or their outlines are mere modifications, depending 

 upon the direction of the veins. The leaf, PL VI, fig. 4, is peltate 

 from the point of attachment of the petiole near the middle. The char- 

 acter of the nervation remains, however, the same. It is somewhat ob- 

 scured in the figure, from indistinctness of the specimen. But a larger, 

 finer leaf of the same species, has been more recently procured by Mr. 

 H. G. Towner, of Clay Center, Kansas, another of those proficient ex- 

 plorers whose researches have greatly increased the materials for the 

 elucidation of the Cretaceous flora. This leaf, preserved in its whole 

 is nearly round, with slightly undulate borders, and the nervation 

 is marked by three pairs of primary veins, on each side of the mid 

 rib, and under them by one pair of true marginal veinlets curving on 

 each side toward the borders. Comparing, therefore, this peltate leaf 

 with that of PL V, fig. 3, the position of the petiole is the only notable 

 difference. The peltate form of these round leaves might perhaps sug- 

 gest the fitness of some slight modification in the characters assigned 

 to the genus Pterosper mites, in the Cret. Flora, p. 94, the leaves being 

 here rounded or subcordate at base. The difference is immaterial, and 

 is remarked even upon leaves of the same species of Menispermum of our 

 epoch. These round peltate leaves, for example, are so much like those 

 of living species of Cissampelos, that they rather prove the adaptation 

 of this generic division to all the Cretaceous leaves which I have referred 

 to it. 



The Magnoliacece, an order of the same class, are equally numerously 

 and definitely represented in the North American Cretaceous flora in 

 about the same proportion as they are in that of Europe. Magnolia al- 

 ternans and M. Capellini have been described by Heer in his Phillites 

 du Nebraska ; and since, these two specie's have been recognized over 



