FLORA OF THE DAKOTA GROUP. 55 



they are effaced near the borders. The secondary veins, two pairs, are 

 alternate, distant, much curved in ascending high toward the borders, the 

 lowest joining the medial nerve above the middle of the leaves, while from 

 the base downward to the fork of the primary nerves the area is filled by 

 a series of thin nervilles derived at right angles from the midrib. The 

 lateral primary nerves are divided in numerous lateral branches, 5, 6 

 curving in passing outside toward the margins, where they become effaced. 



This leaf is well enough represented by the figure in "IT. S. Geol. 

 Rep.," vi, made from a specimen whose borders had been ground from the 

 middle downward and rounded to the point of union of the lateral nerves 

 in such a way that the relative position of the nerves to the base of the 

 leaf could not be ascertained, nor the disposition of the borders in joining 

 the petiole. The size of the newly-found leaf is larger and its broadest 

 point is close toward the base. 



Excepting this last character, and its thinner venation, the Cretaceous 

 leaves are very similar to those described from the Mississippi Eocene as 

 C. Mississvppiense, lately identified with numerous leaves of C. affine, of the 

 Laramie and Carbon Groups. These are of about the same size, but 

 all are rather oval-acuminate than ovate, the broadest part being in the 

 middle. In C. polymorphum, to which both the Cretaceous and Tertiary 

 species have been compared, the leaves are broader above the middle. 



The specimen figured in ''U. S. Geol. Rep.," vi, I. c, came from near 

 Ellsworth, Kansas. That of Nanaimo was, as far as I can recollect, in a 

 still more imperfect state of preservation, and as I have not preserved a 

 copy of the plates delivered to Dr. Evans, which have never been published, 

 I am unable to see, if, indeed, the leaf of Nanaimo is identical with that of 

 the Dakota Group. This, however, could not force a definite conclusion 

 of the age of the flora of Nanaimo, as the Cretaceous type of Cinnamomum 

 appears preserved with very little modification in the different Tertiary 

 stages of this continent. 



OREODAPHNE, Nees. 

 Oreodaphne cretacea, Lesqx. 

 "U. S. Geol. Rep.," vi, p. 84, pi. xxx, fig. 5. 



A fine leaf of this species recently found in Kansas (No. 215, Coll. of 

 the Museum Comp. Zool., Cambridge) has all the characters of the leaf 



