430 



ArrENDTX. 



now. The mere mention of them is sufficient to show the importance of the researches 

 among the remains of our old floras. This fact only seems to derive from the character 

 of the leaves of the Northern Lignitic: that our present flora has types which are peculiar 

 to it, and which are preserved in it since formations as old as the Cretaceous, where they 

 were already recognizable. 



APPENDIX. 



ON FOSSIL LEAVES EllOM FORT ELLSW011T.II, NEBRASKA. 



The previous paper was written, when, through the kindness of Dr. John Le Conte, I 

 received a number of fossil plants collected near Fort Ellsworth, from the same strata 

 where the leaves described by Messrs. Capellini and Heer had been obtained. Stratigraphy 

 and animal palaeontology have identified these formations as Upper Cretaceous. This 

 communication is very opportune, for it enables me to bring into view for comparison the 

 two groups of fossil plants whose character has just been discussed. And as a few of 

 these plants are new, and others complete, by better specimens, some of the species pub- 

 lished by Prof. Heer, this short Appendix is an interesting contribution to our American 

 fossil botany. All the specimens are on brown coarse sandstone. 



1. Populites MiCRoniYM.us, Spec, iiov. PI. xxiii, Figs. 2 and 3. 



Of this species the collection has only the two broken specimens figured here. The 

 leaf is apparently nearly round or large oval, abruptly narrowed at the basc^ crcnate ser- 

 rate on the borders, with sharp teeth pointing outward ; five-nerved at base like a Populus, 

 with all the nerves and veinlets so deeply marked that the surface of the leaves is wrinkled. 

 If the basilar five nervation and the peculiar denticulation of the borders seem to refer 

 these leaves to Populus, their thick coriaceous texture and their wrinkled surface cannot 

 be compared to any known species of that genus. 



2. PqYLLITES BETULvEFOLITJS, Spec. nov. PI. xxiii, Fig. 4. 



Erom the preserved part of this leaf, it appears nearly round, entire from the middle 

 downward, coarsely serrate upwards, with large, somewhat obtuse teeth, and obtuse 

 sinuses ; the medial nerve is deep and narrow ; the secondary alternate nerves of the same 

 thickness, are at first horizontal, curving upwards near the border only, in going up to the 



