APPENDIX. 61 
pair being thinner and more like marginal veins than like primary nerves. 
For this reason the lobes are not distinct, or scarcely more prominent than 
the obtuse large teeth of the borders. By this character this leaf corresponds 
partly to the first of the subdivisions established by Heer in this description, 
leaves as broad as long, short-lobed, broadly obtusely dentate, and partly to the 
fourth division, wherein he includes truncate or sub-truncate leaves. The 
identification of this finely preserved leaf is positive. 
The relation of this species is with the present North American Acer 
spicatum, the mountain Maple, whose range in the Northern States is from 
the Atlantic to the Mississippi. 
Acer, species. 
The specimen shows only the middle part of a leaf. It is ¢rilobed, the lubes 
separated by deep narrow obtuse sinuses ; coarsely sinuate dentate on the borders. As 
far as the characters are recognizable, the fragment represents a leaf equally 
referable to Acer macrophyllum, Pursh, and to Acer grandidentatum, Nutt. It is 
intermediate in size, but comes nearer the last of these species, especially 
similar to a large form of A. grandidentatum, which I collected in the Ogden 
Caiion of Utah. 
It is to be regretted that the fragment is not in a better state of preserva- 
tion, and that it cannot be ascertained if this leaf of the Pliocene does not 
positively represent a species intermediate between A. macrophyllum and A. 
grandidentatum, or an older type, modified by peculiar circumstances forcing it 
to migrations, partly to the mountains where it became dwarfed, partly to 
the south wherefrom it returned later and during the present period with 
an amplitude of foliage resulting from a habitat in a warmer climate. 
Another specimen, No. 50, represents a large leaf, apparently referable to 
Magnolia lanceolata, p. 24, Pl. VI. Fig. 4. : 
The borders are erased, the nervation is obscure, the determination is not 
certain. 
In a lot of specimens, sent for examination by Professor William Denton, I found a few fragments of 
leaves from the Chalk Bluffs, in Nevada County. They represent Quercus convera, Lesqx., Aralia Zaddach i, 
Heer, species already published from the same locality, and an Acer, new for this flora. It is A. sextianum, 
Sap., a species found in France by the author, in the Gypses of Aix, therefore an old type, at least Miocene 
if not older.* The leaf is three palmately nerved and palmate-trilobate ; the medial lobe longer, and 
sparingly dentate or minute-lobed ; but the lower part of the leaf is entire. In all its characters it seems 
* Saporta considers the formation as continuous from the upper Cretaceous to the lower Miocene. It has, how- 
ever, a number of species identified in the Green River Group of the Rocky Mountains. 
