L. Lesquereux on fossil plants from Nebraska. 93 
double nervation of the stems of this genus ; deep, well marked | 
strie, separated by four or five close, thin lines, scarcely dis- 
tinguishable with the naked eye. 
7. Liquidambar integrifolius, sp. nov.—A well preserved, 
large, and nearly entire leaf. Its form is about the same as 
that of the leaves of our Liguidambar Styracyflua. It is 
membranaceous, shining, round in outline, deeply five-lobed, 
with lobes obtusely pomted and enéive. The primary, sec- 
ondary and ultimate reticulation is that of our living Liquid- 
ambar. The petiole of the leaf is destroyed, but it is evi- 
dently surrounded by that small basilar subdivision of the leaf 
which is remarked in our living species. All the fossil Ligquid- 
ambar but this have the borders dentate or serrulate like the 
species of our time. 
8. Populus Lancastriensis, sp. nov.—Leaf of a thin sub- 
stance, with a deeply marked nervation, broadly cordate, prob- 
ably acute (the point is destroyed(, borne on a slender petiole. 
its borders are entire or slightly undulate ; its primary nerves 
in five like the lateral ones are proportionally slender. It is 
broader and more deeply cordate at its base than any of the 
_* of Populus from the Tertiary, resembling by its form a 
sis, 
9. Populites cyclophylla (Populus) Heer.— Leaves round, 
entire, with slightly pitas hevitick Primary nerves in 
three attached to the petiole; secondary nerves (4 pairs) nearly 
Opposite, running straight to the borders in preserving nearly 
the same thickness ; angle of divergence 40°.—This is appar- 
ently Heer’s species: Populus cyclophylla, of which a short 
gnosis is gi in eed. of Acad. of Nat. Sciences, 
Philad., 1858, p. 266. The author remarks that the base is 
= by the nervation which is truly craspedodrome, the sec- 
