NATURAL SCIENCES OF PHILADELPHIA. 
265 
The following are the descriptions by Prof. Heer of the fossil plants from. 
No. 1 of the Nebraska section, referred to on page 257. 
1. Liriodendron MeeJcii, Mihi. 
L. foliis trilolbatis, lobo medio apice rotundato, late emarginato, basi angus- 
tato, lobis lateralibus obtusis. 
Differt a L. Procaccinii, Unger, et a L. tuUpifera, L., lobis rotundatis et lobo 
medio basi angustato. 
This leaf is furnished with a slender petiole, towards which it gradually 
diminishes ; the midrib extends to the apex ; towards the middle of the lobes 
on each side proceeds a secondary nerve, which also sends out on both sides 
tertiary nerves at rather acute angles. Further down on each side (near the 
base) is another secondary nerve, which inosculates with the former. This is 
a mode of structure which characterizes Liriodendron ; further up there arises 
very delicate secondary nerves, which likewise branch oS from the petiole. 
2. Sapotacites Haydenii, Mihi. 
S. foliis obcordato-ellipticis, basi sensim attenuatis integerrimis penninervis, 
nervis secondariis numerosis, ramosis angulo-acuto egredientibus. 
Affinis S. mimusops, Heer. Flora Tert. Helv. I. Taf. ciii. f. 4. 
The leaf gradually diminishes toward the base, rounded toward the apex, 
rather deeply emarginate, margins entire. From the midrib which gradually 
becomes slender and dies out, proceed at acute angles very numerous secon- 
dary nerves which have the peculiarity of ramifying very much, 
3. Lauriis primagenia, Unger. Taf. 13, fig. 1 ? 
Heer, Flora tertiar Helvet. Taf. Ixxxvi. fig. 1. 
Tlie form and nervation agree as far as the leaf has been preserved, with 
the preceding species, only the leaf is diminished in a somewhat less degree 
toward the petiole, and prolonged toward the apex as in Unger. 
It looks quite similar to the leaves of Laurus primagenia, which I have re- 
ceived from Corfe, in the Isle of Wight. 
Dunker (Paleontographica, iv. Taf. 34, f. 2,) has figured a similar leaf as 
Salicites Hartigi, from the chalk of Blankenburg. But in this, along with 
stouter secondary nerves, there are always several more delicate ones. 
4. Legiiminosites Marcouanus, Mihi. 
L. foliis magnis, obovalibus, apice obtusis, emarginatis nervis secondariis 
sparsis ; basilaribus approximatis. 
The leaflet is very large, but ceasalpinia-like, at the base somewhat un- 
equal, obtusely rounded. It is also rounded at the apex and deeply emar- 
ginate. The midrib dies out toward the apex ; secondary nerves very sparse 
and delicate, one on each side near the base, the next following ones distant 
and much curved. 
In its form it reminds one strongly of Ccesalpinia Falconeri, but is much 
larger. It would, however, be important to know whether the leaf is leather- 
like or thin skinned. If the latter is the case, the leaf probably belongs to 
Csesalpinia, but if it is leather-like, the Dalbergia are to be compared, as 
among them similarly shaped leaves are found. 
5. Populus leuce, Unger. Taf. 15, fig. 6 ? 
Phyllites leuce, Eossmassler, Blatter Von Altsaltel, Taf. 3, fig. 12 ? 
Unfortunately this leaf is not preserved entire, and the margin is no where 
complete. So far, however, as the form can be determined, it agrees with 
Populus leuce, as also in the nervation. Thus we have a stout midrib, and from 
this mid rib above the base of the leaf proceeds on either side stout secondary 
nerves, which then send off outwardly two or three rather stout tertiary 
nerves, which are curved toward the apex. Besides these, springs forth on 
each side below them, but almost at the same spot, a delicate secondary nerve 
which does not ramify any further, but dies out near the margin. At about 
the middle of the height of the leaf, there springs from the midrib on each 
1858.] 
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