77 



petiole ; secondary veins numerous, parallel from the base, open, at an angle 

 of divergence of 60°, with shorter intermediate veins, which they join from the 

 base by curved branches or nervilles, forming a continuous irregular polygo- 

 nous areolation to the borders, where they curve in festoons. This kind of 

 areolation is related to that of Ficus geinitzii, Ett., (Flora v. Nieders, PI. ii, 

 Figs. 7, 9-11,) but the facies of these leaves, their consistence, &c, appear to 

 refer them rather to the Laurinece. The numerous fragments of these leaves, 

 though having a common form, may be referable to more than one species, 

 some of the leaves being without any traces of veins on their upper surface. 

 Habitat. — Over the whole of the Dakota group from Minnesota to South- 

 ern Kansas, mostly found as yet in fragments. 



Sassafras, Bauh. 



Leaves 3-paliuately, more or less deeply lobed, lobes entire or obscurely dentate ; primary nerves 

 forking at a distance abovo the prolonged subdecurrent base of the leaves. 



To this genus pertain some lea*ves formerly referred to Ettinghau- 

 senla. Some of the forms here described have characters in accordance 

 with those of the leaves of Sassafras officinale, Nees., so widely distrib- 

 uted in the western slope of North America, and the only species left of 

 his genus. It is especially the case for 8. muclgii. An objection, how- 

 ever, has been made by Count Saporta against the admitted relation of most 

 of these leaves to the genus Sassafras, especially on account of the dentate 

 borders and crasjjedodrome nervation of some of them. The eminent pale- 

 ontologist of France considers them as more evidently related to some Arali- 

 aceoz of Central America of the genus Oreopanax especially. I have been, 

 as yet, unable to obtain any specimens of these living plants for comparison, 

 and, though admitting the relation as ascertained, I find in comparing be- 

 tween themselves the fossil leaves of the Dakota group which have been 

 referred to Sassafras such an intimate coincidence of form and of nervation 

 that, admitting one as representative of the genus Sassafras, I am not able to 

 find any distinct character to separate the others. 



As said before, Sassafras mudgii (PI. xiv, Figs. 3-4) is the form more 

 evidently representing the characters of the leaves of this genus, not only in 

 comparison with leaves of the living species, but also in regard to the forms 

 represented fossit in the Tertiary. The leaf which has been figured especi- 

 ally for this comparison (PI. xxx, Fig. 7) is in its form and nervation interme- 

 diate between this S. mudgii and the leaves which have been separated from 



