142 THE RARITAN FLORA. 



nearly 90°, and the lobes in the modern leaf have their mar- 

 gins inflated and not straight. In these ancient leaves the 

 sinus seldom has a marginal vein, the secondary in this region 

 usually forking and striding it, or curving to join its neighbor. 

 The secondary system seems to be unifo'rm throughout the 

 leaf, while in the modern leaf there is always evidence of changed 

 conditions in that region around the sinus; the secondaries or 

 their representatives from both the primaries and midrib are 

 changed in size and direction, and usually belong toi the tertiary 

 system. None of the Dakota leaves of this species show the 

 characteristic basal venation of the modern leaf. While we 

 should not, necessarily, expect Cretaceous species to conform to 

 the modern type, still the character of the secondary system in 

 the former is so different from what would obtain in a leaf 

 descended from a simple ancestor, such as Sassafras is thought 

 to have done, that we are inclined to associate these leaves with 

 those trilobed forms which have been referred to, Aralia or 

 Sterculia, laying aside, for the present, any consideration as to 

 whether or no they are true species of Aralia and Stercidia. 



However, in view of the present uncertainty, and because of 

 the havoc to the stratigraphic value of these leaves which would 

 be wrought by any change of name, they are retained in the 

 genus Sassafras pending more positive evidence of their affinity. 



Occurrence. — Woodbridge, Milltown. 



Collections. — N. Y. Botanical Garden. 



Sassafras progenitor Hollick. 

 Plate XVIII, Fig. i. 



Sassafras progenitor Hollick, Bull. Torrey Club, vol. 21 : 53, 

 pi. 1/4, f. I, 1894; Bull. Geol. Soc. Amer., vol. 7: 13, 

 1895; U. S. Geol. Surv. Mon. 50: 78, pi. 30, f. 11, 

 1907. 



Newb., Fl. Amboy Clays, 88, pi. 27, f. 1-3, 1896. 



Berry, Bot. Gazette, vol. 34: 443, 1902; Bull. Torrey Club, 

 vol. 31: 78, pi. I, f. 3, 1904. 



