80 

 Sassafras (Araliopsis) cretaceum, Newby., PI. xi, Figs. 1-2 ; PI. xii, Fig. 2. 



Leave3 of medium size, with diverging, slightly obtuse or acutely-pointed lobes, enlarged toward the 

 broad sinuses, broadly wedge-shaped toward the base, decurring to the long petiole ; borders entire or 

 obscurely dentate. 



Sassafras cretaceum, Newby., Extinct Floras, p. 14. 



This species, the most commonly represented in the red shale of the Da- 

 kota group, is always easily recognized by the deep, sharply-cut impressions of 

 its leaves, and of the nervation of its under surface. The leaves are generally 

 smaller ; the lobes sharply-pointed or acuminate, either entire or obscurely 

 dentate ; the secondary veins thicker, passing outside to short teeth or curving 

 along the borders, being often craspedodrome and camptodrome in the same 

 leaf. As it is evident from the examination of transitional forms, the leaf, (PI. 

 xii, Fig. 2,) with its entire borders and slightly obtuse lobes, belongs to the 

 same species. 



Habitat. — Blackbird Hills, Nebraska ; Smoky Hill Fork, Kansas, Hay- 

 den. Fort Harker, &c. 



Sassafras (Araliopsis) cretaceum var. obtusum, Lesqx., PI. xii, Fig. 3 ; 

 PL xiii, Fig. 1. 



This form is recognized from the former by its shorter, especially 

 more obtuse lobes and its very coarse nervation ; the primary and secondary 

 veins are proportionally much thicker, these especially so from the middle 

 downward ; the medial nerve, from the forking of the lateral veins to the 

 petiole, is twice as thick as in the normal form. 



Habitat. — Mostly on the bluffs of Salina Valley. 



Sassafras (Araliopsis) mirabile, Lesqx., PL xii, Fig. 1. 



Leaves coriaceous, very variable in size ; lobes broad, deep, obtusely dentate on the borders ; second- 

 ary veins mostly craspedodrome. 



Sassafras mirabile, Lesqx., Hayden's Report, 1872, p. 424. 



The thick leaves of this species vary in size from 8 to 23 centimeters 

 broad between the points of the lobes, and from 9 to 16 centimeters long 

 without the petiole, which, as seen upon one of our specimens, is from 6 to 7 

 centimeters in length. The three primary nerves separate at a comparatively 

 short distance above the decurrent base of the leaves, the lateral ones bearing 

 outside in the lower part one or two thin marginal veinlets, which follow the 

 borders in successive bows, joining the point of the lowest secondary veins; 



