354 GEOLOGICAL SURVEY OF THE TERRITORIES. 



angle, are thick, undulate, at equal distance, and generally simple. It 

 Las been remarked already, that the characters of the veins, all craspe- 

 dodrome, favor a separation of these leaves from the genus Populus, 

 though the round form and long slender petiole give them the appear- 

 ance of poplar leaves. 



ClSSITES OBTUSUM. 



Sassafras obtusum, Lesqx., Cret. Flora, p. 81, PI. XIII, figs. 2-4. 



Leaves thin, long petioled, flabelliform, tliree-obtusely lobed, entire or 

 undulate on the borders, broadly cuneate or narrowed to the petiole, three- 

 nerved from a little above the border base ; secondary veins parallel, camp- 

 todrome. 



If the relation of these leaves to the Araliacece is marked by the three- 

 lobate form and the nervation, their affinity to the Ampelidewis indicated 

 also by the thinner substance of the leaves, and the long, slender peti- 

 ole. Like many other Cretaceous leaves, they are of a mixed character, 

 and their reference uncertain. Except by their thin substance and long 

 petiole, they are indeed very similar to fig. 4, of PL XI, of the Cret. 

 Flora, representing Cissites Harherianus. By the other characters they 

 relate to the following generic division. 



Ampelophyllum, Lesqx. 



Leaves ovate' or obovate obtuse entire, narrowed to a long petiole or sub- 

 cordate; palmately three-nerved from above the base; nervation craspedo- 

 drome. 



Ampelophyllum attenuatum, sp. nov. PI. II, fig. 3. 



Leaf broadly obovate, enlarged upioard from the cuneate base, rounded 

 at the top, entire, subcoriaceous ; lateral primary nerve from a distance 

 above the base fiexuous, branching outside and inside, ascending to the bor- 

 ders. 



This fine leaf is six and one-half centimeters long without the petiole, 

 nearly six centimeters wide above the middle, rounded at the top, un- 

 dulate by the slight protuberance of the veins, three-nerved from a 

 distance (one centimeter) above the narrowed base, with two pairs of 

 distant alternate secondary veins, reaching the borders like the pri- 

 mary nerves, either directly or by their branches. Connected by ner- 

 villes at right angles, and also divided in very oblique veinlets, they 

 form irregular quadrate large meshes, and pass up in right angle to 

 the borders. There is under the base of the primary nerves one or two 

 pairs of marginal veinlets in the same degree of divergence as the other 

 veins, 40° to 50°. 



The form of this fine leaf and its nervation also are peculiar, and of 

 a character analogous to that of some leaves described under the ge- 

 neric name of Greviopsism the Sezane Flora by Saporta; there is, 

 however, a marked difference in the primary nervation and in the 

 entire borders of the leaves. The two lower pairs of veinlets give also 

 to this leaf an affinity with Credneria, and especially with the small en- 

 tire leaves of Platanus Reerii as figured in this memoir, PI. VIII, fig. 

 5 ; The secondary and tertiary nervation are, however, of a different 

 character. 



Habitat. — South of Fort Harker, Kansas, Chs. Sternberg. 



