328 GEOLOGICAL SURVEY OF THE TERRITORIES. 



from divers localities a large number of specimens representing all 

 the forms described as species in the same work, and I have now- 

 some more data to offer to the consideration of paleontologists on 

 the subject. From historical documents the presence of Sassafras 

 species in the flora of the Dakota group is as legitimately presumable 

 as that ot species of Laufus or Persea. In his Flora Arctica, Heer 

 has described as Sassafras arctica a leaf which, by its form, is similar 

 to those described as Sassafras cretaceum, as remarked by the author, 

 differing merely by its base somewhat less narrowly tapering to the 

 petiole. The nervation is of the same character. Count Saporta 

 considers this Greenland leaf as a true representative of Sassafras. He 

 has himself published in the Sezane Flora,* as S. prwiigenium, two 

 fragmentary leaves whose base, more narrowly tapering, is similar to 

 that of our S. 3Iudgei, as well as the lobes which, enlarged in the mid- 

 dle, have that ovate-lanceolate shape so distinctly marked in the present 

 >S*. officinale. There is also no appreciable difference in the nervation. 

 The lower secondary veins of the middle lobe ascend a little higher in 

 the leaves of the Sezane flora, and unite with those of the lateral lobes 

 somewhat nearer the borders of the sinuses. But in some of the speci- 

 mens of Kansas the same appearance is remarked also, and thedifference 

 between the more or less distance which separate from the sinuses the 

 branch which unites the upper division of the secondary veins, is ob- 

 servable upon leaves of S. officinale, this vein being sometimes mar- 

 ginal, sometimes curving one to three millimeters lower than the border 

 of the sinuses. Comparing leaves of Sassafras officinale with those rep- 

 resented by Count Saporta in the Flora of Sezane and the specimens of 

 S. Mudgei from Kansas, it is impossible for me to recognize any charac- 

 ter, even any specific difference by which these leaves could be sepa- 

 rated. It is, therefore, not surprising that Dr. l!s^ewberry first, and after 

 him Heer and Scliimper, did consider Cretaceous specimens of this kind 

 as rei>resenting species of Sassafras. In the last volume of his superb 

 work on Vegetable Paleontology.t Prof. W. P. Schimper, speaking of 

 leaves of Sassafras cretaceum, of which I had sent him photographical 

 designs, remarks, '• That those leaves, very variable in size, present such 

 a remarkable likeness to those of S. officinale, now living in North Amer- 

 ica, that one would be disposed to consider them as belonging to an 

 homologous species." He rightly adds that the only difference seems 

 to be in the thicker substance of the fossil leaves. Even on this point 

 I have from Texas specimens of the present S. cretaceous, whose 

 leaves appear of a consistence nearly as thick as those of the Dakota 

 group seem to have been. 



But now, and on another side, no species of the Laurinece family living 

 at our time is known with dentate leaves ; and it may be remarked, from 

 the figures, that the two leaves described as Sassafras Cretaceum (Cret. 

 Flor,, PI. XI, figs. 1 and 2) have the borders of the lobes somewhat 

 dentate, and some of the secondary veins running into the point of the 

 teeth or craspedodroroe. This character is still more marked in S. mi- 

 rabile, loc. cit., PI. XH, fig. 1, a form extremely common in Southern Kan- 

 sas, and represented in very numerous and remarkable varieties. In 

 some of the leaves the secondary veins are all camptodrome, and there- 

 fore the borders of the lobes are entire. In others, as seen, PI. XI, fig. 2, 

 the outside lateral veins are craspedodrome, and thus the borders den- 

 tate, wliile on the inside they curve along the borders, which are entire. 



* P. 366, Tab. VIII, figs. 9 and 10. 



t Traite de Paleontologie v6getale, vol. iii, p. 598. 



