FOX HILLS AND LOWER MEDICINE BOW 71 



This species is apparently most abundant in the Black Buttos and Medicino Bow floras. 

 Its reported occurrence in the Lanco formation of eastcrn Wyoming by Knowlton ' has been 

 amply substantiated by his unpubhshed manuscript and figures at tho U. S. National Museum. 

 In the summer of 1936, I visitcd this region and coilected several completc specimens clearly 

 belonging to this same spccies. Brown has also coUected excellent specimens of it in the Hell 

 Creek member of the Lance near Marmarth, North Dakota. There do not appear to be any other 

 reported occurrences of the spocies in North America, although Chaney rcports that Callichlamys 

 zeteki from the upper Eocene (?) of Oregon - is of the same general type. 



Except for their resemblance to leaves of the Uving genus Callichlamys, as pointed out by 

 Chaney, I have found no other forms except Grewiopsis witli which the fossil leavos can be 

 compared. 



Occurrence — Corson Ranch, Wyoming, Loc. P. 372; north of Walcott, Wyoming, Loc. P. 

 373; Elk Mountain road, Wyoming, Loc. P. 374. 



Collection—V. C. Mus. Pal., Plosiotypes Nos. 1363, 1364, 1365. 



Family CORNACEiE 



Genus CORNOPHYLLUM Newberry 



Cornophyllum wardii Dorf, n. sp. 



(Plate 16, Fig. 3) 



Comus sluderi? Heer. Lesquereu.x, Rept. U. S. Geol. Surv. Terr., vol. 7, 244, pl. 42, figs. 4, 5, 1878; Ward, 

 U. S. Geol. Surv., 6th Ann. Rept., 553, pl. 48, fig. 1, 1886; idem, Bull. 37, 55, pl. 26, fig. 1, 1887; Knowlton, 

 U. S. Geol. .Surv. Bull. 163, 68, pl. 15, fig. 3, 1900; idem, Prof. Paper 101, 342, pl. 109, fig. 2, 1917; idem, 

 Prof. Paper 155, 104, only pl. 40, fig. 6, 1930. 



The single, nearly complete specimen figured is one of 6 well-preserved specimens of this type 

 of leaf. It is impossible to distinguish from the Mesaverde specimen referred by W^ard to the 

 European species Cornus studeri. Knowlton has reviewed in detail the status of the various 

 specimens wliich have been referred to this species, referring several to Rhamnus cleburni Les- 

 quereux.' He adds, however, that Ward's Mesaverde specimen and his own specimens from the 

 same formation are not referable to Rhamnus cleburni nor are they similar to the European Cornus 

 studeri. W\t\\ the additional matorial now at hand it seems advisable to describe the species as 

 new, despite the indefinite generic reference. 



Description — Leaves narrowly ovate to elhptic, gradually narrowed to an extended, slightly 

 acuminate or acute tip, and more abruptly bolow to a widely cuneate base; longth 7 to 13 cm., width 

 4 to 7 cm., widest below the middle, midrib very thick bclow, thinning gradually to the apex; 

 petiole thick, up to 1.5 cm. long, secondary venation pinnate, mainly alternate, camptodrome; 

 secondarios more widoly spaced along midrib and more abruptly curved upward in uppor half 

 than in lowor half of leaf, outer onds of secondaries tending to parallel margins for considerable 

 distance, looping indistinctly with tcrtiary branches of secondaries next above; tortiary venation 

 indistinct, nervilles running mainly at high angle to midrib; margin entire; texturo coriaceous. 



This species is of the general type of Rhamnus cleburni, though clearly distinguishable by 

 the more widely spaced, less numerous secondaries, which do not evon approach the type of parallel 

 venation of R. cleburni. There are also discernible cUfTerences in tertiary venation and general 

 shape. It seems ovidont, therefore, that Lesquereux's Donver specimens of Cornus studeri? which 

 Knowlton identified as Rhamnus cleburni bolong rather to the type here called Cornophyllum wardii. 

 Also, one of Knowlton's spocimens of Rhamnus cleburni from the Denver flora (plate 40, figure 6) 

 is clearly referable to Coriiophyllum ivardii. 



In addition to the Aledicino Bow occurrences, and its presence in the Mesaverde, Raton, and 

 Denver formations, this species is also present in my colloctions of Lance material obtained in 

 1936 from two locahties east and northeast of Lance Croek, Wyoming. 



The general shape, entire margin, and secondary venation of this species resemble the leaves 

 of the Uving species of Cornus, to which the previously recorded specimens wore roferred by 



' Knowlton. F. H., Washington .\cad. Sci. Proc, vol. 11, 207, 1909. 

 = Chaney, R. W., Carnegie Inst. Wash. Pub. No. 439, 95, 1933. 

 ' Knowlton, F. H., U. S. Geol. Surv. Prof. Paper 155, 105, 1930. 



