FOX HILLS AND LOWER MEDICINE BOW 73 



Description {Supplcjnentary) — Leavcs palmatoly trilobpd, obovate to cordate in outlinc, 

 with 1 to 4 inconspicuous to wcll-developed subsidiary lobcs on tlie outer margins of the lateral 

 lobes; lobation obtuse, rounded; length 6 to 10 cm., width 4 to 8.5 cm., average dimensions ap- 

 parcntly about 8 by 7 cm.; basc broadly cuncate to cordate; secondary venation tri-pahnatc, the 

 latcral primarics givcn off from the top of the pctiole, curving sliglitly upward and entering the 

 latcral primary lobcs, secoiidary voins along midrib roniote, wide-angled, curving ujjward and 

 looping near margins to join sccondarics above, 3 to 6 prominent secondaries along marginal sides 

 of lateral primaries, the larger ones often branchcd and entering lateral lobes, the smaller ones 

 camptodrome; tcrtiary vonation indistinct, the ncrvillos usually approaching angle of 90° to the 

 primary aiul socondary voins; toxturo rather thin. 



Do7nbeyopsis trivialis has tluis far bcen reported only from the Laramie and the Medicine 

 Bow formations. I am not aware of any other hite Cretaceous or early Tertiary occurrences of 

 leaves which might possibly be the same. 



I do not Ijolieve tliat the affinitios of this fossil species aro with the existing genus Dombeya, 

 as is inchcated in the name Dotnbeyopsis. The species of Dombeija, in my exporience, have in- 

 variably more acutely lobed leaves with well-defined acute teeth along their margins. Although 

 I have not seen any modern leaves which are precisely similar to the fo.ssil species, a closcr re- 

 semblance is seen to the leaves of certain Menispermacea; : Cocculus (Cebatha) diversifolia, C. 

 carolinum, and Menispermum canadense, and of the Vitacece, particularly Cissus rhombifolia of 

 Mexico. 



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

 373; Craig, Colorado, Loc. P. 376. 



Colleclio7i—\J. C. Mus. Pal., Plesiotypes Nos. 1369, 1370, 1371, 1392. 



Family CAPRIFOLIACE^ 



Genus VIBURNUM (Tournefort) Linn6 



Viburnura raarginatum Lesquereux 

 (Plate 15, Figs. 3, 5; Plate 17, Figs. 4, 5) 



Viburnum marginatum Lesquereux, U. S. Geol. Surv. Terr., 6th Ann. Rept. (1872), 395, 1873; U. S. Geol. and 



Geog. Surv. Terr., Ann. Rept. (1873), 382, 401, 1874; idera (1874), 306, 1876; idem (1876), 510, 1878; 



idem, Bull., vol. 1, 380, 1875; Rept. U. S. Geol. Surv. Terr., vol. 7, 223, pl. 38, figs. 1, 4 only, 1878; Har- 



vard CoU. Mus. Comp. Zoology BuII., vol. 16, 51, 1888; Knowlton, Geol. Soc. Am. Bull., vol. 8, 145, 1897; 



Jour. Geol., vol. 19, 361, 370, 371, 1911; Berry, Canada Geol. Surv. Mem. 182, 57, 1935; Brown, U. S. 



Geol. Surv. Prof. Paper, raanuseript, 1937. 

 Plalanus heerii Lesquereux. Ward, U. S. Geol. Surv., 6th Ann. Rept., 552, pl. 40, figs. 8, 9, 1886; idem, Bull. 



37, 34, pl. 15, figs. 3, 4, 1887. 

 Plalanus plalartoides (I^squereux) Knowlton (in part), U. S. Geol. Surv. Prof. Paper 101, 323, pl. 95, fig. 4, 



1917; idem, Prof. Paper 130, 146, pl. 13, fig. 1, 1922. 

 Platanus guillelma: heerii Knowlton, U. S. Geol. Surv. Prof. Paper 101, 323, pl. 96, fig. 5, pl. 97, fig. 1, pl. 98, 



fig. 2, 1917. 

 Platanus marginata (Lesquereux) Heer. Knowlton, U. S. Geol. Surv. Prof. Paper 155, 81, pl. 36, figs. 2, 3, 1930. 

 Plalanxis aceroides lalifolia Knowlton (in part), ibid., 76, pl. 33, fig. 1. 



Specimens referable to this species were encountered at 4 of the 6 Medicine Bow localities, 

 although they were abundant only at LocaUty P. 372, where the field collections contained 241 

 specimens, of which 20 complete or nearly complete samples were collected for study. The 

 majority of these are of precisely the same size and character as the nearly perfect original type 

 spccimen from Black Buttes, Wyoming.i Since Lesquereux's report, this species has become 

 known from a number of scattered localities in the late Cretaceous strata of the Rocky Mountain 

 region. Knowlton has very ably discussed the essential distinguishing features and distribution 

 of the species and has described fairly adequately its average leaf form.- In view of the better 

 and more abundant material in the Medicine Bow collections it scems highly desirable to make 

 additions and corrections to his description and to attempt to justify the inclusion of the species 

 hsted above as conspecific with Viburnum marginatum. 



Description {Supplementary) — Leaves broadly ovate to obovate, narrowing abruptly above 

 to a blunt obtusely pointed or a short acuminate tip, narrowing more gradually below to an acutely 



' Lesquereux, Leo, Rept. U. S. Geol. Surv. Terr., vol. 7, pl. 3S, fig. 1, 1878. 

 = Knowlton, F. H., L". S. Geol. Surv. Prof. Paper 155, 81, 1930. 



