72 CONTRIBUTIONS TO PAL^ONTOLOGY 



Lesquereux, Ward, and Knowlton. I am foUowing the practice of Newberry and Berry in applying 

 the less positive name Cornophyllum to the specimens. In addition to a resemblance to leaves of 

 Cornus, the fossil leaves are also comparable in general form and venation to Rhamnidium (Rham- 

 nacese), Berchemia (Rhamnaceae) and Premna (Verbenacea). 



Occurrence — Elk Mountain road, Wyoming, Loc. P. 374; Craig, Colorado, Loc. P. 376. 



Collection—lJ. C. Mus. Pal., Type No. 1366. 



Family BIGNONIACE^ 



Genus DOMBEYOPSIS Unger 



Dombeyopsis obtusa Lesquereux 



(Plate 15, Figs. 1, 2) 



Dojnbeyopsis obtusa Lesquereux, U. S. Geol. Surv. Terr., 6th Ann. Rept. (1872), 375, 1873; Rept. U. S. Geol. 

 Surv. Terr., vol. 7, 255, pl. 47, figs. 4, 5, 1878; Knowlton, U. S. Geol. Surv. Prof. Paper 130, 162, pl. 13, 

 fig. 4, pl. 20, fig. 11, pl. 27, figs. 1-4, 1922; idem, Prof. Paper 155, 124, 1930. 



Phylliles populoides Knowlton, U. S. Geol. Surv. Prof. Paper 101, 280, pl. 50, figs. 1, 2, 1917. 



Populus? neomexicana Knowlton, ibid., 258, pl. 53, fig. 3. 



Phyllites trinervis Knowlton, U. S. Geol. Surv. Prof. Paper 130, 166, pl. 24, fig. 12, 1922. 



There are four nearly complete specimens in the collections which resemble one or another 

 of the somewhat variable leaves previously referred to this species. Of the specimens here 

 shown, figure 1 resembles more closely the numerous specimens from the Laramie formation, 

 including Lesquereux's type specimen shown in volume 7, plate 47, figure 5. The other Medicine 

 Bow specimen, figure 2, is more of the type of Lesquereux's figure 4, and is clearly the same 

 species as the Vermejo specimens referred to Phyllites populoides and Populusf neomexicana. 

 Knowlton's discussions of Dombeyopsis obtusa in the reports cited above have adequately treated 

 its taxonomic relationships and its variabihty. It may be added here that the apex of the leaf 

 may be sHghtly emarginate, as shown in both my specimens. 



This species is now known from the Laramie, Trinidad, Vermejo, lower Denver, Dawson, 

 and lower Medicine Bow formations, and is not known from beds of indisputable Paleocene or 

 later age. 



I have found no modern leaves closely resembling those of this species. Analogous types are 

 met with in the genera Ficus (Moracese) and Cocculus (Menispermacege), but these are not 

 sufficiently similar for exact comparison. 



Occurrence — Corson Ranch, Wyoming, Loc. P. 372. 



Colledion—lJ. C. Mus. Pal., Plesiotypes Nos. 1367, 1368. 



Dombeyopsis trivialis Lesquereux 



(Plate 15, Fig. 4; Plate 16, Figs. 1, 2, 4) 



Dombeyopsis trivialis Lesquereux, U. S. Geol. Surv. Terr., 6th Ann. Rept. (1872), 380, 1873; Rept. U. S. Geol. 

 Surv. Terr., vol. 7, 255, pl. 47, fig. 3, 1878; Knowlton, U. S. Geol. Surv. Prof. Paper 130, 163, pl. 13, fig. 3, 

 pl. 14, fig. 3, 1922. 



From 31 specimens encountered in the field, 9 well-preserved specimens of this type of leai 

 were collected for study. The average leaf form, shown here in figures 1 and 4, plate 16, re- 

 sembles closely the tri-lobed figured specimen of Dombeyopsis trivialis, which Lesquereux obtained 

 from the Laramie formation. The resemblance to the actual type specimen at the U. S. National 

 Museum is even closer. The drawing of this specimen is not strictly correct. Actually, the central 

 and lateral lobes are more obtuse and rounded, essentially as in tlie Medicine Bow specimens. 



The specimen shown here in figure 4, plate 15, was at first considered quite distinct. For- 

 tunately, the features of the leaf shown in figure 2 seem to be intermediate in character between 

 this smaller, more elongate leaf and the larger, more rounded leaf of figures 1 and 4. There seems 

 also to be a gradational increase in the size of the lateral lobes, and a widening of the base from the 

 smaller leaf form to the larger. Recognizing the types of variations to be expected in a lobed 

 leaf form of this pattern, it seems justifiable to regard the three specimens as conspecific. In 

 view of the variability shown it is desirable to amphfy the original description of this species, which 

 was based on a single fragmentary specimen. 



