FOX HILLS AXD LOWER MEDICINE BOW 61 



Genus LAURUS (Toumefort) Linnd 



Laurus socialis Lesquereux? 



(Plate 7, Fig. 4) 



Laurus socialis Lesquereux, Rept. U. S. Geol. Surv. Terr., vol. 7, 213, pl. 36, figs. 1-4, 7, 1878; Knowlton, 

 U. S. Geol. Surv. Prof. Paper 101, 317, pl. 91, fig. 5, 1917; idem, Prof. Paper 155, 85, pl. 38, fig. 4, 1930. 



There are only 3 fragmentary spccimens of this typc in the collections. They are referred 

 with doubt to this species. The spccimens are closely similar to those from the Raton and Dcnver 

 formations, which seem to mc, however, to differ considcrably from the original type specimens 

 from Evanston, Wyoming. In these the shape is more lanccolatc and the secondaries are more 

 numerous, more obtuse, and less prominently looped near the borders. Except for their more 

 obtuse secondaries, the leaves of L. socialis are also comparable to those of L. utahensis Lesquereux ^ 

 from the Raton formation. It seems probabie that at least the Denver and Medicine Bow speci- 

 mens should be described as a new species. In the absence of better and more nuraerous speci- 

 mens, however, a revision and description cannot be made at the present time. 



In addition to Evanston, Raton, Denver, and Dawson occurrences reported above, Laurus 

 socialis is found also in the Livingston formation of Montana.^ 



Among modern leaves tlie lauraccous gcnera appear to resemble those of Laurus socialis 

 most closely. Several species of Persea and Laxirus with similar leaf characters have been noted. 

 Laurus nobilis Linn6, for example, has leaves of essentially similar sliape and venation. An even 

 closer comparison may be noted in the leaves of Persea carolinensis (L.) Nees.' A general re- 

 semblance is also apparent with leaves of Magnolia (Magnoliaceffi) and Diospyros (Ebenaceae). 



Occurrence — Elk Mountain road, Wyoming, Loc. P. 374. 



Collection—V. C. Mus. Pal., Plesiotype? No. 1335. 



Family TROCHODENDRACE.E 



Genus TROCHODENDROIDES Berry 



Trochodendroides nebrascensis (Newberry) Dorf, n. comb. 



(Plate 11, Figs. 1, 4, 6, 7) 



Populus nebrascensis Newberry, New York Lyceum Nat. Hist. Annals, vol. 9, 62, 1868; Illustrations of Creta- 

 ceous and Tertiary Plants, pl. 12, figs. 4, 5, 1878; U. S. Geol. Surv. Mon. 35, 47, pl. 27, figs. 4, 5, 1898; 

 Lesquereux, Harvard Coll. Mus. Comp. Zoology BuII., vol. 16, 47, 1888. 



Populus arclica Heer. Lesquereux, Harvard CoII. Mus. Comp. Zoology BuII., vol. 16, 48, 1888. 



Populus crenata Unger. Lesquereux, ibid., 48. 



Populus nebrascensis var. grandidenlata Lesquereux, ibid., 47; Ivnowlton, U. S. Geol. Surv. Prof. Paper 155, 

 56, pl. 19, figs. 4-7, pl. 20, figs. 2, 6, 7, 1930. 



Populus 7iebrascensis var. rolundala Lesquereux, op. cit., 47; Knowlton, op. cit., 56, pl. 20, figs. 1, 3-5, 8. 



Populus nebrascensis var. acute-dentata Lesquereux, op. cit., 47; Knowlton, op. cit., 56, pl. 21, figs. 1, 2. 



Populus nebrascensis var. longifolia Lesquereux, op. cit., 48; Knowlton, op. cit., 56, pl. 21, figs. 3-5. 



Populus tenuinervata Lesquereux, op. cit., 48; Knowlton, op. cit., 58, pl. 22, figs. 1-4, 6. 



Populus zaddachi Heer. Lesquereux, op. cit., 47; KJiowlton, op. cit., 60, pl. 22, fig. 8. 



Populus jacksoni Knowlton, op. cit., 58, pl. 21, figs. 6-8, pl. 22, fig. 7. 



Populus zeilkri (Lesquereux) Knowlton, ibid., 54, pl. 18, fig. 8, pl. 19, figs. 1-3. 



Proloficus zeilleri Lesquereux, Harvard Coll. Mus. Comp. Zoology Bull., vol. 16, 50, 1888. 



Cissus? cannoni Knowlton, U. S. Geol. Surv. Prof. Paper 155, 113, pl. 47, fig. 5, 1930. 



Cissus lesquereuxi Knowlton, ibid., 114, pl. 48, figs. 3, 4. 



The imposing synonjTiiy of this species is the continuation of the attempt to rcvise the status 

 of the variable leaves usually referred to species of Populus. That this task is not completed is 

 indicated in part by a recent list given to me by Dr. R. W. Brown of the U. S. Geological Survey, 

 in which he tentatively assigns eleven additional species of the Denver flora to the above species. 

 I have not included these species for want of complete specimcns of them for comparisons. 



' Knowlton, F. H., tj. S. Geol. Surv. Prof. Paper 101, 318, pl. 90, fig. 4, 1917. 



2 Knowlton, F. H., U. S. Geol. Surv. BuU. 105, 56, 1893. 



' See sheet No. 481, Biscayne Bay, Florida, at the Princeton University herbarium. 



