136 



LARAMIE FLORA OF THE DENVER BASIN. 



larger size and broader outline, but in the 

 nervation they are of the same type, as may 

 be seen on comparing especially Lesquereux's 

 figure 4 with the present species. 



Occurrence: Laramie formation, cut on 

 Moffat railroad (Denver & Salt Lake) about 

 6 or 8 miles north of Golden, Colo., collected 

 by A. C. Peale, 1908. 



Ficus? leyden Knowlton, n. sp. 



Plate XIV, figure 1. 



Ficus? leyden Knowlton [nomen nudum], U.- S. Geol. 

 Survey Bull. 696, p. 283, 1919. 



Size and complete outline not known, but 

 apparently very unequal sided; base truncate; 

 margin entire; nervation palmate from the ex- 

 treme base of the blade, the ribs five, very 

 unequally distributed; the first rib on the 

 narrow side of the blade is nearly straight and 

 has four or five slender branches on the out- 

 side; the next rib, which may be called the 

 midrib, is slightly larger than either of the 

 others, with several pairs of thin secondary 

 branches in the upper part; the other ribs 

 supply the full side of the blade and have 

 several branches on the outside which are 

 probably camptodrome, but as the margin is 

 missing at this point it is impossible to be 

 positive; finer nervation obsolete. 



This leaf has the appearance of having been 

 sessile, and the narrow side was naturally the 

 upper side. It is so well shown in the figure 

 that no other description is necessary. 



It is perhaps doubtful if this leaf should be 

 referred to Ficus, but the generic affinity is 

 believed to be with what Newberry called 

 Ficus? alasJcana, 34 from the Kenai formation 

 of the Cook Inlet region of Alaska, especially 

 the one shown in the figure cited. This has 

 the five ribs in the somewhat' unequal sided 

 leaf, but the form under consideration differs 

 in being truncate instead of heart-shaped at 

 the base and in being very unequal sided, and 

 this affects the direction of the ribs. It is 

 possible that this is only an individual varia- 

 tion or abnormal form of Ficus cocJcerelli, 

 though the texture of the leaf and the absence 

 of finer nervation mark it as distinct. 



Occurrence: Laramie formation, Leyden 

 Gulch, about 6£ miles north of Golden, Colo., 

 collected by A. C. Peale. 



c . — 



" Newberry, J. S., TJ. S. Geol. Survey Mon. 35, pi. 55, fig. 2, 1898. 



Ficus post-trinervis Knowlton, n. sp. 



Plate VI, figures 1, 2. 



Ficus post-trinervis Knowlton [nomen nudum], U. S. Geol. 

 Survey Bull. 696, p. 285, 1919. 



Leaves of firm texture, ovate or ovate-ellip- 

 tical, about equally narrowed to both base and 

 apex, three-ribbed from the very base to the 

 blade, all the ribs of equal size, the lateral ones 

 passing up for two-thirds or three-fourths the 

 length of the blade, curving in in the upper 

 portion; secondaries few, alternate, above the 

 middle of the leaf, camptodrome; finer nerva- 

 tion not retained. 



The two leaves figured illustrate this species 

 very well, though neither is quite perfect. 

 They are 6 or 7 centimeters in length and about 

 3 centimeters in width. One has the petiole 

 preserved for a length of 1 centimeter, but it 

 is obviously broken. Where the petiole merges 

 into the blade it splits into three equal ribs 

 which divide the blade into four approxi- 

 mately equal areas. 



This species is undoubtedly most closely re- 

 lated to Ficus praetrinervis Knowlton, from the 

 Vermejo formation of southern Colorado. The 

 leaves are much smaller than is usual in that 

 species, are more nearly elliptical, and are not 

 known to have secondary branches on the out- 

 side of the lateral ribs. The secondaries on 

 the midrib start at a higher point than in F. 

 praetrinervis, but this is perhaps a variable 

 character. This species ; is also related to F. 

 cannoni, described below, which, however, 

 differs in its much smaller size and thinner 

 lateral ribs or secondaries, which join the sec- 

 ondaries on the midrib near the middle of the 

 blade. 



Occurrence: Laramie formation, Cowan sta- 

 tion, 10 miles southeast of Denver, Colo., col- 

 lected by F. H. Knowlton, 1908. 



Ficus cannoni Knowlton, n. sp. 



Plate VI, figure 3; Plate X, figure 1. 



Ficus cannoni Knowlton [nomen nudum], U. S. Geol. 

 Survey Bull. 696, p. 272, 1919. 



Leaves small, of firm texture, obovate-lan- 

 ceolate, rather obtuse above, narrowly wedge- 

 shaped below, perfectly entire; midrib very 

 slender; secondaries about four or five pairs, 

 the lower ones arising at the very base of the 

 blade and running up for nearly or quite half 



