226 rXlTED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



tlic multiplied, irregular disposition and divisions of the lower lateral veins. 

 By these characters, they are similar to tliat descrilnMl hy Heer from North 

 Greenland (fig. 1 h, loc. cit.). This analogy is, however, not sufficiently defi- 

 nite. The secondary nerves, not blackened, are thinner and more irregularly 

 divided than in V. ?narg/7ia(iwi, and the shape is quite different. The relatiim 

 to the species of Greenland is therefore closer or more defined than to T' 

 marginiitujii and its varieties. 



Uabitat. — Black Buttes, Wyoming, with V. marginatum; Point of Rocks, 

 Wyoming {Dr. F. V. Haijden). 



Vibiiriiiiiu Lakesji, Lesqx. 



Plate XXXVII, Fig. 11!. 



Vihumum Lakem, Lesqx., Aunnal Report, 1873, p. 401. 



Leaf coriaceous, round in oatline, and apparently trilobate, ronnd-tnincate to the petiole, dentate, 

 palmately three-nerved. 



The only leaf which represents the species is broken in such a way that its 

 outlines cannot be positively defined. From the character of the nervation 

 toward the point, and also from the obtuse sinus at the right side of the upper 

 border, it is evidently trilobate, the lobes being probably short and obtuse. 

 The substance of the leaf is truly coriaceous, the teeth sharp, turned upward, 

 and not outside, as in the former species, cartilaginous or membranaceous at 

 the point. The primary lateral nerves are thick and much divided outside, 

 and their divisions, branching also, are straight, at an open angle of diver- 

 gence, and in the same relation to the border teeth as in the former species ; 

 the secondary veins, a little more distant from the primary ones, are nearly 

 parallel to it, and also divide and enter the teeth by their branches. In 

 comparing this fragment to those of pi. xxxviii, figs. 8 and 9, described as 

 V. platanoides, the same type of nervation is at once recognizable, for these 

 also have a sui)trilobate form and a corresponding distribution of the primary 

 and secondary nerves and of the veinlets. The difference is, however, 

 clearly marked in tlie more distinctly trilobate shape, the coriaceous sub- 

 stance, and the direction upward of the small cartilaginous teeth. The 

 Platanoidal character is still more evident in this species. 



Habitat. — Golden, Colorado {Rev. A. Lakes). 



