686 GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



rather obtusely acuminate, in other cases quite abruptly ami obtusely 

 acuminate. 



The nervation is strongly marked. The jietiole splits- at the very base 

 of the leaf, almost outside of the blade, into three equal divisions, one of 

 which, the middle one, answering to the midrib, is straight and ends in the 

 apex. The others arch out regularly and pass around and enter the apex 

 also. Each lateral strong nerve or rib branches on the outside, the lowe.st 

 branch, which originates just inside the lower margin of the blade, sometimes 

 passing up and entering the a])ex with the other, at other times being lost 

 below the middle of the blade. In still other instances there are 5 or 

 6 branches in the outside of the lateral ribs which join b}" a broad loop, 

 forming a false nerve. In all cases this outside interrupted nerve is much 

 lighter than the others. 



Smilax appears to be rarely found fossil in North America, as only 5 

 species have been detected. Of these, 3 are from the Dakota group, 

 and 1 each from the Laramie and Miocene. None of them is at all closely 

 related to the one under discussion. 



Smilax lamarensis seems to be closely related to a number of living 

 forms. Thus the smaller rounded leaves are cjuite like S. rotundifolia L., 

 l:)oth in shape and nervation, while the larger forms are hardly to be sep- 

 arated from S. pscudo-cliina L. It is certainly closer to living American 

 forms than any heretofore described from this country. 



Habitat: East baidv of Lamar River, between Cache and Calfee creeks; 

 collected by F. H. Knowlton and G. E. Culver, August, 1888. Fossil Forest 

 Ridge, bed No. 6, "Platanus bed," 1 large sjjecimen; collected by Lester 

 F. Ward and F. II. Knowlton, August, 1887. 



MTISACEiE. 



MUSOPHYLLUM COMPLICATUM Lx. 

 PI. LXXXIII, fig. 1. 

 Musophyllum comxMcatum Lx. : Tert. Fl., ]i. 96, PL XV, tigs. 1-6. 



This species was described by Lesquereux from a "shale over a thin 

 bed of coal, 8 miles southeast of Green River Station, Wyoming," in what 

 he at first regarded as the Waslaaki group, liut which he later ^ decided was 



1 Cret. and Tert. Fl., p. 143. 



