FOSSIL FLOIiA. 



783 



Table nlwiriiHi thi distrihiition of the Terfhtiij plaiils of the Yellowstone Natifiiial P«)-/,— Continued. 



(I The nnmhers refer to the beds in which the plants were found. 6 Up Cache Creek. 



GEOI.OGICAI. COXSIDERATIOX OF THE TERTIARY FEORA. 



Xaturallv the geoloo-ical aspects of this fossil flora are considered as of 

 paramount importance, for it was to- ascertain the bearing- of the phnits on 

 the question of geological age that this investigation was undertaken. As 

 I have already pointed out under the section devoted to the biological 

 aspects of the flora (p. 775), a very large proportion of the plants were 

 foimd to be new to science, and therefore could have only limited value in 

 determining the age, but enough previou.sly described forms were recog- 

 nized to warrant certain deductions. It is the purpose to set these con- 

 clusions forth in this section. 



