knowlton.] DISCUSSION OF THE FLOKA. 77 
the middle of the Colorado formation to the Eocene; and 1 (Finis 
tilicefolia) from the Laramie to the Miocene. 
From this it appears that the species found beyond the present lim- 
its of the Montana formation are rather widely scattered, varying from 
the Dakota group to the Miocene, and suggesting' the possibility that 
they may not all have been correctly identified, either within the Mon- 
tana flora or in the horizon outside. As might perhaps be expected, 
the greatest affinity is shown to be with the Black Buttes locality, 
this being nearest to Point of Rocks, the principal plant-bearing 
locality in the Montana formation. Of the eight species mentioned 
above as common to the two localities, several are open to more or less 
question, as they depend on one or two fragments. That is, species 
have to be admitted as common to the two that may be represented 
at one or the other place by one or, at most, few aud often insufficient, 
specimens. 
Among the live plant bearing localities within the Montana forma- 
tion, there appears to be little in common. This is, perhaps, to be ex- 
plained by the fact that the places are mostly quite widely separated, 
and only one, namely, Point of Rocks, has thus far afforded a large 
flora. Coalville, Utah, which is over 100 miles from Point of Pocks, 
has a flora of about ten species, of which number only two or three 
have been found at Point of Rocks. Several, however, have been 
found in strata of supposed Laramie age. 
Among the localities on the Laramie Plains there is naturally more 
agreement, although the affinity is not so close as it undoubtedly 
would be if these localities had been more fully exploited. 
