33 
beds of Albian age and is a survivor into the Cenomanian Cheyenne sand- 
stone of Kansas, at both horizons being associated with Sapindopsis 
magnifolia which occurs in the Upper Blairmore flora. 
The floral evidence is, therefore, conclusive in proving the Lower 
Blairmore flora to be Lower Cretaceous in age. Its exact correlation is 
limited below by the supposed Barremian age of the Kootenay as set forth 
in the previous section of this report, and above by the Cenomanian age of 
the Upper Blairmore flora which succeeds it. The only alternatives possible 
in the light of these correlations are that the Lower Blairmore flora repre- 
sents Aptian or Albian time or more or less of both. The presence of 
Sapindopsis strongly suggests an Albian age, but offsetting this to some 
extent is the fact that, as far as it is known the Lower Blairmore flora 
shows a greater resemblance to other floras classed asNeocomian-Barremian 
than do either the flora of the Patapsco or that of the Fuson formation, 
both Albian in age. On the other hand, the Lower Blairmore shows the 
same relative increase in coniferophytes as characterizes the Patapsco 
when the latter is compared with the older formations of the Potomac 
Group, and several of these, like Geinitzia, Torreya dicksoniana, and 
Sequoia smittiana are prenuncial of Upper Cretaceous — the first being 
distinctly an Upper Cretaceous type. 
I would be inclined to consider the Lower Blairmore as representing 
the later part of Aptian time and all of Albian time. I do not know how 
far above the base of the Blairmore formation these plants occur and 
possibly unfossiliferous sediments in the lower part of the formation and 
the unconformity at its base represent Aptian time and the flora is wholly 
Albian, although as I pointed out in the preceding paragraph it has in part 
a pre Patapsco suggestion. The latter, of course, may represent merely 
the latter part of the Albian. We are not in a position at the present time 
to be especially precise on such finer points of correlation. Certainly the 
degree of resemblance between the Kootenay and the Lower Blairmore 
floras would suggest that no very extended time interval is represented by 
the unconformity or the deposits between the floral horizons of the two 
formations. 
The detailed distribution of the Lower Blairmore flora, both within 
and outside the area under consideration is shown in the accompanying 
table of distribution. The correlation of the Cretaceous of this part of 
Alberta is shown in the accompanying chart. My conclusion regarding 
the age of the Lower Blairmore, with due reservation because of the limited 
floras with which I have had to deal, is that it is more or less synchronous 
with the Patapsco formation of Maryland and Virginia, possibly reaching 
to a somewhat earlier horizon in its lower limits; that it represents a part 
of the Lakota and all of the Fuson formation of the Black Hills in eastern 
Wyoming; and a large part of the Kome beds of western Greenland. 
