16 
FLORA OF THE MONTANA FORMATION. 
The forms that are specifically named, or so designated that it is 
possible to make use of them in determining their bearing on the ques- 
tion of age, are as follows : 
Pistia corrugata Lx. 
Sequoia Reichenbachi (Gein.) Heer. 
Lemna scutata Dn. 
Populus acerifolia Newb. 
Populus latidentata Dn. 
Nelumbo Dawsoni Hollick. 
Platanus nobilis Newb. 
Acer saskatchewense Dn. 
Of these, three species {Nelumbo Dawsoni, Populus latidentata, Acer 
saskatchewense) were described as new to science, thus leaving only five 
species having an outside distribution. Of these Sequoia Reichenbachi 
is found from the Jurassic to the top of the Cretaceous. It is, however, 
most abundant and best developed in the Lower Cretaceous. Lemna 
scutata was described by Dawson from the so-called "Lignitic-Tertiary" 
near the forty-ninth parallel. It has since, been found by him in the 
Canadian Lower Laramie (true Laramie) of the Bad Lands of Wood 
Mountain and Pincher Creek. It was obtained by Professor Ward in 
Fort Union beds near the mouth of the Yellowstone, and by Lesquereux 
in the Montana formation at Point of Rocks, Wyoming. It has, there- 
fore, considerable range, and it is impossible to fix definitely its most 
characteristic horizon. Pistia corrugata has been found only in the Mon- 
tana formation at Point of Rocks, Wyoming. The remaining species — 
Populus acerifolia and Platanus nobilis — are characteristic Fort Union 
or Upper Laramie forms. 
The two species of Sequoia (of the types of 8. gigantea and S. sem- 
pervirens), the Ginkgo of the type of G. biloba, and wood of dicotyledons 
of the types of modern genera, would seem to indicate somewhat recent 
age, perhaps not older than Tertiary ; but this is more or less a matter 
of conjecture. The affinities of the three species peculiar to the Belly 
River series appear to be with the flora of Upper Laramie or Fort Union 
beds of the United States geologists. 
This Canadian Belly River flora has been supposed to be most 
closely allied to that of the Lower or true Laramie, as it logically should 
be if it occupies a position just below the Laramie, but careful exami- 
nation shows that the evidence of the plants is conflicting. Several of 
the species are found in the Lower Laramie, but only one is confined to 
it and the Belly River series, while perhaps the larger number are 
characteristically Upper Laramie or Fort Union forms. This at least 
suggests the possibility that there may have been a mixture of horizons 
represented in the collections of plants, the more so from the fact that 
the invertebrate fauna seems to point so clearly to Laramie affini- 
ties. Whiteaves has the following to say 1 regarding the bearing of the 
invertebrates : 
In conclusion, it may be remarked that the invertebrate fauna of the " Belly River 
series" seems to be essentially the same as that of the " Laramie" of the United 
States and Canada, unless more than one formation has been confounded under the 
Contributions to Canadian Palaeontology, Vol. I, p. 89 (1885). 
