24 SIR J. W. DAWSON ON THE FOSSIL PLANTS 
Fronds, round, kidney-form or sometimes tending to trilobed, undulate at the edges ; 
half an inch to nearly an inch in diameter. Single or grouped, veinless or with very 
faint veins radiating from a marginal spot. Roots long, filiform, proceeding apparently 
from a slight notch on the edge of the frond. 
This was evidently an aquatic plant, producing rounded or rarely trilobed fronds 
about three-quarters of an inch in diameter, and haying numerous rootlets proceeding 
from a marginal or submarginal thickened spot. The fronds were evidently fleshy but 
not vesicular, and cellular with extremely delicate radiating veins which can seldom be 
seen. Whether this plant is truly a Lemna it is impossible to decide, in the absence of 
fructification, but I feel-certain that it should not be confounded with Lesquereux’s Pistia 
corrugata, with which that botanist compares it. This I have not seen, but as figured by 
him it differs in size, form, and venation. 
The plant is plentiful and very constant in its characters in the Lower Laramie of the 
Bad Lands of Wood Mountain (G. M. D.); also in the Lower Laramie of Pincher Creek 
(T. C. Weston). 
PHRAGMITES, Sp. 
Many leaves referable to plants of this genus occur in all the collections, from both 
Upper and Lower Laramie, but can only be characterized as stems and leaves of large 
grass-like or sedge-like plants of uncertain affinities. 
Scirpus, Sp. 
Report on 49th Parallel. 
Spikes small, numerous, less than a line long, and with from four to five pairs of 
incurved lanceolate scales. 
Lower Laramie, Bad Lands of Wood Mountain. 
Collected by G. M. D. 
Scirpus, Sp. 
Report on 49th Parallel. 
Spikes with about six pairs of scales and about two lines long. 
Upper Laramie, Porcupine Creek. 
Collected by G. M. D. 
5. Dicotyledones. 
PLATANUS NOBILIS, Newberry, (Plate I, Fig. 7.) 
Newberry, Later Extinct Floras ; Dawson in Report Geol. Survey of Canada, 1879-80. 
This magnificent leaf, of which many very good specimens have been obtained, was 
first described by Dr. Newberry in the Annals of the Lyceum of New York for 1868. His 
specimens were from the Fort Union series, near Fort Clarke, on the Upper Missouri, and 
were found in beds then regarded as Miocene Tertiary, though now known to be much 
older, and which are on the horizon of the Lignite Tertiary series of the Souris River. . A 
figure of the leaf is given in Dr. Newberry’s later work, “ Illustrations of Cretaceous and 
Tertiary Plants,” Geological Survey of the Territories, 1878. There can be little doubt 
that this plant is the same with that named by Lesquereux, Platanus dubia, in 1878, and 
subsequently described in his report on the Tertiary Flora of the Western Territories, as 
