knowlton] DESCRIPTION OF SPECIES. 11 
al>le to estimate the thickness of an intermediate portion of the section lying be- 
tween Arrow and Judith rivers, but there is no doubt as to the relative stratigraphic 
position of the hods studied. It is evident from the stratigraphy and from the 
marine invertebrate fauna of the underlying and overlying strata that the sand- 
stones and associated coal beds and plant-bearing horizons in the neighborhood of 
Coal Banks on the Missouri River are on essentially the same horizon to which the 
Belly River series was assigned by Dr. G. M. Dawson, and to which a part of the 
Canadian beds so named undoubtedly belong. But in Dr. Dawson's full and careful 
description of the Belly River series it is pointed out that in certain areas referred 
to that series the stratigraphy is not clear, and the beds may overlie the Montana 
shales instead of underlying them. It happens that most of the Belly River fauna, 
which consists chiefly of Laramie species, was collected in these doubtful areas. I 
suspect that in Canada two distinct formations, separated by marine beds, have 
heen confused under the term Belly River series, and that a large part of the fauna, 
and possibly also of the flora, was collected from the upper horizon, which included 
the Laramie and possibly even later beds. 
DESCRIPTION OF PLANTS COLLECTED BY LESTER F. 
WARD ON THE RIGHT BANK OF THE MISSOURI RIVER, 
7 MILES BELOW THE COAL BANKS, AUGUST 24, 1883. 
THINNFELDIA MONTANA Kn. 
PI. I, figs. 1-3. 
Thinnfeldia montana Kn., Bull. U. S. Geol. Survey No. 152, p. 227 (1898). 
Salisburia polymorplia Lx., Am. Jour. Sci., 2d ser., Vol. XXVII, p. 362 (1869) [nomen 
nudum] ; Ann. Rept. U. S. Geol. and Geog. Surv. Terr., 1872, p. 404 (1873). 
Thinnfeldia polymorph a' (Lx.) Kn., Proc. Biol. Soc. Wash., Vol. VII, p. 153 (1892); 
Bull. U. S. Geol. Survey No. 105, p. 47, PI. V, figs. 1-4 (1893). 
It is impossible to separate the specimens from below the Coal Banks 
rom those found in the Bozeman coal field and figured as already men- 
ion ed. They are, perhaps, a little smaller, but have the identical lacini- 
ite margin and the same nervation. The Bozeman specimens are from 
/he head of Fir Canyon, near the Fort Ellis Eeservation,in true Laramie 
strata. 
Habitat. — Eight bank of Missouri Eiver, 7 miles below the Coal 
Banks. Collected by Lester F. Ward, August 24, 1883. 
QUERCUS? MONTANENSIS U. Sp. 
PI. I, fig. 10. 
Leaf narrowly ovate-lanceolate, broadest at about one-fourth of its 
ength above the base, from which point it tapers below into an obtusely 
sedge-shaped base ; apex long and apparently slender; margin remotely 
jid obtusely toothed above the middle; petiole rather stout for the size 
»f the leaf; midrib strong; secondaries probably about eight or nine 
'This combination — Thinnfeldia polymorpha (Lx.) Kn., 1892— is antedated by T. polymorplia Ett., 
360, which is a totally different plant. It becomes necessary to rename the Montana species, and I 
ave called it, as shown above, Thinnfeldia montana. 
