22 
other hand, they have every feature of the existing Cercidophyllum japoni- 
cum, which may be crenate, dentate, or entire, or Tetracentron sinensis. 
I hope to discuss the geological history of the family Trochodendraceae 
with necessary illustrations in a more appropriate place. 
This species is abundant and widely distributed in the Lance and Fort 
Union of Dakota, Montana, and Wyoming, and has also been recorded 
from Red Deer river, Alberta. 
Trochodendroides speciosa (Ward) 
Plate V, figure 8 
Populus speciosa Ward, U.S. Geol. Surv., Sixth Ann. Kept., 1884-85 [1886]f 
p. 550, PI. xxxiv, figs. 1-4; U.S. Geol. Surv., Bull. 37, 1887, p. 20> 
PI. V, figs. 4-7; Penhallow, Kept. Tert. PI. Brit. Col., 1908, p. 79; 
Knowlton, U.S. Geol. Surv., Mon. 32, pt. 2, 1899, p. 694, PI. Ixxxiv, 
fig. 3; Wash. Acad. Sci., Proc., vol. 11, 1909, p. 189; Jour. Geol., 
vol. 19, 1911, p. 369. 
Populus xantholitherisis Knowlton, Mon. U.S. Geol. Surv., vol. 32, pt. 2, 
p. 695, PI. 85, figs. 1, 2, 1899. 
This is a widespread and variable form in the Lance and Fort Union 
formations, recorded from South Dakota, Montana, Yellowstone National 
park, and British Columbia (Paskapoo formation). 
Several leaves from the Ravenscrag may be assigned to this species. 
They are from 3-2 to 7-5 cm. in width, and from 4-5 to probably 8-0 
cm. in length, with rounded and occasionally markedly cordate base and 
rather blunt apex. The margins are crenate-dentate, commencing a 
short distance from the top of the petiole and frequently double. The 
petiole is long, the preserved part being from 2-0 to 7-5 cm., with a width 
of about 1 mm. The venation is palmate, the middle primary compara- 
tively strong, with two or three pairs of lateral primaries diverging from 
the summit of the petiole, though the principal pair are sometimes 
more or less fused with the middle one near the petiole. The basal pair 
are much finer and delicate. The first and second pairs adjacent to the 
middle one have stronger secondary veins on the outer side than on the 
inner side. The secondaries branch, reach the margins of the teeth, and 
form series of polygonal loops with tertiaries. The characteristic features 
are the rounded teeth and palmate nervation with subacrodrome main 
primaries from the top of the petiole. 
Occurrence. In Ravenscrag beds above a coal bed, sec. 28, tp. 7, 
range 24, W. 3rd mer., below the road bridge on central branch of Fairwell 
creek. 
Trochodendroides sp. 
Two specimens which fail to show details, but apparently with entire 
margins, possibly the same as Trochodendroides cuneata (Newberry) or T. 
speciosa (Ward) of the Ravenscrag beds. 
Occurrence. Estevan beds, SW. \ sec. 16, tp. 7, range 29, W. 3rd mer. 
