216 ROYAL SOCIETY OF CANADA 
which Mr. Tyrrell divides into two series, the Millwood series (or for- 
mation), and “Odanah series,” or formation. The former includes light 
and dark gray or brown, soft, friable or brittle shales and limestones 
which hold numerous Radiolaria. On the Duck and Poreupine mountains 
of Manitoba, the Millwood series is well developed. The Odanah series, 
with its light gray, finely laminated shales and clays, as seen on Shoal 
lake and Deloraine, and along the Assiniboine, in Manitoba, constitutes 
tie uppermost member of the Cretaceous system in the eastern portion 
of the Great plains. In the western portion of the Great prairie plateau, 
including Alberta, Assiniboia, and Saskatchewan, and the districts to the 
north, the following succession obtains: 1, the Dakota; 2, the Niobrara- 
Lenton or Colorado formation; 3, the Belly River series; 4, the Fort 
Pierre, (Fort Pierre and Fox Hills) or Montana formation; 5, the Lara- 
mie formation, which Dr. G. M. Dawson divides into (a) Porcupine Hull 
series; (b) Willow Creek series, (c) St. Mary (River) series; while Mr. 
Tyrrell divides the Laramie of Northern Alberta into two formations, 
viz.: (a) the Edmonton series, or formation (b) the Paskapoo series or 
formation. This latter is of decided Eocene or Tertiary age from the : 
character of its entombed fossil remains. 
The Dakota or lowest formation in the series of upper Cretaceous 
sediments of this region, appears to overlie unconformably and overlap 
rocks of Devonian age in its eastern extension. It is essentially a sand- 
stone formation, and in the United States carries a luxuriant fossil flora. 
The Niobara-Benton formation, consisting for the most part of 
shales and sandstones which are oftimes fossiliferous as in the Peace 
river section, is represented by the Fort St. John shales; the Peace R. 
sandstones, and the Loon River shales, whilst in the Athabasca section, 
these find their equivalent in the La Biche shales (lower part), the Peh- 
can sandstones, and Pelican shales, and the Grand Rapid sandstones, 
and Clearwater shales. In the Peace R. section the Dunvegan sand- 
stones appear overlying the Fort St. John shales, and are overlaid by the 
Montana formation, including the Smoky R. shales, and also the Fox 
Hills sandstones. In the Athabasca R. section the Dunvegan formation 
is absent, and the Montana formation is represented by (a) the La Biche 
shales (upper part), (0) Fox Hills sandstones. In both of these districts — 
Laramie sandstones and shales constitute the newest sediments in the 
Cretaceous system. One of the most interesting features of the Cretace- 
ous of the plains is the interpellation of the Belly River series of estua- 
rine and fresh water sediments, between the Fox Hills and Ft. Pierre 
formations and the Niobrara-Benton constituting a series of beds in 
which the organic remains found resemble those of post-Pierre (or 
Laramie) age—equivalent to the St. Mary River series of Dr. Dawson. 

