151 



levels. To the most recent of these belong the two prairies which surround Lake "Winnipeg 

 and the lakes of that group, including the marshy country to the west of Manitoba lake. 

 This forms the first prairie level. In the vicinity of the Red River settlement its composition 

 is of argillaceous marl, with a deficiency of sandy matter, and it is invariably stratified in 

 thin layers. Underlying this at various depths from the surface is a bed of stiff clay, which 

 forms the immediate margin of the river at many places. The upper layers of this deposit 

 contain leaves and fragments of wood and reeds, and the whole is undoubtedly a fresh-water 

 deposit, indicating a time when the Winnipeg group of lakes covered a much more extended 

 area than at present, the gradual deepening of the rocky channels through the eastern -axis 

 having increased the drainage in modern times." 



He further remarks that the lignites seem to prove the frequent elevation of parts 

 of the area above the surface "of the water, and the general prevalence of plant remains in the 

 intervening sands and clays shows that at no time were land surfaces far distant. The 

 palaeontological resemblance of the beds with those of the typical Port Union is exact. Their 

 lithological similarity, though less to be depended upon, is not less striking ; but the rocks of 

 the 49th parallel, when compared with the section of the Missouri river, appear to show a 

 general tendency of the beds, northward, to more carbonaceous matter. The lignites are 

 more generally found, are usually thicker, and almost always more compact and poorer than 

 those of the eastern extension of the Tertiary to the south. The identity of the rocks on the 

 Line, however, from Roche Percee westward to Wood mountain, with the eastern fresh-water 

 extension of the souther Lignite Tertiary, generally known as the Fort Union Tertiary, does 

 not admit of doubt, and to whatever horizon the one is finally adjusted, the other must follow. 

 He also shows that the Mollusca generally resemble those .from the Fort Union of Missouri 

 and " fix with certainty the stratigraphical position of the beds." 



In showing that from the Souris river westward the Lignite Tertiary nearly always 

 occupies high ground, and frequently forms a well developed plateau resting on Cretaceous 

 clays, the same author expresses little doubt as to the identity of the beds of the 49th parallel 

 with those of the Judith River formation, which the recent studies of Stanton and Hatcheri^ 

 have definitely located in the Montana group, immediately under the Pierre and Fox Hills 

 group, which in turn are. overlaid by the Laramie. 



Sir William Dawson, upon whose work rests very largely our present knowledge of the 

 Lignite Tertiary flora of Canada and its stratigraphical relations, has shown that the plants 

 of the Porcupine Creek group are, for the most part, identical with those found by Ameri- 

 can geologists in the Fort Union series, and which have been described by Prof. Newberry 

 and Lesquereux. They are similar to plants collected by Dr. Richardson in the lignite 

 series of the Mackenzie river, as described by Heer. They also approach very closely to the 

 so-called Miocene floras of Alaska and Greenland as described by Heer. While on the one 

 hand there is a strong resemblance of the flora to the Miocene flora of Europe, on the other 

 hand, the association in the lower beds of reptilian remains of a Mesozoic type, and the 

 association of a similar flora with Cretaceous marine animal remains in Dakota and Van- 

 couver saggests a Lower Eocene age. 



Our own studies have shown that Dawson's conclusions were essentially correct. From 

 the general evidence presented it thus becomes possible to establish the relations of all the 

 Tertiary beds of western Canada, so far as now studied, and this relation is as follows : — 



1 Geology and Palaeontology of the Judith River Beds, U. S. Geol. Surv., Bull. 257 



1905. 



