LAURENTIAN AXIS TO THE ROCKY MOUNTAINS. 41 
The Benton group, though known in the Peace River country, has been recognized as 
yet with some certainty in a single locality in the Saskatchewan basin. The black shales 
of Cole’s Falls in the main Saskatchewan, are supposed by Meek, who has examined fossils 
from them, to be of this period. 
The Niobrara subdivision has been recognised in Manitoba, where the Boyne River cuts 
through the Pembina escarpment, where it precisely resembles, lithologically and in its 
included fossils, that of the Nebraska region. The rock is a cream-coloured limestone, 
chiefly composed of shells of Inoceramus and Ostrea congesta, but becomes in places a white 
chalky material, which under the microscope is resolved into amass of foraminiferal shells, 
coccoliths, and allied minute organisms. Still further north, along the eastern outcrop of 
the Cretaceous, at Swan River and Thunder Hill, west of Lake Winnipegosis, and near the 
line of our section, limestone and marls, containing fossils like those of the last mentioned 
locality and evidently of Niobrara age, are again found. 
The greater part of the Pembina escarpment, with its northern continuation west of 
the Winnipeg group of Lakes, is, however, composed of the dark shales and shaly clays of 
the Pierre group. On the plains, west of the escarpment of the Cretaceous, the drift cover- 
ing is so thick that exposures of the Pierre are seldom met with. It is, however, found, 
wherever it can be seen, to be horizontal, and it probably immediately and continuously 
underlies the country as far west as the Coteau. 
The Fox Hill subdivision of Meek and Hayden’s section is scarcely known in the east- 
ern part of the plains. It constitutes the highest of the marine beds, and is generally littoral 
and sandy in character. Rocks containing fossils referable to this subdivision have, how- 
ever, been described by Hind at the elbow of the South Saskatchewan, not far from our line 
of section. 
Still higher in the series are the beds of the Souris River region. These, on the northern 
continuation of the Fort Union group of the Missouri, and with their eastern boundary 
nearly coinciding with the Coteau or edge of the third prairie steppe, extend still further 
northward at least as far as the North Saskatchewan. 
In the Souris region, where they haye been much more closely examined than on the 
line of section, they consist of sandstones, shales and clays, with layers of ironstone con- 
cretions and numerous beds of lignite. On the Souris Corbula mactriformis, a shell of brackish 
or marine water, is found near the base, but with this exception all the molluscs are those 
of fresh water. These deposits have been accumulated in a great lake or series of lakes, 
with changing outlines, with the frequent local exposure of land surfaces on which coni- 
ferous and broad-leaved trees grow, and the débris of vegetation accumulated to produce 
beds of lignite. As the beds of the Souris region have already been fully reported on else- 
where,* it will be unnecessary to dwell at length on them here. 
The section is, however, intended,to illustrate one point which has, perhaps, so far not 
received sufficient attention. That is the possible occurrence of outliers of this formation in 
the chain of highlands which, beginning on the international boundary line with Turtle 
Mountain, is continued north-westward nearly parallel to the edge of the Coteau by Moose 
Mountain and the Touchwood hills. So far no exposures have been found in the more 

* Report on 49th Parallel, Reports of Geological Survey. 
Sec. 'TV.,'1882. 6 
