40 GEORGE M. DAWSON ON A GENERAL SECTION FROM THE 
passing through the overlapping Cretaceous rocks, the upper part of the Devonian, in the 
Manitoba region, might prove valuable as an oil-bearing formation. 
This suggestion was entered in the Report on the Geology and Resources of the 49th 
Parallel, but remains as yet unconfirmed. 
The unconformable, though very horizontal overlap of the Cretaceous on the Devonian, 
just alluded to, entirely conceals the outcrops of any rocks of Carboniferous age, which 
may exist in this region. It is probable, however, from analogy with the Western States 
to the south, that these rocks consist almost entirely of limestone, and, even if exposed, 
would be found to yield no workable coal seams. 
The waters of the ocean appear to have covered this portion of the continent during the 
Carboniferous period, and the conditions for the accumulation of coal did not occur till amuch 
later stage in the series. 
Rocks of Cretaceous age are those next found in the geological series in this region, 
and they constitute the substratum of by far the greatest area of the plains. 
The typical section of the Cretaceous of the Missouri Valley and eastern portion of the 
interior continental basin generally is that worked out many years ago by Messrs. Meek 
and Hayden in the Nebraska region. 
It may be summarized as follows, the order being descending :— 
LATER CRETACEOUS. 
No. 5. Fox Hill Beds.—Grey ferruginous and yellowish sandstones and arenaceous clays. 
Marine Shells............... 568000003200 0 Bho dondsornage donde Hogdd es0nn dos dons . 500 feet. 
No. 4. Fort Pierre Group.—Dark grey and bluish plastic clays. Marine Shells and Fish 
JR Ting AD OOOO BUGaDOO COTO Soon SS00000 socponondn ooo G.gcccde paps oashounobdo 2506 wiereremen (OOie: 
EARLIER CRETACEOUS. 
No. 3. Niobrara Group.—Calcareous marls, marine shells, foraminifera, fish remains, &c.. 200 “ 
No. 2. Fort Benton Group.—Dark grey laminated clays, with some limestone marine shells. 300 “ 
No. 1. Dakota Group.—Yellowish, whitish and reddish sandstones and clays, with oc- 
casional lignite coals. Marine and some freshwater shells and angiospermous leaves... 400 “ 
Adding together the approximate thickness given for the subdivisions above, a total 
of 2,600 feet is obtained, and it is possible that the Cretaceous system may in some places 
attain this thickness. It is probable, however, that in the eastern part of the region 
traversed by the section now under description the thickness is not so great, as this must 
originally have been near the margin of the Cretaceous sea. Owing, however, to the thick- 
ness of the drift covering, and the nearly horizontal position of the beds, the actual thick- 
ness of any of the subdivisions has not been ascertained here. It is probable that the lower 
subdivisions outcrop below the alluvium of the Red River Valley, and toward the base ot 
the Cretaceous escarpment, west of the Winnipeg group of lakes, but neither the Dakota 
nor Benton groups have been observed in this region. In Nebraska thin seams of lignite 
are known in the Dakota beds and have, owing to the scarcity of other fuel, been to some 
extent marked. Similar lignites are also found in south-western Minnesota at this horizon 
but are not of economic value. ‘ 
While it is therefore possible from analogy that workable lignite beds may occur in the 
representative of the Dakota in Manitoba, it is probable that, even if this formation were 
well exposed and easily accessible, the supplies of fuel it might yield would be of little or 
no economic importance. 
