38 THE ROYAL SOCIETY OF CANADA 



seams of well indurated, woody lignite accompany the clays, but 

 none of the seams seen was thick enough to be of economic value. A 

 bed of pure, coarse-grained, quartz sand, in which is intermingled a 

 small amount of white clay, accompanies the fire-clays at one locality. 



These materials are undoubtedly of pre-Glacial age, but of more 

 recent origin than Upper Devonian. Their age is approximately 

 fixed by certain fossil plant remains in a bed of sandstone included 

 in the clay beds at a point about 6 miles below the foot of Long Rapid, 

 on Mattagami river. 



Through the courtesy of Mr. David White a collection of these 

 fossils was examined by the palaeobotanists of the United States 

 Geological Survey, who stated that "the material you transmitted is 

 so fragmentary that with the few specimens in hand it is impossible 

 to determine even the genera with certainty. However, most of the 

 large fragments belong to a leaf of Taeniopteroid aspect. The nerva- 

 tion suggests som.e of the later types, such as are found in the older 

 Mesozoic. 



It is almost certain that the beds are not younger than Kootenay 

 and they are surely not older than Permian." 



As previously stated, no lignite beds were seen in the section 

 containing the fossils, but there is very little doubt that the lignite 

 and its associated clays, which occur about 200 feet farther down- 

 stream, belong to the same deposit. 



Clays of this type are extremely rare in eastern Canada, the 

 only other known occurrence being one in the Musquodoboit valley 

 in Nova Scotia. The Musquodoboit clays are covered by glacial 

 drift and overlie Lower Carboniferous rocks, but no fossils have yet 

 been found in them. They are very similar to the Lower Cretaceous 

 clays which occur extensively on the Atlantic coastal plain in the 

 state of New Jersey. Certain portions of the clay deposit on the 

 Mattagami correspond in all their physical properties to some of the 

 Musquodoboit clays. 



The nearest point in western Canada where such materials occur 

 is at Swan river, ^ Manitoba. At this locality there are lead-grey 

 clays containing a thin layer of lignite and overlain by soft white 

 sandstone. These beds are of Cretaceous age and are generally 

 referred to as Dakota. 



Cretaceous sediments of Dakota age occur also in a narrow belt 



along the southern margin of the pre-Cambrian rocks in the province 



of Saskatchewan and are evidently the western extension of the 



Manitoba beds. Th e Dakota beds in Saskatchewan, as observed by 



1 Summary Report, Geol. Surv. Can., 1917, Part D, page 37D. 



