﻿122 GEOLOGICAL STRUCTURE Jult, 



of limestone strata, covered by a thick deposit of 

 bituminous sliale, which is probably to be referred 

 to the Marcellus shale of the United States geolo- 

 gists.* The shelving cliff of this shale is one hun- 

 dred and fifty feet high or upwards, and is capped 

 by sand or diluvium. The high cliffs extend for 

 two or three miles up the Clear-water River, 

 above which the sandy slopes for the most part 

 conceal the strata, except at the water's edge, 

 where the limestone crops out. Much of this 

 limestone has a concretionary structure, and easily 

 breaks down. Other beds are more compact. 



The same kind of limestone forms the banks of 

 Elk or Athabasca River for thirty-six miles down- 

 wards, to the site of Berens' Fort, now abandoned. 

 The beds vary in structure, the concretionary form 

 rather prevailing, though some layers are more 

 homogeneous, and others are stained with bitumen. 

 The strata for the most part lie evenly, and have 

 a slight dip, but in several places they are un- 

 dulated, and in one or two localities dislocated, 

 though I did not observe any dykes or intruding 

 masses of trap rock. 



Among the organic remains obtained from the 

 beds of limestone at the water's edge, were Producti, 



* See Appendix for a classification of tlie rocks of tlie New 

 York system. The Marcellus shale belongs to the Erie 

 division. 



