50 



DEPARTMENT OF THE INTERIOR 



2 GEORGE V, A. 1912 



Excepting the Purcell Lava these rocks will be described in the present 

 chapter. The volcanic formations of the range are described in chapter IX. 



WATERTON FORMATION. 



The lowest member of the Lewis series as exposed within the Boundary 

 belt was seen at only one locality — at the cliff over which the waters of Oil 

 creek (Cameron Falls brook of the older maps) tumble from the hanging valley 

 of Oil creek into Waterton lake (Plate 8). This member may be called the 



4 Miles 



Figure 5. — Diagrammatic map showing position of the Structure-section (See Fig. 6) 

 east of the Rocky Mountain Summit. 



Waterton dolomite. At the cascade it is seen to be conformably overlain by 

 the Altyn limestone. From the sharp bend below Oil City the creek faithfully 

 follows the axis of a strong anticline which pitches gently northward. As one 

 descends the creek he also descends in the stratified rock-series, and at Cameron 

 Falls walks upon the Waterton dolomite, the visible core of the anticline. The 



