258 SIDNEY POWERS 



appears to extend under the Bay of Fundy. The coast charts do 

 not show any pronounced submarine ridges parallel to North 

 Mountain, such as some authors have referred to, and therefore 

 there is a lack of evidence of any major fault parallel to North 

 Mountain. Moreover, no geological structure under the Bay of 

 Fundy appears to be deducible from the submarine topography. 



Cross-faults in North Mountain are readily shown by offsets 

 in the ridge of basalt flows because the flows are dipping at a low 

 angle northwest. The offsets are at Digby Gut, Bay View, Gulli- 

 ver's Cove, Petit Passage, Grand Passage, and southwest of Brier 

 Island. The line of these faults is north-south. The displacement 

 of the flows by these faults, with the exception of the first and last 

 faults, is to the north on the west side of the fault. These offsets 

 are shown on the accompanying general map of the region. The 

 offset at Digby Gut is shown on Fig. 30, and that southwest of 

 Brier Island is shown by the position of a short submarine ridge 

 on the coast chart. 



As shown by Daly 1 and by Haycock, 2 these fault lines across 

 North Mountain, and also the depressions at Parker Cove and 

 Sandy Cove were occupied by rivers at the time that the Summit 

 peneplain was being developed over the region. When the pene- 

 plain was uplifted the rivers became rejuvenated and persisted in 

 their courses until the present valleys were cut. Headward erosion 

 up the valley which is now St. Mary's Bay diverted the streams 

 flowing across the basalt south of Bay View, and the more rapid 

 erosion in Digby Gut caused the abandonment of the Bay View and 

 Parker Cove valleys. 



THEORIES OF ORIGIN 



The faults which traverse the rocks of the Newark group are of 

 deep-seated origin, extending into the older formations. The 

 character of the underlying formations varies with the different 

 areas. Thus the Acadian Triassic is underlain in part by Carbonif- 

 erous folded sediments, in part by Silurian and Devonian slates and 



1 R. A. Daly, "The Physiography of Acadia," Bull. Mus. Comp. Zoo!., Harvard 

 College, XXXVIII (1901), 92. 



2 E. Haycock, "Records of Post-Triassic Changes in Kings County, Nova Scotia,'' 

 Trans. N.S. Inst. Sci., X (1900), 297. 



