' PRE-CAMBRIAN ROCKS OF NEWFOUNDLAND 453 



at each point, and hence controlled in a great degree by the gross 

 features of the pre-glacial topography. The directions of ice 

 movement are easily decipherable from the abundant striations, 

 the stoss and lee sides of hills (Fig. 3), and numerous bowlder 

 trains which may be traced to their source. 



Every bay indenting the coast of the Avalon Peninsula presents 

 all the essential characteristics of a fiord, such as high, steep, 

 straight, parallel walls, threshold across its mouth, and small, 

 insignificant streams entering its head. In Trinity Bay (Fig. i) 

 the inner, deepest portion is over 1,100 feet deeper than the sill 

 across the mouth. Where the relations are known there is a remark- 

 able parallelism between the strike of the major fault planes and 



Fig. 3. — Glaciated hills with lee and stoss sides southeast of Harbour Main, 

 Conception Bay. Lee sides are on the north-northeast ends of hills. 



the trend of the coast line, but the writer could find no evidence 

 that faulting was directly responsible for the formation of the 

 fiords. The faults and fractures controlling the lineaments of the 

 bays are of ancient date — older than the peneplains — and their 

 influence on the present topography has been indirect. The 

 formation of the sills across the mouths of the bays by deposits from 

 currents is improbable, since this theory will not hold for the inland 

 fiords of Gander Lake, Red Indian Lake, or Grand Lake, the latter 

 with its deepest part not less than 988 feet below sea-level and with 

 its outlet 116 feet above sea-level. In view of these conditions 

 glacial overdeepening of river valleys probably associated with some 

 submergence followed by the invasion of the sea seems the best- 

 adapted explanation for these fiord bays 



