No. 8.] MATTHEW — GEOLOGY OF NEW BRUNSWICK. 449 



for in all the valleys of this region, there are deposits, varying 

 from 20 to 50 feet in thickness, of Leda-clay, supplying an im- 

 pervious lining to the hollows left by the arctic current. Such 

 clay beds may be seen at Harcourt Lake, rising up on the slope 

 of the gravel mound near by. By a similar covering of the 

 lower slopes of the gravel banks at South Bay, the Saint John 

 River is upheld, and compelled to discharge its waters through 

 the narrow and tortuous passage terminating in Saint John 

 Harbour. So also the Maga'davic River, but for a similar bar- 

 rier, would have found its way to the sea, through Lake Utopia 

 and the L'Etang River ; for the ridge at the head of this river, 

 described on a foregoing page, shews a clay coating at the foot 

 of the slope on each side. Spruce Lake, near (7 miles west of) 

 St. John, is turned eastward by a bank so low that a few feet 

 of elevation would cause its waters to flow into Musquash Har- 

 bour : and the chain of lakes in Loch Lomond Valley, 10 miles 

 east of Saint John, would be drained dry, but for the barrier 

 presented by gravel banks and clay beds at its western end. 

 Finally, the large marshy tract of barren, bog and lake, extend, 

 ing from Cranberry Lake to the basin of the north-west branch 

 of Digdeguash River, is closed at one end by the gravel ridge, 

 No. 4 of the table, and at the other by gravel banks at the 

 mouth of the north-west Digdeguash. 



These few instances are referred to, because the places are 

 easily accessible; but I may add that where I have examined 

 the rims of lake basins in southern New Brunswick, I have 

 found very few examples of lakes having rims wholly of rock. 

 In the m;ljority of cases, the shape and position of the lake 

 basins is more readily explicable by the theory of current 

 erosion than by any other : as regards the rocky hollows in 

 which they lie, the lakes, like the fiord-harbours to which I have 

 referred in a previous article, appear to be pre-glacial ; but as 

 regards the superficial deposits, post-glacial. It^ would be 

 tedious to specify instances in support of the latter conclusion ; 

 but a study of the region to which these remarks relate, with 

 the aid of a good map, will confirm it. 



Tidal Erosion in the Bay of Fundy. 



In order that a comparison may be made of the effect of tidal 

 wear in the Bay of Fundy, with the phenomena of the Syrtensian 

 Vol. VII. FF No. 8. 



