CHANNEL OF THE ST LAWEENCE. 379 



commerce of the river is destined to confer upon the 

 province. 



The geological structure of Lower Canada, to which 

 I have already in general terms alluded, affects the 

 navigable character of the St Lawrence below Quebec. 

 I have described the strike of the beds on the south side 

 of the river as running nearly parallel with the course 

 of the river from Quebec to the district of Gaspe, and 

 the inland country as consisting of parallel ridges of 

 more or less hard rock, with intervening valleys of 

 varying breadth and depth. The bed of the St Law- 

 rence is of a similar character. The channel runs along 

 the strike of the upturned metamorphic beds, and con- 

 sists of alternate ridges and hollows, as the dry land 

 does. Where the ridges are elevated they form islands, 

 rocks, and longitudinal reefs ; while the valleys form the 

 channels along which vessels proceed. 



But from this description it will be understood that 

 the deep water-channels, formed by the washing away of 

 the softer parts or beds of rocks, must, such as these are, 

 be irregular in width and direction. Where the river 

 is broad, there may be several channels or parallel longi- 

 tudinal valleys, any one or all of which may be inter- 

 rupted by narrow and shallow reefs, which will render 

 navigation, intricate, difficult, and — when the tides run 

 with great velocity — dangerous. 



Such is really the case in the St Lawrence. About 

 five miles below Quebec, the Isle d'Orleans divides the 

 river into the north and south channels, and beyond this 

 island, which has a length of twenty miles, it is divided 

 into three irregular — the north, middle, and south — 

 channels, by parallel ridges, the highest points of which 

 form islands, and the lower, rocky or sandy reefs, visible 

 only at low-water. Shoals also, at various points, stretch 

 out from the south shore, which narrow and give still 

 more intricacy to these channels. Hence, at a place 



