NATURAL HISTORY AND PHYSIOGRAPHY OF NEW BRUNSWICK. 457 
flows swiftly, but smoothly, and the whole aspect of this part of the 
valley from above the Upper North Branch is that of an ancient 
ripened, though drift-bottomed valley. At the six and one-half mile 
turn the river bends abruptly northward ; the country happens to be 
burnt, affording an excellent view of the surroundings, and here, 
extending off to the southeastward, in the line of the course of the 
river above, is a series of unmistakeable kame-hills of the typical form 
and appearance. Less than a mile below this turn, at an elevation of 
1,045 feet or less, begin the bad rapids and falls which have made this 
river famous. Here the river narrows and falls over granite ledges 
and through small gorges with vertical granite walls. The whole 
aspect of this stretch to Indian Brook is typically post-Glacial. 
Below Indian Brook, to the North Pole Branch, the river continues 
rough, though not in so marked a degree as above. At the North 
Pole Branch the character of the river changes, and it becomes broader, 
more open, comparatively easy and pleasant for canoeing, with a con- 
tinuous slope, but no bad rapids and no falls. This character continues 
to the mouth of Mains Brook, and beyond it to near seventeen mile 
bend. Evidently ail the river from the North Pole Branch to the 
seventeen mile bend runs in an ancient well-ripened valley, and the 
part between Indian Brook and the North Pole Branch seems some" 
what older than the obviously post-Glacial part above Indian Brook. 
The interpretation of these facts might be difficult enough were it not 
for another brought out by the maps,* namely, that in a line between 
the six and one-half mile bend and the mouth of Mains Brook lies the 
valley occupied by Mains Lake and Brook. All these facts taken 
together seem to point to but one conclusion, namely, that in pre- 
Glacial times the main river flowed through the present valley of 
Mains Lake and Brook. The kame hills at the-six and one half mile 
bend constitute the great glacial dam which turned the river aside and 
sent it over a low part of its valley to fall by a post-Glacial channel 
into the valley of Indian Brook, then a small branch of the North 
Pole Branch. It followed this valley, which it is now enlarging, to its 
junction with the North Pole Branch, then a large stream which fell 
into the old main river at the mouth of the present Mains Brook. It 
* For all the facts of topography referred to in this paper, the original very detailed 
survey map of 1838, by Berton, is much more valuable than the modern imperfect compila. 
tions from it. 
