13G 
15ULLET1N OF THE NATURAL HISTORY SOCIETY. 
4^8. — The JMorrholo(;y of New Brunswick Waterfalls. 
IRead March 5. 1901). 
New Brunswick is a glaciated land of many rivers, and hence has 
many waterfalls. Waterfalls interest us in three ways : for their 
jesthetic charm, for the scientific problems involved in their origin, 
and for their economic value. I shall here discuss particularly the 
second of these phases of the subject. 
Considered as to their origin, waterfalls group themselves into the 
following categories, which, like all of our classifications of natural 
objects and phenomena, are not distinct and exclusive, but merge into 
one another in the most varied combinations. Nor is it possible to 
draw any line between falls and rapids, for not only are there all 
gradations between, but there are some undoubted rapids which are 
much higher than some undoubted falls. 
1. Glacial Falls. — This class includes the greater number, 
the best known and the largest of our waterfalls. Their mode of 
formation is familiar to all. In the Glacial Period masses of drift 
were often thrown into and across our river valleys. Where the 
valleys were deep and not completely filled, the drift was easily washed 
out again, leaving only the larger boulders to form the falls and rapids 
to be considered in the next class. Where the valleys were shallower, 
or the sides very irregular, the glacial dam often forced the water to 
leave its old channel and flow along or over a part of the rocky wall 
of the valley to fall again into the old valley below the obstruction. At 
the latter point a fall would be formed into a basin receiving both the 
old and the new courses of the river. But the fall, as falls always do, 
would begin to cut back into the rock over which the river flowed 
until a deep gorge is formed with the fall at its head. Above such 
falls, the river, still dammed back, often shows but a gentle current 
for a long distance. In this condition are most of the greater falls of 
the prov^ince, particularly those in the main courses of our principal 
rivers. Such are the Grand Falls of the St. John, with its pre-glacial 
valley on the right bank, the Grand Falls of the Nepisiguit, with its 
old valley on the left bank,* the Falls of the Magaguadavic at St. 
(George, with the old valley on the left bank, where the town stands, 
Aroostook Falls and the great falls on the Sisson branch of Tobique. 
On this channel, see this Bulletin, No. XIX, 818. 
