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BULLETIN OF THE NATURAL HISTORY SOCIETY. 
and more smoothly, but ever swiftly, over coarse drift amid inter- 
vales and islands down to the South Branch. 
Throughout this extent the ledges are always of slate or con- 
glomerate (conglomerates resembling somewhat those of the 
Carboniferous appearing eight miles above the Forks, though 
giving way again to slates below), never of granite; yet the 
boulders which fill the river are mostly of the latter material, 
derived no doubt from the granitic interior, though their distance 
of transport is notably great. 
The origin and development of this part of the river seem in 
general plain. It is wholly long pre-glacial, and no doubt a con- 
tinuation of the old valley above, though it may be, in part at 
least, younger than the latter. Two possible former differences 
in the valley may be noted. There appears to be an old valley 
extending westward from the big bend four miles below the 
Little South Branch, through which the latter may originally 
have emptied. In this case it is very possible that the pre-glacial 
course of the waters of North Branch Lake was via the Little 
South Branch lakes to this point, as suggested by the map. Again 
the directions of the river suggest that formerly this river may 
have cut across from two miles above the South Branch by a 
shorter route to the river below, joining it a mile or two lower 
than at present. 
8. The (Main) South Branch . — This branch I know only 
from hearsay. It has several lakes at its head, described to me 
by a lumberman as some ten or twelve in number, and “ very fine 
lakes.” At its mouth it is a beautiful smooth-flowing stream, 
apparently somewhat larger than the North Branch, and it is said 
to be easily navigable for canoes as far as the Lower Falls. 
9. From the Main South Branch to its mouth . — Throughout 
its extent, this part of the river has the typical characteristics of 
all of our rivers flowing through the Carboniferous formation. 
In its eighteen miles to the Dungarvon it falls some 179 feet, or 
less than ten feet to the mile, while in the remaining eight miles 
to its mouth it falls 80 feet, or at about the same rate, a great 
contrast to the upper part of the river. It winds about over 
drift among intervales and terraces in a wide low-walled valley; 
