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NATURE STUDY. 
Tributaries and Water Power. 
The effect of erosion upon the manufacturing possibilities of 
a region was recently set forth in a paper by Prof. John A. 
Dresser, On the Physical Geography of a Northen Section of the 
Appalachian Mountain System, first published in the Bulletin 
of the American Bureau of Geography. 
The Notre Dame Mountains comprise that portion of the Ap¬ 
palachian system which lies within the Provinc of Quebec, and 
are the unbroken extension northward of the Green Mountains 
of Vermont and the White Mountains of New Hampshire. 
After describing the chief geological features, Professor Dresser 
goes on to trace the geological development of water power in 
that region as follows : 
“ Although the region of the Notre Dame mountains has been 
one of great erosion, as well as structural complexity, and con¬ 
sequently its true geological features are often very difficult to 
discern, yet the dependence of important Topographical forms 
upon them is very readily apparent. The trend of the long hills 
of harder or more enduring strata is prevailingly parallel to the 
main axes of folding, and consequently the intervening valleys, 
whether caused by folding or erosion, have the same northeast 
and southwest direction. But these are only secondary valleys 
of drainage; for the principal rivers, such as the St. Francis and 
Chaudiere, have their courses transverse to the mountain ranges, 
still in the main retaining their pre Appalachian valleys, and run 
in a northwesterly direction to the St. Lawrence river of which 
they are themselves tributaries. These antecedent rivers have 
been strengthened by the inclosing of weaker ones, which, being 
unable to cross the barriers raised by the Appalachians, have 
turned their courses into the longitudinal valleys and so become 
their tributaries. Thus these river valleys which are again ap 
proaching the stage of maturity are often much older than the 
valleys of their tributaries. It accordingly happens that several 
of the tributaries still empty into the larger rivers with a consid¬ 
erable fall, thus giving rise to the best water lower of the district. 
The city of Sherbrooke, an important manufacturing center, owes 
its existence, in a large measure at least, to the magnificent wat¬ 
er power afforded by the Magog in its precipitous descent to 
join the St. Francis at that poiut. The Wattopekah is an east- 
