400 
BULLETIN OF THE NATURAL HISTORY SOCIETY. 
trout in the upper reaches of Mill Creek, below Fredericton, al- 
though the how between pools was very small, at a time when the 
stream bed, near its mouth, was as dry as the railway track which 
crossed it. 
The conditions for copious summer flow apparently do not 
extend westward from Andover across Maine, as the Aroostook, 
the main St. John above Allagash, and the Chaudiere River in the 
Eastern Townships, become astonishingly low at times. Indeed 
the steady supply of water for power at Grand Falls depends 
largely on four tributaries of the St. John, the Madawaska, Fish, 
St. Francis and Allagash Rivers, all of which have large lake ex- 
pansions in their lower or middle courses, ideally situated to 
serve as reservoirs. Eastward, in the Gaspe peninsula, those 
rivers I have seen appear to have a summer discharge dispro- 
portionately large for their limited catchment basins. 
Many factors contribute to the general features above noted. 
1. — The extent of forest. The forests retard evaporation by 
their shade, and control, by their sponge-like mosses and under- 
growth, a too rapid flow of surface water. Forest denudation, 
principally by fire, has probably been the primary cause of the 
marked decrease in the summer flow of the St. John, a decrease 
sufficient to greatly shorten, in the last forty years, the period of 
steam navigation above Fredericton. A dense growth of spruce, 
fir and cedar, very common in New Brunswick, is a better pro- 
tection against drought than a growth of deciduous trees. 
2. — Lakes, swamps and “deadwaters”. These store up, as 
reservoirs, the flow of many brooks, producing the more decided 
effect as they are the more remote from the source of the stream. 
Madawaska and Fish Rivers are the best local examples. Even 
the little beaver-dam may be noted in this connection, and the 
obstruction of fallen trees. The lat er often form the nuclei of 
extensive drift dams, such as “The Big Jam” of the Horton 
Branch of the Tuladie, which became so long and tangled that the 
stream-drivers cut a new channel for the river, in preference to 
undertaking its removal. 
3. — The condition and character of the soil as affecting the 
percolation of water. Obviously a soil allowing free percolation 
