4,'U JiULLKTIX OF THE NATURAL HISTORY SOCIETY. 
intrusive rocks which, no doubt, underlaid the Silurian rocks when- 
the valley of the river began to cut its present channel. 
It remains but to speak of the effect of the glacial period upon 
the development of the river as we find it to-day, I can trace but 
four effects. First, the various lakes were formed, at least in part, by 
dams of glacial drift. Second, the Nepisiguit Lake valley was, doubt- 
less, tiu’ned from the Nictor into the Nepisiguit by glacial drift. 
Third, all of the Little Tobique and the Main Tobique are smooth- 
fiowing, gravel-bottomed rivers, because of the masses of drift available 
to the rivers for thus smoothing their beds. That they lack the boulder 
rapids, so abundant in most of our rivers, is due to the character of 
the drift brought into them from the north west — the soft Silurian 
slates easily worn down, instead of granite and felsite. Fourth, several 
falls and gorges have been formed on the river by the blocking of the 
old valley in places with drift. Of this nature are, probably, at least 
some of the falls on the Right Hand Branch, the Little Falls, the 
Ledges, Red Rapids, certainly Sisson Falls with their grand gorge, and 
the Narrows in which the fall is extinct. 
The Tobique, then, despite its apparent complexity, appears to be a 
comparatively simple river with a steady and homogeneous develop- 
ment. It has captured no other rivers, and it has lost to other rivers 
nothing but the part of the Nictor Valley turned into the Nepisiguit 
in glacial times. 
46. — Great Forest Fires in New Brunswick. 
(Read March 5, U»01.) 
By far the deadliest enemies of forests are fires, and their preven- 
tion is the greatest problem of the forester. In New Brunswick they 
have been abundant and disastrous from very early times, doubtless 
from the one near St. John two thousand years ago, which Dr. Matthew 
has described,* down to the present. A list of these great fires, with dates 
and extent, would have much interest and considerable economic use 
in helping to determine the rate of rapidity of natural reforestation in 
given districts. Such data about forest fires are being gathered by 
the Division of Forestry of the United States. I wish here to call 
attention to early accounts of two of our greatest fires. The worst 
» Canadian Record of Science, viii, 213. 
