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BULLETIN OF THE NATURAL HISTORY SOCIPTI'Y. 
this supposition the change of the St. John and origin of the Main 
Tobiqiie would be Tertiary, or post-Tertiary. Second, it is possible 
this change was one cycle older, namely, that it took place by the 
same method of more rapid elevation northward (and scarcely any 
other explanation is under the circumstances imaginable) with the 
elevation of the earlier (Cretaceous) peneplain, and that the peneplan- 
ation of the later plateau was effected largely by rivers flowing into 
the St. John. There are certain facts which tend to substantiate this 
view, notably the very winding course of the rock-valley of the Main 
Tobique, which is best explained by the supposition that it existed as 
a ripe river wandering in a matured flood plain when the latest 
elevation began. This would make its age Cretaceous, or post-Creta- 
ceous, on the hypothesis of that age for this older peneplain. Third, 
the presence of little-disturbed Lower Carboniferous rocks in the low’er 
valley of the Main Tobi(]ue suggests an early connection with the sea 
by way of the present St. John valley, for fragments of that formation 
are found at intervals along the St. John down to the great central 
Carboniferous basin ; while on the other hand, in the northeasterly 
direction, no traces of it are known until the present Bay Chaleur is 
reached. Both the St. John and the Tobique may therefore be the 
successors of rivers which have flowed in their respective directions 
from pre-Carboniferous times. In this case the change of direction of 
the St. John an^ the formation of the Tobique would have occurred 
in consequence of an elevation northward accompanying the profound 
disturbances which took place in this region in the Devonian period, 
disturbances which affected the Upper Silurian rocks of this region, 
but did not affect those of the Lower Carboniferous. 
Further research will doubtless yield facts which will permit a 
decision as to these three ^possibilities. In the meantime it seems 
most probable that the Main Tobique existed prior to the latest 
elevation and assisted with the St. John in the peneplanation of this 
Silurian plateau.* 
* In iny earlier note on the Restigouche (No. 37), I iuiplj' too great an age to that river 
by speaking of it simply as post-Silurian. Its age must, I think, he the same as that of the 
Tobique, although in many ways it seems much newer. Thus, although in i-ocks at least 
as soft as the Main Tobique, its valley is much narrower and more V shaped, and almost 
entirely lacks intervales, which the Tobique nearly everywhere has. Were it not for 
its very winding valley in the lower part of its course, implying that it, like the Tobique, 
was a mature river wandering on a Hood plain at the beginning of the last elevation, I 
would consider it as originating only after the elevation of the peneplain, and hence much 
newer than the Tobique. In any case I think there is no douht its upper waters from the 
Kedgewick. if not from Tracy’s Brook, have been captured from the St. John. 
