&2 ROYAL SOCIETY OF CANADA 



that a larger number and among them some of our most important rivers 

 date from pre-glacial times. From the distribution of the Carboniferous 

 rocks found in nearly horizontal beds in portions of Carleton county and 

 again south of the gi'eat central basin on the summits of the Quaco range 

 and in the upper portion of Shepody Mt., at an elevation of over 900 feet 

 above the present sea level, it would seem probable that at that time the 

 Province was submerged, except perhaps the higher portions of the 

 northern Highlands. In the long period of denudation which followed 

 the Carboniferous era, and during the whole of which the land, as shown 

 by the absence of Mesozoic sediments, was above the sea-level, there may 

 have been brought about such a condition of things as has been already 

 referred to in connection with Prof. E. A. Daly's theory of Cretaceous 

 and Tertiary peneplanes. The Carboniferous tract is such a peneplane 

 4o-day, and the number, position and elevation of its outliers seem to indi- 

 cate its former much wider and higher distribution, and this condition 

 of things probably persisted imtil the beginning of the Quaternary Era. 

 It was probably at the close of the Cretaceous period that deformation, 

 with greater elevation northward, began and determined the general 

 southward slope to which reference has been made. Erosion being re- 

 newed the run-off would be determined by the existing slopes, irrespec- 

 tive of underlying structures, but as denudation proceeded alternate 

 belts of harder and softer rocks would be exposed, the former to be 

 gradually sawed through and the latter to originate smaller tributary 

 streams. The course of the St. John river from its source at Baker Lake 

 io the vicinity of Edmundston is that of a structural valley and the same 

 is true of the Grand Lake depression, the Washademoak, the Belleisle 

 and Long Eeach valley, the Kennebecasis and the Bay of Fundy, while 

 ior most of the way between Edmundston and Fredericton, in the section 

 between the Washademoak and the Belleisle, between the latter and the 

 Kennebecasis and again in the îTarrows about Indiantown its direction 

 is transverse to the geological structure. The transverse up-warping 

 which determined the separation of the rivers flowing easterly into the 

 Gulf from those which flowing westward became tributary to the St. 

 John, could not have been determined prior to Triasslc times and may 

 have been much later. 



The influence of the powers of resistance presented by belts or areas 

 of different degrees of hardness in these processes of erosion is well illus- 

 trated in the case of the St. John, where the form of its valley as well 

 -as its direction shows in many instances a close association with varia- 

 tions of this kind. Thus in the upper courses of the stream where the 

 tatter traverses areas of highly disturbed Silurian slates the valley is 

 narrow and deep; "it exhibits further contraction in the gorge of the 



