54 BULLETIN OF THE NATUKAL HISTORY SOCIETY. 



The River Systems which combined to form the St. John, 



I have said that the St. John was a combination of 

 three river systems. (See map on page 53.) Of these the 

 northern is that of the Restigouche, and embraces a large 

 area in the north of 'Hew Brunswick and Maine, which 

 was a sound of the sea in Silurian times. In later Devon- 

 ian times the sea had withdrawn nearly to the present 

 Baie Ohaleur, but it again invaded the valle}" along its 

 southern side as far as the Aroostook valley, at the be- 

 ginning of the Carboniferous period. The deformation 

 or change of level of the surface of this valley, which drew 

 off the waters of its western part in a southerly direction, 

 which now are tributar}' to the St. John, probably took 

 place during, or after, the Carboniferous period. 



Between the Silurian age, when this valley was filled 

 with marine sediments, and the beginning of the Carboni- 

 ferous period, the strata were folded and uplifted along 

 this valley, and through the hills on its southern side 

 ridges of granite were brought to the surface. The 

 depressing of the south side of the valley was subsequent 

 to this, and went so far as to carry this side lieneath the 

 sea again. ^ Scattered areas of red sandstone and conglo- 

 merate in this area were deposited at this time. 



The middle river-system may be regarded as that of 

 the Miramichi, since this river now drains away to the 

 eastward, the principal waters of this system. As it 

 existed at the close of Carboniferous time, this system 

 included all the central part of ISTew Brunswick, a wide 

 plain, opening and descending to the eastward, and its 

 western border is now marked by the Carboniferous rocks 

 A\'hich extend westward to, and include Oromocto lake. 



The third river system which the St. John made 

 tributary to itself, or of which, perhaps, it would be more 



* See the triangular area on the map, divided off by a line of dashes. 



