Section IY., 1903 [ 143 ] Trans. R. H. C. 



"VII. — A Suhmerged Tributary to the Great Pre-Glacial Fiver of the Gulf 



of Si. Lawrence. 



By H. S. Poole, D.Sc. 



Associate of the Royal School of Mines. 

 (Read May 19, 1903.) 



The chart of the Gulf of St. Lawrence has an interest for the geo- 

 logist, as well as value for the navigator and the geographer. It tells 

 of much more than the mere depth of the water and the position of 

 the shore lines and it certainly suggests more of the unseen than many 

 similar publications. 



When the isobaths that stud the surface of the chart are noted and 

 contoured, more is portrayed than would otherwise be suspected. 



The whole story which these contours and soundings disclose, it is 

 not here proposed to review. Part of it has already been written, and 

 its importance has been fully recognized in the case of the broad valley 

 that carried onward the St. Lawrence river through the gulf and Cabot 

 Strait to the ocean, to the abyss of the Atlantic, 100 miles' beyond the 

 existing shores. 



The part of the gulf to which reference will now be made, lies on 

 the south side of the great valley. It was a high plateau when the St. 

 Lawrence river rolled its erosive floods past it to the sea, and contours 

 on the charts of its surface indicate a previous existence of a complete 

 drainage system, only partially disguised by subsequent deposits and the 

 obliterating effect of waves and currents as the Avater rose and covered 

 the land. The drainage of the region stands revealed when it is 

 elevated a few hundred feet or more above its present level. It was 

 chiefly concentrated in two main channels, one on the east and the 

 other along the west confines of the area, both discharging northward 

 into the ancient great river. The channel to the west was an extension 

 of the present Baie des Chaleurs, and received the waters of the Meta- 

 pedia, the Eestigouche and, by a branch of the estuary, the Miramichi, 

 and other streams of northern New Brunswick; while the eastern chan- 

 nel carried to an embouchure near the island of St. Paul, in Cabot 

 Strait, the rivers that now empty into the gulf from the eastern dis- 

 tricts of Nova Scotia, and the western parts of Cape Breton. 



The necessary data not being at hand to enable the whole of the 

 area to be contoured, the eastern channel only has been worked out. 

 It is the one shewn on the accompanying map. When the subject was 



