NATURAL HISTORY AND PHYSIOGRAPHY OF NEW BRUNSWICK 
425 
of those did valleys. But the group of valleys has been so pro- 
foundly modified by the formation of the Bay of Fundy that much 
careful study will be needed to make its original relations clear. 
The second group of valleys, however, is much plainer in its 
relations. It includes all those from the Petitcodiac-Shediac 
valley to the Main Southwest Miramichi. They all have, this in 
common, that they lie in parallel courses from southwest to 
northeast wholly within the limits of the Carboniferous basin 
while the present rivers mostly head in line with branches of the 
St. John from which they are separated only by low divides, across 
which the original valleys no doubt extended. These divides, 
(the “Present Watershed” of the map), lie in a line running 
northwest between the Petitcodiac and Shediac, clear to the 
Main Southwest Miramichi, which it reaches just to the eastward 
of the remarkable right-angled bends of that river, after which 
it swings to the north across both branches of tTie Miramichi and 
then to the Northeast just east of the Northwest Miramichi 
(Minaqua) and Nepisiguit. This watershed, throughout its en- 
tire course is now crossed by but a single river, the Miramichi. 
The causes of this curious exception I have discussed in an 
earlier note (No. 54). In brief it seems due to the presence here 
of a great synclinal trough, parallel and homologous with the 
deep trough forming Bay Chaleur, the much shoaler trough in 
which lie Richibucto and Grand Lake, and the deep trough form- 
ing the Bay of Fundy. This watershed is obviously comparatively 
modern, and as it runs here parallel with the present coast, and 
hence with Northumberland Straits and with Prince Edward 
Island, I take it that the three latter all have the same origin, viz., 
low synclinal and anticlinal foldings parallel with the present sea- 
coast. However formed, this watershed is of profound im- 
portance in the development of the Northumbrian Rivers, since 
it not only beheaded all those of the group we are considering, 
sending most of their upper courses into the St. John, but also be- 
headed those of the next group, both south and north of the Mira- 
michi, turning their upper courses northward or southward into 
the Miramichi itself. But if the present watershed be modern, we 
