NATURAL HISTORY AND PHYSIOGRAPHY OP NEW BRUNSWICK. 
199 
at an abrupt angle, showing it to be morphologically a branch of 
the broad ancient valley of Back Creek, and not the main stream. 
5. Back Creek and the lower part of the South Branch. — The 
.South Branch from the Forks to Back Creek, and Back Creek 
itself wind about in a continuous single, broad, mature, intervaled 
and terraced, obviously ancient, valley. This valley narrows 
towards its head, but merges gradually, without a break, into the 
valley of the Nerepis, which continues its direction without devi- 
ation to its junction with the St. John and beyond that through 
the Short Reach, Grand Bay, and South Bay. There can be no 
doubt, I believe, that this Back Creek — Nerepis Valley, is morpho- 
logically a single one. The question now at once arises as to its 
original direction of flow. This is easily answered, and in two 
ways. First, certain streams near the head of Back Creek have a 
re-entrant or southward direction,* (compare the map), and sec- 
ond, the general river directions of this entire region necessitate 
a southerly direction. This raises the question as to the original 
head of the valley, and here again I think the answer is fairly clear. 
This same valley extends up the northwest Oromocto, (cutting 
across the Forks near the low hills on the south) and up the 
Yoho River to its head. But it did not end here, for it extended, 
I believe, through a gap in the hills to the flat country at the 
source of Gardner’s Creek, through Lake George and the Pokiok, 
and into the St. John, and this ancient and important valley we 
may well call from its modern remnant The Nerepisian Valley, the 
further extension and relations of which to other neighboring 
rivers will be found discussed in a later note (No. 75). 
6. The Main Oromocto from Forks to Mouth. — This part of 
the river has at present a very uniform character. It is a dead- 
water creek, winding in a very broad valley through extensive 
intervales. In only one place, namely, just above French Lake, 
does it come in contact with rock-formed upland.** In conse- 
* There is, however, another explanation for these re-entrant streams, namely, that in 
immediately pre glacial times the Nerepis headed farther west, and these were branches of 
it, and not of Back Creek, a point still to be investigated. For some distance north of the 
present divide between the two rivers, the Back Creek flows over a ledge-rock bottom, as 
may well be seen from the railway train. This implies that its course here is post-glacial; 
but this is not necessarily the case, for either a pre-glacial channel may exist on one side 
or the other of the present channel, or this may represent the pre-glacial summit of the 
Tocky divide between Back Creek and Nerepis. 
**This, the only case in which the river actually now touches the rocky upland, is on 
the right bank. In general, this river seems to keep nearer to the upland on the right than 
on the left, a supposition confirmed by the representation of the intervale upon the surface 
geology map. This tendency to keep to the right is very likely due to the well-known 
tendency of rivers in the northern hemisphere to erode their right faster than their left 
■banks, due to the effect upon the moving water exerted by the earth’s rotation 
