NATURAL HISTORY AND PHYSIOGRAPHY OF NEW BRUNSWICK. 
203 
There are two very striking facts about this system, of which 
the explanation is not obvious. First, the courses of the rivers 
are in large part independent of the geological formations, for 
many of them, especially the westernmost, run directly across the 
formations, hard and soft alike. Second, the principal river of 
this system, the St. John, has a curious zig-zag form, with some 
of its parts in the prevailing southeasterly course, but others at 
right angles to it, and its course as a whole forms almost a semi- 
circle around rivers west of it. All of these phenomena, I 
think, can now be explained, and the key to their interpretation 
is found in the probable physiographic history of the Oromocto, 
supplemented by that of the Keswick, outlined in the two preced- 
ing notes. 
The general lack of correspondence between river-courses and 
the underlying formations can have, it would appear, but one 
meaning. The river valleys must be much older than the present 
■exposure of those formations, and must have originated on a 
general uniform southeasterly slope which could have been formed 
in either one of two ways. First, this entire country was covered 
by level homogeneous deposits, such as the Carboniferous sand- 
stones form in the eastern part of the Province at the present day ; 
these became elevated from the sea with a southeasterly slope on 
which the rivers formed and gradually eroded their valleys down 
into the underlying deposits. Second, all of the formations were 
planed off uniformly, either by sea or river action, to a great pene- 
plain, which, on its elevation, sloped southeast, thus establishing 
the parallel southeasterly valleys. Which of these two explana- 
tions is correct is not, from our present point of view, important. 
The great crucial point is this, that by one or the other (or possibly 
by some other) method, the rivers of this region were given, after 
all the formations were deposited, a general southeasterly course, 
and this they have largely retained down to the present day. 
Where they have deviated from the arrangement, as they have 
very often, it is because of the influence of the underlying forma- 
tions, as will be shown later in this paper. 
So far as I have been able to work out the original valleys of 
this system, they are as given below. The descriptions can be 
