NATURAL HISTORY AND PHYSIOGRAPHY OF NEW BRUNSWKHC. 441 
As a result of evidence drawn from his personal observations^ 
from a review of the literature of the region, and from a comparison 
with the well-known districts of New England, the author concludes 
that the surface of Acadia consists essentially of two great peneplains. 
The oldest of these, completed in the Cretaceous age, includes all the 
harder rocks, and hence the greater elevations, the surviving facets of 
which are the Southern Plateau of Nova Scotia, including all its 
central and southern parts, the North Mountain, the Cobequid Plateau, 
the Southern Highlands of New Brunswick, and, presumably, the 
Central Highlands also. This peneplain must once (according to 
current theories of the peneplain) have stood at or very near the sea 
level, to which, with the exception of some harder rocks remaining as 
monadnocks, hard and soft rocks alike must have been planed down 
by erosion. Then an elevation began, which, as the progressively 
greater height northward of the surviving facets shows, was much 
greater northward, carrying the New Brunswick highlands much 
higher than those of Nova Scotia, which on the southern coast of that 
province dip down beneath the sea. This elevation of the land per- 
mitted the rivers to begin again their work of erosion, and they 
proceeded to carve the peneplain. In the harder rocks they slowly 
cut deep channels, while in the softer rocks this was relatively quickly 
accomplished, and then lateral erosion began. A long period of 
stability followed in the Tertiary, during which the rivers (possibly 
with some tidal co-operation) carved the soft Carboniferous and 
Triassic rocks down to a new peneplain at sea level, or near it, thus 
giving origin to the second or Tertiary peneplain,* which includes the 
Annapolis Valley of Nova Scotia, the Colchester and Cumberland 
lowlands, and the great Eastern Carboniferous plain of New Bruns- 
wick. An elevation followed, permitting the rivers again to cut down 
deeply into these lowlands, as in many places they have done, and 
this was succeeded by a period of submergence, drowning many of the 
♦The fact that neither Cretaceous nor Tertiary formations occur in these provinces is 
not necessarily a fatal objection to the theory assigning those ages to the peneplains. 
According to the theory, the highest facets of the entire country would have stood near 
sea level at the close of the peneplanation in the Cretaceous ; but since the newer peneplain 
is very much lower than the older, any deposits formed in the Cretaceous would necessarily 
have been eroded away before the erosion could affect the older rocks. Similarly we may 
suppose that any Tertiary rocks formed during the Tertiary planation of the newer and 
lower peneplain have since been washed away, or, more probably, lie outside of the limits 
of this peneplain, which in many places dips beneath the sea. 
