DALY: PHYSIOGRAPHY OF ACADTIA. 90 
latter principle, the completion of the Nova Scotian peneplain may be 
provisionally referred to the close of the Cretaceous period. The grounds » 
for this reference will be readily appreciated by those conversant with 
the similar land-forms of the southern Appalachians, where the dating 
of the plains of denudation does not admit of essential doubt. The gen- 
eral resemblance as to hardness among the rocks of North Carolina, 
Pennsylvania, New Jersey, and Nova Scotia, the striking similarity in 
Jurassic constructional topography in the four regions, and the equal 
completeness of the planation, lead us to infer in Nova Scotia, as _ 
in the other regions, that the peneplain was finished only after a 
large part of post-Triassic time had elapsed. Again, from the study 
of sediments in the southern Appalachian, it has been determined that 
the disturbance of each peneplained area from its position near base- 
level must have occurred in late Cretaceous or early Tertiary time. 
Most of the destruction wrought on the peneplains by subaerial erosion 
has been carried out during a Tertiary cycle that was not ideally com- 
pleted. The opinion of those best qualified to speak on the subject is, 
then, that these classic regions of the south have been wasting through 
post-Triassic time. This long period has been almost wholly occupied in 
the doing of two pieces of work, —the development of a Cretaceous 
peneplain covering each region entirely save for local monadnocks, fol- 
lowed by the etching out of Tertiary lowlands on the soft rocks and 
narrow Tertiary valleys on the hard. In Acadia, we have a parallel 
series of events. At present, I can discover no more trustworthy guide 
for the dating of upland and lowland facets than in this strong analogy. 
As is well known, the recognition of two cycles in New England and 
their placing in the geological record have been influenced by similar 
evidence and a like analogy. It is of course evident that in Acadia we 
are far from our physiographic base of supplies ; and the relations of 
these distant fields can bespeak no more than a strong probability 
for the conclusions stated. 
THE CaRBONIFEROUS LowLaNnps. — The Carboniferous of Cumberland 
County has been described in great detail by Logan and Dawson 
(Acadian Geology, ed. 2, p. 150), and we have added information in 
the Canadian Survey Report for 1895. The long section on the 
shore of Chignecto Bay, including the famous cliffs at South Joggins, 
has furnished the key to the whole area as well as to the structures 
of the Carboniferous elsewhere in Acadia. These beds aggregate nearly 
fifteen thousand feet in thickness and represent all the larger sub- 
divisions of the whole Carboniferous system. In Permian time, they 
