74 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 
rocks, ——a period of important deformation that has also been de- 
monstrated in Virginia. More localized areas of such upturning, 
occurring at times not similarly occupied elsewhere, are represented 
by the Acadian tract which was profoundly disturbed during the late 
Devonian. These local foldings have, however, followed the same laws 
of axial development that were obeyed in the more general mountain- 
building, and have not interfered with the essential tectonic agreement 
of the system. 
Thus a great generalization has been built up, in largest part by 
structural studies, aided, of course, by paleontological evidence, and 
by the lithological investigation of the sediments involved. Of late 
years a fourth efficient means of further developing the conception has 
been wrought out, simply by the recognition of the fact that sedi- 
mentation has its correlative in denudation, and that the later forms of 
subaerial erosion on unsubmerged areas may be expected to show similar- 
ities wherever the conditions of erosion were equivalent along the major 
axis of the system. The remarkable parallelism subsisting among the 
forms of wasted land-surfaces in New England, in the New Jersey- 
Pennsylvania region and in the southern Appalachians, has been 
broadly sketched by Davis? and further emphasized by Willis, Hayes, 
Campbell, Keith, and others. As yet the definite statement as to how 
far this last method of correlation may be extended to the Acadian 
division of the belt has not been made; in the following pages it is 
proposed to describe briefly and illustrate some of the more important 
erosion-forms in Nova Scotia and the adjacent portions of New Bruns- 
wick and to inquire into their interpretation. 
The field-work on which this sketch is based was confined to a ten 
days’ tour on the main lines and branches of the Intercolonial and 
Dominion Atlantic railways, supplemented by a second railroad trip 
from Montreal to North Sydney and a cruise close inshore from Cape 
Canso along the southern coast to Halifax, where the train was taken 
for Yarmouth. Such rapid views of the country may possibly lead to 
results of some value if they be checked and amplified by the study of 
the detailed works published by governmental survey or by private 
individuals. 
The lack of good topographic maps of the inland areas renders 
the discussion difficult, and many interesting questions must on that 
account be left untouched. The best cartographic data are derived 
1 The geological dates of origin of certain topographic forms on the Atlantic slope 
of the United States. Bull. Geol. Soc. America, 1891, Vol. 2, p. 545. 
