392 SURFACE GEOLOGY, PICTOU COAL FIELD—POOLE. 
western end of the North Mountains in Annapolis and Digby 
Counties: such eminences as the Greenhill in Pictou County and 
Onslow Mountain in Colchester are due in great part to the 
removal of soft rocks by denuding agencies of this period, while 
the harder rocks remained in projecting ridges. On the other 
hand it might be shewn that many masses of rock which once 
projected above the surface have been greatly diminished or 
entirely removed.” 
This supposition, that the glacial was a period chiefly of 
denudation, the deposits being little more than sufficient to leave 
a record of its existence is somewhat at variance with that 
already implied in this paper. But while there can be no 
doubt that denudation in part was a result of the glacial period, 
and the rounding of the Atlantic Coast hills certainly effected by 
ice in that and probably similar periods of previous ages, obser- 
vations in the small section of country now under consideration 
seem to point to other conclusions, at least with regard to part 
of its configuration. 
Some influence other than relative hardness of the strata to 
resist the abrading influence of ice would seem to have been at 
work in determining the positions of the hills and hollows. 
Take the case already referred to, the conjectural ancient valley 
of McCulloch’s brook, it is not easy to suppose that ice in any 
form could have plowed it out, and worked in a deposit 60 and 
80 feet thick, and at the same time left at levels two and three 
hundred feet higher measures of much softer texture. The 
conditions observed would be more readily accounted for by 
imagining that the face of the country previous to the drift 
period had very much the same general contour that it has 
to-day though somewhat less reduced in height no doubt, and 
that that contour was acquired by suberial denudation sub- 
sequent to the period of stratigraphical disturbance. 
It would seem to be something more than a coincidence, the 
association of lines of lesser elevation and well marked disloca- 
tions. The bed of tke east river follows through a very broken 
section of ground, the entrances into, and the exits from, the 
basin of other water courses are invariably associated with dis- 
