182 SOME NOVA SCOTIAN ILLUSTRATIONS 
II. GLACIAL TROUGHS. 
It is probable that most observers are familiar with glacial 
markings or striations, the scores left by the great ice-sheet of 
the Glacial Period in the course of its movement southward, and 
which are abundantly exhibited in the Park and elsewhere 
about the City of Halifax. But probably few, if any, have seen 
such a proof of the power of ice action to carve the surface over 
which it moves as is afforded in the photographie plate No. 1x. 
This remarkable view was taken on Lockeport Island, within 
ten or fifteen minutes walk of the town of Lockeport. The 
rocks at the place are Cambrian slates and quartzites, the latter 
predominating, in beds 10 to 15 feet in thickness, and dipping 
south-easterly at an angle of about 50°. The trough, which is 
plainly shown in the picture, runs in the direction of the beds, 
and, no doubt, owes its origin in part to that fact, and to the 
unequal hardness of the two kinds of rocks which the strata 
contain; but even with all allowance for such favoring cireum- 
stances, the magnitude of the result is not only unusual but 
phenomenal. Not having any means of exact measurement at. 
hand, the writer is unable to give precise data as to the dimen- 
sions of the trough, but is safe in saying that its length was at 
least 30 feet, its depth at centre at least 4 feet, and its breadth 
as much as 4 or 5 feet, the larger part being in mnassive quartzite. 
The form of the trough, as seen in the view, was in section not 
unlike that of a canoe, the sides curving gracefully down to the 
middle line, while, along the same sides and parallel with the axis 
of the trough, were numerous striations of the ordinary kind, also 
clearly seen in the photograph, and leaving no doubt as to the 
nature of the agent to which the trough itself is to be ascribed. 
A trough of such magnitude, due to glacial erosion, is 
certainly a very unusual occurrence, at least in this part of the 
world ; but, remarkable as it is, it in turn sinks into insignifi- 
cance in comparison with some other troughs, due to the same 
agency, which were subsquently seen. These occur about mid- 
way between Port-la-Tour and Baccaro, on the coast of Shelburne 
County, and upon a small point, which is almost an island, 
