896 
Proceedings of the Royal Society 
Near Glasgoiu there are rock surfaces presenting two sets of strise, 
one implying a movement from the N.W. and N.E. respectively 
i^Ahstract^ p. 838). 
These different directions in the lines of striae may, in some cases, 
indicate two separate agencies, moving independently of one another 
at different periods. But it is also possible that the same agent 
might he deflected from its normal direction by local conditions. 
An example of such a deflection is given by Sir James Hall, in his 
well-known paper on “Eevolutions on the Earth’s Surface” read by 
him in the year 1812, and printed in the 7th vol. of the Ed. Roy. Soc. 
Trans. He names a locality (p. 196), where “the rock presents 
furrows and scratches similar to those on Corstorphine Hill,” — but 
where “ the action of the stream has undergone a visible modifica- 
tion, by the prominent form of some parts of the rock, in conse- 
quence of which the dressings have in some places been turned 
to the amount of 5° or 6° out of the general direction, which, how- 
ever, they resume gradually in the course of a few yards.” 
In Haddingtonshire, whilst the normal direction is generally 
from W.N.W. on horizontal rock surfaces, the movement slightly 
changes where the striating agent struck upon, and had to pass 
over, a rock which sloped. For example, at Linton, on a rock 
surface sloping down due north, at an angle of 35°, the direction 
on that surface is E. and W. {Abstract, p. 803). 
At the railway cutting, not far from Linton, the rock surface 
slopes down due north, at an angle of 10° to 20° ; and the opposing 
rock surface being here of considerable extent, the direction of the 
striae is E. 15° N. {Abstract, p. 803). 
On North Berwick Laio the smoothed rock surface dips down 
N. 10° W., and the direction of the striae is E. 22° N. {Abstract, 
p. 805). 
3. Another set of facts, hearing on the direction in which the 
transporting agent has moved, is the position of individual boulders. 
A very large proportion of boulders have been lodged on the west 
slopes of hills. Many are hutted up against rocks, or lying on other 
boulders, in a way which shows that they came from the westward. 
4. Another fact has been observed, which shows that there has been 
a general movement over this part of Europe from a westerly point. 
Thus in describing the beds of boulder clay in the neighbourhood 
