260 
Proceedings of the Royal Society 
the bank, there is a small patch of rock, about 10 feet long by 4 
feet wide, at the top of the bank, also smoothed and striated. 
Both rocks dip rapidly, the upper one at an angle of about 55°, 
the lower one in its lowest part is vertical. 
The principal rock is AB on the preceding diagram (fig. 1) and 
the smaller is CD. 
The dip of each is indicated by the section at one side. The two 
rocks do not front exactly in the same direction. The lower rock 
fronts hf. 11° W. for two-thirds from its east end; but near its 
west end it fronts about K 30° W. The upper rock fronts about 
N. 34° W. 
The striae on both rocks are exceedingly numerous. There is not 
half a square inch on either without ruts or scratches. Some of 
the striae on the larger rock are from 5 to 6 feet in length, and 
from \ to \ an inch in depth, and from 2 to 3 inches wide. 
There is, however, a difference in the depth of the striae which 
deserves notice and explanation. In the upper rock CD, they are 
much deeper and wider than they are generally in the lower rock. 
But in the lower rock, the grooves or ruts are deeper at the west end 
than towards the east. An explanation is suggested by the way in 
which the rocks front. If, as the rocks in Linton village indicate, 
the striating agent came from W.hT.W., the obstruction to its 
progress eastward would be greater by a rock facing N. 34° W. 
than by a rock facing N. 11° W. Hence to overcome that obstruc- 
tion, more pressure by the striating agent would occur, and deeper 
ruts in the rock surface would be made in the former than in the 
latter case. 
It may be mentioned, that whilst generally the stripe on the large 
rock AB are horizontal, near the top they rise towards the east at 
an angle of about 4° or 5°. It may be supposed that if the striating 
agent consisted of a mass of detritus, the weight of the mass would 
keep the striating tools in the low parts of the mass in a line more 
or less horizontal, but that at or near the top of the moving mass, 
its component parts would rise, so as to obtain a direction more in 
conformity with the normal movement towards E.S.E. 
In the upper rock, CD, there is a vertical joint, as shown in ihe 
diagram. It has had the effect of breaking the continuity of the 
striae. The joint has a breadth of 6 or 8 inches, forming a face 
