262 
Proceedings of the Boyal Society 
The only parts of the smoothed surface striated were those front- 
ing N.W. by hi., or a few degrees on either side of that point. 
The striae and ruts were quite as numerous and near one 
another as on the North British Railway rock. 
Their direction was from W. by S. or W.S.W., and most of 
them were approximately horizontal. 
Some of the ruts, especially at their west ends, were deep, show- 
ing, as Mr Stevenson says, that the striating agent, whatever it was, 
must have pressed on the rock with great force. Mr Stevenson 
also mentions another important fact, which I observed, that some 
of the ruts were inclined along the smoothed face up towards the 
east at angles of from 4° to 20°. 
SOUTH 
Fig. 2. — Part of Rock, North Berwick Law. 
The particular direction in which the striating agent came on the 
rock from the westward may be inferred, by considering that if it 
came in a direction 'parallel with the rock it might smooth but 
would not rut or groove, as there would be no severe pressure. 
Nor, on the other hand, would it produce grooves or ruts, approxi- 
mately horizontal and parallel, if it struck the rock at right angles. 
A line parallel with the rock would be S.W., and a line at right 
angles to it about N.N.W. The intermediate point would be 
W.N.W., from which direction, therefore, it may be inferred that 
the striating agent moved upon North Berwick Law. 
The annexed, fig. 2, AB and CD, shows a portion of smoothed rock 
with stria? and ruts. These were only upon the rockface fronting 
