David Milne, Esq., on Polished and Striated Bocks. 165 



they occur on the smoothed parts of the rock, shew that they have 

 been worn down by the smoothing agent wherever they were exposed 

 to its operation. There are places where the smoothing agent has 

 not apparently acted so strongly, or at all, on these hard concretions, 

 These are the parts of the rock which face the S. and S W., indicating, 

 therefore, that the rubbing and smoothing agent had passed from the 

 N. or NE. 



Over this knoll there are several large boulders of greenstone, 

 and a multitude of small stones sticking promiscuously in the well 

 known clay usually characterised by them. 



Above this deposit, there are stratified beds of fine clay lying ho- 

 rizontally. 



About 100 yards nearer Linton, there is another ridge of trap, 

 which has been cut through for the railway. Its NW. face exhibits 

 also a smoothed and polished surface, about 8 or 9 feet square, with 

 numerous horizontal striae. 



These smoothed rocks are at a height of about 90 feet above the 

 sea. 



It is proper to mention here, as bearing on the nature of the agent 

 which passed over and smoothed the rocks described, that all the 

 trap ridges in the neighbourhood of Linton are bare on their north 

 sides, and have tails of clay and gravel on their south sides. In 

 particular, there is a remarkable vertical dyke of porphyry, called 

 Smcaton Hughs, running by compass E. and W., the north side of 

 which presents, for several hundred yards, a perpendicular wall from 

 30 to 50 feet high, and which on the south side has an accumulation 

 of debris which conceals its south side, even to the top, 



I may here, also, allude to the recent discovery, in Fife, of trap 

 rocks, smoothed and furrowed, in a way precisely similar to those at 

 Arthur Seat and Linton. I have not, myself, seen the rocks, and 

 am indebted, for the following description of them, to Mr R. Cham- 

 bei*s. The discovery took place in iftiproving the road between 

 Burntisland and Kinross. A cut for that purpose was made in the 

 crest of a low range of hills looking to the north-west, over the wide- 

 spread morass around Beath Kirk. At this point, the ridge consists 

 substantially of a thick bed of greenstone, dipping to the north-west, 

 at an angle of about 40''. At the base of the exposed rock, some 

 diluvium, surmounted by the sandy deposits of a mossy lake, may bo 

 seen. The surface is straight-faced, and bears the manifest appear- 

 ance of having been polished and furrowed by some mechanical agent. 

 This agent has acted in a steady and uniform manner, for the polish- 

 ings and furrowings are all in one direction. It is remarkable, how- 

 ever, that they dip to the SW., at an ani^le of about 25^ 



It appears that this smoothed and furrowed rock is not in any 

 mountain gorge or valley, but is a projecting ridge which stands out 

 facing an extensive morass. Close by, in a hollow produced by two 

 prominences in the original rocky surface?, wo find a mass of dilu- 



