On Striated Rocks on Arthur Seat, 207 



about 200 feet above tbe level of Duddingston Loch, and 400 feet 

 above the sea. Arthur Seat forms on the east side of it a precipi- 

 tous cliff of about 260 feet. 



The walls of the gully consist (so far as yet exposed, in the for- 

 mation of the Victoria road), for about 5 feet upwards, of vertical 

 rock. 



This rock towards the north end of the gully is a compact por- 

 phyry ; towards the south end, of friable porphyry. At the north end 

 the polishing has been greatest. 



The scratches are in general nearly horizontal ; a few slope up- 

 wards to the south ; these are at the north end of the gully, where 

 it is narrowest. 



The longest scratches are about 6 feet long, from ^ to ^ inch 

 deep and an inch wide. 



There are, especially towards the south end of the gully, many 

 »pots of a few inches square, where there has been neither polishing 

 nor scratching. These all face towards the south. 



The deposit immediately above those rocks, and which has com- 

 pletely filled up the gully, is a brown tenacious clay, full of boulders 

 of all sizes. The boulders consist of traps (some of them of rock not 

 existing in the neighbourhood) and sedimentary rocks. Whilst there 

 are sandstone fragments, which are very similar to those on Salisbury 

 Crag, there are limestones, supposed not to exist nearer than Fife. 



This boulder clay is not so tenacious as the blackish-blue boulder 

 clay generally prevalent in the Lothians. It, however, resembles in 

 all respects a deposit of the same kind, existing at the foot of Samp- 

 son'& Ribs, which is about 160 feet below the level of the gully. 



Above the boulder clay in the gully there is a mass of debris, de- 

 rived apparently from the crumbling of the rocks above on the face 

 of Arthur Seat. Three species of marine shells have been found in 

 this mass ; but, as human bones and Roman remains have also 

 been discovered in it, the probability is, that these shells have been 

 brought by human hands. 



In the cuttings for the North British Railway, between Arthur 

 Seat and Musselburgh, the upper sides of the large boulders are ge- 

 nerally found smoothed and scratched. The scratches seem to be from. 

 NW. to WNW. by compass. On some of the boulders there are in- 

 dications of more recent scratches running W. ^ S. by compass. 



The boulders in the railway cuttings between Haddington and 

 Dunbar exhibit scratches running from NW. to WNW. 



The opinion formed by the author on these data was, — 



(1.) That the agent which had polished and scratched the rocks 

 on Arthur Seat, was the same as that which had polished and 

 scratched the boulders, 



(2.) That it had acted from the north-westward over a large and 

 low district of country. 



(3.) That the polishing and scratching had h*ieu effected by the 



