96 



has been hollowed out, and at one part, both of its sides are composed 

 of these smoothed furrowed rocks ; but, in general, it is only on one 

 side, viz., that next to Arthur Seat, that rock exists. There, the 

 appearances of smoothing and rutting extend for about 80 yards. 



The gully runs about NW. and SE. by compass. The highest 

 point in it is near the north end. At both ends it is open and 

 sinks to a level with the adjoining level country. The gully is 

 about 200 feet above the 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 250 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 i to ^ inch 

 deep and an inch wide. 



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

 spots 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 genei'ally prevalent in the Lothians. It, however, resembles in 

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

 son's 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 bhells 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. 



I 



