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



rocks may be seen sticking out from it, partly undermined by the sea. 

 The scratches and ruts on them, run NNW. by compass. Several 

 of these boulders are scratched and furrowed on their west sides,— 

 none of them on their east sides,— a circumstance which shews 

 plainly that the scratching agent had come from the NW. and not 

 from the SE. 



This boulder-clay covers the sandstone of Granton Quarry, and 

 contains a number of large boulders scratched and furrowed on the 

 upper surface. The strise all run east and west by compass. The 

 boulders all belong to rocks in the west country. 



I may add that, when in East Lothian lately, I observed that the 

 Railway had cut through this same boulder-clay near Beltonford. 

 Rounded blocks, precisely similar to those above mentioned, are 

 interspersed through it, and also presenting like marks of rubbing 

 and scratching. I took the bearinojs of the strise on six or seven 

 boulders, and they were invariably WNW., or more correctly, 

 N. 72" W. One of the boulders was so placed, and so marked, as 

 to prove distinctly that its lee side had been to the eastward, — that 

 being the only side free from stricB, and other marks of violent abra- 

 sion. 



A more important discovery was made near Linton, presenting 

 phenomena very similar to those at Sampson's Ribs. The railway 

 (about a quarter of a mile to the west of the station) cuts through a 

 knoll of felspar porphyry, known by the name of Markle Ridge. The 

 distance from the west side of the knoll to the east side along the rail- 

 way is about 60 yards. Both sides of the knoll, and especially the 

 northwest side, present faces which have been smoothed and striated. 

 On the west side, the extent of smoothed surface is about 50 feet in 

 length, and at one place about 15 feet high. The side of the knoll 

 here gradually bends round towards the north, to meet the opposite or 

 east side of the knoll. Accordingly, the smoothed surface on the west 

 side faces successively (reckoning from the south) NW., then NNW., 

 and N. by W. by compass. The small portion of smoothed rock on 

 the opposite side of the knoll faces SE. by compass. The rock on 

 the north side of the knoll is covered by debris, so that it cannot be 

 seen whether it presents any similar appearances. 



These smooth faces, on both sides of the knoll, exhibit ruts and 

 scratches, the most numerous and deeply marked being on the west 

 side. Their direction is ENE. They are generally horizontal, and 

 those which deviate from the horizontal are the deepest ruts. Their 

 dip is uniformly from the ENE., or towards the WSW. 



The parts of the rock most scratched are the lowest. 



This knoll, in the part of it cut through by the railway, slopes 

 down towards the north ; that is to say, the high ground is all to the 

 south, and there is still lower ground adjoining it on the north. 



The rock is a sort of porphyry or tufa, which is full of irregular 

 crystals or Concretions of red jasper. These hard concretions, where 



