Messrs Peach and Home on the Glaciation of Caithness. 323 



direction. In the Jamestown quarries, about two miles south- 

 west of Thurso, the prevalent trend is W. 20° N., but on the 

 same rock surface we noted a fainter set running N.E. These 

 have been well-nigh effaced by the north-west movement, 

 and for this reason they seem to be of older date. This was 

 the only example we noted of a north-easterly trend away 

 from the inland margin of the shelly drifts. 



Between Thurso and Castletown, and eastwards to Brough, 

 similar evidence is obtained of this north-west and south- 

 east movement. On the surface of the grey flagstones in the 

 Castletown quarries the direction is N. 20° to 23° W., and 

 again by the roadside, south of St John's Loch, the trend is 

 N. 10° to 15° W. Several examples were noted on the slopes 

 between Brough and Dunnet Bays, on the surfaces of the 

 coarse yellow sandstones of that peninsular tract. In the 

 old quarries, on the slope to the north-west of Brough, the 

 stria^. point W. 35° K, W. 30° N., and W. 25° N. A few 

 yards to the west of the above locality another instance was 

 observed pointing W. 25° JST. Farther to the south, by the 

 road leading to Dunnet Church, the direction is W. 25° to 

 30° K, and to the west of St John's Loch AV. 35° to 40° N. 

 A careful examination of the striated surfaces on this slope 

 convinced us that they had been produced by ice moving 

 towards the north-west. The gradual rise on the ground to 

 the west of Brough towards Dunnet Head (346 feet) is due 

 to the presence of coarse massive sandstones of Upper Old 

 Ked age. On the south-east slope the sandstones are finely 

 moutonnee, and the smooth faces point to the south-east, indi- 

 cating the direction from which the ice came. When we 

 come to discuss the dispersal of the stones in the boulder 

 clay, we shall see that additional evidence is obtained in 

 support of this conclusion. 



In the undulating plain between Halkirk and Westerdale 

 the same north-west and south-east trend is observable. In 

 a quarry south of Achies farm-house, about three miles south 

 of Halkirk, the direction is W. 30° N., and alongside of these 

 is a fainter set pointing nearly west. 



On the eastern seaboard, between Duncansbay Head and 

 Dunbeath, numerous instances occur which harmonise with 



