490 



Alfred Rarlier — Suh^ieridl Erosion of Skye. 



this distance is always small; in the particular instance selected 

 it is capable of fairly accurate measui'ement, as follows. The upper 

 p irt of Glen Sligachan has the Red Hills on the right and the 

 Guillins on the left. Accordingly we find that granite boulders 

 largely preponderate in the drift on the right side of the valley and 

 gabbro boulders on the left, and a sharp line of division can be 

 drawn along the middle of the valley. Lower down, where tlie 

 floor of the valley consists of basalt, this rock enters increasingly 

 among the boulders ; but the line can be traced to Sligachan and 

 for some eight or nine miles beyond, affording important information 

 concerning the course of the great Sligachan glacier. In the 

 neighbourhood of Sligachan itself this line can be laid down with 

 considerable precision, certainly within a very few yards. As shown 

 by the broken line in Fig. 3, it crosses the river just below the 

 bridge, and thence follows a westerly direction. The dotted line 

 in the figure marks the corresponding division among the stones in 



FIG. 3 



H0T6 



Fig. 3. — Sketch-map of Sligachan Eiver in the neighbourhood of Sligachan ; scale, 

 six inches to a mile. Explanation in the text. 



