104 W. B. W rigid — Preglacial Shoreline in the 



coast it has been entirely removed by tbe recent encroachments of tire 

 sea. These remnants occur between Allt Traigh Leacail and Lower 

 Glen Astle, and also on lludha Euadh west of Maol an Fhitbich. They 

 are loaded with drift, so that no doubt can be felt as regards their 

 age. The cliff behind is generally somewhat rounded off at the top. 

 Measurement with an Abney level showed that the inner angle stands 

 about 95 feet or so above high-water mark of spring tides. 



IV. Mull and Ioxa. 



In the districts already described it has been possible to demonstrate 

 satisfactorily in every case the preglacial age of the rock-platform. 

 In Mull, however, where it lias its most persistent and remarkable 

 development over long stretches of coast, this has been found extremely 

 difficult. No boulder-clay has been found overlying the platform 

 and no striae have been observed on its- surface. In a few cases only 

 has it been possible to detect distinct ice-moulding on rocks which are 

 undoubtedly portions of the platform, and these cases had to be sought 

 for with some diligence. Even apart from the finding of these ice- 

 moulded surfaces, however, there can be little doubt regarding the 

 identity of the Mull platform. Its striking development, great width, 

 and the imposing character of the cliff by which it is backed, make 

 it impossible to refer it to the action of the postglacial sea, the cutting- 

 effect of which in other parts of Scotland has been comparatively 

 trifling in amount. 



The presence of the preglacial beach can be proved here and there 

 along most of the west coast of Mull, but it forms a really striking- 

 feature of the scenery from TJlva and Gonietra north to the Caliach Point 

 in Murnish. In Gonietra the platform is much dissected by hollows 

 and geos, but the remnants of it preserve on the whole a fairly 

 uniform level, and the old cliff behind is very well preserved. The 

 inner angle is distinctly marked for a distance of about a mile and 

 a half around the west and south sides of the island. At its northern- 

 most extremity it is finely developed at a height of 105 to 118 feet 

 above high-water mark of spring tides. On the south coast on both 

 sides of Gonietra House measurement gave 110 feet as the height of 

 the inner angle. Traced east along this coast, however, it appears 

 to decline somewhat, measurements giving successively the figures 

 105, 100, and 95 feet at different points within half a mile east of 

 Gonietra House. An outlying portion of the platform along tbe west 

 coast appears to have a distinctly ice-moulded surface. On the north 

 and south shores of Ulva there are some irregular shelves, which 

 might be interpreted as portions of the preglacial marine platform, 

 but, as little reliance can be placed on them, they will not be 

 described here. 



The preglacial platform fringes with almost perfect continuity the 

 whole west coast of Mull from Port Burg to Treshnish Point, 

 being everywhere backed by very fine cliffs about 200 feet high. 

 Being, like the modern shore, controlled to a large extent by the 

 relative strength of the gently inclined basalt flows, it varies a good 

 deal in height. Where softer strata overlie a powerful lava bed it 

 may begin at a certain spot quite low (100 feet or so above high-water 



