44 BATHYMETRICAL SURVEY OF 



striae point S. 15 to 20 E. ; on the north and west slopes of Ben Ledi, 

 S. 35 E., and on the crest of that mountain, at a height of 2875 feet, 

 the direction is S.E. In like manner the mountains guarding the outlet 

 of Loch Katrine are glaciated to the summit. Striae occur on the top of 

 Ben Venue at a height of 2386 feet, pointing S. 40 E. ; on Ben An, at 

 an elevation of 1750 feet, E. 30 S. ; and on Ben Bhreac, to the west 

 of Ben Venue, the direction of the ice-markings is S. 30 to 40 E. 

 Again, on the watershed between Loch Voil and Loch Katrine, the 

 evidence indicates a south-easterly movement during the great extension 

 of the ice. For instance, at various points on Taobh na Coille, at 

 elevations between 2000 and 2250 feet, the striae point S. 30 E., and 

 on Meall Gaothach, S. 30 E. In the tract immediately to the south- 

 west of Loch Katrine the trend of the ice-markings varies from S.S.E. 

 to E.S.E. For example, on Maol Mor (2249 feet) about the 2000-feet 

 contour-line, to the north of Loch Arklet, the direction is about 

 S. 15 E. ; and on the crest of Ben Uaimhe, to the south of that loch, 

 S. 10 to 15 E. Eastwards, throughout the tract between Loch Chon 

 and the Trossachs, the trend is E.S.E. To the south of the lofty 

 heights stretching from Ben Venue towards Ben Ledi, the direction of 

 the striae is more easterly, thus showing that the ice, after crossing the 

 high ground, was deflected more towards the east (see glacial striae on 

 Plate II.). 



The general south-easterly movement of the ice during the great 

 glaciation, throughout the lake district of the basin of the Teith, is 

 confirmed by the dispersal of stones in the boulder-clay, and by the 

 transport of erratics. Many of the boulders have been carried far from 

 their source, and are now found on the tops of the highest mountains of 

 the district, some even at greater elevations than the parent rock. 



To the east of Loch Lubnaig, on Ben Vorlich, at a height of 3000 

 feet boulders of garnetiferous mica-schist are found resting on glaciated 

 surfaces of pebbly grit. Again, on the same mountain, at a similar 

 elevation, there are erratics of epidiorite and hornblende schist rocks 

 which are associated with the Loch Tay limestone, and which must have 

 been transported from lower ground to the north. Similar boulders are 

 met with on Stuc a Chroin and on Ben Each. Again, in the boulder- 

 clay on the slopes of Ben Ledi, blocks of hornblende schist occur, 

 which must have been transported for some distance. On the south side 

 of Loch Katrine, between Stronachlachar and the aqueduct of the 

 Glasgow waterworks, boulders of quartzite and garnetiferous mica- 

 schist, which are foreign to the basin of Loch Katrine, are found in the 

 boulder-clay. Eastwards near Brenachoil Lodge, on the north side of 

 Loch Katrine, there are blocks of black schist, like that which accom- 

 panies the quartzite of central Perthshire, and which has not been 

 detected within the catchment-basin of Loch Katrine. These examples 

 are sufficient to prove that, during the climax of the glacial period, 



