Glaciers and Icebergs in Scotland, 133 



others which must have come from a considerable distance. 

 Among these are many blocks of greenstone. A very con- 

 spicuous one rests on the surface about a furlong east of 

 Fasslane (near B' in the map), and about 80 or 90 feet above 

 the sea. It is 10 feet long, 8 broad, and 4 deep. I saw no 

 greenstone any where in situ precisely similar in texture. 

 Another is at the road- side, a quarter of a mile west from 

 Fasslane. Some of the smaller blocks, three or four feet in 

 breadth, are apparently identical with the greenstone of the 

 vein at Portincaple (y in the map), which is two miles north- 

 ward. Several of felspar, 2 or 3 feet broad, must either 

 have come from the veins x or z, with which some of them 

 agree in aspect, or from some more distant locality. Many 

 of the blocks on the beach have one side smoothed by abra- 

 sion, and the striae are still visible on some of them, though 

 they have been washed by the tide for ages. Specimens may 

 be seen between h and i. We are sure that these greenstone 

 and felspar blocks have been brought from a distance ; and 

 we may reasonably assume that some of them came from the 

 veins xy z, near Loch Long. What, then, was the agent 

 which transported them from their native seat to the shores 

 of Gare Loch % The history of erratic blocks in the Swiss 

 valleys enables us to say, that it was the glaciers which an- 

 ciently occupied the valley, and which have left upon the 

 rocks such enduring marks both of the direction in which 

 they moved, and of the force they exerted. 



Among the other erratics on the shores of Gare Loch there 

 are many of granite, which must have travelled more than 

 twenty miles. These, however, open up another question 

 which shall be considered by and by. 



The preceding remarks relate to lateral moraines, of whose 

 existence I found no unequivocal direct evidence. At Kow 

 Ferry, however, five miles from the head of the loch, we 

 have what seem to be the remains of a terminal moraine. It 

 is a long narrow tongue of land which extends half across 

 the loch. 



