195 
of Edinburgh, Session 1878 - 79 . 
Also on the north end of the Lewis, granite boulders occur 
traceable to hills situated to the westward. 
As to boulders on the west coasts, if they came from the north- 
west, there can of course be for them no parent rock in this 
country. 
Rock Surfaces. 
The Eeport contains information on other points bearing closely 
on the question of boulder transport. 
I was particularly struck with the fact, that the bare rocks of the 
Islands, and also on the mainland, were smooth on the sides facing 
the west , but rough on the sides facing the east. 
In some parts, the rocks had evidently been ground down under 
the operation of heavy bodies moving over them. The direction in 
Which this grinding had taken place was in many instances shown 
by long lines of farrows and striae, which were uniformly in the 
direction of north-west and south-east. 
Mr Geikie, in his first paper on the Hebrides, read to the London 
Geological Society in 1873, notices one or two of these striated rocks, 
and "admits the direction to be as now stated. He asserts very 
firmly, that the striating agent must have moved from the south-east. 
It appeared to me, however, on a minute examination of the in- 
dividual striae, that the agent which produced them moved from the 
north-west , inasmuch as the striae or ruts were generally deepest at 
the north-west ends, and faded away at the south-east ends. 
In two cases of these striated rocks, I saw clearly what had been 
the tools which produced the striae. The rock was being uncovered 
by work-people for the sake of obtaining road materials. The 
covering of the rock consisted of a sandy clay, having imbedded in 
it angular pebbles of quartz, granite, and other hard rocks. If these 
materials were pushed and pressed over the rock, there could be no 
doubt what the effect would be. 
Submarine Banks. 
Another set of phenomena bearing on this subject, is the existence 
of gravel and clay beds of undoubted submarine formation. I 
visited a brickwork near Stornoway, the clay of which contains 
fragments of sea shells, at a height of 250 feet above the sea. I 
heard of there being similar beds for miles along the coast on both 
