144 Proceedings of the Royal Society 
the north-east. These are supplied partly from the Islands 
(Hebrides, Orkneys, and Shetland), and partly from the striations 
of rocks in different parts of Scotland. (See .Reports from Lanark, 
Elgin, and Lochaber.) This north-east movement, however, does 
not appear to have been so general or so incisive as the north-west 
movement. 
The Committee think it premature to draw conclusions with any 
confidence. They would only observe, that if two separate move- 
ments have taken place over the country, whereby rocks were 
striated, and boulders transported great distances across valleys, 
mountain ranges, and arms of the sea, it is most probable that 
these movements took place when the whole country was under 
the waters of a sea loaded with ice, and in which strong currents 
prevailed. 
II. Beds oe Clay, Gravel, and Sand. 
1. Under this head, the most interesting fact brought out in 
the Reports lately received, is the occurrence at very high levels, 
of beds of boulder clay, gravel, and sand. They are to be seen in 
several parts of Scotland (chiefly the middle and north), at heights 
exceeding 2000 feet above the sea. 
It can scarcely be doubted that the formation of these beds is 
due to large bodies of water. No marine organisms, it is true, 
have been found in these beds at or near this height ; but it is 
difficult to account for them, except on the supposition that the 
whole country had been submerged to the depth of 2000 or 
4000 feet. Currents, probably loaded with ice, have acted on the 
submerged mountains, and carried away from them an immense 
amount of debris, which has been deposited as sediment in the 
hollows, and forming the existing beds of sand, gravel, and clay. 
When the land emerged, and for a long period after, there would 
be numberless lakes in the interior, among the mountains, formed 
of course by the rain which fell on their sides. In the course of 
time, the embankments of detrital matter which kept in the lakes 
would be cut through, and the lakes would sink in level. Most 
probably, when they so sank, beach lines would become visible on 
the sides of .the mountains, like the famed parallel roads of Glen 
Roy. 
