257 
of Edinburgh, Session 1878-79. 
northern Europe into the condition in which it is now occupied by 
man? and it seems marvellous that geologists should not yet he 
agreed as to what that agency was. 
Our own country of Scotland is strewed with boulders, many of 
immense size, and which we allow have been somehow transported 
to their present sites from remote regions. Rocks on our hill-sides 
have been ground down, smoothed, and striated by ponderous 
bodies which have come against and rubbed upon them. Almost 
everywhere there are deep beds of clay, sand, and gravel forming 
knolls and elongated ridges, not only on low-lying districts, but 
even on our highest hills. These things have been attracting 
attention and provoking discussions for more than sixty years ; 
but no explanation has yet been arrived at, which meets with 
general acceptance. Some geologists insist on the agency of an 
ice-sheet, like that in which Greenland is wrapped ; Others stand up 
for local glaciers, such as exist in Switzerland and Norway. Some 
suggest icebergs and other forms of floating ice, in a sea which 
submerged the country. Each of these theories has its partisans ; 
for no crucial test has been discovered to indicate which of them, 
or whether any, is well founded. 
The Transactions and Proceedings of our Society contain many 
papers regarding these phenomena. Of these papers, the earliest 
probably was by Sir James Hall, so long ago as the year 1812, and 
he was followed by McLaren, Chambers, Eleming, and many other 
Eellows of our Society, who specially devoted themselves to this 
branch of geological research. 
The last paper published on this subject in our Proceedings, was by 
our colleague, Mr David Stevenson, who described a portion of the hill 
in East Lothian known as North Berwick Law, which was found by 
him to have been ground down, smoothed, and striated. These effects 
he ascribed to the agency of a glacier, which came from the westward 
against the hill, first smoothing the rocks on its north side by the 
heavy pressure of the ice, and afterwards scratching the smoothed 
surface by hard stones incased in and protruding from one side of the 
glacier. Mr S tevenson suggested that the glacier might even have been, 
and probably was, of such dimensions as to have enveloped the 
whole of the Law, which reaches a height above the sea of 612 feet. 
At the close of his paper Mr Stevenson expressed an opinion 
Vql* x. 2 G 
