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Proceedings of the Royal Society 
(7) That several plants are found on the west of Scotland and 
of Ireland, but nowhere else in Great Britian or ISTorthern Europe, 
which plants are stated, on botanical authority, to abound in Boreal 
America^ as their native habitats. 
With reference to the view thus taken, that boulders in Scotland 
were carried on ice floated by the sea, it is curious, historically, that 
we should now come back to the theory suggested in this Society 
sixty-two years ago by a remarkable man, then President of the 
Society, Sir James Hall of Dunglass, whose views, however, on this 
subject have not always been correctly represented by geological 
authors. It has been alleged that in his well-known paper, dated 
March 16, 1812, “On the Kevolutions of the Earth’s Surface,” 
published in our Transactions, vol. vii. pp. 139-211, Sir James 
sought to explain the transport of boulders by diluvial action alone; 
i.e., by great sea waves, such as those which ingulfed Lisbon and 
several cities on the west coast of South America. But this is a 
mistake, as I should like to show, by quoting one or two sentences 
from his paper. 
At page 161, Sir James, alluding to the different theories started 
by Saussure and others to account for the transport of boulders, 
mentions one, suggested by a Professor Wrede of Berlin, viz., that 
the boulders in Horth Germany “ had been transported across the 
Baltic, by means of the wind on floats of ice, and settling in their 
present place, had been left there by the retiring waters.” 
Sir James then expresses his own opinion thus — “ If the pheno- 
mena on the banks of the lake of Geneva were really occasioned 
by a torrent of water, its magnitude must have been such as to 
leave few vestiges of the human race, and we can only expect 
proofs of it in geological facts. It may, however, be alleged, as I 
have already hinted, that it woidd be impossible for water of any 
depth whatever, or moving ivith any velocity, to carry blocks of such 
magnitude to such situations; and this consideration is of such 
importance, that I am induced, in attempting to unite the ideas of 
Saussure with those of Hutton, to retain part of the system pro- 
posed by Professor Wrede, in so far as to consider those granite 
blocks as having been made to float by means of masses of ice. 
The opinion thus adopted and propounded by Sir James Hall 
was conceived at a time when nothing was known of icebergs and 
