570 Reports and Proceedings—Duke of Argyll’s Address. 
come, at least, from the older gravels of the centre of England, if not 
directly from the Welsh mountains. Now, the paleolithic implements 
of man have been found constantly in gravels which cannot with any 
probability be assigned to existing rivers, and may with tolerable cer- 
tainty be assigned to the same marine submergence which has piled 
heaps of gravel with dead shells on the top of Moel Tryfaen, and on 
the hills above Macclesfield. In the latest work of Sir Charles Lyell, 
which is the last edition of his volume on the ‘‘ Antiquity of Man,” 
he indicates his own clear recognition of the difficulties attending any 
explanation of the gravels and of the drift-boulders found in Scotland, 
which is based on the action of land-ice alone. He refers to the great 
beds of gravel, sand, and silt—one section alone showing some 2000 
layers, which Mr. Jamieson, of Ellon, has described—on a mountain 
rising out of the valley of the Tummel, in the Pass of Killiecrankie, 
beds which are traceable to the height of 1550 feet above the level of 
the sea. He refers, also, to huge angular fragments of mica-schist 
lying on the very tops of the Sidlaw Hills, also 1500 feet above the 
sea, and separated from the rocks whence they came by the broad and 
deep valley of Strathmore. He refers, yet further, to stratified gravels 
on the top of the Pentlands, 1100 feet above the sea; and he confesses 
that ‘‘it seems hardly possible to refer these beds to any but a marine 
origin,” and this, despite the fact that they are devoid of marine 
shells. Hardly possible, indeed! and equally impossible to doubt 
that the sea which deposited these beds was so transitory that no time 
was allowed for the establishment of molluscan or other marine forms 
of life. Here, then, we have a great submergence and elevation as 
clearly proved as any conclusion in the whole range of geological 
science; and yet, as it seems to me, the inevitable consequences of 
that conclusion have not been worked out with even tolerable con- 
sistency in its bearing on another question connected with Pleistocene 
times. As to the cause of that submergence, the facts seem to me 
equally fatal to the theory of Mr. Jamieson and to the theory of Dr. 
Hall. One of these eminent authorities relies on the pressure—on the 
mere weight—of an enormous mass of land-ice sinking down the land. 
The other relies on the mere attraction, under the laws of gravity, of 
the same great mass exercised upon the ocean, dragging the waters of 
the sea in a huge accumulation towards itself. Both theories equally 
rely on ice-masses which are pure assumptions, and the existence of 
which is positively disproved by the demonstrable access of the .sea to 
naked mountains at the very time of the maximum submergence. 
I cannot pursue this subject farther on this occasion. I have not 
thought it best to spend this lecture on songs of triumph over the 
achievements of the past, or recapitulations of the work done by the 
dead or by the living members of our Society. Let it not be thought, 
on this account, that I am insensible to the immense services they 
have rendered. Some of the greatest of these services have been 
rendered in furtherance of theories and explanations which I believe: 
to be erroneous; but these theories have never affected the perfect 
honesty of the work. Now, as ever, speculative opinions are inciting 
to inquiry, and sharpening the vision of rival theorists in the detection. 
of natural facts. I need not here or now mention names. Suffice it 
