332 
ing of lakes by the extension of glaciers from lateral valleys into a 
main valley ; and M. Agassiz is of opinion, that the parallel roads of 
Glen Roy were formed by a lake which was produced in consequence 
of a.lateral glacier projecting across the glen near Bridge Roy, and 
another across the valley of Glen Speane. Lakes thus formed natu- 
rally give rise to stratified deposits and parallel roads, or beds of 
detritus at, different levels. 
The connexion of very recent stratified deposits with glacier- 
detritus, M. Agassiz observes, is difficult to explain ; but he conceives 
that the same causes which can.bar up valleys and form lakes, like 
those of Brienz, Thun and Zurich, may have formed analogous 
barriers af the point of contact with the sea sufficiently extensive to 
have produced large salt-marshes to be inhabited by animals, the 
remains of which are found in the clays superimposed on the till of 
Scotland ; and he adds, that the known arctic character of these fos- - 
sils ought to have great weight with those who study the vast subject 
of glaciers. 
In conclusion, the author remarks, that the question of glaciers 
forms part of many of the great problems of geology ; that it accounts 
for the disappearance of the large mammifers inclosed in the polar 
ice, as well as for the disappearance of the organic beings of the so- 
called diluvian epoch; that in Switzerland it is associated with the 
elevation of the Alps, and the dispersion of the erratic blocks ; and 
that it is so intimately mixed up with the subject of a general dimi- 
nution of the terrestrial heat, that a more profound acquaintance 
with the facts, noticed in this paper, will probably modify the opinions 
entertained respecting it. ) 
Noy. 18.—The reading of the first part of a Memoir on the Evi- 
dences of Glaciers in Scotland and the North of England, by the Rev. 
Prof. Buckland, D.D., Pres. G. S., commenced on the 4th of No- 
vember, was resumed and concluded. 
Dr. Buckland’s attention was first directed by Prof. Agassiz in 
October 1838 to the phzenomena of polished, striated, and furrowed 
surfaces on the south-east slope of the Jura, near Neuchatel, as well 
as to the transport of the erratic boulders on the Jura, as the effects 
of ice; but it was not until he had devoted some days to the exami- 
nation of actual glaciers in the Alps, that he acquiesced in the cor- 
rectness of Prof. Agassiz’s theory relative to Switzerland, On his 
return to Neuchatel from the glaciers of Rosenlaui and Grindelwald, 
he informed M. Agassiz that he had noticed in Scotland and Eng- 
land phenomena similar to those he had just examined, but which 
he had attributed to diluvial action: thus in 1811 he had observed 
on the head rocks on the left side of the gorge of the Tay, near 
Dunkeld, rounded and polished surfaces; and in 1824, in company 
with Mr. Lyell, grooves and striz on granite rocks near the east base 
of Ben Nevis, About the same time Sir George Mackenzie pointed 
out to the author in a yalley near the base of Ben Wyvis, a high 
ridge of gravel, laid obliquely across, in a manner inexplicable by 
any action of water, but in which, after his examination of the effects 
