429 
The appearance of the stria and poUsh, on a close examin- 
ation, is admirably shown by Agassiz in an example on the 
southern side of the Jura, three leagues from Neufchatel, and 
at a distance of more than twenty leagues from the nearest 
glaciers. The entire surface of the Jura mountains is thus 
more or less rounded, and scratched and polished, and from 
the direction of these furrows and streaks, Agassiz has come 
to the conclusion that they were caused by descending glaciers, 
in the same manner as those which have been described in 
different specimens of polished rocks brought from various 
and distant localities, 'the polish being of the same nature. One 
example was detached by Agassiz from under the glacier of 
Zermatt. Another was obtained from the summit of Riffel, 
more than 600 feet above the surface of the glacier as it now 
exists ; and in some cases the polish is so perfect that the 
forms of organic remains are distinctly seen. 
The lithographic plates to which I have referred were ex- 
hibited by Professor Agassiz, at the meeting of the British 
Association at Glasgow in 1840. He then detailed the 
several particulars, by which he accounted for the formation 
of the peculiar forms of rock, and also for his opinion that 
such results could not have been caused by the action of 
water. From the evidence of the glaciers having formerly 
been of enormous magnitude in Switzerland as compared with 
their present extent, he was led to conclude that they must 
have been more extensively spread over the northern and 
central parts of Europe ; and after the meeting at Glasgow, he 
accompanied Dr. Buckland on a survey of the valleys near 
Ben Nevis, and afterwards extending his investigations into 
Ireland and some parts of England, he came to the conclusion 
that distinct evidences of glacial action were traceable in 
various parts of Great Britain, and explained his views in a 
paper read before the Geological Society of London, on the 
4th November, 1840. 
