DR. BUCKLAND AND THE GLACIAL THEORY. 
227 
or a body of water passed over a series of elevations, the diluvium 
would descend with the strike and be disposed in mounds and terraces 
according to the direction of currents, etc. 
Professor Agassiz. —Mr. Murchison has objected to the glacial 
theory in the only way in which it could be objected to. He allows 
that the whole is granted as soon as you grant a little bit. For here, 
as in other cases, we argue from what is proved, to what is to be 
proved. In Switzerland the action of glaciers is yearly seen by 
thousands of foreigners, and of these facts there can be no doubt, [nor 
as to the former] extent of glaciers. In the glacier de I’Aar, grooves, 
etc., are to be found in the valley 7 leagues (22 miles) from the end of 
the present glaciers. Did we find these surfaces only on the hard 
rocks, we might suppose they were merely uncovered by the action of 
the glaciers ; but on the soft limestone rocks these grooves are only to 
be seen on the surfaces from which the glacier has just retreated. 
Many glaciers traverse such rocks only’(equivalents of our Lias), and 
there the grooves are annually renewed in winter, and removed by the 
atmospheric action in summer. I have been many hundred feet under 
the glacier of Monte Rosa, and found the quartzose sand forming a 
bed beneath, and acting like emery upon the rocks. A moraine may 
be distinguished by certain characters from other any accumulation of 
fragmented rocks. From the sides of the glaciers moving faster than 
the middle, there is a continual tendency to throw the fragments into 
lines at the sides (lateral moraines), and when two glaciers descending 
from different gorges unite, a medial moraine is formed. The lateral 
[moraines] are exposed to constant friction with the rocks with which 
they are brought in contact, and their terminations are passed over by 
the whole mass of the glacier, so that they become rounded and 
striated; whilst the medial moraines, remaining on the surface, 
continue angular. When the glacier retreats in the summer, the 
medial moraine, composed of angular fragments, is spread out over 
the surface of the lateral and terminal moraines, composed of rounded 
fragments ; and it is by these characters that we have proved the 
existence of moraines in Scotland, Ireland, and the north of England. 
There are moraines in the Alps 200 feet wide, composed of boulders 
several feet in diameter. 
Mr. Lyell spoke of the size of moraines, and the way in which 
they might, under certain circumstances, attain any magnitude. A 
glacier has been known to retire half a mile in a single summer, [a 
number of] moraines have been in succession left, and in severe 
winters all these might be driven successively into one by the down¬ 
ward motion of a glacier. 
Mr. Grebnough spoke of the arguments derivable from analogy, 
etc., and objected to the mode in which the Geological Society was in 
the habit of accounting for phenomena. Instances of accumulations 
of travelled rocks [occur in] North Germany; from a careful com¬ 
parison some of these must have crossed the Baltic. In the valleys of 
