362, The Glacial Theory of Prof. Agassiz. 
cavated at the bottom of these openings, in localities where no current 
could exist unless enclosed between walls of ice; and, when the ice 
disappeared, the large angular blocks were found resting on a bed of 
rounded pebbles, of which the acellon, often passing into a fine sand, 
orm the base.” 
The description of the supposed md attending the upheaval 
of the Alps, though it forms the very kernel of his theory, is less clear 
than the other parts of M. Agassiz’s work, which is generally very per- 
spicuous ; and instead, therefore, of giving the substance of his state- 
ments in our own language, we have translated the two most important 
passages literally. Ina paper read before the Helvetic Society of Nat- 
ural History in 1837, containing the germs of the theory, more fully 
unfolded in his new work, he thus expresses himself :— 
“ The appearance of the Alps, the result of the greatest convulsion 
which has modified the surface of our globe, found its surface covered 
with ice, at least from the North Pole to the shores of the Mediterranean 
and Caspian Seas. This upheaving, by raising, breaking, and cleaving 
in a thousand ways, the rocks which compose the prodigious mass that 
now forms the Alps, at the same time necessarily raised the ice which 
covered them; and the debris detached from so many deep upbreak- 
ings and ruptures, naturally spreading themselves over the inclined sur- 
face of the mass of ice which had been supported by them, slid along 
the declivity to the spots where they were arrested, without being worn 
or rounded, since they experienced no friction against each other, and, 
even when arrested, came in contact with a surface so smooth; or, af- 
ter being stopped, they were conveyed to the margin or to the clefts of 
this immense sheet of ice, by that action and those movements which 
characterize congealed water when it is subjected to changes of tem- 
perature, in the same manner as the blocks of rock which fall upon 
glaciers, approach their edges in consequence of the continual move- 
ments which the ice experiences, in alternately melting and congealing 
at the different hours of the day and seasons of the mente at caseiiaiea 
Philosophical Journal, No. 48, p. 378. 
_ The words in italics indicate an opinion that some of the boialdent 
might have slid from the Alps to Jura on the surface of the ice, 
while others adhered to it, and only travelled as the angular. blocks 
on glaciers now travel. Nothing equivalent to these words oc- 
curs in the Etudes, and even the distribution of the fragments by the 
more tardy | is not very clearly explained. We are not sure, 
for instance, whether he means that the ancient mer de glace rose above 
Jura, and determined he: Progressive motion of the ice in a direction 
away from the Alpine chain chain at right gndets bearing the boulders first 
detached over Jura into the basin of the Doubs, and. that, owing to the 
