VALLEY OF THE AMAZONS. 
211 
lapses of time and for very gradual changes; 
that the close of this first period would he very 
different from its beginning; and that a rich 
vegetation springs on the very borders of the 
snow and ice fields in Switzerland. The fact 
that these were accumulated in a glacial basin 
would, indeed, at once account for the traces 
of vegetable life, and for the absence, or at 
least the great scarcity, of animal remains in 
these deposits. For while fruits may ripen 
and flowers bloom on the very edge of the 
glaciers, it is also well known that the fresh¬ 
water lakes formed by the melting of the ice 
are singularly deficient in life. There are, in¬ 
deed, hardly any animals to be found in gla¬ 
cial lakes. 
The second formation belongs to a later pe¬ 
riod, when, the whole body of ice being more 
or less disintegrated, the basin contained a 
larger quantity of water. Beside that arising 
from the melting of the ice, this immense val¬ 
ley bottom must have received, then as now, 
all which was condensed from the atmosphere 
above, and poured into it in the form of rain 
or dew. Thus an amount of water equal to 
that now flowing in from all the tributaries 
