138 FIRST FORMS OF VEGETATION. 
sounds were heard but the ceaseless dashing of 
the waves against the snow-white reefs, or the 
shrill cries of some chance flock of sea-birds, that 
made it their temporary resting-place during their 
flight to some happier shore, has become a para- 
dise of bloom and beauty where man takes up his 
abode, and finds every comfort that can minister 
to his simple tastes. 
Even on the desolate rocks that jut out from 
the sides of lofty mountains, where the eagle or 
the condor builds its eyrie, these humble sappers 
and miners of the vegetable kingdom are busy, 
fulfilling the task appointed them in the great 
household of nature, and forming a layer of soil, 
which ever and anon, as soon as it is deposited, is 
carried down by the storm or the stream to fer- 
tilize the valleys at the base. Egypt is the gift of 
the Nile; its rich alluvial soil has been brought 
down by the swollen waters of the sacred river 
from the mountains of Abyssinia, where it was 
formed, perhaps, by the agency of lichens and 
other Alpine plants, and precipitated in its pre- 
sent form over the barren sands of the Libyan 
desert. And who knows how much of the tro- 
pical fertility and luxuriance of the vast plains, 
which stretch onwards from the bases of the 
Andes and the Himalayas, may be owing to 
countless generations of lichens, working cease- 
