LAMARCK’S WORK IN GEOLOGY 103 
detritus of organic bodies successively accumulated, 
which perpetually elevates, although with extreme 
slowness, the soil of the dry portions of the globe, 
and which does it all the more rapidly, as the situa- 
tion of these parts gives less play to the degradation 
of the surface caused by the rivers. 
‘Doubtless a plain which is destined some day to 
furnish the mountains which the rivers will carve out 
from its mass would have, when still but a little way 
from the sea, but a moderate elevation above its river 
channels; but gradually as the ocean basin removed 
from this plain, this basin constantly sinking down 
into the interior (¢fazsseur) of the external crust of 
the globe, and the soil of the plain perpetually rising 
higher from the deposition of the detritus of organic 
bodies, it results that, after ages of elevation of the 
plain in question, it would be in the end sufficiently 
thick for high mountains to be shaped and carved 
out of its mass. 
“ Although the ephemeral length of life of man 
prevents his appreciation of this fact, it is certain 
that the soil of a plain unceasingly acquires a real in- 
crease in its elevation in proportion as it is covered 
with different plants and animals. Indeed the débris 
successively heaped up for numerous generations of 
all these beings which have by turns perished, and 
which, as the result of the action of their organs, 
have, during the course of this life, given rise to 
combinations which would never have existed with- 
out this means, most of the principles which have 
formed them not being borrowed from the soil; this 
débris, I say, wasting successively on the soil of the 
plain in question, cradually increases the thickness 
of its external bed, multiplies there the mineral mat- 
ters of all kinds and gradually elevates the formation.” 
Our author, as is evident, had no conception, nor 
had any one else at the time he wrote, of the slow 
