26 
AMERICAN GEOLOGY. 
peopled with different species than the soft muddy ones. All 
these facts are important in geological reasoning. 
From the foregoing we may also learn the influence of water 
as a formative agent. It moulds and forms, as it were, all the 
coarse and fine materials which are abraded from preexisting 
rocks. It spreads them out upon bottoms, and deposits layer 
after layer. We may have a glimpse also of the time required 
to form rocks. Only a few thin layers, like paper, are deposited 
annually; and it is probably a rare occurrence, that streams are 
so loaded with mud that living shell fish are buried beneath it. 
§ 22. The foregoing details of the distributive, as well as 
constructive agencies of river and oceanic waves and currents, 
will be more complete by a relation of the distribution of an 
animal life upon the ocean bed. The profound depths of the 
ocean are tenantless wastes, except for the dead, who have here 
found their resting places, where no wind or wave can move 
them, or bring up their sacred relics to light, and cast them 
once more upon a troubled shore. Along shore, in the reach 
of soundings, the waves distribute their burdens in ridges. 
These ridges are also in the main desert lands; but the valleys 
being protected by the ridges, teem with activity and life. 
Upon the slopes the rounded and worn materials are cast 
together with the remains of the exuvia of organic life, which 
have been cast off. The deeper valleys are suited to one class, 
while the shallower portions are sought by others. From shal¬ 
low water, or the high water mark, to a depth of thirty fath¬ 
oms, forms the main range in depth of marine animal life. 
Vegetable life, however, rises up from greater depths. Thus 
the gigantic sea weed of the Falkland islands rises from a 
depth of 300 feet. The sea bottom, therefore, like the earth’s 
surface, presents all the variations of contour which are neces¬ 
sary to give life the widest exhibitions of form and character. 
The profound depths, like the snow-tops of the Andes-and 
Himalaya, are dreadful wastes, devoid of life; the one awful 
from its profound solitude, the other fearful from the howling 
blasts which sweep their towering tops. 
