FOSSILS, AND HOW THEY ARE FORMED 7 
ocean or one of its estuaries, settles to the 
muddy bottom of a lake or is caught on the 
sandy shoals of some river, the chances are 
good that its bones will be preserved. They 
are poorest in the ocean, for unless the body 
drifts far out and settles down in quiet waters, 
the waves pound the bones to pieces with stones 
or scour them away with sand, while marine 
worms may pierce them with burrows, or 
echinoderms cut holes for their habitations; 
there are more enemies to a bone than one 
might imagine. , 
Suppose, however, that some animal has 
sunk in the depths of a quiet lake, where the 
wash of the waves upon the shore wears the 
sand or rock into mud so fine that it floats out 
into still water and settles there as gently as 
dew upon the grass. Little by little the bones 
are covered by a deposit that fills every groove 
and pore, preserving the mark of every ridge 
and furrow ; and while this may take long, it 
is merely a matter of time and favorable cir- 
cumstance to bury the bones as deeply as one 
might wish. Scarce a reader of these lines but 
at some time has cast anchor in some quiet 
