I 
FOSSILS, AND HOW THEY ARE FORMED 
“ How of a thousand snakes each one 
Was changed into a coil of stone.” 
Fossils are the remains, or even the indica- 
tions, of animals and plants that have, through 
natural agencies, been buried in the earth and 
preserved for long periods of time. This may 
seem a rather meagre definition, but it is a dif- 
ficult matter to frame one that will be at once 
brief, exact, and comprehensive ; fossils are not 
necessarily the remains of extinct animals or 
plants, neither are they, of necessity, objects 
that have become petrified or turned into stone. . 
Bones of the Great Auk and Rytina, which 
are quite extinct, would hardly be considered 
as fossils ; while the bones of many species of 
animals, still living, would properly come in 
that category, having long ago been buried by 
natural causes and often been changed into 
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