412 Life and Immortality. 
CARBONIFEROUS TIMES. 
Animals and Plants That Prevailed. 
said, it may be gathered that our existing plants and animals 
are for the most part of modern origin, using the term 
modern in its geological acceptation. Measured by human 
standards, many of our existing animals, those which are 
capable of being preserved as fossils, are known to have a 
high antiquity. Not a few of our shell-fish commenced 
their existence at some time in the Tertiary, while one 
species of Lampshell — Zerebratulina caput-serpentis — is 
believed to have survived since the Chalk, and a number of 
the Foraminifera date from the Carboniferous Period. Thus, 
we learn the additional fact that our existing flora and fauna 
do not constitute an aggregation of organic forms which 
were introduced into the world collectively and simultane- 
ously, but that they commenced their existence at very dif- 
ferent times, some being extremely ancient, whilst others are 
of comparatively recent origin. And this introduction of 
existing plants and animals, as admirably shown by the 
study of the fossil shells of the Tertiary Period, was a slow 
