X 
AUTHOR^S PREFACE. 
host of creatures that once trod this earth ! How little in 
comparison has been done for them / Our natural-history 
books deal only with those that are alive now. Few 
popular writers have attempted to depict, as on a canvas, 
the great earth-drama that has, from age to age, been 
enacted on the terrestrial stage, of which we behold the 
latest, but probably not the closing scenes. 
When our poet wrote “ All the world’s a stage,” he 
thought only of “ men and women,” whom he called 
“ merely players,” but the geologist sees a wider applica- 
tion of these words, as he reviews the drama of past life 
on the globe, and finds that animals, too, have had “their 
exits and their entrances ; ” nay more, “ the strange 
eventful history ” of a human life, sketched by the master- 
hand, might well be chosen to illustrate the birth and 
growth of the tree of life, the development of which we 
shall briefly trace from time to time, as we proceed on our 
survey of the larger and more wonderful animals of life 
that flourished in bygone times. 
We might even make out a “ seven ages ” of the world, 
in each of which some peculiar form of life stood out 
prominently, but such a scheme would be artificial. 
There is a wealth of material for reconstructing the past 
that is simply bewildering ; and yet little has been done 
to bring before the public the strange creatures that have 
perished.^ 
To the writer it is a matter of astonishment that the 
^ Figuier’s World before the Deluge is hardly a trustworthy book, and is often 
not up to date. The restorations also are misleading. Professor Dawson’s 
Story of the Earth and Man is better ; but the illustrations are poor. 
Nicholson’s Life- History of the Earth is a student’s book. Messrs. Cassells’ Our 
Earth and its Story deals with the whole of geology, and so is too diffusive ; 
its ideal landscapes and restorations leave much to be desired. I 
