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. 1 



To the writer it is a matter of astonishment that the 



1 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 



