xii AUTHOR'S PREFACE. 



Our present imperfect knowledge renders it difficult in 

 some cases to construct successful restorations ; but, never- 

 theless, the attempt is worth making : and if some who 

 think geology a very dry subject, can be converted to a 

 different opinion on reading these pages, we shall be 

 well rewarded for our trouble. 



We venture to hope that those who will take the trouble 

 to peruse this book, or even to look at its pictures, on which 

 much labour and thought have been expended, will find 

 pleasure in visiting the splendid geological collection at 

 Cromwell Road. We have often watched visitors walk- 

 ing somewhat aimlessly among those relics of a former 

 world, and wished that we could be of some service. But, 

 if this little book should help them the better to understand 

 what they see there, our wish will be accomplished. 



Another object which the writer has kept in view is to 

 connect the past with the present. It cannot be too 

 strongly urged that the best commentary on the dead past 

 is the living present. It is unfortunate that there is still 

 too great a tendency to separate, as by a great gulf, the 

 dead from the living, the past from the present, forms of 

 life. The result of this is seen in our museums. Fossils 

 have too often been left to the attention of geologists not 

 always well acquainted with the structures of living animals. 

 The more frequent introduction of fossil specimens side by 

 side with modern forms of life would not only be a gain to 

 the progress and spread of geological science, but would 

 be a great help to students of anatomy and natural history. 

 The tree of life is but a mutilated thing, and half its interest 

 is gone, when the dead branches are lopped off. 



It is, perhaps, justifiable to give to the term " monster" 

 a somewhat extended meaning. The writer has therefore 



