Xll 
AUTHORS 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 
