PREFACE. 



OUR knowledge of the present and past fauna of 

 Europe is as yet insufficient to indicate with precision 

 the original homes of its component elements, but I 

 hope that the lines of research laid down here, and 

 the method of treatment adopted, will aid zoologists 

 and geologists in collecting materials for a more com- 

 prehensive study of the history of our animals. I 

 trust also that a fresh impulse will be given by the 

 publication of this book to the study of the Geo- 

 graphical Distribution of Species. Collectors of 

 Beetles, Butterflies, Shells, and Fossils may derive 

 some useful hints by its perusal and thus direct their 

 studies, so as to add, by accuracy in observation, 

 to our knowledge of the former geographical re- 

 volutions which have moulded our islands and con- 

 tinents. To geographers, a survey of some of the 

 more important changes in the distribution of land 

 and water in past times based upon the composi- 

 tion of our fauna will be interesting. The subject, 

 however, is a complex one. I have ventured to 

 indicate a suitable method of treatment, and as such 

 this attempt to elucidate the history of the European 

 fauna should be received. 



