INTRODUCTION. 35 



quadrupeds. Everything indicates that conveyance 

 1o small distances is the rule, and that sudden and 

 long migration is the exception." 



The conviction which has been gained by zoologists 

 and botanists, that the British Islands once formed 

 part of the Continent, is based on the present British 

 fauna and flora. The remains, however, of animals 

 which used formerly to live in these countries, such as 

 the Mammoth, the Irish Elk, the Cave Bear, and many 

 others, tell us the same tale. They could not have 

 peopled England by swimming across the Channel, 

 or even by walking across solid ice, as has once been 

 suggested. Nothing but a land-connection induced 

 them to explore this country more closely, and 

 finally to decide on settling there. 



The origin of the British fauna will be discussed 

 more in detail in the third chapter. The methods 

 of investigation adopted, along with a general scheme 

 of this book, will be found in the next. 



The manner in which the origin of the fauna of any 

 particular continental area can be traced is very 

 similar to that adopted in the case of an island. 

 Portions of the continent of Europe can be shown 

 to have been islands in former times. Thus the 

 Crimea, now a peninsula united to the mainland 

 by the narrow isthmus of Perekop, must have been 

 an island in comparatively recent times. The absence 

 of a number of striking and familiar South Russian 

 species of mammals and reptiles proves this to have 

 been the case. It was probably long after the appear- 



