INTRODUCTORY. 



This book has l^een written mainl}' as a chapter on 

 geographical distribution, a subject which of late j^ears 

 has deservedly received a large share of attention from 

 naturalists, and which when thoroughly worked out for 

 the whole of the British Islands, may be expected to 

 show results both interesting and valuable. It may 

 well be doubted whether the system of taking the 

 counties as limits is not an exceedingly ill-chosen one ; 

 but research has in so many instances progressed on 

 these lines, and local enthusiasm is so much more 

 readily stimulated in this direction, that scarcely any 

 choice is left for those portions of the country whose 

 faunal condition yet waits investigation. It can hardly 

 be denied that it would have been far better if, in the 

 division of the ground for local work, regard had been 

 had to physical configuration, and the river valleys, the 

 mountain chains, and the sea-coasts had been taken as 

 boundaries by observers ; but the compiler of some 

 future day will have to gather these results for himself, 

 and to collate and compare from this and like histories, 

 whose limits of observation are so arbitrarily defined. 



The County of Lancashire is bounded on the west 

 by the sea, on the south by the Eiver Mersey, and on 

 the east, as far north as Pendle Hill, by the chain of 

 hills which here irregularly continues the range of the 



