xiv DISTRIBUTION 587 



identity, there is more difference, zoologically speaking, between 

 New Zealand and Australia than between Europe and North 

 America or between England and Japan. 



The reason of this remarkable contrast is not far to seek. 

 ^Geologically speaking Great Britain is a recently detached portion 



FIG. 1170. Map showing the shallow bank connecting the British Isles with the contine 

 The light tint indicates a depth of less than 100 fathoms ; the figures show the depth 

 fathoms. (From Wallace.) 



of Europe, having been united with it during the latter part of 

 the Glacial period (Pleistocene), and, at the present moment, an 

 elevation of the bed of the English Channel to the amount of 

 260 feet, would bring about a re-union (Fig. 1170). Prior to this 

 union, moreover, it was largely submerged so as to leave no trace 



