4 INTRODUCTION. 
these islands from the mainland of the continent did not take place 
simultaneously over the entire area; it was not the result of a rapid 
or even a uniformly slow universal subsidence. On the contrary, 
long periods of time must have elapsed, we are told, between the 
formation of the different groups of islands. And there seems to be 
strong evidence to prove that Guernsey. together with Herm and 
Jethou, and perhaps Sark also, was cut off from the continent at an 
epoch immensely anterior to the detachment of the Jersey and 
Alderney groups ; in other terms, that Guernsey was an island for 
ages, while the others were still united to, and formed part of, the 
French mainland. This is a point of some importance, which it is 
well to bear in mind in studying and comparing the fauna and flora 
of the different islands zw¢er se, and in noting the characteristics of 
each in relation to the opposite French and English coasts. 
Strictly speaking, the indigenous animals and plants of these 
islands cannot be regarded as British in the sense in which the 
term is usually applied to the fauna and flora of Britain proper. If 
a line be drawn down the English Channel midway between the 
shores of England and France, the Channel Islands will be found 
to lie well within the French side of the line. Geographically, 
therefore, they belong to France beyond question, although politi- 
cally they appertain to England, and, it is to be hoped, will always 
continue to do so. But, at the same time, their relationship zoologi- 
cally and botanically to the continental mainland is not nearly so 
intimate as might be inferred from their geographical position ; and, 
since the French naturalists regard them as foreign territory, and, 
indeed, practically ignore their existence altogether, it is only just 
and fair that the mother country should take them under her 
sheltering wing. 
With considerably more than twice the land area of Guernsey, 
the sister island of Jersey naturally possesses a much more varied 
and extensive flora, but perhaps it is not really more rich in species 
in proportion to its size. In 1896 Mr. J. Piquet published a paper 
entitled ‘The Phanerogamous Plants and Ferns of Jersey,’ in which 
he gave a list of all the species he had himself collected during forty 
years’ botanising in the island. In this list Mr. Piquet enumerates 
721 plants, of which twenty-three are ferns and fern-allies ; but it is 
obvious that it would admit of some extension, as, for example, in 
the genus fzbus, which is represented solely by the aggregate 
species FR. fruticosus. Many of the woodland and marsh plants 
of Jersey are not to be found elsewhere in the Channel Islands, 
whilst, on the other hand, certain species which are undoubtedly 
indigenous to Guernsey and the smaller islands are unknown in 
Jersey.* If sufficient materials were at hand, it would be extremely 
* In the concluding pages of this volume will be found a list of the Jersey plants 
recorded by Mr. Piquet which are not known to occur in any of the other islands. 
