GEOLOGICAL AND ZOOLOGICAL RELATIONS. 261 
Campbell Island is formed of two chief elements—viz, Ist, 
by a band of limestone; and, 2ndly, lavas. The limestone band 
is jammed between two volcanic dykes, the overflows from which 
have partly covered it; as a formation it is, therefore, anterior 
to them. This layer, the thickness of which is about 70 metres, 
has evidently been formed in a very deep sea. Fossils are abso- 
lutely wanting in it, and micrographic sections have only enabled 
me to note the presence of globigerina. This limestone, which 
is of a yellowish colour and of a very characteristic appearance, 
is not met with again in any part of New Zealand. Its upper 
surface, at those parts where it is not covered by the lava, is not 
overlaid by any other terrestrial deposit. Consequently the 
position of this calcareous layer, in relation to the eruptive pro- 
ducts, can only be explained in one of two different ways : either 
it has been carried up to the surface of the sea after having been 
grasped (pineée) between the volcanic dykes which enclose it ; or 
perhaps it corresponds to the margins of the fracture which has 
formed the passage for the lava. Whichever of these two suppo- 
sitions is admitted, it is perfectly certain that the geological age 
of the island, constituted as we now see it, corresponds to the 
epoch of the appearance of the volcanic eruptions. In order to 
determine the date of these eruptions, I have endeavoured to 
seek a point of comparison in those which have taken place in 
New Zealand during well-known geological periods. In the 
prosecution of this delicate research, M. Fouqué has very kindly 
given me his assistance, and in consequence the determinations 
made at the College de France are quite trustworthy. All the 
New Zealand lavas of the eocene, miocene, and commencement 
of the pliocene periods are absolutely different from those of 
Campbell Island. These last contain the mineral Anorthite, 
which is not met with in any other of the New Zealand eruptive 
products up to the geological epochs just spoken of. They are 
therefore much more basic. On the other hand, we know that 
lavas containing Anorthite have up to the present time only been 
found in post-pliocene formations ; for example, in Ireland, or in 
St. Paul and Reunion, as has recently been shown by M. Velain. 
It follows from this, that the limestone which the eruptions of 
Campbell Island have brought up, or which perhaps by its frac- 
ture has formed a passage for the lava, must have been formed 
during post-pliocene periods, that is to say, in the epoch during 
which New Zealand possessed its last great geographical exten- 
sion. It was not therefore before the very end of the pliocene 
that Campbell Island, as it now exists, appeared above the sur- 
face of the sea. 
Again, I would call attention to some facts which tend to 
show that Campbell Island has never been in connection with 
New Zealand. Throughout the whole extent of the three 
islands forming that country lizards exist, but none of their 
species are to be met with in Campbell Island. Similarly in 
none of the recent deposits of this island are the remains of moas 
