II. 



On the Relation of the Fauna and Flora of 

 Australia to those of New Zealand. 



THAT the flora of New Zealand should present so many features 

 akin to that of Australia, and yet entirely want the distinctive 

 botanical characters of its nearest continent, is a problem to which 

 Hooker first drew attention. No solution was attempted by that 

 writer, who limited his discussion of the question to a clear statement 

 of the facts in a passage ^ so frequently quoted that it need not be 

 here repeated. 



The explanation offered by Wallace in " Island Life," and 

 generally accepted, is: (i) commencing the biological history of 

 Australia with the Cretaceous era, that Eastern and Western 

 Australia were then totally severed ; (2) that Eastern Australia 

 was at that time quite devoid of a typical Australian terrestrial fauna 

 and flora, which was then confined to Western Australia ; (3) that 

 a large area of what is now the floor of the Tasman Sea was upheaved, 

 and nearly, or quite, connected New Zealand with Australia, whereby 

 the flora and fauna, then existing in Eastern Australia, were enabled 

 to colonise New Zealand; (4) that this hypothetical bridge then 

 sank, isolating the New Zealand colonists, and afterwards dry land 

 appeared between Eastern and Western Australia, upon which the 

 characteristic Australian forms first crossed from west to east. 



Apart from the difficulty they are supposed to satisfy, little or no 

 evidence is advanced for the support of these propositions. That a 

 Cretaceous sea separated Eastern from Western Australia may be 

 granted, but that at any time Western Australia possessed a monopoly 

 of characteristic Australian plants or animals is improbable. Recent 

 discoveries show that the dry land re*presenting Western Australia 

 in Cretaceous times was much less than Wallace supposed, and than 

 appears in the sketch map on p. 497 of the second edition of " Island 

 Life." In the region explored by the Elder Expedition, " an area of 

 Mesozoic formation extends as far as long. 123°."-^ The shallow 

 inland Cretaceous sea was studded with islands, large and small, which 

 served the fauna and flora as stepping-stones in their migrations 

 from west to east and from east to west. Some of these are now 



ij. D. Hooker, "Introductory Essay to the Flora of Tasmania," pp. Ixxxviii.-ix. 

 2 V. Streich, " Scientific Results cf the Elder Exploring Expedition, Geology," 

 p. 88. 



