MEETINGS OF SOCIETIES. 93 
ocean, but their number must be almost inappreciable, and cannot 
affect the general result. 
While many of the immigrants thus introduced may have 
transmitted their characters almost unaltered through many suc- 
cessive ‘generations, so that we still rank their descendants as 
belonging to species yet to be found outside New Zealand, others 
gave rise to variations and sports, and in course of time the 
accumulation of these variations has amounted to specific 
importance, and in some cases even to generic. 
I believe that some such explanation as that sought to be 
given here will account for the present gecgraphical distribution 
of our flora, but it will be long before we can trace the parent 
forms of many of our plants, and detect the alterations and 
variations they have undergone. A knowledge of the tertiary and 
secondary floras of New Zealand and Australia will help much 
towards elucidating this problem, but the paleo-botany of this 
part of the world is yet in its infancy, and very little is known on 
the subject. 
It may be considered that too much stress is laid in this 
explanation on the elevation and subsidence of great masses of 
land, but a little consideration will show that this is not the case. 
The deeply gouged-out character of our western lakes and sounds 
shows that they were cut out by ice, and to account for this we 
must either assume that the land stood very much higher than it 
does now, or the climate was very much more frigid. But even 
in the latter case, we must assume a considerable elevation, as 
glacial action would cease at, or very near, sea level, and our 
sounds are gouged down to great depths below present sea level. 
Further, most of the low-lying eastern portions of this island have 
been tormed at comparatively recent times by the denudation of 
our mountain chains, and most of this eastern coast is rapidly— 
one might almost say visibly—rising out of the sea. Again, the 
occurrence of fringing and barrier reefs in tropical seas is an 
almost certain mark of subsidence, as coral zoophytes cannot live 
at greater depths than about 120 feet, so that when we find these 
huge masses of rock surrounding islands, and standing out of an 
ocean in some cases 1000 fathoms or more in depth, we are bound 
down to the conclusion that the base on which the zoophytes 
commenced their labours was only a few fathoms from the surface, 
though now 6000 feet deep. 
In bringing these remarks to a close, I may just point out 
that a probably most important factor has been throughout left 
out of our calculations—viz., the physical changes which have 
affected the whole of our globe during comparatively recent 
geological epochs. Many theories have been advanced ot late 
years to account for the glaciation of parts of the northern hemis- 
phere, and the theorists have in some cases called in as auxiliaries 
all the powers of heaven and earth. But we may be sure that 
whatever causes could lead to results which are so apparent in one 
large portion of the world, must have at the same time caused 
great alteration in all other parts. But until we know with more 
certainty than we do at present what these great causes were, we 
cannot estimate what their effects on this portion of the world 
have been, 
