PRESIDENT’S ADDRESS. ; 337 
from one land to the other by an Antarctic bridge, and, on 
reaching each of these continents, have passed into it, and 
‘given origin to other genera, which have wandered still 
further northwards and peopled the land, meeting as they 
proceeded members of other families which have developed 
in the Northern Hemisphere and migrated southwards. 
We have at present little evidence of the age, or length of 
duration, of this Antarctica. We may look forward to in- 
teresting discoveries by the various expeditions exploring 
those regions now or intheimmediatefuture, which may give 
us some clue to the solution of the problem. It is, by most 
authorities, believed to have been in existence, at any rate 
during the Mesozoic period, and to have shrunk away from 
the northern connections during some part of the Tertiary 
period; but at what particular time this shrinkage took 
place, whether late or early, we cannot speak with certainty, 
for, as you are aware, the matter is still under dispute. For 
our present purpose, the exact date matters nothing; but, 
from the small amount of geological evidence available, the 
rocks seem to be of very great age. I quote from Professor 
Gregory’s article in ‘‘ Nature” (April, 1901) :—‘‘ The speci- 
mens of rocks collected by Wilkes, and the boulders dredged 
by the Challenger or Valdivia, mclude Archean and Sedi- 
mentary rocks, similar to those in Southern Australia; while 
rocks collected by the staff of the Southern Cross are prac- 
tically identical with some of the Lower Paleozoic rocks of 
Victoria.” 
At some part of the period at which this Antarctic con- 
tinent existed, the land in the region now occupied by New 
Zealand and the outlying islands was at a much higher level 
than at present, so that most of these islands were continuous 
with the mainland. To this great island Hedley gave the 
name “‘ Melanesian Plateau,” to which reference has been 
already made. bd 
At one period the “‘ Melanesian Plateau’ was connected 
with the Papuan Land, represented by New Guinea. The 
various land connections here were probably not syn- 
chronous. 
It was in the more limited Antipodea that the Acantho- 
drilids seem to have originated, or, at any rate, this area 
was a centre of migration. — 
From this Antipodea the Acanthodrilids appear to have 
passed northward into Papua Land ; and, after this, in Cre- 
taceous times, Antipodea became cut off from it. It then 
became united with the Antarctic continent, and the Acan- 
thodrilids, wandering across it, gained access to South Africa 
x 
