PRESIDENTIAL ADDRESS. 21 
All of these Pacific elements, inclusive of Western, 
Central, and Hastern Australia, the Tasman and Coral Seas, 
of New Zealand with the great Pacific Knot, the Aldrich 
Deep, and the outer belts of islands and sea troughs, com- 
prise several important earth waves whose crests are 
represented by the plateaus and submarine ridges and whose 
troughs are represented both by land valleys and ocean 
bases. Allare of the same age if they are considered as 
groups and not as individual islands thereof. 
These earth waves reveal the influence of progressive 
instability from South Australia to the Aldrich Deep. 
Similarity of External Structure in Individual Island 
Groups. 
For the purpose of simplicity it would be advisable to 
supply a few additional details of structure for several types 
-of the Pacific groups of islands. 
The types selected for description are :— 
a1 Australia. 
a2 New Zealand. 
as New Caledonia. 
az The Greater Solomons. 
as Fiji. 
ag Tonga. 
az Society with Paumotu Group. 
a, Australia.—The plateaus of Australia are the revivals 
-of a series of the crests of earth undulations or waves which 
date from the early Kainozoic at least, beginning at that 
time as forms of slight relief, only they have been worn 
-down, and raised successively from the plains to the plateau 
stage. The present highlands or plateaus, are the alge- 
braic sum of the warping movements attendant on the 
Kosciusko, or closing Kainozoic Period. The uplifts have 
been gradual and vibratory, with pauses of stable equi- 
