34 
Plateau is separated from another upon which rest the 
islands of Norfolk, Lord Howe, New Zealand, Chatham, &c., by a 
deep abyss of over 2,000 fathoms, which heads in the Gulf of Papua. 
The course of the northern portion of this submarine valley agrees in 
its general trend with that of the Fly River, after its divergence to the 
eastward by the rocky islands of Torres Straits, which are merely the 
northern projection of the Peninsula of Cape York. In the centre of 
this valley, there appears a bank upon which rest New Caledonia and 
the Loyalty Islands. From Norfolk Island northwards, the plateau is 
connected with the Great Barrier Reef by numerous islets, reefs and 
quays, just appearing above the tidal mark, the summits, I take it, of a 
submerged range. What may be called the New Zealand fork of the 
Melanesian Plateau is separated from the Continent of Australia by 
another deep valley heading somewhere near Sandy Cape, on the 
Queensland Coast. 
From these data we are enabled to trace an approximate parallel- 
ism between the mean trend of that arc which includes the Barrier 
Reef and the north-west island of New Zealand, and that which may 
be appropriately designated as the Papua-Fijian arc. A careful 
study of the deep-sea soundings reveals the presence of folds 
in the earth’s crust of which the continents are merely such 
portions as are elevated above sea level ; these continental masses 
have formed a nucleus around the old outlines, of which the principal 
changes in configuration have taken place. The broad problems raised 
by a study of what may be called this ancient geography, which has a 
fascination peculiarly its own, find in geology much of their final solu- 
tion, hence the light thrown upon the evolution of this portion of the 
earth’s surface by an account of the salient geological features of a part 
of one of the islands of the rim bounding the Australian Continent, may, 
perhaps, be of additional interest to those of the Society who find a 
little of their private pleasure in matters scientific. 
PREVIOUS OBSERVATIONS. 
As far back as the year 1844, Mr. J. Beete Jukes, the Naturalist to 
H.M.S. “hly,” visited, in the course of his travels, a portion of New 
Guinea at the head of the Papuan Gulf, but the absence of any men- 
tion of geological facts in the record of the journey is probably ex- 
plained by the following passage by Mr. J. MacGillivray, summarising 
the results of the work of the “ Fly ” : — 
“This country presented a great sameness of aspect ; low muddy 
shores covered at first with mangroves, and further back with dense 
forests, were lound to be intersected by numerous channels of fresh 
water, the mouths, there is reason to suppose, of one or more large 
