Speight. — Petrological Notes on Rocks from the Kermadecs. 249 



Tonga, and a sea of triangular shape would be included between the north 

 east and north-west ridges. A few islands would dot the fringes of this sea. 



The land connection, here established in part, would be the line of com- 

 munication between New Zealand, Norfolk Island, Lord Howe Island, 

 New Caledonia, and northern Australia on the one hand, and between 

 the Kermadecs, Fiji, and Tonga on the other ; but as yet the continental 

 areas to the north, embracing northern Queensland, New Caledonia, and 

 Fiji, would be separated by narrow straits. A deep sea would lie to the east 

 of the Kermadecs and Tonga, and a similar one on the south-west of Lord 

 Howe Island, between it and the coast of New South Wales and south- 

 eastern Queensland. 



If now we imagine the sea-bed raised another 1,000 fathoms, the north- 

 westerly ridge would be joined on to northern Queensland, but would still 

 be separated nearly as much as ever from the east coast of Australia. New 

 Caledonia, the New Hebrides, Fiji, and Tonga would all be completely linked 

 wath New Zealand. Samoa would remain separate. Immediately north of 

 New Zealand would be an inland sea rudely square in outline ; south-west of 

 New Caledonia would be a long narrow depression filled with water, running 

 parallel to the direction of New Caledonia, and there would be a similar 

 depression, but deeper, between it and the New Hebrides. Very deep sea, 

 over 3,000 fathoms, would still lie east of the Kermadecs and Tonga. The 

 land embraced at this stage probably represents roughly the extent and form 

 of the tropical and subtropical Pacific continent, though no doubt recent 

 warpings up and down of the earth's crust and local elevations and de- 

 pressions would modify it somewhat. It will show a certain regularity in 

 the arrangement of its physical features. The general structure will exhibit 

 north-westerly and south-easterly trend-lines in the part to the west and 

 north of New Zealand. The New Zealand ridge, the lines of New Caledonia, 

 New Hebrides, Loyalty Islands, the depression and troughs between them, 

 even certain indentations of the coast-line and valleys, would show the 

 general orientation. This would seem to be parallel with certain lines of 

 folding at present shown by some of the older rock-systems of New Zealand ; 

 but the identity is probably a mere coincidence, as the structural features 

 spoken of as existing in the restored continent are in all probability of much 

 later date. 



If, however, we pass to the eastern side of the continent, the trend-lines 

 are found to run in a north-easterly and south-westerly direction. The 

 Tonga Group, the Kermadecs and their connections, the Kermadec trough 

 and Tongan trough exhibit this to a remarkable degree. Their line is that 

 of the main folding exhibited in the mountain-structure of New Zealand, 

 and much more recent than the old north-westerly folding. At the ends 

 of the north-easterly-running physical features there seems to be a tendency 

 to turn north and north-west, so that the two main directions may be part 

 and parcel of the same great crustal movement. 



These, then, would be the main structural features of this restored con- 

 tinent, if it is possible to rely on the evidence afforded by the present form 

 of the sea-bottom. Now, does the geological evidence afford any indication 

 of the age of the hypothetical continent ? The Kermadec Islands apparently 

 furnish none, except that some time or other the granite rock no doubt 

 formed a land-surface. The same remarks apply to all the eastern islands 

 of Polynesia. Although Fiji is continental, yet its history is uncertain. 



Dr. Woolnough says, " The rocks of Fiji consist of two main groups : 

 the first of these includes continental rocks of high but undetermined 



