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126 | ` Transactions: 
be considered in the main as a geanticline which has been developing inter- 
mittently from Permian times, the diverse strikes of the successive foldings 
resulting, probably, from the apposition of the folds formed at the surface 
7 ; in strata lying on the eroded surface of those formed 
Meise at depth. Further, though active orogenic move- 
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z ment has ceased, a slight warping of the ridge is still 
& = in progres. The foundering of the north-eastern 
5.5 coast may suggest the occurrence of block-move- 
E 8 ments in association with the Tertiary folding ; but 
œg Davis (1918) is of the opinion that the generally 
, 
rectilinear, cliffed yet embayed, north-eastern coast 
is not a fault coast, but has resulted from an ex- 
tensive and very recent submergence of a series of 
wave-cut cliffs formed after an earlier period of long- 
continued emergence. No late Tertiary or Recent 
voleanie activity has been recorded in connection 
with these crust-movements. 
t is now possible to contrast the structure of 
the Australasian margin as displayed on either side 
of New Guinea. Though Kober (1921) has classed 
the whole into a single orogen, and Gregory (19234) 
has supported in some degree his conception of the 
Banda region as a bilaterally outthrust structure 
with a subsided central zone, it is by no means 
clear that such an arrangement is continued into the 
central ranges of New Guinea, as Gregory suggests 
in his diagram, and the actually observed trend-lines 
in the western portion of that island do not accord 
with the suggestion that might be raised by Suess's 
phrasing that New Guinea as a whole, with its out- 
thrust coastal ranges and iongitudinal depression, 
should be regarded as the continuation of the Banda 
structures. Still further difference is seen to the 
south-west, where (omitting New Britain), in place 
of a bilateral arrangement, the structure is that of 
a series of parallel unilateral chains, running con- 
centrically about the Australian nucleus and super- 
cially thrust in that direction. It might perhaps 
be argued that the deep west of the Solomon - New 
Hebrides chain is not a true foredeep, as its seismic 
Eocene; 8 
quartz-schist and phyllites; 3 
1, sericite-schists ; 2, 
5, Middle Eocene; 6, 7, older and younger Upper 
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the normal case the thrusting would have been in 
the opposite direction — ?.е., to the north-east — 
symmetrically with the south-westerly thrusting of 
New Caledonia. In support of this view might be 
cited the overturning of the folds in the east of 
New Caledonia itself towards this depression, which 
Piroutet (1917) has pointed out. The alternative 
suggestion that the deep is a true foredeep, and the 
New Hebrides-Solomon ridge is but the marginal 
fold of the former continent now represented by the 
Fra. 4.—Section across New Caledonia (after Piroutet, 1917). 
4, Upper Jurassic - Cretaceous coal-measures ; i 
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