Benson. Structural Features of the Margin of Australasia. 105 
other, and isolated rock-masses of older formations are found resting on 
younger oceanic deposits; as is clearly visible among the deep ravines 
cut on the recently elevated islands, Timor and Babber. The structure 
is usually chaotic, and is similar to that of the higher overthrust sheets 
of eastern Switzerland, which were moved in the near-surface zone, where 
the rocks yielded to pressure not by flow, but mostly by fracture. The 
comparative method of study leads to the supposition that on Timor the 
deeper complicated but less chaotic overthrust structures such as are 
found in the Western Alps have not here been uncovered by erosion " 
(Brouwer). 
There is, however, a marked variation in the intensity of disturbance. 
foreland, also, the folding-structures in Timor are of somewhat simpler 
character, for the southern coast-range of this island has merely an imbri- 
cated strueture with fairly uniform dip. The Aru Islands, believed by the 
Dutch geologists to be on the margin of the continental massif, form bu 
a swelling thereon. They exhibit only Pleistocene (and Upper Pliocene ?) 
marine limestones, &c. 
Again, in north-western New Guinea north of MacCluer Gulf erp 
зант низ rocks occur, as also in the Misol-Obi-Sula chain of islan 
which even the Jurassic strata, which are of shallow-water origin, are 
зае E horizontal, though locally sharp folding without over- 
thrusting may occur (Boehm, 1906; Brouwer, 192158). This region then 
seems to have been comparatively stable, and at least adjacent to a land- 
mass during the Cretaceous and Tertiary periods of вожа The schistose 
re-Jurassic rocks of the Sula Islands, the strike of which is markedly 
oblique to that of the Tertiary folds, may perhaps ropresdat a portion of 
that ancient block. This block, thus relatively stable during the Cretaceous 
and Miocene foldings, seems to have been in some measure like a foreland 
great outward-moving superficial thrusts of the Miocene folding in 
Ceram. According to the views of the Dutch geologists, the strike of these 
folds is in the main the continuation of the Banda arc, but is complicated 
in regard to details. It is not parallel, but oblique, to the coast of this 
island, running south-east - north-west through middle and eastern Ceram, 
bending into an east-west direction in western Ceram, and inclining to the 
south-west into the terminal Huamoal Peninsula. These directions of strike 
are displayed both by the crystalline schist and gneisses along the southern 
side of the island, and the fossiliferous Triassic and later Mesozoic sediments 
along the north. Crossing жир» Strait, however, the strike bends sharply 
to the north-west, as is shown by the schists of Manipa Island itself, and 
&c.; Triassic sandstones and shales ; сели Triassic,* later Mesozoic, 
and early Cainozoic sediments ; and the ey are therefore arranged in the 
opposite order, as regards the Banda Sea, to that displayed in Ceram. 
According to the Dutch geologists, there is an outward or northern thrust 
* Professor Wésmer has informed the writer (22nd May, о that the supposed 
b 
Upper r Cretaceous molluscan fauna of Buru characterized by sotia, mentioned in the 
previous paper (Baton, 1923, p. 50), is really "m Triassic (Norio ), the characteristic 
form, when better specimens were examin y Krumbeck, having proved to -be 
Marce ge. The Upper Cretaceous form T'ri ilis ioa reported to have been found 
in a Belgian shell, and was probably brought there by a Belgian prospector. 
үү süner "himself found no trace of Cretaceous foie in this island. 
