BENsox.— Structural Features of the Margin of Australasia. 113 
g . . . agree with those of the 
Kober (1921, p. 157) is also of the view that a 
from the Indus, through Timor and New Guinea, to New Caledonia, 
and terms it the Indo-Australian branch of the Mediterranean orogen. 
On his interpretation, the Sunda and Ceram-Buru chains would be 
respectively the outward-thrust lateral chains of a single but widened 
orogen, the central portion of which had subsided to form the Banda Sea, 
while New Guinea would represent the restricted portion of the same 
structure. 
'This diversity of interpretation of the structure of the eastern end of 
the Banda naturally involves a corresponding variety of conceptions 
of the struetural relationships of western New Guinea, to which attention 
must now be given. Converging towards north-western New Guinea are 
two arcuate lines of strongly folded mountains, the Buru-Ceram line 
already described and that running south-eastwards from Halmahera. 
"Phe structure of this island, which Suess (1909, p. 308) assigned entirely 
to the Asiatic framework, is as yet but little known, but is perhaps 
Tertiary basic igneous rocks (Wanner, 1913; Brouwer, 1922 and private 
communication). It seems to lie at the meeting-point of an Asiatic arc 
extending south-westwards from Yap and the Pelew Islands, with that 
running south-east into New Guinea. Between the latter and the Buru- 
Ceram arc is the resistant wedge made up by the crystalline rocks of 
eastern Celebes, the Sula Islands, and Obi, and the rather more yielding 
Misol mass. According to Brouwer's view, illustrated in fig. 2, the south- 
eastern Halmahera arc strikes across the southern peninsula of western 
New Guinea, and is here shown by steeply dipping Eocene Alveolina lime- 
stones, which appear to be drained by strike-streams, and bends round to 
the east and east-south-east into the Snow Mountains. It separates, 
therefore, the crystalline rocks of the Sula Islands from those of the 
northern peninsula of western New Guinea (the “ Vogelkop ") and the 
adjacent regions about Geelvinck Bay and farther east. In Suess's view 
e Buru-Ceram trend-line (though it may be locally deflected to the 
south-east in the southern peninsula) is continued into the Snow Mountains, 
while he groups into a single series not only the crystalline rocks of the 
Sula Islands, Obi, Misol, the northern peninsula, and Geelvinck Bay, which 
are overlain by nearly horizontal shallow-water marine Jurassic rocks, 
but also those which extend farther east, along the north coast and 
highlands of New Guinea as far as the Louisiade Islands, beyond its 
south-eastern extremity. Stanley (19214) is of the opinion that the 
Halmahera arc swings into Waigeo Island, the northern peninsula, and 
Jappen Island, and thence extends along the north coastal ranges. On 
the view of Gregory (1923) it would seem as if the Snow Mountains and 
their eastward prolongation must be considered as a complete bilateral 
orogen, and to correspond with both the northward-thrust Ceram trend 
and the southward-thrust Timor trend, with a narrow central zone 
corresponding to the widened depression of the Banda Sea. No evidence 
yet advanced seems to indicate the existence of such an arrangement in 
