Brenson.—Structural Features of the Margin of Australasia. 115 
lands (Staniforth Smith, 1912; Stanley, 19244). The t occupy 
especially the regions about the middle : course of the Fly Riv Farther 
east the foothill region rises directly from the south coast of fb sie It 
is composed in part of pre-Miocene formations; contorted semi-crystalline 
grey or white limestones, which may be Eocene or Mesozoic; more or 
less silicified limestones with interbedded sediments; and the radio larian 
cherts of-the Port Moresby series, originally held to be Pliocene, but now 
considered pre-Miocene, though it lies — above the wides espread 
Boioro grey limestone. Farther inland are sandstones with lignites which 
may be placed in this group. These are considerably crushed, folded, 
and faulted, and appear to have been overthrust towards Australia. They 
are succeeded unconformably by the Miocene-Pliocene petroliferous series 
—limestones, sandy татів, clays, grits, and sandstones with lignite, &c., 
volcanic agglomerates, and interstratified flows of andesite. Several minor 
unconformities appear to be present. The beds undulate, with a general 
south-easterly strike, but the lowest formations dip much more steeply 
than the uppermost. They are capped by raised coral-reefs along much 
of the coast. This foothill zone is succeeded to the north by the high 
ranges which form the backbone of New Guinea, and are known as the 
Charles Louis Range, the Snow Mountains, the Star Mountains, the Victor 
Emmanuel, the Bismarck, and the Owen Stanley Ranges, with various 
subordinate and spur ranges. In the western end of this central range 
littoral Permian (?) sandstones (Heldring, 1911; Martin, 1911; Brouwer, 
1917). The structure of the ranges has been investigated by Heldring 
and Hubrecht (1913). “ There is a huge thickness of strata with a fairly 
uniform dip to the north over long distances, and it does not seem 
impossible that recumben t folds, imbricated structures, and overthrusts, 
to 15,000ft. in height, and are composed of limestone, possibly Permian, 
Eocene Alveolina* limestone occurs.  Crystallin e rocks lie eath these 
and serpentines have been аа from the бен гас “of the range 
in the headwaters of the Rouffaer River (Gelder, 1910); and in the 
Setekwa, Eiland, and Digul Rivers to the south are pebbles of augite- 
granite, diorite, more or less gneissic gabbro, and also nepheline-syenite 
(Heldring, 1911). 
n addition to these rocks there is a covering series of Middle Jurassic 
claystones represented by specimens from the ee in each of the 
streams draining south from the Snow Moun and extending 
into Papua across the upper waters of de Fly ed Strickland Rivers. 
Eocene age of си limestone was originally determined by Martin (1881, 
1911) and Schlumberger (1894). It was held by David to be Cretaceous, ке like 
w was pig ore by Stanley up ret the present year. Rutten (1914) has again 
pronounced it to be Eocene, and he is followed in this by R. B. Newton (1916, 1918), 
in whose papers the earlier work is fully discu 
