Geology. — “On Foraminifera-bearing Rocks from the Basin of 
the Lorentz River (Southwest Dutch New-Guinea)’. By 
Dr. L. Rurren, correspondent of the Academy. 
(Communicated at the meeting of October 25, 1919). 
The Dutch South-New-Guinea Expeditions of 1907 and 1909 made a 
pretty large collection of rocks from the basin of the river Lorentz 
(North-River). Many specimens of rocks bore Foraminifera of Ter- 
tiary age. They will be briefly described in the present paper. 
After the latest résumé of the Foraminefera literature?) of 
New-Guinea, only one more publication was brought forward by 
R. Burien Newron’), in which are described some Lepidocyclina- 
bearing limestones, found near the snowline on the summit of 
mount Carstensz. For the literature we, therefore, refer to this résumé. 
The rocks of the above-mentioned expeditions were taken from 
a zone, of which K. Marrin*) described numerous fossils as early as 
1911; in this zone, extending from the 187th degree to 141th 
degree longitude, the basin of the Lorentz-River covers only a 
small area. It could, therefore, be anticipated that the collection — 
with regard to the boulders it contained — would not open up 
many new viewpoints. Of course the fragments struck from the 
solid rock were of greater interest; they are however few in number. 
For geological purposes, therefore, we do not feel called upon to 
give a detailed discussion of the collection. Neither did paleonto- 
logical considerations require more than a short description of the 
material. The vast majority of the fragments are limestones, in 
which Lepidoeyelinae and Nummulites predominate. These fossils 
cannot be removed from the rock and must, therefore, be exam- 
ined from microscopical sections. True, our knowledge of the 
systematic arrangement of the Indian Lepidoeyclinae has been 
somewhat clarified, but the various species can with difficulty be 
1) L. Rurren. In Nova Guinea, VI. 2. 1914, p. 22—25. 
2) R. BuLLeN Newron. Organic Limestones etc. from Dutch New Guinea. Reports 
on the collections made by the British Ornithological Union Expedition and 
the Wollaston Expedition in Dutch New Guinea, 1910—1913, Vol. IL. Report 20, 1916. 
For British New-Guinea see also R. Butten Newron, Geol. Mag. (6). V. 1918, 
p 203—212. 
8) K. MARTIN. Samml. Geol. Reichsmus. Leiden (1). IX. 1911, p. 84 e.v. 
