¢ 1492) 
Geology. — “On Orbitoides in the neighbourhood of the Bahk 
Papan Bay, East-coast of Borneo.” By L. Rurren. (Commu- 
nicated by Prof. A. WicHMANn). | 
(Communicated in the meeting of February 25, 1911). 
During a four months’ exploration near the Balik-Papan Bay 
executed by order of the ‘Nederlandsche Maatschappij tot het 
verrichten van Mijnbouwkundige Werken”, the general geological 
results of which are described elsewhere, I collected rocks containing 
Foraminifera in several places. 
With the consent of the Director of the Department of Agriculture, 
Mr. Lovixk I could make a thorough study of part of these fossils 
in the laboratory for geological observations at Buitenzorg, where 
the superintendent Dr. J. Monr, with the greatest affability, set a 
room apart for me and was constantly ready to lend me a helping 
hand during the investigation. 
I regret I had to dispose neither of sufficient time, nor of suffi- 
cient literature to be able to determine all Foraminifera ; the greater 
part of the work was devoted to the Orbitoides which ocenrred in 
different species and a great number of specimens among my material. 
Together with the description of the Orbitoides, likewise the other 
Foraminifera will be mentioned, in so far as they could be determined. 
For orientation a sketch-map on a scale of 1.250.000 is added 
to this communication, on which the places where the fossils have 
been found, are indicated, the principal ones by crosses, the others 
by circlets. Whereas Foraminifera occur chiefly in pure limestone 
or in hard marl, in which they can only be seen distinctly in thin 
sections, I succeeded in finding looser marl, from which the Fora- 
minifera could be washed out in great quantities. The first place 
lies on the Sungei (river) Palamuan, about 2 km. west of the 
kampong of that name, the second on the Sungei Blakin, the last 
on the upper-course of the Sungei Mentawir. These three places are 
indicated on the map by a cross. Of these three places the one on 
the Sungei Pamaluan is the oldest, that on the Sungei Mentawir the 
youngest. The greater part of the Foraminifera collected at these 
spots is in the collection of the Mineralogical-Geological Institute of 
the University of Utrecht; during my investigation I only disposed 
of small specimens which I had left behind here, so that it is not 
impossible that the chief material contains still some other forms 
than those ] am about to describe. 
The greater part of the forms I am going to describe, come from 
the three places mentioned; I found only one species in a limestone at 
