1148 
containing limestone. While these localities are all pretty near to 
the coast and only little is known of the inland in these northern 
regions, we see, that farther in the South of East Borneo the litoral 
neogene limestones appear more and more towards the interior. Of 
the basin of the Berau river I possess Lepidocyclina-bearing lime- 
stones from the rivulets Birang and Lassan, collected by Dr. F. Wege. 
As known, on Sangkulirang neogene sediments are widely diffused. 
Towards the south, certainly as far as South of the Balikpapan Bay, 
a coastal belt of rather more than 100 km. in breadth is built 
up of folded neogene rocks. We know that not all these sediments 
are of marine origin; important and numerous ingressions and 
regressions must have taken place’). That these ingressions have 
encroached far on the inland once at least, is borne out by the 
findings of oligomiocene limestone near Udju Halang’*) and Kiham 
Halo*) at the Upper-Mahakam-river. Contiguous with this towards 
the south are the old neogene reeflimes of the Middle-Barito-river 
near Batu Putihf) and of the Mahangjongriver in the basin of the 
Sg. Kapuwas Murang®). Still farther to the south I do not know 
of any occurrence of neogene coastal deposits. 
When we cross to the Northwest coast of Borneo, we find farthest 
into the inland the formation of neogene limestones at the Melinau 
river, a left affluent of the Barram-river (BULLEN, Newton and HorLAND 
Le). Data produced by J. Morrey (l.c.) seem to point to the existence 
on the Redjang-river of neogene deposits of a litoral character. On 
the other hand the rocks of Klias and Labuan described above are 
all lying in the litoral zone. 
On the accompanying map we have, on the basis of all these 
data, indicated very roughly which territories of Borneo were not 
covered by the sea during the farthest neogene ingression. We see 
here a central landmass rather narrow in the North and broadening 
towards the South-West, where it is connected with the old Sunda 
continent’), 
This sketehmap enables us to realize the stupendous changes 
undergone by Borneo in the neogene. After the farthest old- 
1) L. Rurren. These Proceedings l.c. 1916. 
2) |. Provare. Rivista italiana di Paleontologia. XV. Catania 1909. p. 95. 
3) N. Wine Easton. Tijdschr. Kon. Ned. Aardr. Gen. (2) 34. 1917. p. 680—695. 
4, L. Rurren. Samml. Geol. Reichsm. Leiden. (1) IX. 1914. p. 320—3822. 
5) L. Rurren. Samml Geol. Reichsm. Leiden. (1) IX. 1912. p. 218—217. 
6) In several places the old central landmass of Borneo was no doubt still 
smaller than is shown on the map; but no published data are at our disposal. 
On the other hand it is probable that out of this central core, e.g. in the farthest 
South East of the island, some territories were not transgressed by the sea. 
