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shelf on the east coast of Borneo. The coral-island of Ambungi lies 
about 120 km. to the south of the mouth of the Kutei-river. Our 
barrier-reef runs from the Ambungi coral-island in southeastern 
direction to a point opposite to and at the same latitude of Tand- 
jong Ongkona on the coast of Celebes. There the reef is at a distance 
of 230 km. from the present coast of Borneo, but only 44 km. 
from that of Celebes. To the west of the reef, towards Borneo, the 
depth of the sea is very uniform, and nowhere exceeds 75 m.; on 
the east of the reef, towards Celebes, the depth of the sea increases 
abruptly to 200 m., from there rapidly to 1000 and somewhat 
further to 2385 metres. From this point the reef proceeds first 
towards the south-west, then towards the south-south-west to about 
5°40' southern latitude. 
A well-nigh continuous portion of the reef, which at ebb-tide is 
laid bare in many places, lies between 4°'20 and 5°30’ southern latitude. 
It is known on the charts as the Laurel-reefs. The total length of 
the Sunda barrier-reef from Ambungi to 5°40' southern latitude is about 
500 km. The reef cannot be traced on the charts beyond 5°40’, 
but about 100 km. farther south it reappears again in the Kwong- 
Eng reef aud may even be traced along a number of coral islands 
as far as the Kangeang islands, marking here again the extreme 
limit of the Sunda Shelf, i.e. of the submerged Sunda Land. 
The gap of over 100 km. in the reef faces the entrance to a large 
inlet or bay, the Kast Bay, into which, in all likelihood, the large stream 
(or streams) discharged itself, which drained the Sunda Land in the 
pleistocene period in the direction of the most southern portion 
of Macassar Strait. This readily accounts for the absence of reefs there. 
According to the sea-charts the Great barrier-reef *) is interrupted 
in many places and only occasionally reaches the surface of the 
sea; in most places it is found a little below the surface and only 
to the southwest of the Laurel-reefs its depth increases gradually. 
Probably on account of the insufficient salt-content of the water the 
conditions for the upgrowth of the former fringing-reefs were less 
favourable here than more towards the north in Strait Macassar. 
1) NIERMEYER (lc. p. 884 and Chart XIII No. 2) has already considered and 
described a portion of this great reef as a barrier-reef, but I think that he failed 
to see the relation between the genesis of the Borneo Bank and of this barrier-reef. 
Regarding the part of the reef that does not reach the surface of the sea between 
the Laurel reefs and the ‘Kleine Paternoster-eilanden’’, he puts the question: “Isa 
reef building itself up here from the seabottom?’’ My answer is obviously in the 
affirmative, but [ conceive this building-up as having taken place not from a depth 
of 200 m., but from a depth of 75 to 90 m. simultaneously with the gradual 
rise of the sea-level after the glacial period. Let it also be stated here, that I do 
