423 
was indicative of the orogenetic movements that are still in opera- 
tion in the eastern part of the archipelago. It appears then, that 
already before the commencement of the Pleistocene the unstable 
Kast here encroached upon the stable West. Now, what is the history of 
these islands, the Kalukuang-, the Paternoster- and the Postiljon- 
islands? Initially they were raised at least 72 m. relatively to the 
sea-level, just as the entire Sunda Land. It is not known, but it is 
presumable that these islands, before the sea-level began to sink, 
were protected against the destructive effect of the surf, by fringing- 
reefs, and, accepting DarY’s opinion expounded in his glacial-control 
theory *) we may conceive that in pleistocene time they were entirely 
abraded by the breakers and converted into banks of shallow depth. 
Day believes that the abrasion and the truncation took place chiefly 
during the maxima of glaciation, i.e. the periods of lowest sea-level, 
through destruction by wave-action. It would appear to me that 
the abrasion and the truncation must have been especially 
strong and progressing during the periods of transition from glacial 
to interglacial, i.e. during periods of slow and prolonged rise of the 
sea-level. At the beginning of every interglacial period the abrasion 
and the truncation of the islands, which every time were penepla- 
nized more intensely, was brought nearer to completion, so that at 
last, at the conclusion of the Pleistocene, the islands were completely 
truncated and were reduced to submarine banks, which consequent 
on the final rise of the sea-level after the close of the glacial period, 
were covered by the sea to a depth of more than 72 m. The coast- 
reefs, which happened still to exist at the close of the Pleistocene 
and the reef-structures which were generated here and there during ~ 
the last submersion, grew up gradually with the rising of the water 
and were converted into atolls and atoll-like coral-islands, such as 
are found at the present day. . 
3. The Spermonde Bank. 
Accepting the Kalukuang-, the Paternoster-, and the Postiljon- 
islands to have been portions of the Sunda Land, which have developed 
into coral-islands, one is easily led to suppose the large shelf on the 
west coast of South-Celebes, which bears the group of coral-islands 
known as the Spermonde Archipelago, to have been likewise closely 
related to the Sunda Land. The Borneo Bank and the Spermonde Bank 
have many things in common; both are on an average 50 and at 
1) R. A. Davy. Pleistocene glaciation and the coral reef problem. Amer. 
Journal of Science XXX p. 297, 1910; Origin of the coral reefs. Science 
Conspectus I p. 120, 1911; The glacial-control theory of coral reefs. Proc. of the 
Amer. Acad. of Arts and Sciences LI p. 157, 1915. 
