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in late-pliocene time. The chart accompanying his paper gives his 
idea of the distribution of land and sea at that time. On that map 
also the courses of drowned rivers in that extensive late-pliocene 
and early-quaternary land are indicated, derived by the author from 
several of the isobaths in the present Java- and South-China Sea. 
He imagines in pleistocene time a subsidence of the land and a 
consequent transgression of the sea to have occurred beyond the 
present coastline. During that time barrier-reefs originated by up- 
growth of the coast-reefs along the late-pliocene and early-quaternary 
coastline and also atolls arose, where small islands occurred. During 
the post-pleistocene time van Es assumes upheaval of the land 
and corresponding retreat of the sea. He conceives the upheaval, 
just as the preceding subsidence, to have been irregular, and most 
pronounced where previous earth-movements had been strongest. 
The chief differences between his opinion and mine are: 
1st. in pleistocene time van Es assumes subsidence of the land 
relatively to the sea-level, where I assume upheaval, whereas during 
the post-pleistocene time he admits upheaval where [ assume sub- 
sidence of the land relatively to the sea-level. 
2d. van Es ascribes all shiftings of the coastline, the pre-pleisto- 
cene as well as the pleistocene and the post-pleistocene to orogenetic 
movements, whereas I claim the greater influence in pleistocene and 
in post-pleistocene time for oscillations of the sea-level in connection 
with the ice-age. 
3rd, van Es does not distinguish between the stable and the un- 
stable portions of the East-Indian Archipelago, i.e. between the two 
areas which, at any rate ever since the beginning of the Pleistocene, 
have been stable or unstable, whereas it is my opinion that only 
the great stability (which implies the total absence of earth-movements) 
of the greater part of the ancient Sunda Land can account for the 
remarkably uniform character of the present Sunda Sea and for the 
distribution and the mode of development of the coral-reefs in that 
part of the Archipelago. 
Il. BIOLOGICAL PART by Max Weger. 
The theory of the subsidence of the Ocean-waters in the pleisto- 
cene ice-period and its geological and hydrographical consequences, 
so well expounded in the preceding pages by Professor MOLENGRAAFF, 
also concerns in many ways the biological sciences, first of all the 
faunistics and the zoo-geography of the Indo-Australian Archipelago, 
to what extent also the phyto-geography, lam not competent to judge. 
