233 
This western portion with the tranquil topography both of the land 
and the sea-bottom, has not taken part in the more recent crustal 
movements ; since the upheaval which raised the miocene sandstone 
formation in Central-Borneo to a level of more than 1000 M. above 
the sea, no movements of the soil have been recorded there, probably 
with the exception of the area immediately bordering the Street of 
Macassar. In the eastern portion of the archipelago, where a com- 
plicated topography of the land and the sea bottom prevails, deep 
sea-basins have been formed by subsidence; and, during the same 
time, ranges of islands have been elevated above the sea, caused by 
antagonistic movements which are probably still in course of progress. 
It thus appears that in the latest geological period the crustal move- 
ments, in the geosynclinal or movable area between the Australian 
and the Asiatic continent, have been confined to the portion, immediately 
adjoinina the Australian continent, te. between Borneo and Australia. 
In tropical regions generally, a coating of coral-limestone is formed 
along an elevated coast, as long as there are no causes to counteract 
or annihilate the results of the growth of successive fringing reefs 
during the period of upheaval. | 
This easily recognisable coating of coral-limestone (series of fringing 
reefs in different levels one above the other) in tropical regions, 
affords an excellent criterion from which may be judged whether a 
coast has been elevated in proportion to the level of the sea. 
Now in the entire western portion of the archipelago with its 
undisturbed topography i.e. the land surrounding the Java-sea where, 
according to my opinion, no movements of the land in relation to 
the level of the sea have taken place in the latest geological time, 
raised coralreefs have not been recorded *). 
In the eastern portion of the archipelago with its complicated 
topography, where crustal movements have occurred, elevated coral- 
reefs are found on the great majority of the islands. 
I believe, that generally speaking it may be accepted, that where 
coralreefs (Le. p. 817). VERBEEK, however, believes in an indirect cause for such’ 
a phenomenon. In his opinion the upheaval of the islands took place only after 
the deep sea-basins had already been formed, by the subsidence of landmasses ; 
pressure exercised by the suuken blocks caused later folding at a great depth, as 
well as the upheaval of the islands (le. p. 816). In my opinion, however, the 
causal origin was of a direct nature; the subsidence of tlie deep sea-basins 
and the elevation of the islands took place at the same time, and both anta: 
gonistic movements were tlie results of one and the same phenomenon of thrust 
and folding at a certain depth. 
1) Java, especially the southern coast, would have been subjected again to the 
crustal movements, which had occurred at the border belween the Indian Ocean 
and the East-[ndian archipelago. 
