612 
reefs and atolls took place. That such fluctuations of the sea-level, 
as Dany assumes, caused by the pleistocene glacial periods, have 
indeed taken place can hardly be doubted. 
The remarkable shelf seas of the East Indian Archipelago, such 
as the Java sea and the Sahul bank, strongly support Daxy’s theory. 
From the geological structure of these two regions may be inferred 
that they have not been affected by the strong contrasting crustal 
movements which in recent geological times have either caused the 
very uneven relief and the complicated topography both of the land 
and the seabottom in the eastern part of the East Indian Archipelago 
or at any rate have made it much more prominent. The Java-sea 
is shallow *) and has a very constant depth which, on the average, 
does not deviate much from 50 and 60 metres, which is exactly 
the figure accepted by Day for the rise of the sea-level (apparent 
subsidence of the land) in aequatorial parts since the pleistocene 
epoch. The same holds good for the Salnl bank. In both the Java- 
sea and the Sahul bank the bottom of the sea at present gives the 
impression of a submerged, strongly peneplainized land-surface. The 
mature forms of erosion which are met with on the islands of Bangka 
and Billiton, the Karimata islands and in West Borneo, which may 
be said to show a near approach to a peneplain, justify the surmise 
that those groups of islands are nothing but the harder more resist- 
ant parts or monadnocks left by erosion in the broad peneplain 
which in pleistocene times, the ocean-level being lowered, has been 
formed between the mountain-land of Sumatra and Java on the 
one hand and that of Borneo on the other. In late- and post-pleisto- 
cene times this peneplain has been submerged through the rise of 
the sea-level to a depth of some 50 to 60 m., by which submer- 
gence the present Java-sea was formed with its remarkably constant 
depths. In a similar way the Sahul bank was submerged along the 
north-west coast of Australia, a shelf thus being formed of equally 
remarkable constant depth. 
In Dany’s “glacial-control theory” a factor is brought forward for 
the origin of barrier reefs and atolls, which certainly has been of 
primary importance for the possibility of the formation of many of 
those types of coral-reefs. 
Marine abrasion in the pleistocene period at lower sea-level, 
1) Quite erroneously WEGENER quotes the floor of the Java-sea as an example 
of a shelf of great depth, according to him about 300 m. The werds “Getreuer 
Querschnitt durch den Javaschelf” (true section through the Java shelf) accompa- 
nying his figure 10, had therefore better been omitted. Compare A. WEGENER. 
Die Entstehung der Kontinente und Ozeane, p. 36, Braunschweig 1915. 
