403 
variations of the extent of the glaciated areas in and after the 
pleistocene period, with certainty in tropical regions, especially in 
those that have maintained their stability ever since the commence- 
ment of the Pleistocene. 
In the following pages we purpose to consider the relations be- 
tween land and sea, the submarine topography and the distribution of 
the coral-reefs in a portion of the East-Indian Archipelago, in con- 
nection with the pleistocene ice-age. 
The stable and the unstable part of the Hast-Indian Archipelago. 
In the East-Indian Archipelago we distinguish two strongly con- 
trasting portions, one with ‘an exeeptionally uniform and undisturbed 
submarine topography and another with a strikingly complicated 
submarine relief. Both areas are indicated on the accompanying 
sketchmap (Fig. 1). To the former belong the Sunda Sea and the 
Sahul Bank, to the latter all the other seas of the Hast-Indian 
Archipelago. 
It deserves notice that this contrast has already been observed by 
W. Hare as early as 1845'). He termed the Sunda shelf the Great 
Asiatic Bank and the Sahulbank the Great Australian Bank. He 
noticed the unvarying mean depth of the sea above those banks, 
estimated by him at 30 fathoms and called attention to the fact that 
the character of the land and the coasts surrounding these banks is 
very similar and differs largely from that of the other regions in 
the Indian Archipelago. 
1) W. EARLE. On the Physical Structure and Arrangement of the islands of 
the Indian Archipelago. Journ. Royal Geogr. Soc. XV. p. 358, 1845. 
EARLE says l.c. pag. 359: 
These banks, which extend from the continents of Asia and Australia, form very 
remarkable features in the geography of this part of the world, and, as such, are 
deserving of more attention than has hitherto been bestowed upon them, since 
it will be found that all the countries lying upon these banks partake of the 
character of the continents to which they are attached; while those which are 
situated on the deep sea which separates them, are all of comparatively recent 
volcanic formation, with the exception of a few small coral islands, which, in all 
probability, are constructed upon the summits of submerged volcanoes. The depth 
of water on these banks averages about 30 fathoms, deepening rapidly as the 
edge is approached, and shoaling gradually towards the land. It will be seen that 
the one [ have termed the Great Asiatic Bank extends into the Archipelago from 
the south-eastern extreme of Asia to a distance of nearly 1000 miles, in fact to 
within 50 miles of Celebes, and I| strongly suspect that it will be found to extend 
to the south-western extremity of that island also; but as there is a space of 
nearly 30 miles across which no soundings have been carried, | have preferred 
reducing the bank to the limits for which we have actual data. 
