DESCRIPTION OF THE EXPEDITION. 3 
the first three of these we have no immediate concern, but one of the chief objects 
of the expedition was the investigation of the extent to which the topography of the 
ocean-hed supports or opposes the fourth. A glance at any chart shows a mass of 
islands between India and Africa, some of which (tiie Seychelles) may be the remnants 
of this ancient land-connection, while others, groups of coral islands and reefs, may 
be built upon foundations formed by its remains. There was no evidence from the 
charts, as they existed before our investigation, to prevent such views appearing quite 
reasonable. Except a few scanty soundings by the German ‘ Valdivia’ expedition, nothing 
showed the great depths found by us between the Maldive and Chagos Archipelagoes, 
or between either of the latter and the Seychelles. And although on other grounds we 
had reasons to expect a bank between Mauritius and the Seychelles, there were no 
soundings to lend support to the view that the two were connected, nor could we tell 
whether the latter bank was in any way joined to Madagascar. Finally, it was only by 
the low temperatures of the deep sea that we had any indications that the Arabian and 
Antarctic seas were connected anywhere by a depth of over 2000 fathoms *. 
Anticipating somewhat, we may at once say that we found no trace of any bank 
connecting these lands. The evidence from other sources, however, is so strong that the 
question still remains whether the ocean-bed between India, Madagascar, and South 
Africa may not have attained to its present deep level in the comparatively short 
tertiary period +. Our own researches in the Maldive and Laccadive Archipelagoes, of 
Mr. J. Y. Buchanan and Prof. Alexander Agassiz in many seas, and of the ‘Siboga’ 
expedition in the Malay Archipelago, forbid us to accept subsidence, the simplest and 
most comprehensive way of accounting for the disappearance of land, without further 
inquiries. Although prepared to find that these connecting-banks did not exist, we 
thought that the western part of the Indian Ocean would present an area singularly 
suited for the examination of the interaction of land and sea, especially as regards the 
deeper currents. This anticipation was abundantly fulfilled, and our only regret is that 
adverse circumstances, lack of time and gear, bad weather, and the pursuit of our other 
work, prevented us from making more than isolated observations in this direction. 
For the consideration of questions relating to the distribution of land-organisms 
in general, a more accurate knowledge of the present means of dispersal of land-forms, 
as well as of the actual forms capable of crossing large stretches of sea, seemed desirable. 
It might have been anticipated that the Seychelles, situated as they are in the western 
part of the Indian Ocean, would give definite evidence in its land-organisms of former 
connections with Madagascar and India. On the other hand, other islands and groups 
scattered over this area, being of corai-formation, would show only those organisms 
* Vide map, p. 14 of ‘The Fauna and Geography of the Maldive and Laccadive Archipelagoes.’ 
+ The late Dr. W. IT. Blanford in his Address at the Anniversary Meeting of the Geological Society in 1890 
(p. 98) said: “The evidence relating to the old land-connexion between India and South Africa has been given at 
greater length than would otherwise have been necessary because of its importance, and because this is a crucial case. 
So far as I am able to judge, every circumstance as to the distribution of life 1s consistent with the view that the 
connexion between India and South Africa included the Archean masses of the Seychelles and Madagascar, that it 
continued throughout Upper Cretaceous times, and was broken up into islands at an early Tertiary date. Great 
depression must have taken place, and the last remnants of the islands are now doubtless marked by the coral atolls 
of the Laccadives, Maldives, and Chagos, and by the Saya de Malha bank.” 
