IHE MALAYAN ARCHIPELAGO. 109 



Neocene Orbitoides-hearmg limestone, forming an inland cliff. 

 Wichmann*^^^ found leucite rocks in the tnffs, which may justify 

 us in saying that these rocks occur largely among the volcanics 

 of this region. The east chain of South Celebes runs parallel 

 to the west coast of the Gulf of Boni, and, with the already- 

 mentioned west range encloses the long central basin of Walanne 

 with inundation lakes of Tempe and Sidenreng. 



The geological history of South Celebes, deduced from the 

 foregoing, may, following Wichmann, be summarised in the fol- 

 lowing few words. The island of crystalline schist on the west 

 coast had become faulted, and through the meridian fissure the 

 neo-volcauic rocks had intruded and overflowed, and then formed 

 detached islands fringed with the Neocene coral reef, which has 

 become now a compact limestone. At the same time, materials 

 of schists and volcanics, in consequence of transgression, had 

 formed the sandstone, holding Callianassa DijM Mart., on the 

 Boni coast. At the end of the Neocene time, a considerable 

 negative movement had caused detached islands to unite into a 

 peninsula ; the encircling coral reefs and the thick sandstone- 

 deposits had also risen from the sea. During the early Pleisto- 

 cene time, further changes in the configuration of South Celebes 

 took place. The south was the scene of great eruptions and by 

 the accumulation of the matter ejected Lompo-Battang, as well 

 as Bulu Bonte Uhu were built up. Contemporaneous with these 

 subterranean convulsions, the sandstones of the Boni coast were 

 folded and upraised, thereby producing the tectonic valley of 

 Walanne in the interior. This great longitudinally folded basin 



61) ' Lencitgesteine von der Insel Celebes ', Nahmrknndig Tijdschrifl voor NcdedandUch- 

 Lidic, Deel LIU, Aflevering u, p. 315. 



