92 B. KOTO : THE GEOLOGIC STRUCTURE OF 



Serua, Namuk, and the Banda Islands, collectively called the 

 South-west Islands, whose arrangement is ciirviform, with the 

 inner side towards the north-west. All are entirely volcanic. 

 An active volcano of Eiadur crowns Koma; Dammer has the 

 active Wuarlili and a few solfataras ; there are volcanoes and 

 solfataras also in Nila; Tiouw has its record of eruption in 1660 

 and 1693. Upon Serua are three volcanoes, one of which made 

 destructive explosions in 1683, 1694, 1844, and 1862?, while 

 Pulu Manuk (Bird island) has a crater and large deposits of 

 sulphur. In a north-westerly direction we have the Banda Is- 

 lands, one member of which is Gunung Api (burning mountain) 

 which was in eruption in 1820 ; and with this apparently ends 

 the Banda chain. We shall come again to it later on. 



A glance at the map will suffice to convince us that the 

 geological position of Timor and its neighbouring islands between 

 the Banda and Sunda chains is a peculiar one. Of Sumba or 

 Sandal-wood island there is nothing known from the geological 

 point of view, except that its interior is table-shaped, fringed by 

 raised coral-reefs which are overlaid by marls; but Timor is the 

 classical ground of geology in the whole East Indian Archipelago. 

 Near the boundary between the Dutch and Portuguese posses- 

 sions, which divides the island into nearly east and west halves, 

 several formations'^^ appear to be fairly represented, which, count- 

 ing upwards, are as follows: — (1) the Archœan amphibolite, (2) 

 the Permian and (3) Trias, and finally reef-limestones. At Baung, 

 not far from the well-known Kupang, the reef-limestones cap the 

 Eocene Nummulitic limestone with Alveolina ;^^^ in other places 



23) Wichmann, Tijdschr. v. h. Kon. Nederl. Aardrijksk. Gen., Jaargang 1S92, p. 255. 



24) K. Martin, ibid. 1890, p. 269, and Yerbeek, ibid. 1891, p. 15. 



