86 B. KOTO : THE GEOLOGIC STRUCTURE OF 



and finally Borneo, unless, according to the recent researches of 

 Verbeek and Fennema, Karimon Java should be taken to be the 

 true prolongation of the Billiton line.^' 



The Pegu region and the adjoining countries are not free 

 from traces of volcanic activity. In the neighbourhood of Pegan, 

 the basaltic volcano of Puppa-doung, 500 feet high, raises its 

 head from the surrounding Tertiary formation, as well as a 

 trachytic hill near the mouth of the Bassein river. Connection 

 of these with the volcanoes of Sumatra can be traced through 

 Narcondam and Barren Islands. 



Sumatra. 



Sumatra, the soutliern continuation of Pegu and the Malayan 

 peninsula, shows, according to Suess,*^^ intrusive granite, schists. 

 Carboniferous* and Tertiary beds with greenstones, all thrown 

 into manifold long ridges producing steep cliffs on the south 

 side, and in the north flattening out into a nearly impene- 

 trable but partly inhabited swampy land. Two parallel chains 

 of volcanoes run along the axis of the mountain folds, one of 

 them near the southern steep coast, whose ejected matter is 

 Miocene andésite, the other lying far in the interior and cons- 

 tituting a chain of modern volcanoes. Many transverse fissures 

 cross the latter chain, along which the seats of active vent are 

 shifting to and fro, as in the Andean cordillera. About nine- 

 teen volcanoes can be counted, of which seven belong to the 

 active kind, Gunung Korintji and G. Dempo being lofty sum- 

 mits amonof them. 



5) 'Description Géologique de Java et Madoura.' 



6) ' Das Antlitz der Erde.' 



* U])per Carboniferuuö Limestone with I'lmdutu, in I'adang un the west cuatit. 



