4 DUTCH BORNEO-EXPEDITION. 



into the Kapoeas at a short distance above Pontianak. 

 More to the east the peaks gradually become lower, the 

 last prominent and somewhat isolated ones being Mount 

 Kenepai and Mount Toetoep, west of the Batang Loepar 

 Lake-region. At the north of that Lake-region the eleva- 

 tion , separating the Kapoeas-basin from that of the Ba- 

 tang Loepar River, does not rise much higher than 50 meter 

 above the level of the sea. 



East of the Lake-region we have to deal with a new 

 mountain-region of considerable height, one of the highest 

 peaks of it being Mount Lawit (1870 meter). This enorm- 

 ous range, forming the northern and north-eastern 

 frontier of the Upper Kapoeas-basin , and at the same time 

 the frontier between Dutch territory and that of Sarawak , 

 sends down , in a southern direction , a great number of 

 important northern tributaries of the Kapoeas, the largest 

 of which are the Embalau- , the Palin- , the Sibau- and 

 the Mendalam Rivers. 



The Kapoeas River itself has its source in a very distant 

 north-eastern corner of this mountain-range , and after a 

 wild course, forming innumerable rapids and falls, it 

 reaches the vast plain at some distauce above Nanga Era, 

 after having received from the East two large tributaries : 

 the Boengan- and the Keriau Rivers. From Nanga Era 

 the river proceeds rather slowly , forming a number of ser- 

 pentines, through the plain, which has, at Poetoes Sibau , 

 an elevation of only 50 meter above the sea. At Poetoes 

 Sibau , where the Controleur of the Upper Kapoeas came 

 to reside a short time ago , the Kapoeas has a width of 

 208 meter, and small steamers can easily reach this place 

 and even proceed to the Mendalam River when the water 

 is not very low. About 10 English miles below Poetoes 

 Sibau , the Kapoeas is joined by the Mandai River, a south- 

 ern tributary , draining a large mountain-region , which 

 is formed by a very much eroded plateau of volcanic tuff. 



Below the mouth of the Embalau River follow some other 

 large southern tributaries , such as the Boenoet River, the 



Notes from the Leyden IVIuseum, Vol. XIX^. 



