I 



BORNEO 227 



fifty miles, and trading praus ascend it for an immense 

 distance. 



The Mahakkam, like all the great rivers of Borneo, 

 rises in the unexplored regions of Mount Tebang, and 

 follows a south-east course for over 400 miles, to pour its 

 waters into the Strait of Makassar. It receives numerous 

 tributaries, and exhibits in a marked degree the phe- 

 nomenon of lake expansion. The permanent lakes in its 

 course are filling up gradually, but they are still of con- 

 siderable depth, for Mr. Carl Bock, who lately travelled in 

 this region, speaks of getting soundings of 8 feet or more. 

 The Mahakkam has the large town of Samarinda at its 

 mouth, and forms, like the Kapuas, a very considerable 

 delta. Farther north, the rivers in Dutch territory are 

 little known. The most important waterway in British 

 North Borneo is the Kinabatangan, which debouches be- 

 tween Darvel and Sandakan Bays, and is navigable by 

 boats for about 200 miles. 



Certain marked characteristics, then, are exhibited by 

 the majority of Bornean rivers, but more especially by 

 those of the southern and eastern portions of the island, 

 and these peculiarities are determined to a great extent 

 by the flatness and slight elevation of the surrounding 

 land. Most are surrounded in the lower part of their 

 course with a greater or less extent of impassable morass. 

 In most cases deltas are formed, sometimes of very large 

 size, and here, aided by the mangroves, the land gains 

 very rapidly on the sea. The slight fall in the river 

 beds causes daily tidal inundation, and periodic flooding 

 of vast areas occurs in the rainy season. For like 

 reasons the rivers are extremely serpentine in their 

 course, and in flood time the intervening land is often 

 cut across at the narrow part of the bend. The old bed 

 becomes partially blocked, and the phenomenon is thus 



