463 TRAVELS IN THE EAST INDIAN ARCHIPELAGO. 



of limestone. Wlien we came raund to the south 

 side of Mount Sngo, before us lay the charming val- 

 ley of Biia, perhaps the most l^eautiful valley in 

 Sumatra. On our left was a range of hundreds of 

 sharp peaks, a continuation of the limestone chain 

 noticed yesterday between Fort de Kock and Paya 

 Kombo, Near their feet is the Sinamu, no^v a small 

 liver, flowing away to the southeast. At Paya Kom- 

 bo this stream flows to the southeast, which is its 

 general eom'se for about twenty-five miles after it 

 passes Mount Sago ; it then changes to the east, 

 and is knoi^Ti as the Indragiri. It is a fair sample 

 of the tortuous course of all the streams in the 

 mountainous parts of Sumatra. They wind to and 

 fro so abruptly, that sometimes the traveller comes 

 to the banks of a river without suspecting for a 

 moment that it is the very one which he was follow- 

 ing in a wholly different direction the day before. 

 The only way it is possible to realize the irregulari- 

 ties of these sti'eams, is to examine a map of this 

 region on a very large scale. On our left was an- 

 other high range walling in the nan^ow valley, the 

 bottom of which curves gradually upward as it ap- 

 proaches either side. The level parts of the valley 

 are all changed into beautiful sawas^ which are now 

 filled with young rice ■ blades of a bright gi'een. 

 Riding down the valley for four or five miles, we 

 came to the c<mtroleiir\^ house at Bua. It is sit- 

 uated near the west side of the valley, facing the 

 north. Thick clouds^ that had been hiding the top 

 of Mount Sago, now vanished into pure air, and the 

 old crater-waUs came grandly into view. They are 



