108 SPOLIA ZEYLANICA. 



gave one an impression of a curiously patterned ceiling. There were 

 similar patches on the sides of the cave. The roof dipped towards 

 the west, evidently along a certain weak foliation, or may be along 

 the junction plane of limestone and gneiss, which I could not ascer- 

 tain. Huge blocks of rock had fallen down and were scattered on 

 the floor. At other places the roof was irregular and rugged, but 

 covered with white patches. Fine blackish dust and bats' dung lay 

 evenly over the blocks lying on the floor, so that we had to move 

 very cautiously. The dust in several places I found more than 5 feet 

 thick, and lying so loose that one might have sunk through it if one 

 had walked unwarily. In some places it was thicker than 5 feet. 

 It was easily disturbed, and our walking had raised quite a large 

 amount ; but it was stifling when we started digging. 



The number of bats here was enormous. Like a whirlwind they 

 hovered round us. They constantly dashed against us, settling 

 on us, one even clinging to the mouth of a cooly. 



Very high in the roof of some parts of the cave were funnel-shaped 

 openings communicating with the surface. Light streamed in and 

 dimly lit up the rugged sides of these openings and the part of cave 

 immediately below. It gave one an impression of a deep dark 

 dungeon only lit up from a side window from a tower high above. 

 This, with the bats flitting aimlessly in the sombre light, made a 

 most melancholy and gloomy impression. 



We crossed the hall, which I believe is more than 200 yards long 

 and more than 150 yards broad, for the further end. Here we had 

 to climb on all fours about 20 feet, when we found ourselves at the 

 entrance of small tunnels which opened into chambers. These appear 

 to have been worked by men. 



Here the stench was overpowering. We worked up a smaU tunnel. 

 It was very low and narrow, so that only one person can pass at a 

 time in a stooping posture. The bats having perhaps no other egress 

 from the passage dashed against us in a continuous stream. We 

 dug in one of the chambers. By the time we finished it was simply 

 stifling, also the heat was tremendous. So we returned to the 

 entrance of the cave. 



The economic value of the tons of manure found in this and several 

 other caves is yet to be proved. Davy states that this cave was 

 worked for many years for saltpetre by " natives, a party of whom, 

 whose express occupation and duty it was, came annually from the 

 neighbourhood of Passara for the purpose." 



The formation of saltpetre in the cave is due to the decomposition 

 of alkali-bearing silicates, such as the felspars, in contact with bats' 

 dung. It does not occur in the bats' excreta. 



Davy gives a very interesting account of the manufacture of 

 saltpetre by the ancient Sinhalese in his book, pp. 265 et seq., which 

 should interest many a reader. 



January 4, 1908. JOSEPH A. DANIEL. 



