700 ON THE VOLCANO OP TAAL, 



deep crevasses or dry water-courses of very rugged and broken 

 appearance, with a certain amount of tangled jungle in the bottom. 

 The inhabitants get water from wells near the side of the lake, 

 though, as already observed, the water in the lake itself is only 

 slightly brackish. In Australia we should consider such water 

 quite serviceable for all domestic purposes. 



Geology. — The exterior slopes of the volcano are of uniform 

 character, composed of volcanic sand, scoriae, breccia, tufa, 

 alternating in strata of diverse thickness and different colours. I 

 was surprised to see the difference there was between the colour 

 of the soil and the appearance of the volcano from a dis- 

 tance. It was yellowish-brown when near, with fragments of 

 yellow, black, and white rock. At a distance it appeared 

 grey. There was the strongest contrast between the nature of 

 the walls of this crater aad that of Bromo in Java. The latter 

 had crater walls of loose grey ash so fine that one sank into it 

 ankle deep in ascending the slopes. There were, of course, larger 

 fragments of stone and scoriae, but the general character of the 

 ash was exceedingly fine. Bromo continually emits a roaring 

 noise, which is like a succession of violent explosions, which follow 

 each other with such rapidity as to mingle the vibrations. These 

 explosions, I have no doubt, are the cause of the fine fragments 

 or dust into which the cinders of the volcano are blown. At 

 Taal, on the contrary, there is scarcely any sound, and there are 

 not consequently the detonations and explosions causing the fine 

 rain of volcaiiic dust. The greater part of the slopes of Taal 

 volcano, and especially on the north side, is covered with a fine 

 stratum of ash decomposed into alluvium. In the lower portion 

 there are large trachytic blocks, especially on the east and south- 

 east sides. In the "Barrancos" or gullies already spoken of, 

 scoriaceous lava streams of very hard dolerite can be perceived. I 

 append at the end of this paper a description of the various 

 minerals which are met with on the slopes of the volcano. This 

 list, which is that of Senor Centeno, will afford me an opportunity 

 of mentioning any details or observations which may be necessary. 



