Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/306

296 vault of heaven appeared studded with innumerable stars, while the valleys of Orotava were hidden from our view by a thin veil of light fleecy clouds, that floated far beneath the elevated spot we had chosen for our resting place; the solemn stillness of the night was only interrupted by the crackling of the fire round which we stood, and by the whistling of the wind, which coming in hollow gusts from the mountain, resembled the roar of distant cannon.

Between two and three in the morning we resumed on foot our ascent of the same pumice mountain, the lower part of which we had climbed on horse-back the preceding evening; the ascent became however much more rapid and difficult, our feet sinking deep in the ashes at every step. From the uncommon sharpness of the acclivity we were obliged to stop often to take breath; after several halts we at last reached the head of the pumice hill at its point of intersection with the two streams of lava, the direction of which I have before described. This is the commencement of that division of the mountain called el Mal Pais; after resting some short time here, we began to climb the stream of lava stepping from mass to mass, the ascent is steep, painful and hazardous, in some places the stream of lava is heaped up in dykes or embankments, and we were often obliged to clamber over them as one ascends a steep wall, this lava is of the same porphyritic appearance as the masses we found in the plains, it is not covered with a thick scoria, and seems never to have been in a very fluid state, but to have rolled along in large masses. The felspar is crystallized in the lava itself, which is slightly cellular at its surface, yet though I searched carefully I was unable to discover any extraneous substance. The whole composition of the stream seems to be felspar imbedded in a brown clayey paste, remarkably hard, of a close texture and heavy; judging from the sharp declivity of the mountain it appears