256 Some Account of the Island of Tener'tffe. 



Ill a very fluid state, but to have rolled along in large masses. 

 The feldspar is crystallized in the lava itself, which is slightly 

 cellular at its surface ; yet though I searched carefully I was un- 

 able to discover any extraneous substance. The whole compo- 

 sition of the stream seems to be felspar imbedded in a browTi 

 clayey paste, remarkably hard, of a close texture and heavy : 

 judging from the sharp declivity of the mountain, it appears sur- 

 prising that the lava should have flowed so short a distance ; as 

 it does not exceed two and a half or three miles from the base of 

 the cone to the point of union with the pumice hill. The mass of 

 lava as well as its depth is prodigious ; M. Escolar told me that 

 its greatest breadth was above two miles, its depth it is not easy 

 to determine : there are however several ravines or valleys in the 

 course of the stream, some of which may be from 60 to 100 feet 

 deep. The fusion of the mass does not appear to have been 

 perfect ; it is very earthy, and though vitrified pieces are found, 

 there is no general appearance of vitrification : there are some 

 pieces that exhibit an union with the pumice and the gradation 

 from the, stony structure to the vitrified, and thence to pumice. 

 Immense heaps of this latter lie scattered on the surface of the 

 lava, some of them containing large crystals of felspar, which 

 abounds in, or more properly forms the constituent part of, the 

 lava of the Mai PuU. 



We halted several times during the ascent, and at last reached 

 a spot called La Cueva, one of the numerous caves that are found 

 on the sides of the mountain : this is the largest of them, and 

 is filled with snow and the most delicious water, which was just 

 at the point of congelation: the descent into it is difficult, it being 

 thirty or forty feet deep. One of our party let himself down by 

 a rope : he could not see the extent of the cave, but the guides 

 declared it to be 300 feet in length and to contain thirty or forty 

 feet of water in depth: the roof and sides are composed of a fine 

 stalactitic lava similar to that found on Vesuvius, and it is of the 

 same nature as that which flowed on the surface. We rested here 

 about half an hour, during which we had an opportunity of ob- 

 serving the rising of the sun, and that singular and rapid change 

 of night into day, the consequence of almost an entire absence 

 of tvvfilight. As we ascended the north-east side of the moun- 

 tain this view was strikingly beautiful: at first there appeared a 

 bright streak of red on the horizon, which gradually spread it- 

 self, lighting up the heavens by degrees, and growing brighter 

 and brighter till at last the sun burst forth from the bed of the 

 ocean, gilding as it rose the mountains of Tentriffe and those of 

 the great Canary : in a short time the whole country to the 

 eastward lav spread out as a map, the great Canary was easily to 

 be distinguished ; anil its rugged and mountainous character, si- 

 milar 



