Mr. Be'N -NET on the Lhmd of Teneriffe. 297 



surprising that the lava should have flowed so short a distance ; as it. 

 does not exceed '^\ or three miles from the base of the cone to the 

 point of union w^ith 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 cr 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 Pais. 



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 observing the rising 

 of the sun and that singular and rapid change of night into day, the 

 consequence of almost an entire absence of twilight. As we ascended 

 the north-east side of the mountain this view was strikingly beautiful, 



Vol. II, 2 p 



