SCIENTIFIC NEWS. €>§Q 



appears to be contained either in the unstratified trap, or in 

 the slaty grauwacke, nor did there occur in them, with the 

 exception of one equivocal instance, the smallest trace of 

 any organic remain. 



May the 15th.— An account of the Island of Teneriffe, Island of T** 

 by the Hon. Henry Grey Bennet, M. G. S. was read. The neriffe * 

 greatest length of this island from north to south is about 

 70 miles, its greatest breadth does not exceed SO miles. In 

 the S. W. part of the island is situate the mountain called 

 by the Spaniards el Pico di Tiede> but better known by the 

 name of the Peak of Teneriffe, the height of which, from the 

 mean of several observations, appears to be about S2500 

 English feet. The rocks and strata of this island appear 

 to be wholly volcanic. A long chain of mountains passes 

 through the interior, sloping on the E. W. and iN. sides to 

 the sea, but on the S. and S. W. elevated into nearly per- 

 pendicular mountains, which are intersected by deep and 

 .narrow ravines. The lowest bed of the island is porpbyritic 

 lava, composed of hornblende and felspar, in its upper 

 part porous, scoriform, and sometimes passing into the state 

 of pumice. Upon this rests a bed of the same substance, 

 as already mentioned, but in structure nearly approaching 

 to greenstone. This is covered by a thick bed of pumice, 

 which itself is overspread with basaltic lava, on which, in 

 many places, rest beds of tufa and volcanic ashes. This 

 basaltic lava decomposes sooner than any of the other rocks, 

 and contains the greatest variety of imbedded substances : 

 it is sometimes divided by a layer of olivine in crystals some 

 inches long, and is often intersected by thick veins of por- 

 phyri tic slate. Zeolite and chalcedony also occur in it. The 

 number of small craters and extinct volcanoes is prodigious, 

 They are to be found in all parts of the island ; but none of 

 them have been in activity of late years. The great streams 

 of lava have flowed from the Peak : those of the years 1J04 

 and 1797 (which was the last) are basaltic. This latter flowed 

 so slowly, notwithstanding the steep descent of the moun- 

 tain, that it was several days in advancing three miles. On 

 the western side of the Peak is an ancient lava, not at all de- 

 composed, several miJflj BBength, and in a perfect state of 

 vitrification resembiu^HP^dian. 



m» Mr. Vauquelin 



