.510 ANNUAL IIKGISTEU, 1S14. 



not distinguish its southern or 

 western declivity. M. Escolar as- 

 sured nie they are similar to, 

 though more rapid than, the side by 

 which we ascended : from this side 

 flowed the baLsatic lavas of 1704 

 and of the last eruption in 1797: 

 this latter stream of lava flowed in 

 a remarkably slow current, for not- 

 withstanding the sharp descent of 

 the mountain, and the length of 

 the lava not exceeding three miles, 

 several days elapsed before it reach- 

 ed the spot where it stopped ; how 

 little fluid this lava must have been 

 is evident, when it is remembered 

 that the lava of Vesuvius in 1794, 

 which destroyed Torre del Greco, 

 reached the Sea from the bottom of 

 the cone, a distance of eight miles, 

 in little more than six hours. M. 

 Escolar further told me that there 

 is on this south-western side of the 

 Peak an ancient lava, at present not 

 at all decomposed, of several miles 

 in length, and in a perfect state of 

 vitritication : the whole of this 

 stream has the appearance of obsi- 

 dian. All these lavas appear to 

 have flowed from the bottom of the 

 cone, and to have run from its base 

 in the same manner as that of Ve- 

 suvius in 1794, the crater of which 

 vomited out ash and |)umice, and 

 large pieces of rock, while the cur- 

 rent of lava issued from its side. — 

 It is not, however, improbable that 

 the cone itself is of anterior forma- 

 tion to this vitrified lava, as the 

 summit of the Peak is similar to 

 the lava of the Mai Pais, and that 

 being porphyritic is considered as 

 of more ancient date than the one 

 above-mentioned, which is basaltic. 

 If one might hazard a conjecture 

 upon a subject where the data are 

 so few, 1 should be inclined to sus- 

 pect that the Peak itself, as well as 



the whole of the country around 

 it which forms its base, were pro- 

 duced by that immense crater call- 

 ed Las Cauales, the shape and mag- 

 nitude of which I have before taken 

 notice of when traversing the pu- 

 mice plains ; it is also well worthy 

 of remark that there is no volcano 

 in action at all to be compared in 

 size of crater to those that are ex- 

 tinct. The ancient crater of Ve- 

 suvius is considerably larger than 

 the present, and those in the vici- 

 nity of Naples, the eruptions of 

 which probably created that district 

 of Italy, are of enormous extent. 

 The crater of the Camaldoli is 

 somewhat more than two leagues 

 in circumference, and the superfi- 

 cies of the Canales is estimated at 

 12 square leagues. These vast 

 craters were probably capable of 

 ejecting from their bosom those 

 stupendous beds of lava, which be- 

 ing so much more extensive than 

 any that have flowed from more 

 recent eruptions, have led some per- 

 sons to deny the former to be the 

 eff'ects of a central fire. That all 

 the Island of Tenerifte was voica* 

 nically produced no man who ex- 

 amines it can have any doubt, and 

 though the smallness of the exist- 

 ing crater of the Peak may lead one 

 to imagine that it alone could not 

 be the effiective cause of all the 

 phsenomena, yet the innumerable 

 volcanoes on all sides of the island, 

 the appearance of Las Canales, and 

 its elevation, are able to account for 

 the extent of the streams and beds 

 of lava, and of the deposits of tufa 

 and puniice, of which the island is 

 composed. Having no data to 

 proceed upon but what is given by 

 the measurement of the eye, it is 

 not easy to determine the magni- 

 tude of the cone at its base ; one 



