142 Mr. Alison's Narrative of an Excursion to the 



tion [?] : some are an obsidian of a jet black colour, possessing 

 internally a shining vitreous lustre, breaking with a conchoi- 

 dal fracture, and translucent at the edges; others are a brown- 

 ish porphyritic lava mixed with large crystals of felspar, partly 

 destroyed by the action of fire ; others have an earthy ap- 

 pearance, and although cellular, are hard and heavy ; and to- 

 wards the upper part of the stream were several blocks of 

 phonolite of a greenish gray-colour. 



After a fatiguing but not a difficult ascent, which took us 

 three quarters of an hour to accomplish, we arrived at a part 

 of the Peak which is 9930 feet above the level of the sea, 

 called La Estancia de los Ingleses de Abaxo, the lower resting- 

 place of the English : the pumice here forms a tolerably level 

 surface of a few hundred feet square; towards the N.N.E. side 

 of it are scattered several large blocks of obsidian ; under the 

 lee of one of them we lighted a fire of dried mountain broom, 

 and piled up some stones to form a shelter from the wind, 

 which was then blowing a hurricane. 



One hundred and twenty-eight feet above this Estancia, 

 is another called La Estancia de los Ingleses de Arriba, the 

 upper resting-place of the English, and is to be noticed as the 

 highest point at which the Spartium nubigenum is to be found; 

 after inspecting it, I think this place affords better shelter in 

 summer to a small party of visiters to the Peak, than the one 

 below. 



After taking some refreshment, we resumed the ascent with 

 the intention of observing the temperature of the summit that 

 evening, and likewise next morning; the acclivity became 

 more and more difficult, the pumice frequently gave way be- 

 neath our feet, and in many places the frozen state of the snow 

 gave us considerable annoyance from the extreme difficulty 

 of climbing up it. 



In an hour we arrived at Alta Vista Arriba, which is 

 10*621 feet above the sea, and is at the end of the surface of 

 pumice, at the point of intersection of the two branches of 

 lava, between which we had been ascending. Here my guide 

 declined to proceed any higher that evening, because we 

 should not be able to arrive at the top of the Peak before 

 dark ; and even if we gained the summit, we should be obliged 

 to remain there all night without the slightest shelter, which 

 would have been fatal at that season of the year. I was there- 

 fore obliged to defer my journey till next morning, and to 

 retrace my steps to the Estancia. 



The remaining hours of light were employed in endeavour- 

 ing to obtain some shelter from the wind, by forming a wall 

 of lava and pumice : for some time all our various contri- 

 vances 



