237 



other primitive rocks, were laid bare by the 

 rains, we might have thought them as rare at 

 Vesuvius, as they are, at least in appearance, at 

 the Peak of Teneriffe. 



With respect to the fragments of granite* 

 gneiss, and mica-slate, which we find on the 

 shores of Santa Cruz and Orotava, they do not 

 come from the opposite coasts of Africa, which 

 are calcareous, but were probably brought in 

 ships as ballast. They no more belong to the 

 soil where they lie, than the feldsparry lavas of 

 Etna, which we observe in the pavements of 

 Hamburgh and other towns of the north. The 

 naturalist is exposed to a thousand errors, if he 

 loses sight of the changes, which the intercourse 

 between nations produces on the surface of the 

 Globe. We might be led to say, that man, ex- 

 patriating himself, is desirous that every thing 

 should change country with him. Not only 

 plants, insects, and different species of small 

 quadrupeds, follow him across the ocean ; his 

 active industry covers the shores with rocks, 

 that he has torn from the soil in distant climes. 



If it be certain, that no enlightened observer 

 has hitherto found at Teneriffe primitive strata, 

 or even those trappean and ambiguous porphy- 

 ries, which constitute the basis of Etna *, and of 



* The Chevalier Gioeni, who, like several mineralogists of 

 Germany and France, distinguishes the basalts from the mo- 

 dern lavas, considers Etna as a mountain of porphyry, sur- 



