133 



ly less affected by great changes in the tempera- 

 ture, than those which grow in land that affords 

 but little nutriment *. 



In order to pass from the town of Laguna to 

 the port of Orotava and the western coast of 

 Teneriffe, we cross at first a hilly region covered 

 with black and argillaceous earth, in which are 

 found some small crystals of pyroxene. The 

 waters most probably detach these crystals from 

 the neighbouring rocks, as at Frascati near 

 Rome. Unhappily, strata of ferruginous earth 

 conceal the soil from the researches of the geo- 

 logist. It is only in some ravines, that we find 

 columnar basalts, somewhat curved, and above 

 them very recent breccise, resembling volcanic 

 tufa. These breccise contain fragments of the 

 same basalts which they cover; and it is as^ 

 serted, that marine petrifactions are observed 

 in them. The same phenomenon occurs in the 

 Vicentin, near Montechio Maggiore. 



The valley of Tacoronte is the entrance into 

 this charming country, of which travellers of 

 every nation have spoken with rapturous enthu- 



* The mulberries, cultivated in the meagre and sandy soils 

 of countries bordering on the Baltic Sea, are examples of 

 this feebleness of organization. The late frosts do more in- 

 jury to them, than to the mulberries of Piedmont. In Italy 

 a cold of 5° below the freezing point does not destroy robust 

 orange trees. According to Mr. Galesio, these trees, less 

 tender than the lemon and bergamot orange trees, freeze only 

 at ten centesimal degrees below the freezing point. 



