242 RAMBLES OF A NATURALIST. 



Speedily enabled us to commence our researches in 

 the little archipelago of the ^gades, which had 

 never yet been visited by any naturalist. The field 

 which was thus opened to our explorations consisted 

 of some naked rocks, forming so many islets, and 

 three principal islands, Favignana, Levanzo, and 

 Maritimo. We thouo-ht it would be of no use to 

 extend our excursions as far as the two latter of 

 these ; for Maritimo was too far distant, and Levanzo 

 was entirely formed of calcareous rock, which rose 

 in abrupt mountains, and was so completely devoid 

 of all vegetation that it could not support many ter- 

 restrial species. We were, moreover, well acquainted 

 with the nature of this rock ; for we had always found 

 it associated with Caryophyllia, the presence of which, 

 as I have already remarked, invariably indicates 

 great poverty, when considered from a zoological 

 point of view. We did not, therefore, waste any 

 time in examining the coasts of either of these 

 islands ; one of which is entirely deserted, while the 

 other has no inhabitants beyond the few men who 

 garrison the small fort, and work the telegraph 

 which is situated on the island. 



Favignana, moreover, was in itself sufficient to 

 occupy the whole of our time. Larger than either 

 of its sister islands (for it measures about twenty 

 miles in circuit), it also presented a much greater 

 variety in its geological constitution. Its central 

 part is entirely occupied by a range of mountains, 

 similar to those of Levanzo, and about 1000 or 1200 

 feet in height. The highest point of the range is 

 occupied by Fort St. Catharine, a state prison, which 



