and Vegetation of Sicily. Ill 



are the ruins of Taormina, consists of a compact limestone 

 resting on the mica slate, which stretches far into the interior, 

 and constitutes a sort of boundary between the volcanic and 

 Neptunian districts, a barrier beyond which the lavas of Etna 

 have never yet penetrated. 



We will now briefly describe the several formations of these 

 three parts or divisions. 



The granitic rocks of the Pelorian chain contain also em- 

 bedded masses of a mixture of quartz and hornblende. They 

 extend uninterruptedly as far as Melazzo. The peninsula on 

 which the castle and town have been built is composed of 

 well-marked gneiss, upon which there rests a compact greyish 

 limestone containing fossil remains. This Dr. Daubeny con- 

 jectures to be of a recent origin. At Cape Minjivio (Mons 

 Jovis), the mica slate alternates with a bluish crystalline lime- 

 stone without shells, a granular rock, consisting principally of 

 quartz and mica, which the author names quartzy rock, and a 

 sandstone made up of minute fragments of the above two in- 

 gredients. The red sandstone which succeeds the slate form- 

 ation is not micaceous, but contains red iron-shot grains of 

 sand. This continues to Cefalu, except in places where it is 

 interrupted by a bed or two of compact greyish limestone 

 without petrifactions. The bold promontory of Cefalu consists 

 of a bluish fetid limestone (called a Lumachella marble), 

 and possessing organic remains. This formation, which rests 

 upon the sandstone, extends to Trapani, including the Nebro- 

 densian and Palermitan mountains. It contains magnesia. 

 But the valleys and coast between Cefalu and Termini, 

 about Palermo and Castell* a mare, are covered with a coarse 

 pudding-stone, containing fragments of quartz, and of the 

 magnesian limestone on which it rests, or of a calcareous 

 breccia, in which sand is also present, and many fossils. The 

 line of demarcation between this, and the older calcareous 

 formation, is very distinctly marked by the character of vege- 

 tation. The compact limestone like that of the Apennines, 

 or of Nismes * is chiefly adapted for the olive, and affords but 

 a scanty pasturage, vegetation being obstructed by the frag- 

 ments of chert; whereas the breccia affords the finest crops 



* To compare the geological structure of Sicily with that of the island 

 of Sardinia, see Memoire Geologique sur VIsle de Sardaigne par M. de la 

 Marmoroy in the 11 th volume of Memoires du Museum d'Histoire Naturelle, 

 Where it appears that the east side, comprehending nearly one half of the 

 island, is of primitive and transition rocks, consisting of granite, porphyry, 

 and mica slate ; the west side is composed of calcareous strata of the 

 tertiary class, where volcanic rocks principally occur ; and there is seen in 

 some places a secondary limestone, which probably corresponds with that 

 of the Palermitan and Madonian mountains. 



