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which passes across the mountain of Sancta Diana, extends between 

 the hill on which the castle stands, and the small hill of S. Catarina 

 on its north, and thence across the valley to the east of Mistretta. 

 At the Monte di Castelli, the highest point near Mistretta, the strata 

 have two different bearings, one nearly east and west, and the other 

 north and south : and a similar observation was made at Nicosia. 

 The author directs attention to the fact, as indicative of the central 

 chain having been raised during at least two distinct periods of ele- 

 vation. 



2. The formation next in order to the sandstone, and of more recent 

 origin, is the limestone and dolomite composing the north-western 

 part of the island, and which the author considers as the equivalent 

 of the Jura or Apennine limestone. It rises in bold, precipitous cliffs 

 flanking the bay of Palermo, and at the distance of about two miles 

 inland bounds the rich plain which lies along the coast. The dolomite 

 closely resembles that of the Tyrol, presenting a bold, rugged outline, 

 without a trace of stratification, and having its naked sides traversed by 

 numerous rents and fissures. Caves, sometimes containing bones, are 

 frequent, formed probably by the enlargement of fissures by the action 

 of water. The limestone, which frequently contains magnesia, is 

 stratified, and the strata are often highly inclined. 



3. The third formation distinguished by the author consists of marls 

 and limestones containing Nummulites and Hippurites, and which he 

 believes to belong to the chalk and green-sand formations of other 

 parts of Europe. These beds are horizontal, and lie on trap-tufa and 

 basalt. They were observed at the most southern extremity of Sicily : 

 they extend from the village of Pachino to the sea — occupy the upper 

 part of the island of Cape Passero — and form the base of the small 

 island named the Isola delle Correnti. 



4. The next rocks in the series are cretaceous limestones and marls 

 ot the older tertiary epoch. In the order of superposition they occupy 

 a place immediately below the tertiary limestone next to be described, 

 which contains shells of existing Mediterranean species, and is hence 

 probably of much more recent origin. 



5. The fifth formation is an extensive tertiary limestone, found both 

 north and south of the great central range. Its prevailing character is 

 that of a coarse, yellowish or white limestone, extensively quarried in 

 several places as a building material. Most of its shells belong to 

 species now existing in the Mediterranean, the most abundant being 

 Pectens and Oysters. The genera Cardium, Pectunculus, Area, with 

 Echini, Serpulce, and Corals, are also very common. In the plain of 

 Palermo the strata are perfectly horizontal ; but in the valley of the 

 Oretus, where they lie close upon the dolomitic limestone, they are 

 considerably inclined, and are higher by 100 feet than in the plain. 

 A similar disturbance was observed at the Cape delle Mandre. At 

 the south of the central chain the tertiary rocks are still more dis- 

 turbed, being elevated to several thousand feet above the level of the 

 sea. The direction of these inclined strata is parallel to that of the 

 principal chain. 



6. The next formation is a conglomerate still more recent than the 



