1 1 Geography^ Geology^ 



In order to elucidate more clearly the above account of the 

 different formations, and of their position and extent, I will 

 give this short description, taken from the excellent Sketch of 

 the Geology of Sicily^ by Dr. Daubeny. * 



The geology of Sicily may conveniently be divided into three 

 parts, corresponding nearly with the three sides of the triangle 

 which represents the figure of the island. It contains rocks of 

 the primitive, transition, secondary or floetz, and tertiary classes. 



T\ie first division will comprehend the rocks from Messina 

 (or rather from Taormina) to Trapani. These are primitive, 

 transition, and secondary. The first are only found at the 

 north-east corner near Messina, where the prevailing rock 

 appears to be gneiss. The transition constitute a chain of 

 hills, extending obliquely from Melazzo, on the north coast, 

 to Taormina on the east. They consist chiefly of mica slate 

 and clay slate, quartz rock, grey wacke, sandstone, and lime- 

 stone. The secondary rocks are found principally in a line 

 parallel with the north coast. They consist, first, of red sand- 

 stone, with beds of shale extending from Cape Orlando to 

 Cape Cefalu ; secondly, of a compact limestone, with beds of 

 chert, jasper, and agate, which constitutes the Madonia moun- 

 tains, and extends from Cefalu to Palermo, and from thence 

 to Trapani. It perhaps corresponds with the magnesian lime- 

 stone of England. 



The second division embraces the rocks that occur near the 

 western coast, from Trapani to Cape Passaro, the most 

 southern point of the island, and consist chiefly of a series of 

 formations which Dr. Daubeny is inclined to refer to the most 

 recent epoch in the history of our planet, namely, that poste- 

 rior to the formation of the chalk. These tertiary rocks con- 

 sist, first, either of beds of blue clay and marl, containing 

 much gypsum and selenite, sulphur, sulphate of strontian, 

 alum, and common salt ; secondly, of a calcareo-arenaceous 

 breccia, replete with shells of a recent date, which is seen ex- 

 tensively on the western coast, at the level of the sea, and, as 

 we trace it south, is found to rest on the blue clay ; thirdly, of 

 beds of shelly limestone, which occupy all the south of the 

 island, and alternate repeatedly with beds of volcanic matter. 



The third, division, which takes in the line of coast on the east, 

 from Cape Passaro to Taormina, exhibits indications of volca- 

 nic action, occurring at very different epochs, from the lavas 

 which flowed during the period at which the tertiary beds were 

 being" deposite^d, to the comparatively recent eruptions that 

 have taken place from Mount Etna. But the hill, on which 



* See Jameson's Edinburgh Philosophical Journal, vol. 13. 1825. 



