Notices of ihe Geology and Mineralogy of Sicily. 211 
at Roccalumiera. ‘They are now wholly abandoned, and 
the island is supplied from Tolfa. 
Sulphate of Magnesia in many mineral waters; also in 
minute incrustations in the rocks of Monte Albano. 
Muriate of Ammonia, found in immense quantities in the 
fissures and cavities of the lavas of Autna, after cooling and 
before the rains have dissolved it. It forms a large part of 
the white smoke of the volcano. It is collected after erup- 
tions for sale. 
Carbonate of Soda, found also in the lavas after cooling ; 
also in cavities of the ancient lavas, where protected from 
rains. Collected in great abundance in the ancient lavas 
of Bronte. Great quantities of soda are manufactured in 
Sicily from the Salsola Kali. 
Muriate of Soda is extremely abundant in Sicily, associ- 
ated with sulphur and gypsum. ‘The mines of Castrogi- 
ovanni, Catholdea, Regalmuto, and Cammarata in the ter- 
ritory of Girgenti, are well known. It is wrought exten- 
sively at Raddusa, near Catania. Its mineral associations 
are the same as those of sulphur. The mine of Castro- 
giovanni is wrought like a quarry. The river Salso re- 
ceives the waters which flow from it,—whence its name. 
‘There are other mines extensively wrought at Augusta, 
Trapani, Palermo, &c. Around these mines are extensive 
salines destitute of all vegetation. ‘The purer specimens 
are called Sal Gem, occhi dz sala, &c. They are of a bril- 
hant white, and not deliquescent. 
The volcanic products of Sicily are of two very distinct 
periods—the ancient or those of the extinct volcanoes of 
Val di Noto, and the base of Aitna, and the modern, or those 
of more recent eruptions of AUtna.—The former are sim- 
ple, the latter compound.—The ancient lavas consist of a 
compact homogeneous paste-like basaltes, containing only 
a few very minute scales and threads of feldspar, grains of 
red quartz, and very minute particles of pyroxene and 
chrysolite (olivine ?) many of these are schistose, and some 
break into irregular blocks like trap. Such lavas are 
found at Pedagaggi ; they havea striking resemblance to 
primitive trap from Monte Albano in Pelorus.—The la- 
vas of the rock of Motta near Catania are basaltic ; they 
form columns of long prisms and sound like bronze. j 
The modern lavas of Attna are all compound, i. e. they 
consist of a paste stuck full of large and distinct crystals of 
