Notices of the Geology and Mineralogy of Sicily. 211 
at Roccalumiera. They are now wholly pebioned, and 
the island is supplied from Tolfa. 
Sulphate of Magnesia in many mineral ivaters =? “also i 
“minute incrustations in the rocks of Monte Albano. 
Muriate of Ammonia, found in immense quantities in the 
ures and cavities of the lavas of tna, after —— 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 Sel near Catania. Its mineral associations 
are the same as those of sulphur. The mine of Castro- 
giovanni is eco like a quarry. The river Salso re- 
ceives the waters which flow from it,—whence its name. 
: ther mines extensively wrought at August 
ipa i, Palermo, &c. Around these mines are exte 
pa destitute of all vegetation. ‘The | 
are called Sal Gem, occhi di sala, &c. 
liant white, and not deliquescent. 
he volcanic products of Sicily are of two very digtiact 
periods—the ancient or those of the extinct volcanoes of 
Val di Noto, and the base of tna, and the modern, or those - 
of more recent eruptions of #tna.—The former are m- 
ple, the anttoe oo ae pace Sete lavas aimee fa 
Primiti ant 
vas of the rock of Motta near Catania are basaltic ; they 
form columns of long prisms and sound like bronze. 
The modern lavas of tna are all compound, i. e. they 
Consist of a paste stuck full of large and distinct crystals of 
bn. cel 
