238 Dr. Baubeny on the Geology of Sicily. 
decompose into rhomboidal fragments, Near Palermo 
there are beds of a siliceous limestone, segs a good 
deal of magnesia, which decompose muc the same man- 
ner. The pulverulent Palermo bideneone pan in great re- 
quest formerly, as a remedy for various disorders, and large 
quantities of it, under the name of the Earth of Biada, used 
to be exported or sold for domestic consumption: at present 
itis rarely to’ be met with in the shops, although it may have 
been useful as an antacid, for the same purpose fors which we 
employ magnesia, and, therefore, perhaps has better preten- 
sions to eeu than many substances that still maintain their 
place in pharmacy. 
Before I quit the subject. of the Palermo limestone, | must 
not omit a circumstance relative to the rock of Mount Pelegri- 
no, near that city, which seems to deserve notice. _ Notwith- 
standing the uniform compactness of this stone, wherever it 
as been recently quarried, we find it in those parts which 
have been exposed to the weather, honeycombed in an extra- 
ordinary degree, by holes of considerable ‘size, which pene- 
trate’ becencl iiches below the surface, bat indicate, from the 
_ gradual decrease of their dimensions, that the cavities were 
oat v8 we action of the weather, sinking gradually inte 
| ne. 
ties, in their size and appearance, remin ded an 
of thine hich occur near me surface of a hard siliceous one. 
stone, belonging to the Oolite formation, found near Cirences- 
ter in a eae = has obtained the local name of 
the hiciees alum-sto 
weather ; bit it would be interesting to discover, whether . 
itl ig in these two instances, 
be derived from any peculiarity in the nature of the rock itself 
or in the circumstance under.which it has been placed. | 
With regard to the age of the Palermo pi i I cannot 
speak with confidence, but I conceive, that the facts already 
stated, ean me in ‘considering it, for the present, as cor- 
res ing tothe Zechstein of the Germans,. and the Mag- 
nesian limestone of England; in corroboration of which, 1 
may perhaps add, that most of the specimens contain mag- 
nesia, h not generally in very large proportion. 
I the high ground near Palermo is occupied PY this an- 
cient caleareeus fiemaiien; but the valleys and ceast ara 
