and Vegetation of Sicily. 109 
stone is easily worked, but it soon decays, and it may even be 
said to rot; and it remdens the buildings i in that calcareous 
country by no means durable. ‘The earthy calcareous form- 
ation, which may also be called argillaceous marl, since it is 
mixed with siliceous earth and with clay, forms the small hills 
and extensive plains of Sicily: it is in this that deposits of 
shells of the ancient sea are discovered, masses of sulphuret of 
iron, and the mines of salt and of sulphur in which this island 
is so extremely rich. It is in this formation that the lavas of 
the ancient voleanoes are found buried around Etna, and in 
volcanic Sicily, which extends from Etna to Cape Passaro, 
where, in fact, besides the lavas buried in the earthy calcareous 
formation, or marl, there appear traces of the ancient fires of 
this part of the isle mixed with the shell limestone, and the 
beds alternate with it for a surprising number of times. Where- 
ever these formations prevail, we find throughout Sicily masses 
of gypsum; they are observed in the intervals between the 
mountains of Pe lorus, in the volcanic limestone of the south 
of Sicily, in the interior behind Alimena, where they consti- 
tute some miles of heights and of low lands, as well as in the 
west of the island. In the calcareous formations posterior to 
the primitive are found quartzose and siliceous pebbles, agates, 
jaspers, coloured stones, in which the island is extremely rich, 
and bituminous rocks, from which, most probably, naphtha 
exudes, and petroleum issues in many places. Pieces of amber 
and of asphaltum are found among the argillaceous beds. 
Beautiful crystallisations of sulphur, of sulphate of barytes, 
and of sulphate of strontian, are discovered in the clefts, and 
in the cavities in the sulphur mines. ‘The limestone of all the 
formations, whenever it is sufficiently compact to receive a 
polish, affords the immense variety of marbles of different 
colours, for which Sicily is so very famous. 
The perfect resemblance * of the two opposite countries of 
Sicily and of Italy, and the continued direction of the range of 
Apennines, prove their ancient union, and compel us to con- 
sider the straits of Messina as a valley formed by the two 
ranges of mountains which extend par allel to each other, and 
into aithie interior of the two countries. The forces of nature 
acting in an ordinary manner could not produce this separa- 
tion; it therefore, very probably, took place in the last cata- 
strophe which modified the surface of our globe, and esta- 
blished the present system. 
* Dr. Daubeny observes on the gneiss of Messina, “ This is the form- 
ation which probably extends on the Italian side of the straits, if I may 
‘judge from the specimens I brought from the celebrated rock of Scylla.” 
