Page 2 - valerio agnesi - geographical-phisical aspect Sicily

24 Agnesi: Sicily in the last one million years

some of which hosting prehistoric settlements (caves in the area of Isnello). The highest
reliefs are bordered by wide slopes mainly covered by talus involving to superficial and
deep landslide phenomena. Even more westwards, following the valley of the Imera
Settentrionale and Torto Rivers, the chain, whose lithological composition becomes main-
ly calcareous, divides into the Termini Imerese–Trabia Mountains, reaching 1,326 m with
Mt. San Calogero, and into the Palermo Mounts, reaching 1,333 m with Pizzuta. The
reliefs, today almost completely lacking of arboreous vegetation, are affected by the
remarkable diffusion of epigean and hypogean karst morphologies and with these, in the
costal areas, there are also numerous sea caves used by prehistoric man (caves of Addaura,
San Ciro, Carburangeli, Puntali, etc.).

At last, separated by Piana di Partinico, there follow the calcareous Trapani Mounts, of
which the Aegadi Islands form the westernmost part. The highest point is Mt. Sparagio,
in the peninsula of San Vito, reaching 1,110 m. The whole area is characterized by hill and
steep reliefswith several caves of remarkable archaeological importance, as Grotta
dell’Uzzo.

The northern coastal zone, characterised by areas with low and sandy coasts alternat-
ing areas with cliffs, is divided into numerous gulfs; the largest is the Castellammare Gulf,
till a couple of decades ago, characterized by dune-like sandbars but no longer existing
today because of the presence of man. Moreover, the coast still saves in different areas
edges of degrading marine terraces witnessing different Pleistocenic sea levels and pres-
ents a wide coastal plain bordered by marine terraces which is located in the central part
of the Termini Imerese Gulf; such plain has originated not to long ago from flood supplies
of the Torto and Imera Settentrionale Rivers.

Besides the rivers already mentioned, also the S. Leonardo and the S. Bartolomeo
Rivers debouch along Sicily’s north coast, the former in the Termini Imerese Gulf and the
latter in the Castellammare Gulf.

The Sicani Mountains, which occupy the south–west sector of the island, set up a south-
ern appendix of the chain’s western segment, similar as for the geological structure profile.
It is a very articulated mountain range with isolated reliefs, as Rocca Busambra (1,613 m),
Mt. Cammarata (1,578 m) and Mt. Genuardo (1,180 m).

The foredeep area is characterized by Tertiary and Quaternary rocks of different
lithologyAmong these, very important are the Messinian evaporitic successions, whose
most common lithological type is gypsum, that, due to its solubility, is involved with
karstic phenomena; the gypsum caves of this area too, host important sites of prehistoric
settlement.

West of the Sicani Mountains, there are inner areas characterised by hilly reliefs that
join the coast by means of marine terraces lowering at sea. Hydrography is characterised
by the wide Belice River basin, whose end sector is morphologically characterised by flu-
vial terraces. Eastwards there is the typical hilly landscape of the Altopiano Solfifero dom-
inated by wavy forms due to the Miocenic outcrops of gypsum and evaporitic limestone
and, in some cases, of sandstones and conglomerates. The widespread outcrops of clayey
rocks favours the development of intense erosive processes and landslide phenomena
which render these lands extremely unstable and deserted.

Going towards East, there rise the Erei Mountains, made up of arenaceous and calcare-