Walker - 1967 - A geography of Italy

PART i n : REGIONAL GEOGRAPHY
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which the whole peninsula was subjected in the post-Pliocene and which was
accompanied by vulcanicity throughout the Anti-Apennines, revealed wide
expanses of Pliocene clays and sands sometimes to heights o f over 8oom. They
occur widely in that part o f the Tuscan uplands drained by the Era, Elsa and
Pesa, where the overlying sands have been extensively preserved, and in the
valleys o f the Orcia, Arbia and upper Ombrone further south where clays and
marls predominate. These Pliocene sediments, which also occupy much of the
Val di Chiana, have been moulded by erosion into a sea of hills whose morphology
varies locally in response to minor structural peculiarities. In general the permeability
o f the sands gives them greater resistance than the clays so that tabular
forms are not vmusual and the valleys tend to be narrower and more steep-sided;
occasionally, as in the halze of Volterra, the sandy plateaus end abruptly in precipitous
cliffs. The clays favour a rolling landscape o f gently rounded hills often
gullied in their lower slopes; the marls o f the Crete Senesi, whose surface is in a
state o f continuous disintegration, present many o f the features associated with
badland.
Since the Mesozoic ‘Tuscany’ has been the scene o f repeated earth-movements,
tangential at first and later radial, and these have been associated with successive
volcanic phases. Deep-seated intrusions have been exposed in the granites of
Elba (M. Capanne), Giglio and Montecristo and they have contributed to the
metamorphism and mineralization o f the Colline Metallifere. Topographically
the most obvious product o f vulcanicity is the Pliocene cone of M . Amiata; like
M . Calvi and Capraia it is mainly trachytic. At present volcanic activity is confined
to those phenomena associated with decadence, notably thermal springs
and soffionv, the former support several spas (Montecatini, Chianciano, Bagni di
Lucca) and the latter, besides providing borax, are used to generate thermal
electricity at Lardarello in the Cecina valley.
Throughout the Tuscan uplands mezzadria is the commonest form of operation
and there is a high degree o f dispersed settlement. T he poderi vary in size
from about 5 to 15 hectares in the north where sands predominate to about 15 to
30 hectares in the less intensive clay zones further south. The landowner’s home
farm (fattorid), usually set on a hill, is easily distinguished by its size and outbuildings
from the more modest farmsteads o f the mezzadri. The Tuscan upland
is dotted with little towns, almost invariably perched defensively on a hill or
plateau, each o f which has provided at least a footnote in the colourful pages of
Italian Medieval and Renaissance history, and many can claim a place in the
broader tapestry o f European art. Siena (61,000) is the only sizeable town on the
Tuscan plateau; it has agricultural processing and craft industries but, like its
ancient rival Florence, it leans heavily on tourism. The same can be said of
Arezzo (75,000), the largest o f several towns flanking the Val di Chiana.
As its valley widens below Pontassieve the Am o passes successively through
three lowlands separated by M . Alburno and M . Pisano. The alluvial and
lacustrine deposits flooring the Florence and Fucecchio basins were not satis-
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