Walker - 1967 - A geography of Italy

CENTRAL ITA LY
Terni lake, remnants o f which survive. The upper Arno too once ran southwards
into the Val di Chiana but either accumulated debris or warping diverted it into
the trench cut by the Sieve. Another major complication was the accumulation
of volcanic ash and lava southwards from M . Amiata which obstructed the Tiber
Fig. 32. The principal intermontane basins of the Apennine system
and Nera and obliged their waters to force a tortuous outlet to the sea through
the hills of the Campagna. Along the coast, through the many vicissitudes o f the
Quaternary, rivers and waves combined to choke the shallow inlets and channels
between the offshore islands and so build up a series o f coastal lowlands, whose
seawards edges are fringed with spits festooned between headlands.
IV[a] The Northern Apennines
Convenience and convention suggest the Cisa and Bocea Serriola passes as suitable
limits to define this sector o f the range, which is sometimes referred to as the
Tosco-Emilian Apennines. Although it has a geographical personality of itspwn,
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