Geoscience Reference
In-Depth Information
FIG
63.
Headlands, bays and beaches of the Newquay area (Fig. 52,
c2
), looking east-
wards from a point 2 km west of Figure 62. Crantock Beach is visible in the middle dis-
tance. (Copyright Dae Sasitorn & Adrian Warren/www.lastrefuge.co.uk)
The Flandrian sea-level rise, which ended only 5,000 years ago, has also left its
mark on West Cornwall. The most obvious legacy is the extensive array of tidal estuar-
ies at the mouths of the main rivers, which are flooded river valleys or
rias
. The most
striking example is the series of branched rias around Falmouth known as the Carrick
Roads (
c7
). These extend northwards across half of the width of West Cornwall and
have had an obvious major influence on the road and rail transport pattern of the area.
Major branch rias to the west, north and east around the Carrick Roads divide this part
of the Cornish landscape into numerous isolated peninsulas. The inland valleys of the
killas areas tend to be deeply incised with little widening, and the branching patterns
of these valleys are very clear on the slope map. The rias are obviously the direct result
of the drowning of valleys of this form by the Flandrian sea-level rise.
The coastline of the killas landscape of West Cornwall is extremely varied: small,
sandy coves alternating with rocky promontories and high cliffs are typical of this part
of the north coast (Figs 62 and 63). This irregular coastline is due to local variation
in the type and strength of the killas bedrock, with weaker units (often slates) eroding
to small bays while the more resistant rocks (often limestones or quartzites) form the
headlands.
The sandy bays of north Cornwall (
c1
, Padstow and the River Camel Estuary;
c2
,
Newquay Bay;
c3
, Perranporth and Perran beach;
c4
, St Ives Bay) are famous for surf-
ing, due to the splendid waves that roll in from the Atlantic Ocean. Apart from Padstow
Bay (
c1
), at the mouth of the River Camel, most of the north Cornwall beaches are not
obviously linked to river sources of sand and so must have been filled by sand trans-
ported from offshore sources by storm waves. At many famous surfing beaches, such
as Perranporth (
c3
), sand banks built up by winter storms can be eroded in the sum-
mer, resulting in dangerous currents sweeping out to sea. The wind-blown dunes of the
