Geoscience Reference
In-Depth Information
Landscape B: The Lizard
Lizard Point is the most southerly headland in Britain, part of a wider Lizard landscape
comprising a flat heathland plateau bounded by dramatic cliffs and small coves (Fig.
60). Notice how steep many of the sea cliffs are, and that they show little in the way of
well-developed, regular layering or fracturing. Unlike the other upland areas of Corn-
wall, the Lizard is not underlain by granite. As mentioned in the general section of this
chapter, some of the area is underlain by serpentinite, a distinctive, decorative rock that
was originally part of the Earth's mantle, below the crust and many kilometres below
the surface (see Chapter 3). Other parts of the Lizard bedrock were originally basalt
lavas and minor sheet-like intrusions along with small amounts of sediments, all simil-
ar to successions elsewhere that appear to have formed in or below the Earth's oceanic
crust. During the Variscan mountain building, this mixture of distinctive bedrock types
appears to have been squeezed up amongst the strongly compressed Devonian killas.
Today, the exceptional bedrock chemistry of the unusual Lizard rocks is the reason why
the peninsula has such a variety of rare plant habitats. Much of the peninsula is a Na-
tional Nature Reserve (NNR) or owned by the National Trust.
As in Carnmenellis and Land's End, a wave-cut platform has been identified on
the Lizard, although its level is rather lower. In fact, the platform actually forms the
Lizard Plateau and is remarkably flat, the ground surface varying between 60 and 100
m above sea level over large areas. This relative flatness probably reflects the rather
uniform composition of the rock materials involved, and their uniform resistance to
weathering and erosion.
The coast of the Lizard Peninsula is formed almost entirely of steep cliffs, par-
ticularly around its southwestern perimeter. A few small beaches do occur in sheltered
locations, such as at Coverack (
b1
), and picturesque fishing villages are scattered along
the east side of the peninsula around small coves and gullies.
