The ancient art of dry stone-wall building may be getting rare but it rewards the builder with a sturdy structure that adds to the familiarity many landscapes.
The walls also give easy clues about the kind of rock that outcrops nearby because the sole building material was provided from a local quarry. Here are examples from the three main kinds of rock, recognised by geologists since the 1770s as igneous, sedimentary and metamorphic.
On Dartmoor in south west England, walls are made of igneous rocks such as granite which come from volcanic activity. As they age they are firm substrates for lichens and moss –
Sedimentary rocks are deposited under water, mostly under the sea and form the limestone surface in the southern Pennines of Derbyshire –
In Wales there is plenty of slate, around 400 million years old. On the much younger Greek island of Andros the 35 million year old metamorphic rock is quartz mica schist –
The styles of the walls reflects the character of the builders and some are better maintained than others.