4 Dry Valley
The shallow valley immediately to the right is referred to as a dry valley. The formation of the dry valleys on Bredon Hill probably started in the late Ice Age, in what is referred to as periglacial conditions, that is, in an area adjacent to a glacier.
Towards the end of the last Ice Age, the hill was peripheral to the ice sheet that covered most of northern Britain and the land was cold with a deep frozen layer (permafrost), very much like the present tundra of northern Siberia and Canada.
During periods when the glacier was receding, melt water flowed in abundance, vigorously eroding the adjacent landscape, and forming valleys. As the climate got warmer after the Ice Age, available surface water lessened, and ultimately percolated into the thawed limestone fissures to take an underground route.
How this valley may have appeared towards the end of the last Ice Age, around 8000 years ago.
Nowadays on Bredon Hill, any rain falling on the ground will immediately flow into the fissures within the limestone and run underground, leaving dry valleys above. Clays underlie the limestone and form a barrier to the water. On reaching the clay, the ground water flows south (the direction of dip) following the junction of the two rock types, and reappears on the surface as a spring line, predominantly along the southern edge of the hill.
There are several dry valleys on the south side of the hill, but this is one of the better examples, where the valley form can clearly be seen, but there is no surface water.
In the past the springs formed the principal source of water for the various communities in the area. The location of the villages along the southern edge of Bredon Hill are all related to the occurrence of springs.
The Mirror Pool at Overbury is fed by a spring.
The woollen industry was once a major industry in the Cotswolds. The name Cotswold is sometimes defined as sheep-cotes (a place) in open country, emphasizing the fact. There is even a Cotswold breed of sheep.
The rolling grassland around the dry valley is typical of the Cotswolds, and it is not unusual to see sheep grazing in this locality. The soils that form on limestone produce rich, bright green grass.
The wool trade made many Cotswolds towns very wealthy in the 18th and 19th centuries, as evidenced by the big churches and grand buildings in towns such as Northleach and Winchcombe.
Task 4 Question
Water flows from the base of the limestone because
a) It rains a lot on Bredon
b) It cannot penetrate the underlying clay
c) There is no reservoir to contain it
Route to Task 5
Sundial Barn is the site of Task 5.
Jurassic fossils up-close
Sundial Barn provides the opportunity to take a close-look at Jurassic sea floor life.