During Permian times, massive global warming led to the reduction in coal deposits and glaciations (the icehouse world disappeared) and it changed to desert deposits and arid environments (becoming a greenhouse world). In Worcestershire, the period is marked by the subsidence of the Worcester Basin, leading to the thick accumulation of red sandstones and mudstones in a dry, arid environment.
In this area, the Permian is represented here by two formations occupying patches in the north and west of the county. This formation (the Clent Formation), locally known as the Haffield or Clent Breccia, has a patchy outcrop in Worcestershire, occurring on Ankerdine, Woodbury, Abberley, Stagborough and Church Hills, which were all previously quarried for aggregate. However, the largest outcrop is here at the type locality where the formation underlies, and is the reason for the presence of, the Clent Hills. In Herefordshire an outcrop south of Ledbury is the type locality for the equivalent unit, the Haffield Breccia Formation.
The rock is identified by its characteristic breccia, consisting of unsorted, angular clasts up to 256mm in diameter. This consists of immature compacted gravel, rich in volcanic clasts with some sedimentary rocks, in a sandy or muddy matrix, The clasts consist of pre-Cambrian rocks from the Malvern Hills and Shropshire, with subordinate clasts from Silurian and Devonian units. There are few Carboniferous rocks. It is thought to have been deposited by during flash floods in rivers that were flowing through a desert, somewhere between 200 and 280 million years ago. The presence of the angular fragments shows that they have not been transported over a long distance.
The hills along with the Lickey Hills form a range of hills in north Worcestershire known as the Clent-Lickey range (or the Clent-Lickey ridge). The largest of the Clent Hills is Walton Hill which is 1,037 feet (316 m) high followed by Clent Hill at 1,014 feet (309 m). They are separated by a valley known as St. Kenelm's Pass, which starts as an escarpment one side of which along with the sides of the two hills falls away towards Uffmoor Wood; water flowing down this slope enters streams which become the River Stour. Close to the top of the escarpment, but just on the other side, stands High Harcourt Farm. Below the farm the escarpment falls away and becomes a sharp V valley in which a stream flows down into Clent village. Where the valley sides are at their steepest the Walton Hill side of the valley is known as Clatterbach. In the past, before steam power replaced water power, the stream in the valley was dammed at regular intervals to provide power for watermills. The remains of one such dam can be seen behind the Vine Inn in Clent which was once a mill.
At the given co-ordinates you will find a group of stones. It is difficult to imagine that prehistoric peoples did not visit Clent, but, unfortunately, firm evidence of their permanent presence is presently lacking. In some ways this might be considered surprising, as Clent Hills seems to have been seen as an area of prehistoric activity in the 18th century, when it is thought the mock 'Druidical' monument you will see here was erected. Although recognising that the erected stones are a folly, Timmings, writing in 1836, felt that the hills were an area that would reward antiquarian study.
To log your find please send me the answers to the following questions:
Ideally please use the e-mail facility rather than the new messanger service.
1) At the listed co-ordinates you will find a number of upright stones. Firstly, please confirm to me how many are there.
2) Examine these stones. Look at the grains closely that make up the stones. Look at the colours and examine the texture of the rock. There are a number of stones here, but there are two very different rock types that make up these standing stones - some are one rock type, some the other.
i) From what the listing tells you and their appearance, do any of them appear to be the local stone found in this hill?
ii) From your examination of the stones, can you tell me what type of rock you think they are from the following options: Gritstone, Granite, Sandstone, Mudstone or Limestone.
iii) Justify your choice in your answer by describing the colours and the textures and explain why therefore you think it is the type of rock you have chosen.
If you are not familiar with the different rock types listed you may need to take notes at the site and quickly research each rock type afterwards and make your decision, or you could research a brief definition of each rock type and take it with you when you visit. From the choices I have given it should not be too hard to come to the right answer.
3) In the listing I have talked about the angular fragments that make up this hill. Can you find any whilst visiting the hill and
i) describe their size and texture
ii) briefly explain why the fact that they are angular proves they weren't transported far
iii) include a photo of one with your log (optional)
You may need to look away from the given co-ordinates to answer this question, so keep a look out whilst climbing the hill.
4) I have mentioned that the Clent Hills were formed during the Permian period. Can you research and tell me which geological era it comes from?
5) Optionally, please include a photograph of yourself or your GPSr with the stones or somewhere nearby with the bench or view. This is good proof that you have visited the location. If photographing the stones, please don't go too close so you don't give away the answers.
Many thanks to the National Trust for kindly granting permission for this earthcache.
Please send in your answers when you submit your log or soon afterwards. If your answers are not received within a reasonable time you will be contacted and your log may be deleted. Please make your best attempt at the answers but don't panic if your are unsure on anything as everyone has a different level of geological knowledge. Many thanks for visiting.