Great Edney wood offers beautiful scenery, where deer are often seen in abundance. The woods are also the home to many marl pits.
The “glacial drift” left behind by the Ice Age created swathes of sand and marl along the contour lines of slopes left by retreating ice. Since Roman times the spreading of clay over sandy soils enriching soil and improving it’s water holding capacity has been known as “marling”. The marl was common at depths of 1 to 2 metres and had to be dug out of the ground – creating marl pits.
Marl or Marlstone is a calcium carbonate or lime rich mud also known as mudstone which contains variable amounts of clays and silt. The main mineral in most types of marl is calcite, but other minerals can also be present. Marl was originally an old term applied to various materials, most of which occur as loose, earthy deposits consisting mainly of a mixture of clay and calcium carbonate, which are formed in freshwater conditions.
Marl pits, very different from sand and brick pits, are easily distinguishable by the square edged gentle slope at one end of the pit and a steep rounded slope at the other. The shape was the result of a few hundredweights of marl being dug out and loaded into carts which were then hauled up the sloping end of the pit, a process that was repeated time and time again. Over twelve months the pit would partly fill with water so another pit was dug a few yards away.
To log this cache, please complete the tasks below using the information above and your observations at ground zero. Please email or message your answers to us via our profile page. You can log your find once you have sent the email, there is no need to wait for a reply.
1. At the coordinates estimate the height of the bank?
2. Describe the exposed layer of the Marl pit, what colour is the bank? what do you see?
3. Look at the marl stones in more depth, describe the colour and the texture?
4. Marlstone can contain other carbonate minerals, please name one of them?
5. As an optional extra, post a picture of yourself or your GPS.