As an earthcache, there is no “box” or “container” to discover. Rather, with this cache, you discover something about the geology of the area. For more info about Earth Caches take a look at www.earthcache.org
During the Second World War, elephants from circuses were put to use to fell trees. At GZ there is a pond named The Elephant Pond where the elephants could bathe at the end of the day.
Looking across from GZ you will see a cross section of the bank. Looking at the banks of this pond you will see that they are made up from boulder clay. Boulder clay is a deposit of clay, usually full of boulders. If you look carefully you will be able to see small boulders sticking out at various points. The boulder clay found here will probably have been formed beneath glaciers and ice sheets during the Glacial Period of northern Europe.
An ice sheet scrapes the clay from the top of older rock. The ice sheet also pushes rocks, stone and boulders in it's path and this is how boulder clay is formed. The colour of boulder differs depending on what type of rock it has been mixed with. It can be red from 'Old Red Sandstone areas, black from carboniferous rocks, white and chalky from chalk, blueish-grey, grey or buff from Silurain rock. Although once it has been exposed to weather it can often turn brown.
The name 'boulder' clay may be misleading as the 'boulders' can range in size from small pebbles to those that weigh many tonnes in weight. They often have a smooth or flat side where the ice sheet has smoothed it during the glacial shift. Where hard rocks are to be found, these can often have grooves and dints in them where they have been rubbed against other rocks in the glacial shift.
Different types of rocks can be found in boulder clay and rocks from other countries have been found as the ice sheet has moved across countries and continents. Here in the East of England, Scandinavian rocks have been found showing the glacial shift route.
Logging Requirements
To be able to log this Earthcache as found you need to first email the answers to the following questions to CO through the mail link in the above profile, you can then log as found. Please don't include any answers in your logs or they will be deleted.
1. Stand on the bridge at the Co-ordinates above and look at the cross section of the bank of the pond, what is the depth of the gravel substrate layer above the clay layer.
2. From the same location observe the clay layer around the edge of the pond and tell me what colour it is.
3. What type of rock do you think this boulder clay moved through to become this colour?
4. From GZ how far away is the bank in front of you?
5. Please post a Pic of you and your GPSR at GZ (Optional)
