Camulodunum Defended! EarthCache
-
Difficulty:
-
-
Terrain:
-
Size: 
(not chosen)
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
Bluebottle Grove is close to Church Lane in Colchester, follow the brown-and-white tourist signs and your gpsr to the site. Although it is possible for wheelchair users to log this cache, they will not be able to get down into the ditch.
.·:*¨¨*:·. FTF – andy_uk63 .·:*¨¨*:·.
The purpose of this earthcache is to discover something of the way in which our Iron Age ancestors protected their territory from invasion and attack from other tribes. As well as the historical nature of this earthcache, it is also to discover the effect those ancestors had on the landscape and geography of the places they occupied, and give an insight into the geology of the area that they built their defences on.
In common with the rest of North East Essex, over the past 60 million years, the Colchester area has been formed by a number of geological episodes. It has been beneath a tropical sea, under hundreds of metres of ice and rivers, and glaciers have shaped the landscape.
In geological terms, the age of the rocks in the Colchester area are relatively young. Laid down around 55 million years ago, the geology of the area consists mainly of London Clay with some Upper Chalk. There are also superficial deposits of semi-pervious Boulder Clay, sands and gravels.
Deeper down, there are ancient Palaeozoic rocks, movement along a fault of which, affecting the overlying Cretaceous and Tertiary strata, may have caused the famously destructive Colchester earthquake in 1884, supposedly the strongest tremor in recent British history. Although felt as far away as France and Belgium, as well as a considerable part of southern Britain, it is known as the Colchester earthquake because the town seems to have been the epicentre of the tremor, as most of the structural damage appeared to occur in the Colchester and Wivenhoe area.
Built on, and shaped from, this geological base, the Bluebottle Grove earthwork is part of a series of defences, created in the late Iron Age, that protected pre-Roman Camulodunum (modern-day Colchester) on its western side. Camulodunum was the capital of both the Trinovantes tribe and the Catuvellauni tribe, ruled over by Cunobelin (Shakespeare's Cymbeline).
Camulodunum, covering an area of about 12 miles, was defended in the north, south and east by the river Colne and the Roman River, and the Bluebottle Grove earthworks are part of the 15 mile system of defences that comprised the western boundary between the rivers. Most of the dykes were composed of a V-shaped ditch and a bank that was built from the tons of earth that were removed from the ditch. In the case of this section of the dyke system, there was a ditch on both sides of the bank, although this cannot be seen now.
There was some variation in the depth of the ditches, from dyke to dyke, from around 5 feet deep to around 13 feet deep. The banks could be up to 10 feet high, making a barrier of up to 25 feet. This would be of particular use against chariot attack.
The defences are thought to have been constructed in the early first century CE, but later added to post-Roman invasion and possibly even post-Boudican.
To claim this earthcache you will need to perform three tasks:
1. Estimate the height of the bank from the bottom of the ditch as it is now
2. Estimate the length of this section of the earthworks (from the English Heritage sign to where the ditch is interrupted by the concrete footpath)
3. Take a picture of yourself and your gpsr with the bank of the earthwork in the background (there is a concrete path along the top of the bank, so wheelchair users will still be able to claim this cache, just take your photo with your gpsr at one of the entrances to the ditch)
Email the answers to tasks one and two to me at gt@geotrowel.com at the same time as you log your find. Post your picture with your log.
That's about it, hope you enjoy this earthcache!
Sources, and for more information:
(visit link)
(visit link)
(visit link)
(visit link)
Additional Hints
(No hints available.)