The Hadleigh Saddleback
The ridge, or known locally as the saddleback, runs from the castle towards Leigh. Some may think this has been built especially for the castle but is in fact the South East part of the Rayleigh Hills.
Research has shown that the River Medway in Kent is a very ancient river and before the diversion of the Thames to its present course the Medway flowed across eastern Essex to join the Thames in what is now north Essex or Suffolk. The route of this river has left behind evidence of its existence as layers and patches of gravel between Hadleigh and Bradwell-on-Sea. The higher the altitude of this gravel the older it is and the highest of this gravel (known as Daws Heath Gravel and Claydons Gravel) is on the Rayleigh Hills between Hadleigh and Hockley which, in places, is over 80 metres above sea level.
The existence of this high level river gravel may even have contributed to the creation of the Rayleigh Hills by protecting the Bagshot Sands and Claygate Beds from erosion while the surrounding areas were slowly reduced to the present lowland. It is a vivid reminder of the immense erosion that has taken place during the ice age and how the land surface can be considerably reshaped in relatively short periods of geological time.
It is difficult to believe that this gravel, which caps some of the highest ground in south Essex, was originally the floor of an ancient river valley. However, this must have been the situation over 700,000 years ago. Like the gravel on the summit of the Langdon Hills (which was deposited by another northward-flowing tributary of the ancient Thames), the Rayleigh Hills gravel contains distinctive pebbles of chert from the Lower Greensand of The Weald, together with other rock types that could only have been deposited by a river flowing from the south. It also contains boulders of sarsen stone which must also have originated in Kent. An example is the 45 centimetre diameter specimen in the south wall of Hadleigh Church although nineteenth century observers have described much larger boulders that were formerly present on the roadside in several parts of the district.
To claim this earthcache you will need to perform four tasks:
1. Either starting at the west point. N51 32.649 E0 36.651 or the east point, N51 32.565 E0 37.223 take a photo of GPSr and/or yourself against the gate.
2, From either of these points estimate how long the ridge is to the other point.
3. From the easterly point, N51 32.565 E0 37.223, estimate the difference in elevation to the westerly point, N51 32.649 E0 36.651
4. At this halfway point, N51 32.612 E0 36.873, take a photo of the castle and estimate the width of the ridge from fence to bush.
Message me the answers to the tasks at the same time as you log your find. Post your picture with your log.