We have tried to make sense of the results of augering by plotting the layers within our mapping project using QGIS and analysing them with a useful plug-in (‘Midvatten’) originally designed and intended to record the stratigraphy and hydrology from well boreholes. While most of the hydrology functionality is of no relevance, the associated database and the display features are ideal for producing a display which we hope can be used to interpret past topography of our site at Millhams. So far our augering has generally terminated when we reach a gravel layer which resists penetration from our hand auger tool. Intermediate results our confusing, giving a complex picture of inter-penetrating layers of silty- sand of various colours from orange to blue-grey. A typical Midvatten plot from Auger Line 1 is shown in the illustration, representing a horizontal scale of some 40m, with a greatly exaggerated vertical scale; the topsoil is shown in yellow with the impenetrable gravel layer in green. Noteworthy is the evidence of an ancient channel running through the site, with the edge of the gravel a little further to the east.
It’s almost time to put our site at Millhams to bed for the winter months. Last weekend the combination of heavy rain and a high tide produced a very soggy and puddled site to work in. We have been continuing to work on the augered holes and have almost completed Auger Line 4, with just six positions left to auger. All the lines extend roughly east-west across the garden from the banks of the Mill Stream to the partially silted channel (fed from the River Avon) which borders the eastern side of the site.
While browsing through the Google Earth imagery, tcablogmaster was amused to discover that the latest satellite image of our area of excavations in Little Millhams at Christchurch clearly shows the evidence of our working. The satellite imagery is dated to 26 May 2017 (a Friday). In the top left hand corner of the Google Earth image reproduced to the left you can clearly see the blue plastic sheeting which we use to pile up the spoil from the excavated pits. There are two sites visible in the image – from the site log, these would be Pits 51 and 52. In the centre of the image the scatter of white rectangular shapes are the beehives, whose aggressive occupants kept us well away from starting any work in their vicinity.
The idea to auger a series of test pits proved successful but we soon realised that the little sampling auger we had been using was too short the reach the levels at which we had discovered medieval traces. In order to sample these layers, Mike Tizzard constructed our new monster auger, known as ‘Big T’, from a piece of irrigation pipe attached to a sharpened piece of angle iron. Well over 2m tall, Big T requires us to remove the shallow layer of topsoil found at Millhams, before being used to auger through the relatively softer layers of silt. Although we cannot extract cores, we can bring up soil samples from depth and classify them.
Using Big T, we hope to be able to obtain a view of the stratigraphy in the garden without the labour of excavating test pits and thus adopt a more targeted approach in our excavation strategy.
Encouraged by the spell of warm and dry weather, a small group of TCA members embarked on the first session of the 2018 season at Little Millhams on the May Day Bank Holiday weekend. Readers of this blog will perhaps recall that we have had several skirmishes with the bees which patrol and defend vigorously the area in the vicinity of the beehives in the Millhams garden. It now appears that the bees are on holiday while their hives are in the process of being transported to another area of the garden, so this seemed an ideal opportunity to investigate an East-West line of the garden in an area just North of the previously occupied by the beehives.
In order to clarify and perhaps bring some order to the confusing results of the various layers in adjacent pits, it was decided to investigate systematically the layers along the East-West line selected by first removing the topsoil and then auguring downwards from the topsoil interface. Steve Fox reports that out of 13 points laid out across the site, the first 5 were studied in this first session and while too soon to claim any success, there are definite differences in the profile of each pit that will hopefully combine to make a cross-section of the whole site. (Photograph and report courtesy of member Steve Fox)
We have published the latest issue of our occasional newsletter, dated March 2018. We apologise for it being so long overdue and we hope you will find something of interest in it, to make it worth the wait. Copies are being posted or delivered to all our registered members and should arrive within the next week or so. If you haven’t received your copy after say two weeks please contact the Secretary.
Those of us who regretted the closure of Christchurch’s Electricity Museum will welcome SSE’s initiative in providing a Doors Open Day on 21 February 2018. Entry was free but required prior booking which was arranged for a small group of us by our chairman, Mike Tizzard.
Previous visitors to the Museum will notice the absence from the Main Hall of the ‘jewel in the crown’ exhibit, the tram, which has been returned to its owner, the Science Museum. We were told that every remaining item in the museum has been catalogued and much of the collection of portable items now stands on shelves without any display or explanation. Thus in some ways the building is a store, with items possibly available for loan to other museums for temporary display. However the main items of heavy machinery are still in place in their previous positions.
It is to be hoped that further Open Days can be arranged so that visitors can enjoy this excellent collection housed in Christchurch’s original Edwardian electricity generating station, now a Grade II listed building.