The antepenultimate day

“Antepenultimate” is my second favourite word. At least I get more use of it than I do of my favourite word, “defenestrate”. I used to defenestrate my Christmas tree until I moved and now I can only deport it. Anyway, enough of this nonsense.

Today the mag re-did a few problematic blocks of data before moving on the survey a batch of new grids.  Here is the overall plan.

The total area surveyed after day 17.

The total area surveyed after day 17.

I think we should all be very pleased with the progress we have made.  Looking at the new area in more detail.

Detail of the area surveyed on day 17.

Detail of the area surveyed on day 17.

The large ditch which runs from the SW to the NE of the westernmost part of the survey is the return leg of our old friend, the 1955 ditch.  It looks like the northern part of this feature has been substantially backfilled with non-magnetic material as it is only visible faintly.  The sinuous ditch clearly crosses the 1955 ditch  and heads west up the shallow valley.  At least we can be sure now that the sinuous ditch post-dates the 1955 ditch.  Part of the western part of the sinuous ditch was found in the 2000 English Heritage survey.  The line of pits which appears to join to the thinner NW-SE ditch could be all one long linear feature.  This area may not have the big stone buildings found in the central part of the town, but it still asks a great many questions.

The GPR has now covered quite a large area.

All areas surveyed using the GPR overlain on the mag data.

All areas surveyed using the GPR overlain on the mag data.

Today they covered another 80x40m block to the south of the “uber magnetic” building.

The GPR block surveyed on day 17.

The GPR block surveyed on day 17.

The same area for comparison to the previous image.

The same area for comparison to the previous image.

We picked up quite a bit more of the building which was in the SE corner of yesterday’s block, as well as this missing corner of the corridor building to the SE.  The road does show, but not very clearly in the time slices.  There is also quite a solid area in the western part of today’s block; it maybe another building.

Tomorrow may be the last day if the weather forecast is accurate.  Fingers crossed that it isn’t!

 

Bring me sunshine, bring me smiles…

Magging (c) Mike Smith 2015.

Magging (c) Mike Smith 2015.

For a change, or so it seems, it didn’t rain.  It got very threatening at the end of the day so we were pretty efficient packing up, but on the whole it was a lovely day with white fluffy clouds, We were a slightly smaller team than usual, but we still managed to run the mag and the GPR today.

Following yesterdays problems with the mag, Ellen implemented a high-tech solution…

The hi-tech solution.

The hi-tech solution.

The flowerpot came from our garden but sadly Homebase didn’t stock duct tape so we had to make do with “duck” tape.  What do ducks do with tape, I wonder?  When the season is over I think the machine is going for a service.

The mag started by re-doing one of yesterday’s dodgy squares, then complete the transect with its final partial, before starting the next transect.  Here is the overall view.

The mag survey after day 16.

The mag survey after day 16.

Sadly, I don’t think we’ll get the whole next transect done in the next three days.  The area we did today is an interesting contrast to earlier days.

The area surveyed on day 16.

The area surveyed on day 16.

There are quite a few pits, and a ditch which seems to continue the line of pits seen yesterday to the WSW of the “uber magnetic building”.  One of tomorrow’s grid squares should show us how this new ditch and the “sinuous ditch” meet.  No sign of the 1955 ditch’s northern arm yet, however.

Mike Langton, of Mala, kindly processed one block of GPR data — that surveyed on day 12 — for us using Reflex-W.  The results are very good. I have (a) a lot to learn and (b) a lot to do!

Time-slices of the dat 12 data by Mike Langton.

Time-slices of the dat 12 data by Mike Langton.

The eight slices start at 10ns and are 2ns thick.

Mike and I completed a grid square with the GPR in the morning, tidying up the block of grid squares so far surveyed.  Unfortunately, there doesn’t appear to be very much in it.

The centre block is the data collected on days 15 and 16.

The centre block is the data collected on days 15 and 16.

The same area without the GPR data for comparison.

The same area without the GPR data for comparison.

I decided that I couldn’t wait a year to find out more about the “uber magnetic” building, especially after the repeated failures of the res meter on that area.  Mike and Julia valiant struggled up and down the slope, occasionally assisted by myself.  Surprisingly, given the strength of the magnetic signal, the GPR showed very little apart from one corner.

GPR results over the "uber magnetic" building.

GPR results over the “uber magnetic” building.

The same area as the previous image for comparison.

The same area as the previous image for comparison.

It seems unlikely that a building like a bath house would show so poorly in the GPR data and so it seems more likely we are dealing with a burnt down timber structure.

We are on the last leg of this year’s survey.  Despite hiccups, rain and technical failures we already have some stunning results.  Let’s hope for a few more in the last days.

Many thanks to everyone who turned up today and did such sterling work.

A smooth road?

Not, I think. It was raining as we were packing the car this morning and the wisdom of going to site was in question. On site, however, the weather seemed fine.  Then we realised I had left a vital cable for the GPR at home.  Whilst Mike and I retrieved it, the mag got to work and managed an excellent four grids before lunch.  I tried checking connections on the resistance frame but couldn’t see a problem, and when I tried it by the car all seemed fine.

After lunch, the GPR team resumed work but the mag developed a problem.  We seem to have a damaged cable.  With some tweaking and keeping fingers crossed we managed to carry on.  The resistance system still seems to be non-functional.  I’m beginning to despair!

Despite the problems we did manage to collect some good data.  First of all, the progress image.

The survey after day 15.

The survey after day 15.

As can be seen, we have one last partial grid square to complete our long 80m wide swathe across the town.  It is a long way from one end to the other, and with all the days lost to bad weather it was a while ago that we were looking down over the town from the southern heights.

Looking at the new area in detail we can see some interesting things.

Detail of the area surveyed on day 15.

Detail of the area surveyed on day 15.

The annoying white strip is a sensor freeze so ignore that.  The sinuous ditch, however, seems to be swinging round to the west and perhaps even slightly to the south-west.  The “uber-magnetic” building does not extend further to the west, but there is a ditch running SW–NE nearby.  Most curious is the large blank area which shows almost nothing, not even much ferrous litter!  To the south of the magnetic building and the open area is a sinuous line of pits.  All very curious and fascinating.  There are faint white lines just north of the sensor freeze strip which indicate another building with stone footings.  All good stuff.

The GPR was also very successful today.

GPR results from day 15. The slices are 12-16, 16-20, 20-24 and 24-28ns.

GPR results from day 15. The slices are 12-16, 16-20, 20-24 and 24-28ns.

We have quite a grand looking building with a corridor, a number of rooms, and a big area (courtyard?) to the SE.  Placing it on the mag plan we can see where this fits in.

The day 15 GPR results overlain on the mag data.

The day 15 GPR results overlain on the mag data.

The same area as the previous image without the GPR data for comparison.

The same area as the previous image without the GPR data for comparison.

Given that we only have four days left, deciding where to send the GPR next is a hard decision.  Try to make tidy blocks, or target some interesting buildings such as the uber-magnetic ones and the row of smaller buildings along the road?  Decisions, decisions!

Let us hope for nicer weather tomorrow.

At 1pm precisely…

The Met Office predicted rain at 1pm, and at 1pm it began to rain.  We had, however, managed to do four mag grids before lunch, and finished off another one and a res grid in the drizzle.  Many thanks to everyone who turned out on a unpromising morning and helped us complete a fair bit in the time we had.

The bad news first.  The Chess Valley Archaeological and Historical Society were kind enough to lend me their resistance meter and cable to try and work out what is wrong with ours.  Unfortunately, it looks like it might be the wiring on the resistance frame as the results we got today were utter nonsense.  Many thanks for John Glover for lending me the equipment and Jim West for bringing it over.

The five mag grids were, however, extremely interesting.  First the overall image:

The mag survey after Day 14.

The mag survey after Day 14.

Weather permitting, we should be up by the drive by the end of tomorrow, and hopefully will have picked up more of the ‘sinuous ditch.’ Zooming into the area we did today reveals some interesting features.

Detail showing the area surveyed on day 14.

Detail showing the area surveyed on day 14.

An annotated version of the previous image.

An annotated version of the previous image.

We have picked up the cross-roads between streets 11 and 25 very nicely.  Along street 25 there seems to be a line of smaller buildings.  More modest dwellings, perhaps, or maybe workshops and shops?  On the north corner, however, is a weird looking and extremely magnetic feature, probably a building as it seems too rectangular to be something else, and is approximately 20m by 10m in size.  Perhaps the building burnt down, or maybe it is an industrial feature?

Tomorrow we should be able to survey the grid next to our first “uber magnetic” building as well as picking up, we hope, some more of the infamous sinuous ditch.

We have also made the news on the Institute of Archaeology‘s website!

Rain stops play

Yesterday we had warning that it was going to rain in the early afternoon, but we went out anyway.  We managed a 40x40m block of GPR data and all the annoying partials around the end of the hedgerow with the magnetometer.  Then, in the early afternoon, it started to drizzle.  Luckily we decided to head home as later it really started to rain.  Today has also been washed out.  We’ve had 31mm of rain in the last 24 hours.

The break has, however, enabled me to catch up on some data processing, especially with the GPR.  Firstly, we can see how much we have done so far.

The magnetometry survey after day 13.

The magnetometry survey after day 13.

As can be seen, we have already covered a good sized area of the theatre field.  Still quite a bit to do, however, and the weather forecast is looking a little grim.

Zooming into the area we are working on at the moment…

Mag survey near the hedgerow.

Mag survey near the hedgerow.

We have a part of the SW-NE road (street 25 in Niblett and Thompson 2005) and buildings alongside it.  It looks like we have buildings around the outside edges of Insula XXX and a quite open area in the middle.

The rain has given me a bit of time to work on the GPR results.  Here is the overall plot. Please remember this is a simple mash-up in Google Earth and that I should be able to get much better plots eventually.

All the GPR results up to day 13 plotted together in Google Earth.

All the GPR results up to day 13 plotted together in Google Earth.

The same area as before without the GPR data.

The same area as before without the GPR data.

If you compare the mag and GPR data you can see that some features that look like walls in the mag data show clearly in the GPR data, but some show as faint negative (light) areas. This is probably the difference between buildings which have had their footings robbed and those where they survive.  The temple does not show very clearly in either data set.  It seems likely it was badly robbed.

The area surveyed on days 12 and 13 is especially interesting.

The block of GPR data collected on days 12 and 13.

The block of GPR data collected on days 12 and 13.

The same area with just the mag image.

The same area with just the mag image.

The corridor building shows very well, but the sinuous ditch is conspicuous by its absence.

Hopefully the rain will let up long enough for us to manage a little more survey tomorrow.

Scorcher

It was a hot and sticky day but we soldiered on with excellent results. Just a few quick images as I have to go and collect more data. Did you know that archaeological geophysicists are renowned for wanting to collect just one more grid of data?

Firstly, the overall survey after day 12.

The overall survey after day 12.

The overall survey after day 12.

We’re getting there!  Now a detail of the area surveyed.

Detail of the area surveyed during day 12.

Detail of the area surveyed during day 12.

We have some more of the ‘1955 ditch’ at the bottom, then some buildings, a large open area with some pits, then in the top-left corner more stone buildings along the road.

The GPR did some blocks near the temples, specifically to cover part of the sinuous ditch.

The day 12 GPR data (top 76.5x40m block.

The day 12 GPR data (top 76.5x40m block).

The same area as the previous image without the GPR data.

The same area as the previous image without the GPR data.

As you can see, the long building with the corridor on the north shows spectacularly well. The ditch, however, does not show at all.  This may be because of my quick ‘rough and ready’ data processing and a more detailed examination in the future may show something.

Off to survey more before the rain which is forecast for 2pm.  Let’s hope it is late!

Back down the hill

Just a quick posting with some images this evening as I have been out celebrating the publication of a book I edited.

We started off with some partials in the bottom corner and then began the long transect back to the north.

The survey after day 11.

The survey after day 11.

It will be another couple of days before we hit the hedge line by the drive.  Looking at the new area in more detail we can see we have picked up more of the 1955 ditch.

The area surveyed on day 11.

The area surveyed on day 11.

There is an interesting rectangular enclosure in the far south, lots of pits and other cut features, but nothing which looks like the stone buildings further south.  Neil Linford in his report on the 2000 survey suggests this might have been more of an industrial area.  There is also what looks like one side of a break in the 1955 ditch.  Tomorrow’s results will be important to see if this is so.

The program processing the GPR data is still running!  I’ll post the results tomorrow.