Yesterday saw the sun shine on us, as a team of seven ventured into Verulamium Park. Thanks to everyone who turned out to help on a cool, but beautiful, autumn day. As a result of the fair sized team, we managed to survey in plenty of grids both for that day and for next week. In the afternoon, three of us went back up to the western field to continue the resistance survey we started last week.
As can be seen from the above image, we are working our way steadily up the area between the footpath and the lake. Another 80m (two rows of grids) and we’ll be up to the footpath and the splash pool near the lake.
As can be seen from the second image, we are starting to pick up some more of the roads in this area. The buildings are not showing all that clearly, probably due to the upcast the lake being dumped in this area. In particular, we are not really seeing the third century defensive wall. Another curious observation is that the roads do seem to be of variable widths.
In addition to the mag, we managed another two 20x20m res squares. It is slow because of my insistence on using a half meter spacing between readings, which quadruples the number of readings compared to the more common 1m spacing used in many surveys.
As can be seen from the two images above, there are many interesting areas of comparison between the two plots. Some of the linear features that are so clear on the mag do show on the res, but only faintly. On the other hand, there are some strong positive anomalies in the res data that lie in between the linear features seen on the mag. It seems to be that we have reasonable evidence for a building in the NW corner of the res plot. I think it is worth continuing. It would also be useful to try using a 1m spacing between the mobile probes to increase the effective depth from 0.5m to 1m. Unfortunately, the TRCIA machine we are using has a fixed 0.5m spacing on its frame. If anyone knows of a 1m-wide frame for the TRCIA machine, do let me know. Otherwise, I’ll borrow the UCL machine.
We will be out in the Park again next Friday, weather willing. It would be great to have a good sized team again so we can continue both surveys.