angel_09 said:
I think you're too late. based on what you had said, and what you've found, anything of value had been taken off.
I'm not sure why you come to that conclusion. Perhaps I wasn't clear enough ... the Japanese dig was witnessed during the war - 1945, and some 50 metres from the house in which the Japanese family were living. The interest being shown in our land by 'passers-by' is very current and frequent. The nearby well work was about 1/2 km away from our site (our farm is about 11 hectares).
On another nearby site (about 1km away), the owner had just completed the build of a new house. Then, he vanished a couple of years ago, never to be seen again, but leaving a large pit on his land. The local opinion has been that he found something of value and simply vanished into obscurity with it.
As for applicability of detectors - I'd be interested to hear more details. Other finds in the area seem to have been at around eight feet. I was thinking that a two-box type detector ought to save us from a lot of 'blind' digging and must be better that the locally-procured detectors which sound to be no more than dowsing rods.
It might also be worth stating that the soil on our farm, certainly in the area of current interest, is very clean, slightly clayey, orangey/brown, down to around five or six feet. There are no hard mineral items in there at all. I have been amazed at how easy it is to dig drainage ditches. At the five - six foot level, there are a few more solid elements, but not densely packed, and the colour becomes a little darker, slightly blue/grey in colour. I really hope/believe that this ought to be easy terrain in which to use a detector.
Also, it is this lack of hard mineral in the upper layers that makes the presence of the 'marker stones', and the larger pieces which support them from below, so peculiar that I can only believe that they were deliberately placed by human hand. As far as I can make out, the markings on the stones themselves take the form of lines and arrows. I want to clean the green moss/lichen from the stones so that the markings should become clearer.