I doubt my reply will be of any help to you at all as I am based in Western
Australia.

However, I have used a metal detector on a late 19th century cemetery, It
delinated things like the location of spikes associated with former head and
foot markers, nail scatters associated with former wooden fence surrounds
and the former location of a metal surround. I would never use it for the
coffins, ours are 10ft under, only stacked burials get near the surface. In
that cemetery I used a combination of physical survey of depressions, aerial
photographic analysis and the metal detector survey to find about 180
missing graves, I forget the exact number.

In our main colonial cemetrey physical survey does not locate many
depressions as they graded it. There I have used aerial photographic
analysis (the graves and other features mostly show up really well), probing
with a metal probe (not very sucessful in a sandy soil). probing with an air
probe (much easier in sandy soil) for the coffin remains (hard to determine
results without digging up the graves to find out if the hard bits really
were coffins) and GPR.

All projects were just pilot projects. The GPR survey was on an area showing
glaring white on the aerial. There were two marked graves in a plot 18 by 15
metres. The GPR survey indicated 57 occupied grave plots within the area
with fairly regular differences in height suggesting some shafts held one
coffin while others held two or three stacked coffins. The third uppermost
coffins were at about 1.2 metres depth. The survey indicated 123 people were
buried within the test area.

Cheers Gaye


----- Original Message -----
From: "Lyle E. Browning" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, 13 May 2003 9:52 AM
Subject: Re: Locating Historic Graves


On Monday, May 12, 2003, at 12:44 PM, Jamie Brandon wrote:

> Greetings all:
>
> I am currently looking for references (including mentions in State
> Plans, Laws, gray literature, methodological papers, etc.) on the use
> of metal detectors in finding the locations of historic grave sites. .
> . Or more to the point, are there statements out there in the
> literature to the effect that metal detectors may not be (putting it
> diplomatically) "the best way to go about" delineating a
> historic-period grave (I mean, 5-6 ft down?!?). . . .
A metal detector has a fall-off of signal with depth of about 1/d9th
which means that the signal falls off very, very, very rapidly. The
larger the object, the deeper it can be detected. However, a typical
coffin with nails has very little metal mass to be detected. A MD is
not the best bet for grave detection at those depths.

Physics in Archaeology by Martin Aitken (1971) has a good write-up on
them and their limitations. The essentials haven't appreciably changed
over the years.

Lyle Browning=