Here is the link you requested.
http://bachelorsgrove.net/forum/viewtopic.php?t=62As has been mentioned about the possibility of markers in the pond, personally I believe there just might be. While I don't think that most of the missing ones are in there I would hope there would be at least 6. From looking at the site there, I will say it would be relatively easy to drain the pond since there is a stream not far away that is lower than the level of the pond. I would think it would be possible to dam it back up again so that once an investigation is completed that the pond could refill.
As to any headstones or grave markers in the pond, I will say that the stone should (at least I believe so) be in ok condition. maybe in need of a really good cleaning and with one of the old plat maps it would be possible to put the markers back where they belong.
The ideal thing would be for draining the pond would be to do it early (middle to late spring) so that when the summer arrives most of the soil will dry out. Once that is done you could easily begin to dig nicely to see if any markers are in there. If any are found it would take either a backhoe/payloader to lift them out so they could be cleaned and then reset to their origional location or even a heavy duty tow truck with a rotator boom could lift it out from 143rd. If any have been in there I doubt that they would be all that far down, I am guessing maybe at the most 2 foot into the soil of the pond.
Any other thoughts on this folks?