Did the shard found 3 ft down actually reside there or was in inadvertently mixed by shoveling and actually resided much closer to the surface.
Contamination of the dig, percentage is low IMHO.
Lets assume the money was buried and the bills deteriorated over time. the fragments should be in the same general area of the bundles, packs, clump, wad etc. Brian comes along and exposes the bills. the FBI returns and starts digging. yes, Brian would of shifted the frags to a certain degree, but not much..
The start of the dig will only be breached by the shovels. the bodies would be several feet from the dig area. now, the surface area as been removed where the money was found. that should also mean all the pieces went with the surface dig down to a foot or so. the fragments that came off the bills couldn't have separated downward? as the hole got bigger and bigger shouldn't be a concern if the money was buried. that area has been dug up long before a 5-10 round hole is dug. I'm not sure how they addressed the top layer surrounding the money location. did they sift the sand like seen in later photo's during the dig?
I just don't think fragments got transferred to different depths, especially, if the money was buried in 1971. even if it got exposed and buried again. they should stay pretty much together. the other problem I've had a hard time with is the story surrounding the spreading of the sand and Palmer showing where the dredge lines were. how can this be if the sand was not pushed that far it's like telling a story of me walking from point A to point B and showing tire tracks as proof? the story line is skewed.