Hello Mr. MacFadden. Thank you very much for this information.
The fossil is prepared and visible from above. There are some foot bones of the hind legs that have fallen off and drifted a bit, but they are in higher niveaus of the rock. At this time the tail must allready have been fully covered. All other bones are in the original position. I have found no remains whatsoever of other animals associated in this rock.
All this makes it unlikely to me that they are drifted bones or fragments from other parts, yet of course if there were chevron bones at any joint some must have drifted or ly underneath the vertebrae.
I add a photo of the entire tail with the marked bones and details of the small bones 1, 2 and 4. Bone 3 and 5 are allready depicted.
Please do show the photos to a colleague if helpfull.