The area of soil with bright yellow inclusions (likely highly organic) is a small circle (45 cm diameter) which is located on the border between L525 and L526. It is a very thin lens (2 cm thick).
In L525, we found a worked horn core (Ar/Ge.T19.525.B.02), just west of the wall fall in about the center of the locus. Near to that, we collected a piece of charcoal (3cm x 3 cm x 2 cm) for radiocarbon dating (Ar/Ge.T19.525.C14.01). We found a small piece of groundstone (Ar/Ge.T19.525.L.02), just west of the wall fall, at about the center of the locus.
We took a macrobotanical sample (Ar/Ge.T19.527.MB.01) from the center of L527. The soil was mottled yellow/brown and black, which may indicate that the circular black stain is not a feature.