This is the locus that lay directly below Locus 18, the matrix that surrounded the human remains (Locus 20) found near the W corner of WSDB during its second extension to 6 m long. It is a lighter soil, very clayey, with inclusions of charcoal. Its dimensions: NW: 58 cm; SW: 2.52 m; SE: 1.2 m; NE: 2.7 m. Opening elevs: N: 2137.39; W: 2137.41; S: 2137.21; E: 2137.24; center: 2137.42. Its stratum is still unclear, because of the question of dating the burial. It is possible that it is stratum 3, but uncertain.