Provenience Reassessment of the 1931–1933 Ngandong Homo erectus (Java), Confirmation of the Bone-Bed Origin Reported by the Discoverers

The Geological Survey of the Netherlands Indies unearthed 14 Homo erectus fossils in 1931–1933 from a single ex-cavation site on Java (Excavation I Ngandong). Survey geologists attributed the hominin discoveries (along with thousands of other vertebrate remains) to a thin, gravelly volcaniclastic stratum situated near the base of a fluvial-terrace remnant ~20m above the Solo River. The geologists were present 24 days during the 27-month-long opera-tion, witnessing and documenting only a few human fossils in situ. Moreover, they published limited amounts of detail about the discoveries. Their provenience account is nonetheless substantially corroborated by surviving records. Key materials are presented here for the first time, including the geologists ’ photographs of two human fossils in situ and a 1:250 site map from 1934 showing individual Homo erectus discovery points. Calvarial specimens Ngandong I, II, V, VI, and VIII are the five best-documented finds. Each is securely attribut-able to the basal volcaniclastic fossil bed. In March 1932, geologist W.F.F. Oppenoorth photographed Ngandong V while it was still embedded in the fine volcaniclastic gravel <0.5m from the basal terrace contact. He previously had examined the contexts of Ngandong I and II when only <150m2 of the excavation were open and all vertebrate fossils reportedly were being found in the gravely sandstone comprising the bottom ~0.7m of the sequence. In June 1932, geologists C. ter Haar and G.H.R. von Koenigswald photographed the Ngandong VI in a ~2m x 2m horizon