- Source: Kabuh Formation
The Kabuh Formation is a Plio-Pleistocene geologic formation from Central Java, consisting of several unnamed members belonging to the Kendeng Group. Many of the fossils discovered from Sambungmacan belonging to this group were discovered in an accumulated sediment deposit in a flood-controlling canal near the Solo River, including a series of hominin crania that are similar in anatomy and geologically younger than the Ngandong hominins upstream. This area was excavated throughout the 1970s.