According to Pringgoprawiro (1983), there are plenty of vertebrate fossil remains found around Pandan Mountain (East Java) such as Kedung Brubus, Butak and Rejuno. Those vertebrate remains were positioned in the strata of Lower and Middle Pleistocene sedimentary rock so-called Pucangan and Kabuh Formation.
In Java island especially in Central and East Java, the famous sites for vertebrate fossils including hominid fossil are Sangiran and Trinil (Arif, 1998). That two sites along with another sites which also contains of vertebrate fossils such as Ngandong, Sambung Macan, Watu Walang and so on, located in the vicinity of Bengawan Solo (Bengawan mean is River). Pandan Mountain itself situated far from Bengawan Solo at least southward of Bojonegoro.
There are many scientists had carried out an extensive research in Sangiran and Trinil area (e.g. Van Es, 1931; Koenigswald, 1940; Semah, 1984). From 1976 to 1979, there is a joint research project so-called the National Project CTA-41 of the International Co-operation program between the Department of Mines and Energy of the Republic of Indonesia and Japan International Co-operation Agency (JICA). This project resulted in a large amount of new information on the geology -especially geochronology- of the hominid fossil-bearing formation in Java, which particularly from surrounding Bengawan Solo (see Itihara et.al., 1985, 1994).
But until recent, another sites -such as Kedung Brubus, Butak, Rejuno and so on- have not yet undertaken an extensive research like Sangiran and Trinil. Therefore, the sites surrounding Pandan Mountain is also interesting for study of palaeontology and paleo-anthropology as other promising sites.
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