VII.   PRELIMINARY POTASSIUM-ARGON DATING OF EARLY MAN IN JAVA

Teuku Jacob and Garniss H. Curtiss

Professor of Anthropology

College of Medicine

University of Jogjakarta

Department of Geology and Geophysics
University of California, Berkeley

Specimens of volcanic rock collected in 1969 at the principal hominid
sites in Java, namely Sangiran, Trinil, Ngandong, Ngawi, Modjokerto and Boe-
tak, are now being dated at Berkeley. Owing to contaminants, mainly carbon-

ate and zeolite, which contribute large quantities of air, it has been diffi-
cult to obtain meaningful dates from most samples worked on up to this time,
but a fair date of 1. 9 m.y. + .4 for a tuff underlying the site of a mandi-
bular fragment of Meganthropus can be reported. The Meganthropus fragment
was found by Marks in 1952 in Djetis beds of continental origin near Mod-
jokerto. Although the pumice tuff lies several meters below the hominid

site, the site itself lies at least 400 meters below late Pleistocene beds
all of which have been folded into an anticline and truncated by erosion,
and it is believed that the pumice and hominid remains are penecontempor-
aneous.

The date of 1.9 m.y. makes this hominid, thought by many anthropolo-
gists to be an Australopithecine, contemporaneous with African hominids of
similar evolutionary development. It seems reasonable to suspect that

hominids were in southeast Asia long before Meganthropus was entombed at
this spot in Java.

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