Copyright © 1998 by McGraw-Hill, Inc. All rights reserved. Printed in the United States of America. The entire contents or parts of this Update may be reproduced for use with Physical Anthropology, Sixth Edition, or Physical Anthropology: The Core, second edition, by Philip L. Stein and Bruce M. Rowe, provided each reproduction bears the copyright notice. The publisher's written permission must be obtained for other use.
See Physical Anthropology, 6th edition, Chapter 17, pages 442-448; Physical Anthropology: The Core, 2nd edition, Chapter 12, pages 292-296.
During the height of the ice ages many of the islands of Indonesia, including Java and Bali, became connected with what is today the mainland of southeast Asia as falling sea levels exposed the lands lying beneath the shallow seas. Yet the islands laying to the east of these lands were not connected to Asia because they are separated by deep water. Even when the level fell to its lowest level, 19 kilometers of open water separated the eastern islands from the continental area of southeast Asia. Alfred Russell Wallace, who is often credited as the codiscoverer of natural selection along with Charles Darwin, noted that animal and plant life differed significantly between islands to the east and to the west of this deep water area, often referred to as Wallace's line.
Archaeologists working on the island of Flores, located east of Wallace's line, have recently obtained accurate radiometric dating of archaeologist material. The site of Mata Menge has yielded 14 chert flakes that appear to have been manufactured by human agency. Chert is not normally found in the deposits and is thought to have been transported to the site. Microscopic analysis reveals evidence that the latter were used in the processing of plant material.
The strata that contain these artifacts have been dated by biostratigraphy, paleomagnetism, and, most recently by fission-track dating. The latter method provided a date of 880,000 ± 70,000 B.P. This date is consistent with the dates given by the other techniques.
If these dates are accurate then we must conclude that some form of hominid had reached Flores at around 880,000 B.P. This requires that these hominids were able to cross at least 19 kilometers of open sea, presumably in some type of water craft. The hominids that were present on the Asiatic mainland at this time were members of the species Homo erectus. If this fact is true, it adds a totally new dimension to the cultural abilities of H. erectus and opens up new possibilities as to the possible distribution.
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Reference: M. J. Moorwood, P. B. O'Sullivan, F. Aziz, and A. Raza, "Fission-Track Ages of Stone Tools and Fossils on the East Indonesian Island of Flores," Nature, 392 (12 March 1998), 173-176.