Problems With Stratigraphy
Unfortunately for archeologists, it is not always the case that the oldest layer lays at the bottom of an excavated site. In one excavation, an archeologist found the surface of a site littered with old coins dating to the seventeenth century. Subsequent investigations, however, revealed that a bulldozer had earlier overturned the soil at the site to a depth of several feet as part of a preparation for building homes on the site.
The problems of relying entirely on stratigraphic analyses to evaluate the antiquity of a find were made even clearer in an incident known as the great Piltdown hoax. Between 1909 and 1915, an amateur British paleontologist made claims of having discovered the fossils of a prehistoric human being in a gravel pit in Piltdown, Sussex (England). But in 1953, tests revealed that the Piltdown man actually had the jaw of a nineteenth-century ape, and the skull of a modern human. The planting of faked remains at a site of known stratigraphic antiquity had in this case succeeded in deceiving even the head geologist at the British Museum, who had been among many who authenticated the find.
Fagan, Brian M., ed. The Oxford Companion to Archeology. New York: Oxford University Press, 1996.
Lyman, R. Lee, Michael J. O'Brien. Seriation, Stratigraphy, and Index Fossils—The Backbone of Archaeological Dating. New York: Kluwer Academic Publishers, 1999.
Maloney, Norah. The Young Oxford Book of Archeology New York: Oxford University Press, 1997.
Nash, Stephen Edward, ed. It's about Time: A History of Archaeological Dating in North America. Salt Lake City, UT: University of Utah Press, 2000.