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578 A · ANALYTICAL CHEMISTRY, VOL. 58, NO. 4, APRIL 1986
units. The Masmas (deposited about 40,000 years ago) is the oldest Nile sediment exposed in the area and can be distinguished from other Pleisto cene Nile units (e.g., the Sahaba for mation) by trace element differences in the bulk sediments. These can be distinguished from the Nile silts that were being deposited contemporane ously with the development of the wadi settlements more than 6000 years ago. The Nile floods were not as high 6000 years ago, and the Predynastic Egyptians occupied an area along the wadi that was above the flood plain but contained the rich Nile silts from the previous era. Using trace ele ment analysis we have shown that the extensive pottery production that oc curred in the area was a localized in dustry. Predynastic potters used the earlier Nile silts on which they built their kilns as the source of clay. Trace element data suggested that tne pot ters used some type of separation to remove some of the coarser material, especially in the finer Plum Red Ware and later Hard Orange Ware pottery found primarily in the cemetery areas. This was confirmed by microscopic analysis of ceramic sherds and the Pleistocene Nile sediments. Although the level of the earliest oc cupation of the area around Kom ElAhmar has not yet been reached by excavation, the oldest pottery sherds from the cores indicate that the site was occupied from at least as early as the Badarian Period (ca. 4000 B.c.). This site is much nearer to the Nile than the settlement areas along the Great Wadi. Although the occupation site may have been high enough to avoid many of the floods, the sedi ments in which the artifacts are found (Unit N, Figure 1) are intercalated sand and fine-grained mud deposits. Across the Nile at another Predynas tic site, Vermerersh and co-workers identified a Nile unit that they called Nekheb and estimated its time of de position to be during a period begin ning about 9000 B.c. Comparison of the samples from the Nekheb litho zone formation at El-Kab to those of Unit Ν at Kom El-Ahmar shows they are part of the same Nile depositional unit. The cultural deposition of pot tery within this unit at Kom El-Ah mar indicates that this period of Nile flooding lasted until at least 3200 B.c. Evidently, the Kom El-Ahmar site was at a high enough elevation that only periodic, abnormally high floods reached the inhabited area. After about 3200 B.C. the deposits are evidence that all flooding by the Nile at Kom El-Ahmar ceased as the height of the Nile floods declined. The next sediment deposits around Kom El-Ahmar are from a completely dif ferent source. The trace element data
