given Predynastic site can be ascertained by examining its pottery. As the Predynastic period progressed, the handles on pottery evolved from functional to ornamental. The degree to which any given archaeological site has functional or ornamental pottery can also be used to determine the relative date of the site. Since there is little difference between Tasian ceramics and Badarian pottery, the Tasian Culture overlaps the Badarian range significantly. From the Tasian period onward, it appears that Upper Egypt was influenced strongly by the culture of Lower Egypt. Archaeological evidence has suggested that the Tasian and Badarian Nile Valley sites were a peripheral network of earlier African cultures that featured the movement of Badarian, Saharan, Nubian and Nilotic populations. Bruce Williams, Egyptologist, has argued that the Tasian culture was significantly related to the Sudanese-Saharan traditions from the Neolithic era which extended from regions north of Khartoum to locations near Dongola in Sudan. Badarian culture The Badarian culture, from about 4400 to 4000 BC, is named for the Badari site near Der Tasa. It followed the Tasian culture, but was so similar that many consider them one continuous period. The Badarian Culture continued to produce the kind of pottery called blacktop-ware (albeit much improved in quality) and was assigned Sequence Dating numbers 21–29. The primary difference that prevents scholars from merging the two periods is that Badarian sites use copper in addition to stone and are thus Chalcolithic settlements, while the Neolithic Tasian sites are still considered Stone Age. Badarian flint tools continued to develop into sharper and more shapely blades, and the first faience was developed. Distinctly Badarian sites have been located from Nekhen to a little north of Abydos. It appears that the Fayum A culture and the Badarian and Tasian Periods overlapped significantly; however, the Fayum A culture was considerably less agricultural and was still Neolithic in nature. Several biological anthropological studies have shown strong biological affinities between the Badarians and other African populations. In 2005, Keita examined Badarian crania from predynastic upper Egypt in comparison to various European and tropical African crania. He found that the predynastic Badarian series clustered much closer with the tropical African series. Although, no Asian or other North African samples were included in the study as the comparative series were selected based on "Brace et al.’s (1993) comments on the affinities of an upper Egyptian/Nubian epipalaeolithic series". Keita further noted that additional analysis