The classic account of the riparian lifestyle of this period comes from investigations in Sudan during World War II by British archeologist Anthony Arkell. Arkell's report described a Late Stone Age settlement on a sandbank of the Blue Nile which was then about higher than its present flood stage. The countryside was clearly savanna, not the present-day desert, as evidenced by the bones of the most common species found in the middens — antelope, which require large expanses of seed-bearing grasses. These people probably lived mainly on fish, however, and Arkell concluded, based on the totality of the evidence, that rainfall at the time was at least three times that of today. The physical characteristics derived from skeletal remains suggested that these people were related to modern Nilotic peoples, such as the Nuer and Dinka. Subsequent radiocarbon dating firmly established Arkell's site to between 7000 and 5000 BCE. Based on common patterns at his site and at French-excavated sites already reported from Chad, Mali and Niger (e.g., bone harpoons and a characteristic "wavy line" pottery), Arkell inferred "a common fishing and hunting culture spread by negroid people right across Africa at about the latitude of Khartoum at a time when the climate was so different that it was not desert." The originators of the wavy line pottery are as yet unidentified.