Editing Butte County, South Dakota (section)

==History==
===Prehistory===
In 1975, [[Plesiosauria|plesiosaur]] fossils dating to the [[Cretaceous]] Period (ca. 110 million years ago) were discovered in Butte County. In the 1980s, a 90-million-year-old fossil of a clawless [[lobster]] was discovered. A [[Tyrannosaurus|''Tyrannosaurus rex'']] skeleton was found in 1981.

The early human history of the Belle Fourche River Valley has been traced to about 3000 BC. The first people of the area were [[Plains Indians|Native Americans who resided on the northwestern plains of North America]]. The earliest known evidence of human activity in the area dates to the Middle Plains Archaic Period of the Plains Indians (ca. 3000–1500 BC). Traces of [[tipi ring]]s dating from this period have been found. In 1979 and 1980, archeologists excavated a fortified and previously inhabited site west of Belle Fourche that dated to AD 1000. This site was called the Smiley-Evans Site and had been recorded in 1959. Until 1984, only 47 archaeological sites had been recorded, but after the excavation of the Smiley-Evans Site, several investigations were undertaken. {{as of|1989}}, 199 archaeological sites had been discovered in the county.<ref>{{Cite book |last=Engebretson |first=Pat |title=A History of Butte County, South Dakota |last2=Heck |first2=Kay |last3=Herrett |first3=Helen |publisher=Curtis Media |year=1989 |isbn=0-88107-139-0 |location=Dallas TX}}</ref>