Thunderbird Archaeological District  The Thunderbird Archaeological District, near Limeton, Virginia, is archaeological district described as consisting of "three sites—Thunderbird Site, the Fifty Site, and the Fifty Bog—which provide a stratified cultural sequence spanning Paleo-Indian cultures through the end of Early Archaic times with scattered evidence of later occupation." This archaeological site, located in Warren County Virginia, near modern-day Front Royal in the Shenandoah River Valley is a major site of the Paleoindian Clovis culture in Virginia. It was designated a National Historic Landmark in 1977 because it yielded dense archaeological remains as well as evidence for what is quite possibly the oldest structure in North America. The site is one of three which make up the Thunderbird archaeological complex which consists of 2,500 acres of sites spanning the prehistoric era. The major occupations at Thunderbird site are known to date to the Late Pleistocene-Early Holocene epochs and include Clovis and later projectile points forms, as well as an array of other tools and manufacturing debris. Radiocarbon dates indicate some of the occupations date to 9900 BP (before present). Thunderbird consists of a group of sites located in and around a jasper quarry, Thunderbird is considered a part of the Flint Run Complex. The site's relation to the quarry is important because the Paleoindians used the jasper to create tools, such as the Clovis points. Jasper is a mineral that is usually red and is known to break with a smooth surface: it can also be used for decoration but has also been used for creating bow drills that create fire. Thunderbird yielded Clovis points that date between 9500 and 9000 B.C. The inhabitants of the site are presumed to have been hunters since the tool kit found is associated with hunting wild animals. Thunderbird is a stratified site that has evidence structures found just below the plow zone along with tools, points and flakes of points. Because of its stratified deposits, Thunderbird is one of the sites used to develop a sequence of Paleo-Indian and Early Archaic assemblages in Eastern North America. Not only does the site have Clovis points, Thunderbird also has been credited with a point that is rarely found throughout the Middle Atlantic region: the Hardaway Dalton point, a point with shallow side notches and a deep basal concavity. This point averages of 60 mm in length, 35 mm across and has an average thickness of 7 mm. The microblades found at Thunderbird site are rare and linked to a few other sites, which include the Williamson Site in Dinwiddie County.