Agate Basin Projectile Point: Identification, Age & Range
Agate Basin points are long, slender Plains Paleoindian lanceolates with straight ground bases, found across the Great Plains and beyond.
At a glance
Period
10,550 - 9,350 B.P. · Transitional Paleo
Typical size
33–147 mm long, 18–39 mm wide
Region
This point is primarily associated with the Plains region (Great Plains and High Plains) of North America.
The Agate Basin is a long, slender lanceolate of the Plains Paleoindian bison-hunting tradition and a member of the Plano Lanceolate cluster. The type owes its name to Frank H. H. Roberts Jr., who defined it in 1943 from the Agate Basin site in eastern Wyoming; Marie Wormington first published it in 1957. Frison's excavation work showed Agate Basin material consistently lying above Folsom levels at stratified sites, though radiocarbon dates hint the two may overlap somewhat.
A word of caution before you label your find: this is probably the most over-applied name in Paleoindian typology. All sorts of ordinary lanceolate points get called Agate Basin. The genuine article is a finely made, symmetrical point, and a few specific traits separate it from the look-alikes.
How to identify a Agate Basin point
Shape first. A true Agate Basin is noticeably long and narrow, with smoothly excurvate edges that run roughly parallel through the middle and taper in toward the base. The widest spot sits at or below the midpoint, in the middle to lower third. The base is straight or very slightly convex — never concave. A hollowed base alone disqualifies a point from this type. There is also no basal thinning; instead, the hafting area shows heavy grinding along the lateral edges, often reaching as far up as the blade's widest point.
Workmanship is the other tell. These points show a high level of craft, usually in a random flaking pattern (rarely collateral or transverse), on high-quality and often exotic stone. Even examples knapped from mediocre material keep an even, symmetrical blade. The cross section is elliptical, 6 to 10 mm thick, with the blade typically two to three times as wide as it is thick. Length runs 33 to 147 mm — most fall between 55 and 70 mm, about the length of a business card — and width runs 18 to 39 mm, averaging 24 mm.
Age and where it's found
The type dates to approximately 10,550 to 9,350 B.P., in the Transitional Paleo period at the Pleistocene-Holocene boundary. Its named relatives in the Plano tradition include Hell Gap, Angostura, Plainview, Milnesand, and Browns Valley.
The heartland is the Great Plains and High Plains, extending through the Midwest and northern Plains, with finds into Texas and western Ohio. Outliers have been reported from Nunavut and the Northwest Territories in Canada, from Oregon west of the Continental Divide, from Plenge in Pennsylvania, and south into the Tehuacan Valley and Valley of Mexico — but east of the Mississippi and west of the Rockies the type is rare.
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