The Shape of a Point

by Elizabeth S Paynter  – CART Lab Director

There are many characteristics that help categorize a projectile point and identify what time period it was created. Projectile points are in part defined by their shape, specifically looking at the shape of the base, blade edge, basal edge and cross section. It is good to keep in mind, as with most things archaeological, that different groups may use different terminology to describe the same thing and that the nomenclature and identifying attributes may differ slightly.

The tip or distal end of a projectile point is the pointed part at the top. From the tip down, a projectile point includes the tip, the blade, the shoulder, the half element or stem, and the base at the bottom.

Anatomy of a Projectile Point

Basic Point Shape

Some basic base shapes used to help classify a point include Bifurcate, Lanceolate, Notched, Pentagonal, Stemmed and Triangle. Pervious blog posts have covered descriptions for some of these shape types such as Corner Notched and Side Notched and Triangle Points.

Stem Shape

More recently, CART has excavated a stemmed projectile point (pictured above). Stemmed points can be identified in several ways such as Straight, Expanding or Contracting. A straight stem has somewhat parallel sides. An expanding stem widens at the base. A contracting stem converges towards the base.

Basal Edge

Descriptions for the basal edge include flat, concave, convex, and oblique. A flat basal edge has a fairly straight proximal edge of the base. A concave basal edge is a base that indents. A convex basal edge protrudes. An oblique basal edge exhibits angles that are acute and obtuse.

Blade Edge

The blade edge is yet another helpful tool in typing a projectile point. Straight blade edges do not curve. Excurvate edges bulge out in a smooth convex curve. Incurvate edges indent in a smooth convex curve.

Cross Section Shape

If a projectile point is cut across the blade horizontally, the shape of the cross section varies. Cross section shapes often include biconvex, median ridged, plano-convex, and flat cross section. A biconvex cross section protrudes out on both faces in a convex curve making an elliptical shape. Median ridged is diamond shaped. Plano-convex is somewhat flat on one face and protrudes outward in a smooth curve on the other side. A flat cross section is flattened on both faces of the projectile point.

The projectile point pictured at the beginning of this post is broken at the top exhibiting its biconvex cross section.

Read Let’s Get to the Point about Typologies to understand why identifying the projectile point type is important.

References:

MAC Lab. 2012. Diagnostic Artifacts in Maryland. Maryland Archaeological Conservation Lab (MAAC Lab). Originally Published 2002. Electronic. http://www.jefpat.org/diagnostic/index.htm accessed February 21, 2018

VDHR Collections. Native American Comparative Collections. Virginia Department of Historic Resources. Electronic. http://www.dhr.virginia.gov/arch_DHR/archaeo_lpc.htm accessed February 21, 2018

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About cartarchaeology

We are the County Archaeological Research Team, part of the Archaeology and Collections Branch, Resource Management Division, Fairfax County Park Authority. We are tasked with understanding and managing the cultural resources on Park land throughout Fairfax County.
This entry was posted in Archaeology, Artifacts and tagged , , . Bookmark the permalink.

One Response to The Shape of a Point

  1. Pingback: Bifurcated Projectile Points | C.A.R.T. Archaeology

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