• Argillite's class is sedimentary rock therefore it is created from the cementing of clasts

• It is a durable material, but it is extremely soft

Various argillite Indian artifacts from a variety of locations in Central Jersey. Photo by Jim Wade

Because the material occurs naturally in the Delaware Vally, it can be found in the mountains rivers, and streams of southern New Jersey and dispersed in the central region. There are also large deposits of the material found in more northern regions of the state as well such as Hunterdon County. It is found so abundantly in New Jersey that many indigenous communities of the area chose to make many of their projectile points and tools out of the material. There are several shales, compressed sedimentary rock from clay, that can be found adjacent to the Delaware River near Trenton that formed during the Mesozoic era (225-65 million years ago). Sometimes indigenous communities would create “pre-forms” or “blanks” to be used in trade. These were partially completed tools and projectile points to be later completed by their owner.