Avon Chert
AKA: Avon Valley Porcellanite
Description of Physical Characteristics:
Color: Avon
Chert is mottled and ranges from porcelain white to light brown or light
gray with brown chalcedony inclusions.
Texture: Medium to fine grain
Luster: Dull to porcellaneous
Silica Fabrics / Fossils:
Patina: Chalky white
Heat Treatment:
Knapping:
Notes: Though this is referred to as chert,
it is silicified freshwater marl (mixture of calcite and clay occurring
in nearly equal amounts) or porcellanite (mixture of silica and clay
with some calcite present).
Primary Source
Distribution:
Distribution Comments:
Named for outcroppings in Avon Valley, Montana, it is found throughout
Northwestern Montana into the southern Canadian Rocky Mountains.
Primary outcroppings occur on the western Slope of the Rocky Mountains
west of Helena, Montana and the northeastern edge and southwestern edge
of Antelope Hill. Outcroppings also occur at Rhine Hill. This is an exotic material.
Projectile point made from this material:
Pictures Provided By:
References: (See Reference Page, Entry Number):
Archaeological Context:
Commonly found in Late Middle Prehistoric period (3,500 to 1,800 B.P.).
However, it was not extensively used outside the source areas.
