AN ARCHAEOLOGICAL GUIDE TO CHERT TYPES OF EAST-CENTRAL ILLINOIS

Lenville J. Stelle
and
Thomas P. Duggan



Parkland College
Champaign, Illinois



2003 by the Center For Social Research, Parkland College



CHERT TYPE KEY CHERT INDEX



**Note that the full sized images of the chert specimens are quite large (8X).... Be patient.



REFERENCES CITED



CITING THE GUIDE





Chert is the proper name for the vast majority of raw materials from which the hafted bifaces ("arrowheads") and other stone tools of east-central Illinois were fabricated. In Europe similar appearing material would be referred to as flint. Both are rich in silicon dioxide (SiO2). A modern industrial expression of relatively pure silicon dioxide is window glass. You might want to think of chert as window glass with impurities and a slightly different molecular arrangement.

Many types of chert were exploited by the prehistoric people of the area. This condition likely reflects both the size of their territories and the effects of trade and exchange. The assignment of a particular object to a particular type category is fraught with many difficulties. There is much overlap between type criteria and there is much variation in chert coming from a particular source. What we will try to do in the type key is make use of those qualities of a particular chert that are conspicuous to the unaided eye, distinctive to the chert, and typical of a source. A majority of artifacts should be assignable to a chert type.

The type key is based on five properties of chert: texture, luster, color, fossils, and structural characteristics.

While we don't employ it as a sorting criterion, heat treatment or thermal alteration was a technology applied to several types of chert. The macroscopic effect was to alter color and/or luster. We will provide descriptions of the changes as they are known and appropriate.

A final point of confusion for those of us working in east-central Illinois is that much of the chert being exploited was recovered from glacial deposits. Glacial deposits contain EVERYTHING. Consequently, Glacial Till Chert represents our "Other" or catch-all category. One should probably begin an analysis by reviewing the properties of Glacial Till Chert.

To start the process of identification, click on the "CHERT TYPE KEY" above.

To learn about specific chert types, click on the "CHERT INDEX" above.