Mill Creek chert

Mill Creek chert is a type of chert found in Southern Illinois and heavily exploited by members of the Mississippian culture (800 to 1600 CE).Artifacts made from this material are found in archaeological sites throughout the American Midwest and Southeast. It is named for a village and stream near the quarries, Mill Creek, Illinois and Mill Creek, a tributary of the Cache River. The chert was used extensively for the production of utilitarian tools such as hoes and spades, and for polished ceremonial objects such as bifaces, spatulate celts and maces.

Chert is a siliceous (silica) stone, a variety of quartz similar to flint but more brittle. It naturally occurs as large, flat, elliptically shaped nodules in creek beds, and sometimes as hill-top residuum. The nodules were formed as part of the Ullin limestone formation during the Mississippian geologic period (roughly 359 to 318 million years ago). Mill Creek Chert is a tough, coarse-grained chert, usually brown or gray in color, and occurs as large tabular shaped nodules, a shape used by members of the Mississippian culture for the manufacture of broad bifaces such as hoes, spades, and ceremonial maces and spuds. At the turn of the twentieth century archaeologists began realizing that in the hilly lands of Southern Illinois was the location for the quarrying and production centers, one of the greatest in prehistoric North America for this type of stone. The sites were located near Mill Creek, Illinois, a village in Union County, located between Jonesboro and Cairo on the Alexander County line. From this collection of sites, known colloquially as the "Indian Diggings", Native Americans quarried, worked into tools and blanks, and exported this stone to the wider Mississippian world. The chert found here was one of the major exported raw materials of the Mississippian culture and its distribution and procurement was one of the largest mining and production efforts organized during the Mississippian period. The raw material was dug up in the quarries and then transported to small hamlets for production in hoes, spades and blanks. Archaeologists believe they were then transported to and traded at regional mound centers such as the Hale Site, a palisaded village with a platform mound and a burial mound. From these local sites they were then transported and traded at sites even further afield. These materials were some of the most widely exchanged items during this period, with especially large amounts transported to the American Bottom region. Examples are numerous at Cahokia, where it was especially prized for hoes and spades, but finds have been made in locations as distant as Spiro and Moundville.

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