Four Archimedes Screw Bryozoan Fossils - Illinois

Here are four nice examples of Archimedes collected from the Warsaw Formation of Illinois. This unusual cork-screw shaped bryozoan commonly referred to as an "Archimedes Screw" is unique to the Mississippian-aged rocks of North America.

It comes with an acrylic display stand.

Bryozoans are microscopic aquatic invertebrates that live in colonies, forming skeletal structures similar to corals. Each skeletal structure has a form unique to each particular species. The individual byrozoans forming these colonies are filter feeders called zooids, straining nutrients from the surrounding water.

SPECIES

Archimedes sp.

AGE

Mississippian