is a small animal of unknown origin that is often classified with molluscs
or even as marine worms
with a hard body. The genus Tentaculites
was named in 1820 by von Schlotheim. This particular species was named in the late 1960's and is known from the Upper Ordovician
rocks of the Maquoketa Group
. It ranged from Oswego, IL (Kendall County) to possibly Kankakee River State Park
(KRSP) in Will County, Illinois. At KRSP it appears in the basal Silurian of the Kankakee Formation but has not been found in the underlying Ordovician rocks.
This particular species is approximately 0.75 to 1.25 inches in length. In Oswego, Illinois it is found mostly in clusters at Waubonsie Creek in the Basal Brainard Formation, just west of the railroad tracks. This entire class of animal became extinct at the end of the Devonian and leaves no known descendants or related species.
This is a sample of a bound grainstone with abundant invertebrate marine fossil debris from Waubonsie Creek.
1996, P.V. Rich & T.H. Rich, The Fossil Book, A Record of Prehistoric Life, p.184-185