Ordovician

Blackriverian

Bromide Formation, Poolville Member, Criner Hills,

Carter Co, OK, USA

Excellent 0.7 inch cystoid

Cystoid,

Quadrocystis is a genus of cystoid known only from the Ordovician of Oklahoma.  Cystoids belong to an extinct order of echinoderms from the Ordovician to Devonian Periods.  Similar to crinoids, they had somewhat rounded, plated bodies attached to a stalk that was anchored to the sea bottom.

This species was named in honor of the late Allen Graffham, a paleontologist who ran Geological Enterprises, a well-known fossil and natural history item business.