Globulocystites levatus
Cystoid
Ordovician (Blackriverian)
Bromide Formation – Mountain Lake Member
Johnston County, Oklahoma, USA

33mm on small 49mm piece of matrix.

Echinoderm.

Globulocystites is a genus of cystoid that lived during the Ordovician Period. Its remains have been found in Oklahoma and Kentucky.

Interesting piece still on matrix.

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.