Agaricocrinus americanus Lepidesthes wortheni (Echinoid) CRINOID, Echinoid and Gastropod Mississippian Edwardsville Fm. Montgomery Co., Indiana Size: 5.2 cm crinoid crown plus long stem. Echinoid averages 3.5 cm. There is an additional unknown crinoid next to the echinoid. Echinoids from this formation are extremely rare. Price: $250 US ID number: f2234