Aganaster gregarius
From the collection of Yale Peabody Museum. Free to download, adapt and use — no permission needed.
Geological context: Early Mississippian, Edwardsville Fm. Collection locality: quarry at Corey's Bluff on Sugar Creek, near Crawfordsville, Montgomery County, Indiana, USA. Collected by Richard Jones, Doris Jones. IP number 527910; lot count 1; institutional specimen number 520; institutional specimen number MPRI 0520; accn=YPM.12060; associatedwith=on same slab: IP.237219,on same slab: IP.237220,on same slab: IP.527899,on same slab: IP.527900,on same slab: IP.527901,on same slab: IP.527902,on same slab: IP.527903,on same slab: IP.527904,on same slab: IP.527905,on same slab: IP.527906,on same slab: IP.527907,on same slab: IP.527908,on same slab: IP.527909,on same slab: IP.527911.
Yale Peabody Museum’s own description