Wikimedi'Òc

Ironstone concretion (lower Pottsville Group, Lower Pennsylvanian; Pleasant Valley Limestone Quarry, Muskingum County, Ohio, USA) 1 (30226085737).jpg - Ser Amantio di Nicolao

Ironstone concretion (Lower Mercer Ore, Middle Pennsylvanian; Rt. 16 roadcut near Trinway, Ohio, USA) 2 (38438091796).jpg - Ser Amantio di Nicolao

Ironstone concretion (Lower Mercer Ore, Middle Pennsylvanian; Rt. 16 roadcut near Trinway, Ohio, USA) 5 (26718140809).jpg - Ser Amantio di Nicolao