devonian

Hexagonaria sp. (fossil coral) (Devonian; Lake Michigan shoreline, near Bay View, Michigan, USA) 1
by James St. John

Hexagonaria percarinata (fossil rugose coral) (Traverse Group, Middle Devonian; Michigan, USA) 4
by James St. John

Cone-in-cone limestone bed (interbed in the Ohio Shale, Upper Devonian; Glen Echo Ravine, Columbus, central Ohio, USA)
by James St. John

Mess of Stems
by subarcticmike

Boyle Formation (Middle Devonian; Emmanuel Baptist Church roadcut, Estill County, Kentucky, USA) 3
by James St. John

Columbus Limestone (Middle Devonian) (Hayden Run, Dublin, Ohio, USA) 7
by James St. John

Holonema sp. (fossil fish armor) (Silica Formation, Middle Devonian; quarry northwest of Paulding, Ohio, USA)
by James St. John

Hexagonaria (fossil coral) (Columbus Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 2
by James St. John

Columbus Limestone (Middle Devonian) (Hayden Falls, Dublin, Ohio, USA) 1
by James St. John

Columbus Limestone (Middle Devonian) (Hayden Falls, Dublin, Ohio, USA) 3
by James St. John

Large potassium feldspar & quartz crystals in pegmatitic granite (Ruggles Pegmatite, Devonian; Ruggles Pegmatite Mine, New Hampshire, USA) 2
by James St. John

Striated cone-in-cone limestone (likely an interbed from the Ohio Shale, Upper Devonian; creek bed of an Alum Creek tributary, northern Delaware County, Ohio, USA) 5
by James St. John

Stylolite in limestone (Columbus Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 3
by James St. John

Pyrite (Delaware Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 2
by James St. John

Columbus Limestone (Middle Devonian) (Hayden Run, Dublin, Ohio, USA) 5
by James St. John

Weathered, oxidized pyrite (Columbus Limestone or Delaware Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 3
by James St. John

Macropetalichthys rapheidolabis (fossil fish) (Columbus Limestone, Middle Devonian; Seneca Caverns, Ohio, USA) 12
by James St. John

Devonian Harbour Park
by colink.

Model of Dunkleosteus terrelli (fossil placoderm) (Late Devonian; Cleveland, Ohio, USA) 4
by James St. John

Fossil brachiopod in limestone (Columbus Limestone, Middle Devonian; Quarry Trails Park, Columbus, Ohio, USA) 2
by James St. John

Protitanichthys sp. (fossil fish armor) (Silica Formation, Middle Devonian; quarry northwest of Paulding, Ohio, USA) 1
by James St. John

Fossiliferous limestone (Columbus Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 4
by James St. John

Slickenlined fault surface (Roberts Mountain Thrust Fault; near Cortez Gold Mine, Nevada, USA)
by James St. John

Cumberlandite (porphyritic titaniferous magnetite melatroctolite) (ferrogabbro) (Neoproterozoic to Late Devonian, ~620 to ~370 Ma; Iron Mine Hill, east of Woonsocket, Rhode Island, USA)
by James St. John

Hexagonaria percarinata (fossil coral) (Traverse Group, Middle Devonian; Bay View, Michigan, USA)
by James St. John

Corals in fossiliferous limestone (Jeffersonville Limestone, Middle Devonian; Falls of the Ohio, southern Indiana, USA) 6
by James St. John

Kimberlite (Arkhangelskaya Pipe, Late Devonian; Arkhangelsk Region, Russia) 3
by James St. John

Model of Dunkleosteus terrelli (fossil placoderm) (Late Devonian; Cleveland, Ohio, USA) 2
by James St. John

Stylolite in limestone (Columbus Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 10
by James St. John

Quartz-calcite-dolomite vein in New Albany Shale (Upper Devonian; Interstate 65 entrance ramp roadcut, Bullitt County, Kentucky, USA) 3
by James St. John

Impact melt breccia (Alamo Breccia, Upper Devonian; southeastern Neveada, USA) 1
by James St. John

Arthroacantha carpenteri (fossil crinoid) (Silica Shale, Middle Devonian; Sylvania, Ohio, USA) 3
by James St. John

Manlius Formation overhang over Rondout Formation
by Kyle Hartshorn

Diorama of a Devonian seafloor - Terataspis trilobite
by James St. John

Fenite (Late Devonian; Selsurt Mountain, Kola Peninsula, Russia) 3
by James St. John

Glacial grooves on limestone (Kelleys Island, Lake Erie, Ohio, USA) 5
by James St. John

Striated cone-in-cone limestone (likely an interbed from the Ohio Shale, Upper Devonian; creek bed of an Alum Creek tributary, northern Delaware County, Ohio, USA) 4
by James St. John

Karst & Columbus Limestone (Middle Devonian; Indian Village Canyon, Columbus, Ohio, USA) 5
by James St. John

Cycadella sp. (fossil cycad) (Morrison Formation, Upper Jurassic; Freezeout Hills, Wyoming, USA) 5
by James St. John

Model of Dunkleosteus terrelli (fossil placoderm) (Late Devonian; Cleveland, Ohio, USA) 3
by James St. John

Fish bone (Chattanooga Shale, Upper Devonian; Burkesville West Rt. 90 roadcut, Kentucky, USA) 1
by James St. John

Diorama of a Devonian seafloor 11
by James St. John

White fossiliferous chert (Columbus Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 2
by James St. John

Stylolite (Lucas Formation, Middle Devonian; Paulding County, Ohio, USA) 1
by James St. John

Gastropod internal mold (Columbus Limestone, Middle Devonian; abandoned quarry, Kelleys Island, Lake Erie, Ohio, USA) 6
by James St. John

Karst & Columbus Limestone (Middle Devonian; Indian Village Canyon, Columbus, Ohio, USA) 7
by James St. John

Glossopteris fossil seed fern leaves in claystone (Illawarra Coal Measures, Upper Permian; Dunedoo area, New South Wales, Australia)
by James St. John

Elaeacrinus verneuili (fossil blastoid head) (Columbus Limestone, Middle Devonian; Ohio, USA) 3
by James St. John

Brachiopods in fossiliferous limestone (Delaware Limestone, Middle Devonian; Olentangy River at Lazarus Run, Delaware County, Ohio, USA) 2
by James St. John

Partially silicified Hexagonaria (fossil coral) (Columbus Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 6
by James St. John

Muscovite mica & biotite mica derived from pegmatitic granite (Ruggles Pegmatite, Devonian; Ruggles Pegmatite Mine, New Hampshire, USA) 2
by James St. John

Fossiliferous limestone (Columbus Limestone, Middle Devonian; Olentangy River at Lazarus Run confluence, Delaware County, Ohio, USA) 2
by James St. John

Fossiliferous limestone (Columbus Limestone, Middle Devonian; Olentangy River at Lazarus Run confluence, Delaware County, Ohio, USA) 3
by James St. John

Leptaena fossil brachiopod in fossiliferous limestone (Columbus Limestone, Middle Devonian; Ohio, USA) 2
by James St. John

Garnet schist (Waits River Formation, Devonian; Route 9 roadcut between Marlboro & Brattleboro, Vermont, USA) 1
by James St. John

Phacops rana crassituberculata (fossil trilobite) (Silica Formation, Middle Devonian; quarry northwest of Paulding, Ohio, USA) 13
by James St. John

Gummite (Ruggles Mine, Grafton Center, New Hampshire, USA) 1
by James St. John

Striated cone-in-cone limestone (likely an interbed from the Ohio Shale, Upper Devonian; creek bed of an Alum Creek tributary, northern Delaware County, Ohio, USA) 1
by James St. John

Platyceras dumosum (fossil gastropod) (Columbus Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 1
by James St. John

Dunkleosteus terrelli (fossil fish) (Cleveland Shale Member, Ohio Shale, Upper Devonian; Rocky River Valley, Cleveland, Ohio, USA) 31
by James St. John