silicified

Fossiliferous limestone (Columbus Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 7
by James St. John

Mookaite (Windalia Radiolarite Formation, Lower Cretaceous; Western Australia) 29
by James St. John

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

Quartz sandstone pebble in conglomerate ("Sharon" Conglomerate, Lower Pennsylvanian; Jackson North roadcut, Ohio, USA) 1
by James St. John

Brachiopod fossil (Ashlock Formation, Upper Ordovician; Paint Lick Elementary School outcrop, Garrard County, Kentucky, USA) 4
by James St. John

Coral in fossiliferous limestone (Jeffersonville Limestone, Middle Devonian; Falls of the Ohio, southern Indiana, USA) 29
by James St. John

Chertified fossiliferous oolitic limestone boulder in conglomerate ("Sharon Conglomerate", Lower Pennsylvanian; Jackson North roadcut, Ohio, USA) 1
by James St. John

Agatized coral (Tertiary; Withlacoochee River, Georgia, USA) 16
by James St. John

Fossil rugose coral in limestone (Girkin Limestone, Upper Mississippian; Dixon Cave Trail, Mammoth Cave, Kentucky, USA) 7
by James St. John

Paraspirifer bownockeri (pyritized fossil brachiopod) (Silica Formation, Middle Devonian; quarry in Lucas County, Ohio, USA) 7
by James St. John

Paraspirifer bownockeri (pyritized fossil brachiopod) (Silica Formation, Middle Devonian; quarry in Lucas County, Ohio, USA) 8
by James St. John

Fossiliferous dolostone (Rockford Limestone, Lower Mississippian; Burkesville West Rt. 90 roadcut, Kentucky, USA) 11
by James St. John

Columbus Limestone (Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 18
by James St. John

Paraspirifer bownockeri (pyritized fossil brachiopod) (Silica Formation, Middle Devonian; quarry in Lucas County, Ohio, USA) 9
by James St. John

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

Columbus Limestone-Delaware Limestone contact (Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 1
by James St. John

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

Leptaena fossil brachiopod in fossiliferous limestone (Columbus Limestone, Middle Devonian; Ohio, USA) 1
by James St. John

Brachiopods in fossiliferous limestone (Jeffersonville Limestone, Middle Devonian; Falls of the Ohio, southern Indiana, USA) 16
by James St. John

Quartz-permineralized fossil wood 37
by James St. John

Fossiliferous limestone (Columbus Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 9
by James St. John

Delaware Limestone over Columbus Limestone (Middle Devonian; Indian Village Canyon, Columbus, Ohio, USA) 1
by James St. John

Hot Creek (Long Valley Caldera, California, USA) 20
by James St. John

Orthid brachiopod in limestone (Ashlock Formation, Upper Ordovician; Route 52 roadcut, near Point Leavell, Kentucky, USA) 1
by James St. John

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

Delaware Limestone over Columbus Limestone (Middle Devonian; Indian Village Canyon, Columbus, Ohio, USA) 3
by James St. John

Paraspirifer bownockeri (pyritized fossil brachiopod) (Silica Formation, Middle Devonian; quarry in Lucas County, Ohio, USA) 10
by James St. John

Rockford Limestone over Maury Shale (Lower Mississippian; Burkesville West Rt. 90 roadcut, Kentucky, USA) 3
by James St. John

Weathered-out gray quartzite pebble from conglomerate ("Sharon Conglomerate", Lower Pennsylvanian; Jackson North roadcut, Ohio, USA) 2
by James St. John

Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 16
by James St. John

Fossiliferous limestone (Columbus Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 6
by James St. John

Corals in fossiliferous limestone (Jeffersonville Limestone, Middle Devonian; Falls of the Ohio, southern Indiana, USA) 4
by James St. John

Cone-in-cone limestone (likely an interbed from the Ohio Shale, Upper Devonian; Alum Creek Lake area, Delaware County, Ohio, USA) 6
by James St. John

Mookaite (Windalia Radiolarite Formation, Lower Cretaceous; Western Australia) 9
by James St. John

Coral in fossiliferous limestone (Jeffersonville Limestone, Middle Devonian; Falls of the Ohio, southern Indiana, USA) 24
by James St. John

Sandstone & conglomerate ("Sharon" Conglomerate, Lower Pennsylvanian; Jackson North roadcut, Ohio, USA) 10
by James St. John

Cone-in-cone limestone (likely an interbed from the Ohio Shale, Upper Devonian; Alum Creek Lake area, Delaware County, Ohio, USA) 8
by James St. John

Favositid coral in fossiliferous limestone (Columbus Limestone, Middle Devonian; Olentangy Indian Caverns, central Ohio, USA) 2
by James St. John

Coral in fossiliferous limestone (Jeffersonville Limestone, Middle Devonian; Falls of the Ohio, southern Indiana, USA) 22
by James St. John

Solitary rugose corals (Marblehead Member, Columbus Limestone, Middle Devonian; lakehore outcrop near Marblehead Lighthouse, Ottawa County, Ohio, USA) 15
by James St. John

Cone-in-cone limestone interbed in shales (Ohio Shale, Upper Devonian; Glen Echo Ravine, Columbus, Ohio, USA) 3
by James St. John

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

Fossiliferous limestone (Columbus Limestone, Middle Devonian; Melvin Stone Quarry, near Williamsport, Pickaway County, Ohio, USA) 6
by James St. John

Mookaite (Windalia Radiolarite Formation, Lower Cretaceous; Western Australia) 16
by James St. John

Cone-in-cone limestone 3
by James St. John

Columbus Limestone (Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 19
by James St. John

Columbus Limestone-Delaware Limestone boundary bed (Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 3
by James St. John

Fossiliferous limestone (Columbus Limestone, Middle Devonian; Emerald Parkway roadcut, Dublin, Ohio, USA) 16
by James St. John

Favositid coral in fossiliferous limestone (Columbus Limestone, Middle Devonian; Olentangy Indian Caverns, central Ohio, USA) 3
by James St. John

Coral in fossiliferous limestone (Jeffersonville Limestone, Middle Devonian; Falls of the Ohio, southern Indiana, USA) 19
by James St. John

Coral in fossiliferous limestone (Jeffersonville Limestone, Middle Devonian; Falls of the Ohio, southern Indiana, USA) 21
by James St. John

Cone-in-cone limestone (likely an interbed from the Ohio Shale, Upper Devonian; Alum Creek Lake area, Delaware County, Ohio, USA) 7
by James St. John

Mudshale clasts in quartz-pebble conglomerate ("Sharon Conglomerate", Lower Pennsylvanian; Jackson North roadcut, Ohio, USA) 60
by James St. John

Fossiliferous limestone (Columbus Limestone; Middle Devonian; Ohio, USA) 8
by James St. John

Mudshale clast in quartz-pebble conglomerate ("Sharon Conglomerate", Lower Pennsylvanian; Jackson North roadcut, Ohio, USA) 55
by James St. John

Oolitic limestone pebble in ferruginous quartz-pebble conglomerate (boulder in "Sharon Conglomerate", Lower Pennsylvanian; Jackson North roadcut, Ohio, USA) 3
by James St. John

Weathered-out gray quartzite pebble from conglomerate ("Sharon Conglomerate", Lower Pennsylvanian; Jackson North roadcut, Ohio, USA) 1
by James St. John

Fossil gastropod in limestone (Columbus Limestone, Middle Devonian; Quarry Trails Park, Columbus, Ohio, USA) 1
by James St. John

Ferruginous quartz-pebble & lithic conglomerate (derived from boulder in "Sharon Conglomerate", Lower Pennsylvanian; Jackson North roadcut, Ohio, USA) 28
by James St. John

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