James St. John:
Erionite siltstone with gaylussite crystal casts (Green Beds, Upper Pleistocene, 40 ka; southeastern shoreline of Lake Magadi, Kenya, East African Rift Valley)
James St. John:
Lepidodendron fossil branch in ferruginous siltstone (lower Pottsville Group, Lower Pennsylvanian; Irish Ridge East Outcrop, near Trinway, Ohio, USA)
James St. John:
Siltstone
James St. John:
Carbonaceous siltstone (Price Formation, Lower Mississippian; Cloyds Mountain roadcut, Valley Coalfield, Virginia, USA)
James St. John:
Tidalites (Mansfield Formation, Lower Pennsylvanian; southern Indiana, USA) 1
James St. John:
Tidalites (Mansfield Formation, Lower Pennsylvanian; southern Indiana, USA) 2
James St. John:
Trace fossils in siltstone (Hinton Formation or Bluefield Formation, Upper Mississippian; Oakvale School outcrop - Rt. 112 roadcut, Oakvale, West Virginia, USA) 1
James St. John:
Trace fossils in siltstone (Hinton Formation or Bluefield Formation, Upper Mississippian; Oakvale School outcrop - Rt. 112 roadcut, Oakvale, West Virginia, USA) 2
James St. John:
Trace fossils in siltstone (Hinton Formation or Bluefield Formation, Upper Mississippian; Oakvale School outcrop - Rt. 112 roadcut, Oakvale, West Virginia, USA) 3
James St. John:
Trace fossils in siltstone (Hinton Formation or Bluefield Formation, Upper Mississippian; Oakvale School outcrop - Rt. 112 roadcut, Oakvale, West Virginia, USA) 4
James St. John:
Carbonaceous siltstone (Nonesuch Formation, Precambrian; Keweenaw Peninsula, Upper Peninsula of Michigan, USA)
James St. John:
Cowbell Member over Nancy Member (Borden Formation, Lower Mississippian; Portsmouth Bypass roadcut, Ohio, USA) 1
James St. John:
Cowbell Member over Nancy Member (Borden Formation, Lower Mississippian; Portsmouth Bypass roadcut, Ohio, USA) 2
James St. John:
Cowbell Member over Nancy Member (Borden Formation, Lower Mississippian; Portsmouth Bypass roadcut, Ohio, USA) 3
James St. John:
Cowbell Member over Nancy Member (Borden Formation, Lower Mississippian; Portsmouth Bypass roadcut, Ohio, USA) 4
James St. John:
Cowbell Member over Nancy Member (Borden Formation, Lower Mississippian; Portsmouth Bypass roadcut, Ohio, USA) 5
James St. John:
Cowbell Member over Nancy Member (Borden Formation, Lower Mississippian; Portsmouth Bypass roadcut, Ohio, USA) 6
James St. John:
Pseudotrilobite (differentially weathered/eroded siltstone) (Licking River gravel bar, Licking County, Ohio, USA)
James St. John:
Differentially eroded siltstone (gravel bar clast, Licking River, near Black Hand Gorge, Licking County, Ohio, USA)
James St. John:
Siltstone (Bedford Shale, Upper Devonian; Rocky Fork, Gahanna, Ohio, USA) 1
James St. John:
Siltstone (Bedford Shale, Upper Devonian; Rocky Fork, Gahanna, Ohio, USA) 2
James St. John:
Siltstone (Corry Formation, Upper Devonian; Tionesta Creek, Forest County, Pennsylvania, USA)
James St. John:
Siltstone (Raccoon Shale Member, Cuyahoga Formation, Lower Mississippian; outcrop along the South Fork of the Licking River, Heath, Ohio, USA) 1
James St. John:
Siltstone (Raccoon Shale Member, Cuyahoga Formation, Lower Mississippian; outcrop along the South Fork of the Licking River, Heath, Ohio, USA) 2