Where is Fossiliferous Shale found?
Shale with plant fossil impressions
Got a photo? Identify rocks instantly with the Rockby app
Open the appFossiliferous Shale occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Fossiliferous Shale
Mazon Creek, Illinois, USA
World-renowned for exceptionally preserved Carboniferous plant fossils (and invertebrates) within ironstone concretions found in the Francis Creek Shale.
Green River Formation, Wyoming, Utah, Colorado, USA
Famous for Eocene lake deposits with abundant and exquisitely preserved plant fossils, fish, and insects in finely laminated shales.
Joggins Fossil Cliffs, Nova Scotia, Canada
A UNESCO World Heritage Site with extensive Carboniferous coal-bearing strata containing upright fossil trees and abundant plant impressions in shales and sandstones.
Rhynie Chert, Scotland, UK
While primarily chert, associated shales and mudstones in the Devonian Rhynie Chert preserve early land plants with cellular detail.
Various Coal Basins Worldwide
Coal-bearing sequences from the Carboniferous, Permian, and other periods often contain fossiliferous shales in close association with coal seams, preserving the flora that contributed to coal formation (e.g., Appalachian Basin, Ruhr Basin, Sydney Basin).
Collecting tips
- Look for Outcrops in Sedimentary Basins. Focus on areas known for sedimentary rock exposures, particularly those associated with ancient lake beds, swamps, or marine shelf environments. Road cuts, river banks, and coastal cliffs are good places to start.
- Identify Fissility and Fine Grain Size. Shale will split into thin layers. Look for very fine-grained rocks that feel smooth to the touch. The presence of dark coloration often indicates organic matter.
- Examine Broken Surfaces Carefully. Plant fossils are often revealed on the bedding planes when the shale is split. Look for distinct patterns, textures, or color variations that suggest organic remains.
- Use a Hand Lens. A hand lens (10x magnification) can help to discern fine details of plant impressions or small fossil fragments that might be missed by the naked eye.
- Check for Associated Sediments. Fossiliferous shales are often found interbedded with siltstones, sandstones, limestones, or coal seams. The presence of these associated rocks can indicate a favorable depositional environment for plant preservation.
- Consult Geological Maps and Paleontological Guides. These resources can pinpoint specific formations or localities known for plant fossils, increasing your chances of a successful find.
Quick Check
- Color:
- Dark gray, black, brown, or greenish-gray
- Luster:
- Dull to earthy
- Streak:
- White, gray, or brownish-gray (depending on clay and organic content)
Explore Fossiliferous Shale
Identify rocks anywhere
Free on iOS, Android, and Web. Photo identification, full database, and your personal collection.