Where is Fossilized Coral found?
Rugose Coral (Horn Coral) fossil in chert or limestone
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Open the appFossilized Coral 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 Fossilized Coral
Michigan, USA
Famous for 'Petoskey Stones,' which are silicified Hexagonaria percarinata (a colonial rugose coral) found in Devonian limestones (e.g., Traverse Group) and glacial till. These are often found along the shores of Lake Michigan and Lake Huron.
Indiana, USA
Numerous rugose coral fossils are found in Devonian and Mississippian limestones and shales, particularly in the Falls of the Ohio State Park area.
Kentucky, USA
Similar to Indiana, rich in Devonian and Mississippian marine fossil beds containing abundant rugose corals.
Ohio, USA
Devonian limestones and shales yield various rugose coral fossils.
New York, USA
Silurian and Devonian marine strata contain diverse rugose coral faunas.
United Kingdom
Carboniferous limestones across the UK (e.g., Derbyshire, Yorkshire) are well-known for their rugose coral fossils.
Australia
Devonian and Carboniferous marine sequences in various states contain significant rugose coral occurrences.
Canada
Devonian and Silurian strata, particularly in Ontario and Western Canada, are known for rugose coral fossils.
Collecting tips
- Look in Sedimentary Rocks. Focus your search on outcrops of ancient marine limestones, shales, and chert beds. Riverbeds, road cuts, quarries, and coastal exposures are good places to start.
- Identify Coral Morphology. Learn to recognize the characteristic horn-shape, radial septa, and concentric growth lines of rugose corals. Silicified specimens often show these features in high relief.
- Check for Contrast. Fossils often stand out from the surrounding matrix due to differences in color, texture, or weathering patterns. Look for distinct patterns or shapes that don't conform to the general rock fabric.
- Wet the Rock. Wetting the surface of the rock can often enhance the visibility of fossil structures, especially in chert, by increasing the contrast and revealing subtle patterns.
- Safety First. Always obtain permission before collecting on private land. When collecting in quarries or road cuts, be aware of unstable rock and traffic. Wear appropriate safety gear, including eye protection and sturdy footwear.
Quick Check
- Color:
- Variable (matrix dependent), often contrasting with matrix
- Luster:
- Dull to waxy (chert), earthy (limestone), waxy to vitreous (polished silicified coral)
- Streak:
- White (for both chert and limestone)
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