🦴 Fossil facts
| Age | Carboniferous to Permian, about 360–250 million years old |
|---|---|
| Origin & sources | Coal measures worldwide, including the Arkansas River Valley, Illinois (Mazon Creek), the UK and Germany. |
| Composition | Ribbed stem casts and impressions in sandstone and shale |
How it forms
Calamites were tree-sized horsetails with jointed, ribbed, hollow stems. Sediment filled the hollow centres and left the familiar ribbed and jointed casts.
🌍 Where it's found
- Type locality
- Notable source / deposit
- Country of origin
Marker positions are approximate (region or locality level). Type localities from Wikidata; notable sources curated by Crystopedia.
Learn more
Fossil
Gray
RootHeart
Healing crystal
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