Sedimentary/Metamorphic

Fossiliferous Shale or Slate with Plant Fossils

Fossil-bearing argillaceous rock

Dark gray to black color, fine-grained, smooth texture where unfractured. Hardness varies depending on whether it is shale (softer, ~3) or slate (harder, ~3-4). Contains lighter-colored, elongated, striated impressions which are fossilized plant remains (likely calamites or similar Carboniferous flora).

Identified May 31, 2026More sedimentary/metamorphic →

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Physical properties

Formation & geological history

Formed from compacted mud and clay in low-energy environments such as swamps, lakes, or deep marine basins. The fossils suggest a terrestrial or near-shore swampy environment, typical of the Carboniferous period (approx. 300-350 million years ago) during coal-forming eras.

Uses & applications

Often collected for educational or paleontological purposes. Slate can be used in construction (roofing, flooring), but heavily fossilized sections are generally kept as collector pieces or museum displays.

Geological facts

The fossils visible appear to be sections of ancient plant stems or wood, possibly Calamites (an extinct giant horsetail), which grew in vast swamp forests that eventually formed modern coal deposits.

Field identification & locations

Identify by the dark, fine-grained matrix with distinct, often lighter-colored or carbonized impressions of flora. Commonly found in coal-bearing regions or sedimentary basins worldwide. When collecting, care should be taken as the rock can be brittle and flake along bedding planes.

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