Pennsylvanian - About 323–299 million years ago
Ancient wetlands lay the groundwork for Preston’s coal
Vegetation accumulated in waterlogged wetlands across the region during Pennsylvanian time. Some plant material survived decay as peat. Later, heat and pressure from burial transformed peat into coal. Repeated changes in the landscape left coal seams among layers of other sedimentary rocks. Those deposits, including the Upper Freeport coal in Preston County, would eventually become part of the county’s mining history.
Research status
This entry has been checked against its named source.
The timeline wording accurately reflects the source listed below. This status does not necessarily mean the event has been independently corroborated against additional records.
Sources and further reading
Where this entry comes from
WVGES: Historical Geology of West Virginia — sedimentation and coal-forming environments; see date caveat in Research Notes
Geological descriptions reviewed by Dr. Joe Lebold, West Virginia University.
Research notes
What the evidence establishes
The interval describes the accumulation of coal-forming material, not a single moment of completed coalification. Upper Freeport is one example among the county’s coal beds.
Regional plant research is not a Preston County fossil inventory. The historical resource assessment is not a current reserve estimate.
Numerical boundaries follow the ICS June 2026 chart. WVGES’s older overview contains outdated numerical dates; it is used for depositional processes, not those dates.
Modern place names locate the evidence; they do not imply that present-day communities or county boundaries existed at the time.
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