skos:altLabel | - Marcellus
- Devonian Marcellus Shale
- Marcellus Group
- Marcellus Shale
- Marcellus Shale Formations
- Marcellus Shale formation
- Marcellus Shale formations
- Marcellus plays
- Marcellus shale
- Tioga Ash Bed
- Marcellus Formation#Drilling and environmental issues
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