Wikimedi'Òc

Bulletin of the Geological Society of America (1923) (14778711541).jpg - SteinsplitterBot

NPS shenandoah-geologic-map.jpg - RKBot

NPS valley-forge-geologic-map.jpg - RKBot

Bulletin 799 Plate 8A Harpers Schist.jpg - Jstuby

Bulletin 799 Plate 2A Harpers Schist photomicrograph.jpg - Jstuby

Quartzite (Harpers Formation, Lower Cambrian; Verona, Virginia, USA).jpg - Ser Amantio di Nicolao

Harpers phyllite over Ledger dolomite Sgw01319.jpg - Jstuby

Harpers Phyllite Pottery Hill outcrop 2022.jpg - Jstuby