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Stratigraphic Layers

Bed-by-bed descriptions of every section that has stratigraphic data.

#1 Zinzilban Section — GSSP

Lower Devonian · 416.0–397.0 Ma

  1. 0.0–12.5 m

    Massive grey limestone with stromatoporoid biostromes; uppermost Pragian.

  2. 12.5–18.0 m

    Crinoidal grainstones with abundant brachiopod debris — Pragian–Emsian boundary interval.

  3. 18.0–31.7 m

    Dark argillaceous limestone yielding Polygnathus dehiscens — formal GSSP marker bed.

  4. 31.7–55.0 m

    Bedded limestone with chert nodules; basal Emsian.