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Anchor text: Carboniferous (Chronostratography scale)

Wikipedia: Carboniferous

Anchor text: Cretaceous (chronostratigraphy scale)

Wikipedia: Cretaceous

Anchor text: Cenozoic (chronostratigraphy scale)

Wikipedia: Cenozoic

Wikipedia: Devonian

Anchor text: Chronostratigraphy benchmarks

Wikipedia: Geology

Anchor text: ghK Classification

Wikipedia: Holocene

Anchor text: Jurassic (chronostratigraphy scale)

Wikipedia: Jurassic

Anchor text: Mesozoic (chronostratigraphy scale)

Wikipedia: Mesozoic

Anchor text: Neoproterozoic (chronostratigraphy scale)

Wikipedia: Neoproterozoic

Anchor text: Ordovician (chronostratigraphy scale)

Wikipedia: Ordovician