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Sagawau Canyon Nature Preserve Interreef Outcrops

Image of Sagawau Canyon at the Cook County Forest Preserve taken in summer of 2014 by Eric Ma. Rock wall shows thin bedded Silurian dolomite typical of inter reef deposits.
Image of Sagawau Canyon at the Cook County Forest Preserve taken in summer of 2014 by Eric Ma. Rock wall shows thin bedded Silurian dolomite typical of inter reef deposits.

In southwest Cook County near Lemont, Sagawau Canyon exposes Silurian Racine Formation dolomite in Cook County's only natural canyon. The thin bedded dolomite was deposited between reefs and a level bottom marine community dwelled here including crinoids and corals, while cephalopods jetted through tthe waters above.

Photo Gallery

Image of Silurian cephalopod at Sagawau Quarry at the Cook County Forest Preserve taken in Fall of 2014 by Paul Mayer. Fossil is a Silurian orthoconic nautiloid cephalopod on beding plane surface of an interreef deposit. Quarter and size 12 boot for scale and size.
© The Field Museum - CC BY-NC
Image of Silurian cephalopod at Sagawau Quarry at the Cook County Forest Preserve taken in Fall of 2014 by Paul Mayer. Fossil is a curved Silurian cephalopod on beeding plane surface of an Interreef deposit. Quarter for scale.
© The Field Museum - CC BY-NC
Image of Sagawau Canyon at the Cook County Forest Preserve taken in summer of 2014 by Eric Ma. Rock wall shows thin bedded Silurian dolomite typical of inter reef deposits.
© The Field Museum - CC BY-NC

Sites

  • North America, USA, Illinois, Cook, Sagawau Canyon Nature Preserve southwest Cook County near Lemont. [LL]