Cambrian Silicified Faunas: Orr Formation
Orr Ridge, western Utah

  • Main Collaborator: Steve Westrop
• Westrop, S.R. & Adrain, J.M. (2009) The late Cambrian (Furongian; Steptoean) trilobite genus Xenocheilos Wilson, 1949: systematics and biostratigraphic significance. Memoirs of the Association of Australasian Palaeontologists, 37, 351-368.

The classic section of the Orr Formation on Orr Ridge, northern House Range, yields excellent silicified faunas in the upper Steptoean and lower Sunwaptan.

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View down Orr Ridge from the lower Sunwaptan sampling localities.
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View to the southwest from Orr Ridge.
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Upper Steptoean silicified samples, Orr Ridge.

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Some of the trilobites from the upper Steptoean at Orr Ridge. From left, Cliffia, Elvinia, and Irvingella.