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.

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

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