“…The Gibson Jack is assigned to the Lower Cambrian on the basis of its possible correlation with the OleneUus-bearing beds. Lithologic equivalents of the Gibson Jack Formation are not known to be present elsewhere, unless part of the Gibson Jack is the lithogenetic equivalent of the Pioche Shale, as suggested by Maxey (1958, p. 649), and of the Lower Cambrian Cabin Shale and Busby Quartzite of northwestern Utah (Nolan, 1935;Staatz and Carr, 1964).…”