"O . clarki " is found in Upper " Olenellus "-zone of California ( Bristol Mountain, near Cadiz, on the Santa F?Railroad, 100 miles East of Barstow, Mohave Desert, probably Latham Shale; Latham Shale treated as the " Bristolia "-zonule Marble Mountains, ?mile East of Cadiz, In California also from the Carrara Formation, Funeral Mountains, Resting Spring Range, Eagle mountain, Grapevine Mountains, Salt Spring Hills ); and in Nevada ( Nevada Test Site, Desert Range ).
