PLATE 1. Tesselacauda depressa Ross, 1951 in Revision of the Early Ordovician (late Tremadocian; Stairsian) cheirurid trilobite Tesselacauda Ross, with species from the Great Basin, western USA

PLATE 1. Tesselacauda depressa Ross, 1951, from Section HC5 106.7 m, east side of Hillyard Canyon, and Section FB7 102.1 m, Franklin Basin, both Garden City Formation (upper Tremadocian; Stairsian; Bearriverops loganensis Zone), Bear River Range, Franklin County, southeastern Idaho, USA. 1, 2, 6, 9. Cephalon and thoracic segments, SUI 147507, dorsal, ventral, right lateral, and anterior views, x7.5 (FB7 102.1 m). 3–5, 10. Thoracic segments and pygidium, SUI 147508, dorsal, dorsal, ventral, posterior, and left lateral views, x7.5 (FB7 102.1 m). 7, 8, 11, 13. Cranidium, SUI 147509, dorsal, dorsal, right lateral, anterior, and ventral views, x10 (HC5 106.7 m). 12, 14, 15. Cranidium and thoracic segment, SUI 147510, dorsal, dorsal, right lateral, and anterior views, x10 (HC5 106.7 m).