Trilobites Figured From United States Geological Survey Professional Paper 1047, Physical Stratigraphy and Trilobite Biostratigraphy of the Carrara Formation (Lower and Middle Cambrian) in the Southern Great Basin, by Allison R. Palmer and Robert B. Halley

Trilobites from the Lower-Middle Cambrian Carrara Formation, Death Valley National Park. All specimens are from Plate 7, and greatly magnified. Middle Cambrian Albertella zone. Figures 8-10, Syspacephalus obscurus from the Grapevine Mountains. Figure 8, top view of holotype cranidium; Figure 9, "small cranidium showing dorsal furrows moderately well developed;" Figure 10, "cranidium--variant with unusually well developed globellar furrows."