FIGURE 1 in The Lower Ordovician (upper Floian) bathyurid trilobite Aponileus Hu, with species from Utah, Texas, and Greenland 3293

FIGURE 1. Schematic diagram of stratigraphic distribution of species of Aponileus and the outgroup species Strigigenalis plicolabeona (Young) in Blackhillsian (upper Floian) sections of the Fillmore Formation in western Utah. Measurements are in metres. Meterages are not to scale. Zonation is that established by Adrain et al. (2009), with new informal subdivisions of the "Pseudocybele nasuta Zone" discussed in text.