Figure 2 in Caecidae (Mollusca: Gastropoda) from late Miocene exposures of the "Imperial" Formation in Riverside County, California

Figure 2. Correlation chart of the stratigraphic sections including the "Imperial" Formation s.l. from west to east, at Lion Canyon, Super Creek, Garnet Hill, and the Imperial Formation s.s. in the Indio Hills, Riverside County, and in Imperial and San Diego counties from Split Mountain Gorge/Vallecito area, and the Coyote Mountains. Note the age difference between the "Imperial" Formation in Riverside County (exception for the Indio Hills) and the Imperial Formation in Imperial and San Diego counties. The Imperial Formation in the Indio Hills correlates with the type exposures in Imperial and San Diego counties. The ages of all boundaries are approximate. Numbers represent numerical age determinations: 1) Matti et al., 1985 (6.04±0.18 Ma and 5.94±0.18 Ma); 2) Peterson, 1975 (about 10 Ma); 3) Rymer et al., 1994, 1995 (between 8 and 7.6 Ma); 4) McNabb et al. 2017 (3.0-2.6 Ma); 5) Ruisaard 1979 (24.8 to about 15 Ma). Abbreviations: cong. = conglomerate; fm=formation; lac beds = unnamed lacustrine beds; ss = sandstone. In part after McDougall (2008).