INVITED POSTER: The Orocopia Schist is a latest Cretaceous low-angle subduction channel, part of a larger subduction complex, the Pelona-Orocopia-Rand Schist (PORS), that underlies much of southern California and southwest Arizona (Fig. 1; Jacobson et al. 1988, 2007, 2011; Haxel et al. 2002; Chapman 2016). The principal locus of Orocopia Schist, the Chocolate Mountains anticlinorium extending from the Orocopia Mountains east to Neversweat Ridge, has been known since the mid 1970s (Haxel and Dillon 1978). Recently, two more exposures of the oceanic Orocopia Schist have been found at isolated localities farther inland in southwest Arizona: Cemetery Ridge (Haxel et al. 2015, 2018b, 2021; Jacobson et al. 2017) and northern Plomosa Mountains (Strickland et al. 2017, 2018; Seymour et al. 2018). These discoveries raise the possibility that additional inboard areas of Orocopia Schist have yet to be found. Hence a review of criteria for recognition of Orocopia Schist is warranted.