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fine-grained materials from a thin (<50m thick) portion of the Pekin Formation (Trp as mapped by Reinemund, 1955). As part of the operation large (~1–5+m maximum dimension) boulders consisting primarily of crossbedded sandstone, silt- stone, and conglomerate are pushed out of the way and left to weather (the softer, fine-grained sediments are mined immedi- ately). All of the fossils reported here, and most fossils recovered from this quarry, including dicynodonts (Green et al., 2005; Green, 2012), traversodont cynodonts (Liu and Sues, 2010), the crocodylomorph Carnufex (Zanno et al., 2015; Drymala and Zanno, 2016), the aetosaur Gorgetosuchus (Heckert et al., 2015), and a largely unpublished assemblage including a phytosaur and a sphenosuchian were found in several of these isolated, massive blocks that were abandoned on the quarry floor so that precise stratigraphic data for the material is not available. The same block that yielded the aetosaur skeleton described herein also yielded a traversodont cynodont skull (NCSM 20665). Most of the fossils were recovered in a fine-grained red
greatly in thickness across the half-graben from west to east (Fig. 1.2, 1.3). Both the Pekin and Sanford formations are pre- dominantly red, sandstone-dominated units sandwiched around the middle, predominantly gray and fine-grained, Cumnock Formation. The brick operation is focused on mining clay and other
siltstone, but a coarser-grained (greywacke) matrix has also yielded a few of the osteoderms described here. We interpret the coarse-grained lithologies in these blocks as channel and/or alluvial fan deposits derived from the nearby rift margin. The majority of these blocks are probably derived from a single persistent bed near the floor of current quarry operations, but determining their exact provenance beyond the level of “upper Pekin Formation” is not feasible at this time. Reinemund’s (1955) map shows the area encompassed by the quarry as stratigraphically high in the Pekin Formation, but the quarry sediments lack calcareous nodules (caliche) characteristic of the uppermost Pekin Formation (P. E. Olsen, personal communication, 2015). Thus, the specimens are clearly derived from the upper half of the Pekin Formation but their exact position within the Pekin Formation is not known. Traditionally, palynostratigraphers have assigned the Pekin
Figure 1. Index map and generalized stratigraphy of the Deep River Basin, North Carolina. (1) generalized map showing the location of the Deep River Basin in North Carolina; (2) schematic cross-section (modified from Olsen et al., 1991) showing stratigraphic position of NCPALEO 1902 in the Sanford sub-basin; (3) generalized stratigraphic section of the Sanford sub-basin showing the distribution of vertebrate localities, including NCPALEO 1902.
Sanford sub-basin stratigraphy, as originally developed by
Campbell and Kimball (1923) includes, in ascending order, the Pekin, Cumnock, and Sanford formations, which increase
Formation to the Carnian (e.g., Cornet, 1993; Litwin and Ash, 1993), and this age assignment was corroborated by vertebrate biostratigraphy (Huber et al., 1993; Lucas and Huber, 2003) and incorporated into tectonic and lithostratigraphic work (Olsen et al., 1991; Olsen, 1997; Weems and Olsen, 1997). More recent work demonstrates that at least some supposedly Carnian strata, including much of the Newark Supergroup long thought to be Carnian (e.g., Kent and Olsen, 1999, 2000) may in fact be Norian in age as the base of the Norian stage is now considered ca. 228Ma (Muttoni et al., 2004; Furin et al., 2006). Although the “long Norian” is disputed by some (e.g., Lucas et al., 2012), Whiteside et al. (2011, table S2) provided an estimate of 231Ma for the Pekin Formation, based on paleomagnetostratigraphic correlation with other Newark Supergroup sections. This estimate is a Carnian age, and consistent with both Muttoni et al.’s (2004; Furin et al., 2006) and Lucas’ (2010) Triassic timescales for the Carnian.
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