The Proceedings of the Eighth International Conference on Creationism (2018)

Billingsley and Dyer (2003) report that the Coconino occurs as a thin and discontinuous cross-bedded unit incorporated within the base of the Toroweap. Fisher (1961) reported a transitional contact within Parashant and Andrus Canyons. Additionally, Cheevers and Rawson (1979) presented evidence that the Coconino even grades into the Kaibab Limestone (where the Toroweap is absent) in eastern Arizona. We located the northern margin of the Coconino in Kaibab-Buckskin Gulch area in Utah. At this location, the Coconino was sandwiched between the Hermit and Toroweap, but it consisted of planar-bedded sandstones, carbonate beds and only some meter-thick cross-bed sets (Fig. 42). Sumner (1999) visited Kaibab Gulch, but apparently did not recognize the change in the lithology of the Coconino or thought it was part of the Toroweap (see pp. 109-110). Doelling et al. (2003) recognized about 19.6 m of Coconino in this area. They interpreted it as a near-shore deposit grading southward into its typical lithologies (p. 205). The Coconino probably correlates with the Scherrer Formation, which is a marine sandstone, in southeastern Arizona (Blakey 1990, p. 1216) and transitions eastwards into the Glorieta Sandstone of New Mexico which is also thought to be marine (Baars 1961, p. 199). L. Flat contacts Most are familiar with the base of the Coconino as it outcrops along the South Rim trails of the Grand Canyon forming a sharp and flat contact with the Hermit Formation below (Fig. 43). Some recognize an unconformity here as more than 600 m of Schnebly Hill Formation can be found between the Hermit and Coconino from core in the Holbrook area (Blakey and Knepp 1989), probably representing an approximately 10-million- year hiatus in conventional terms. 4. Paleontology A. Vertebrate trackways No body fossils have been reported from the Coconino Sandstone, with the possible exception of some unidentified microfossils along the northern margin of the outcrop (Cheung et al. 2009). However, the Coconino is known for the abundance of its ichnofossils (Fig. 44; Baird 1952; Braddy 1995; Gilmore 1926, 1927b, 1928; Lull 1918; Spamer 1984) and has been described as one of the richest and most important Paleozoic track sites known (Kramer et al. 1995). Descriptions and systematic discussions of the Coconino vertebrate trackways were published by Lull (1918), Gilmore (1926, 1927b, 1928), Baird (1952) and Haubold (1971, 1984). In a major revision of Permian vertebrate ichnotaxonomy, McKeever and Haubold (1996) reclassified vertebrate tracks from the Permian Corncockle and Locharbriggs Sandstones of Dumfries and Galloway, Scotland, giving priority to names first assigned by Owen (1842) and Jardine (1850, 1853). They recognized one ichnogenus, Chelichnus , consisting of four ichnospecies distinguished by pes size. The four species were C. bucklandi (10-25 mm), C. duncani (25-75 mm), C. gigas (75-125 mm) and C. titan (>125 mm). They extended this new classification to the ichnofaunas of the Coconino and the Cornberger Sandstein of Germany and attributed the Coconino tracks to three of their ichnospecies ( C. bucklandi , C. duncani and C. gigas ). Ichnospecies Whitmore and Garner ◀ The Coconino Sandstone ▶ 2018 ICC 588 Figure 8. Map showing sorting within the Coconino Sandstone (from Whitmore et al. 2014).