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

away is problematic because there are no dips and gullies at the contact between the two formations as might be expected in such a terrestrial deposit. Flat contacts are common between marine deposits as well-documented in the walls of most of the Grand Canyon. Roth (2009) argues that these types of “flat gaps” are a serious challenge to long geological ages. 4. Paleontology A. Vertebrate trackways McKee (1944, 1947) reported sand trough experiments with several reptiles including spiny lizards ( Sceloporus ), side-blotched lizards ( Uta ) and chuckwallas ( Sauramalus ). The animals were induced to walk over a ridge of sand with varying slope and moisture content. Small reptiles failed to leave tracks in anything other than dry sand. Only the largest animals (chuckwallas) made tracks in wet or damp sand and even then the tracks were not as clear as in dry sand. McKee concluded that the tracks had formed in loose, dry sand that was subsequently dampened by mist or dew. Since then, most investigators have followed McKee in interpreting the Coconino Whitmore and Garner ◀ The Coconino Sandstone ▶ 2018 ICC 614 Figure 45. Invertebrate traces in the Coconino Sandstone. A) double-furrowed trace from the underside of cross-bed surface (in situ) near the bottom of the Coconino, Bright Angel Trail (photo by JHW 4866-2004); B) Four traces from near the bottom of the Coconino along a cross-bed surface, South Fork of Rock Canyon (photo by JHW 5255-2009); C) bioturbated cross-bed surface near the bottom of the Coconino, Tanner Trail (photo by JHW 4.19-1999); D) underside of an in situ cross-bed surface along Bright Angel Trial (same area as A), near the bottom of the Coconino (photo by JHW 04850-2004). Scale bar in the bottom left of each photo is 5 cm. For additional invertebrate traces, see Fig. 34. Table 2. Invertebrate ichnotaxonomy of the Coconino.