Investigation of the nature of the folding of the Cambrian Tonto Group strata in the Grand Canyon necessitates first investigating the petrology of those strata. At the base of the Tonto Group the Tapeats Sandstone is the 30-100m thick cliff-forming formation that prominently outcrops through ~500km in the walls of the Grand Canyon and beyond. Erosion of the underlying Precambrian basement rocks produced the Great Unconformity on which the Tapeats Sandstone was deposited as the basal part of the fining upwards Sauk megasequence that blankets North America, and both have been traced across other continents. Tracks and traces left by trilobites and other invertebrates are fossilized in the Tapeats Sandstone, which consists of 0.3-1.0m thick non-bioturbated beds that are strongly cross laminated with shallow dips characteristic of water transport of the sand and many lens-shaped scour-and-fill "channels." The predominant paleocurrent direction is between west and southwest. Detrital zircon U-Pb ages confirm the conventional age and the source of the sandy sediment. The consensus uniformitarian interpreted depositional environments for the Tapeats Sandstone are intertidal to subtidal shallow-marine environments with local beach and fluvial deposits, yet it has been described as "one of the most dramatic global marine transgressions in Earth history." K-feldspar content ranges from 1.8-33.1%, with variously sized K-feldspar grains scattered through the rock, and occasional detrital muscovite flakes wedged between quartz and K-feldspar grains. The fabric is cemented by silica as quartz overgrowths. Being poorly to moderately well-sorted and dominated by sub-angular to sub-rounded, coarse silt to very coarse sand-sized quartz grains, with some granules and small pebbles, makes this a well-cemented sub-mature arkosic sandstone. There are no signs, either macroscopic or microscopic, that the sandstone or its constituent grains have been even slightly metamorphosed. Instead, the mineralogical content, textural features, sedimentary structures, continental-scale deposition, paleocurrent directions matching continental patterns, and even the tracks and traces of transitory invertebrates, all indicate rapid burial. Furthermore, all are consistent with the catastrophic erosion of the Great Unconformity near the initiation of the global Genesis Flood cataclysm only about 4,350 years ago, and the subsequent hurricane-and tsunami-driven rapid short-distance transport and deposition of the Tapeats Sandstone, likely in the first few days or weeks of that year-long event.