File:Utah Flats.jpg

English: View of Utah Flats from the South Kaibab Trail.
The Box section, at Granite Gorge, outfall of Bright Angel Creek, on Granite Gorge. (en:Isis Temple peak is center right; Shiva Temple, on horizon)
(Intersection point of horizontal Tapeats with Shinumo Quartzite, resistant "island", in Tapeats Sea.)
Also, en:Tapeats Sandstone horizontal unit, the en:caprock on the Granite Gorge (Inner Gorge) Vishnu Schist (or other member).
The Tapeats Sandstone, erosion resistant unit, forms the Tonto Platform-(dendritic, Tree-shaped, following connected creeks, washes, canyons, etc.), overlying the 1-Vishnu Group (Vishnu Basement Rocks), and 2-Grand Canyon Supergroup Rocks. The Tonto Platform (Tapeats) allow the slope-forming, top Muav Limestone, and (greenish) Bright Angel Shale to accumulate. During climate timeperiods of extensive water erosion, the platform "regolith" would be removed, until a new erosion forming timeperiod. Deep in the Grand Canyon, usually removed from massive rain events, the accumulation of slope-forming deposits is quite extensive, and quite obvious to visual observation.
The contact between the bottom of the Tapeats Sandstone and eroded upper surface of the units below, is the en:Great Unconformity, the erosion unconformity (a deposition unconformity) of about 1,000 million years (1.0 billion years).