However, these members have found to be confusing and unhelpful in understanding the stratigraphy of the Bright Angel Shale and are typically ignored and rarely used in the published literature.

A reddish brown coloration is imparted to a number of the sandstone and siltstone beds by the high percentage of hematitic ooids and iron oxide cements that they contain.

The gravel fraction of these beds contain quartz, minor amounts of potassium feldspars, sedimentary rock fragments, and glauconite.

These sedimentary structures include horizontal laminations, small- to large-scale planar tabular and trough cross-stratification, and wavy and lenticular bedding.

The isolated coarse-grained and conglomeratic sandstones are typically structureless and crudely stratified and overlie a locally scoured surface.

Overall, when compared with other Middle Cambrian formations in the region, the Bright Angel Shale body fossils are fragmentary and rare.

Individual beds within the Bright Angel Shale are as productive as many of the other Cambrian formations in the Great Basin and Rocky Mountain regions.

[10] The trace fossils found in the Bright Angel Shale consist of arthropod tracks and trails, worm burrows, and dwelling structures.

[11][12] Initially, the Bright Angel Shale, largely on the presence of glauconite, was regarded to have accumulated within the deeper part of a marine shelf.

This interpretation is based on the type of cross-bedding in sandstones and presence of wavy or lenticular heterolithic bedding, both of which indicate a changing tidal environment.

[4][11] Finally, the lack of acritarchs in the shales, the dominant lithology of the formation is regarded as evidence for minimal marine influence during their deposition.

[1][11] The units of the Tonto Group and the colorful Bright Angel Shale are easily identified as a geological sequence beneath the tall cliffs of the Redwall Limestone (the Redwall sits upon a short resistant cliff of Muav Limestone); the Tonto Group is also easily seen beside Granite Gorge of the Colorado River and the Vishnu Basement Rocks