JURASSIC

Navajo Sandstone - Moderate-reddish-orange to moderate-orange-pink, massively cross-bedded, poorly to moderately well-cemented, well-rounded, fine- to medium-grained, frosted quartz sandstone; locally very pale orange to yellowish gray, especially in upper part; forms bold cliffs; lower 300 feet (90 m) forms transition zone characterized by planar bedded, very fine- to fine-grained sandstone and fine-grained silty sandstone with thin siltstone interbeds, and less common but resistant cross-stratified sandstone; wavy bedding, dark flaser- like laminae, and soft-sediment-deformation features, including flame and load structures, are common in transition zone; deposited in a vast coastal and inland dune field, transition zone represents deposition in a sabkha environment; about 2,300 feet (700 m) thick.

Kayenta Formation - Interbedded, thin- to medium-bedded, moderate-reddish-brown to moderate-reddish-orange siltstone, fine-grained sandstone, and mudstone with planar, low-angle, and ripple cross-stratification; contains several poorly  exposed, 1- to 5-inch-thick (2.5-12.5 cm), light-olive-gray weathering, light-gray dolomite beds; lower part weathers to poorly exposed, commonly gypsiferous slopes, upper part to ledges and small cliffs; upper contact locally marked by a 3-  to 8-inch-thick (7-20 cm), light-gray limy dolomite bed (dm); deposited in fluvial, distal fluvial/playa, and minor lacustrine environments; 925 feet (282 m) thick.

Moenave Formation

Moenave Formation, undivided - Shown on cross section only.

Springdale Sandstone Member - Medium to very thick-bedded, fine-grained or rarely medium-grained sandstone, with planar and low-angle cross-stratification, and minor, thin, discontinuous lenses of intraformational conglomerate and thin interbeds of moderate-red dish-brown or greenish-gray mudstone and siltstone; weathers to rounded cliffs and ledges; contains locally abundant petrified and carbonized fossil plant remains; host to ore deposits of the Silver Reef mining district; deposited in braided-stream and minor flood-plain environments; 120 to 164 feet (36-50 m) thick.

Whitmore Point Member - Interbedded, pale-red-purple, greenish-gray, and blackish-red mudstone and claystone, lesser moderate-reddish-brown very fine- to fine-grained sandstone and siltstone, and uncommon dark-yellowish-orange micaceous siltstone and very pale-orange, very fine- to fine-grained sandstone; weathers to poorly exposed, brightly colored slopes; contains several 3- to l8-inch-thick (8-46 cm), bioturbated, cherty, dolomitic limestone beds with algal structures and fossil fish scales of Semionotus kanabensis (Hesse, 1935; Schaeffer and Dunkle, 1950); the dolomitic limestones vary in color from light greenish gray to very light gray and yellowish gray, and weather to mottled colors of pale yellowish orange, white, yellowish gray, and pinkish gray, commonly with green copper-carbonate stains; lower 25 feet (7.5 m) consists of moderate-red dish-brown sandstone similar to that of the Dinosaur Canyon Member; deposited in flood- plain and lacustrine environments; 64 to 125 feet (19-38 m) thick.

Dinosaur Canyon Member - Interbedded, generally thin-bedded, moderate-reddish-brown to moderate-reddish-orange, very fine- to fine-grained sandstone, very fine grained silty sandstone, and lesser siltstone and mudstone with planar, low- angle, and ripple cross-stratification; slope forming; deposited in river and flood-plain environments; 163 feet (50 m) thick.

unconformity (J-O)

TRIASSIC

Chinle Formation

Petrified Forest Member - Varicolored mudstone, claystone, siltstone, lesser sandstone and pebbly sandstone, and minor chert and nodular limestone; lower part contains Shinarump- like sandstone and pebbly sandstone lenses up to 40 feet (12 m) thick; swelling mudstones and claystones are common throughout and although typically poorly exposed, their bright colors of various shades of purple, grayish red, dark reddish brown, light greenish gray, brownish gray, olive gray, and similar hues locally show through to the surface; mudstones weather to a "popcorn" surface and are responsible for numerous foundation problems in the area; commonly forms slumps, especially along steep hillsides; contains petrified wood, commonly well silicified and brightly colored, especially in the upper part of the member; deposited in a variety of fluvial, flood-plain, and lacustrine environments; about 400 to 450 feet (120-135 m) thick.