USGS: Geological Survey Professional Paper 132

Geological Survey Professional Paper 132—A

Rock Formations in the Colorado Plateau of Southeastern Utah and Northern Arizona

SEDIMENTARY ROCKS.
(continued)

LOCAL SECTIONS.

General section of rocks near Lees Ferry, Ariz.
[Measured by Kirk Bryan.]

Feet.

Brown thin-bedded sandstone and shale, which are probably the equivalent of the beds of marine Jurassic farther north

(?)

Navajo and Wingate sandstones: Massive tangentially cross-bedded red to buff sandstone. No parting visible at the center, but upper half has lenses of dense gray limestone 6 inches to 3 feet thick at intervals, and near the top nodules of limonite the size of peas are common. In the Vermilion Cliffs the upper half is distinctly lighter in color. The Todilto (?) formation is apparently absent

1,100-1,200

Chinle formation: Blue, green, and red shale; white, gray, purple, and red sandstone; and cherty limestone. Upper part consists of heavy-bedded sandstone and red shale; lower part contains fossil wood

1,000±

Shinarump conglomerate: Gray conglomerate with lenses of sandstone and shale; much fossil wood

0-40

Unconformity.

Moenkopi formation: Red sandy shale and thin-bedded sandstone with seams of gypsum. In places has beds of red and gray sandstone 2 to 6 feet thick, and in one locality 12 feet of gypsiferous limestone at the top. Base, generally, 1 to 10 feet of chert conglomerate

500±

Unconformity.

Kaibab limestone: Yellow limestone with numerous more or less rounded nodules of chert

250

Coconino sandstone: Gray cross-bedded massive sandstone

300

Unconformity (?).

Hermit (?) shale: Red shale and sandstone	(observed)
Unconformity (?) (not observed).
Supai formation: Red shale with beds of blue limestone.

500±

Section about 3 miles southeast of Piute Farms on San Juan River.
[Measured by R. D. Miser.]

	Feet.
Wingate sandstone:
Massive cross-bedded tan sandstone forming sheer cliff; cut by numerous vertical joints; face of cliff is stained dark brown	270
Coarse brown sandstone with pebbles of shale and sandstone up to 2 inches in diameter	4
Chinle formation: Green and pink marly clay with beds of mottled pink and gray compact limestone as much as 4 feet thick in upper part. Some of the limestone is conglomerate. Pebbles in conglomerate are limestone. Pink and gray flint on slope may have been derived from weathering of limestone. Some parts of clay contain irregular concretions of calcareous earthy material	830
Shinarump conglomerate: Massive gray sandstone	10
Moenkopi formation:
Chocolate-colored shale with some green shale in upper half; light chocolate-colored shale with some thick beds of brown fine-grained sandstone in lower half	340
Brick-red sandy shale and earthy sandstone in beds of uniform thickness. The De Chelly (?) sandstone is absent at this place but wedges in farther south near the top of this part of the formation	500
Moenkopi or Coconino: a a Transition beds" like those described in section at Zahns Camp.
Coconino sandstone.

Section at Zahns Camp on San Juan River.
[Measured by H. D. Miser.]

	Feet.
Chinle formation: Variegated marly shale. Shinarump conglomerate: Massive gray pebbly sandstone; forms cliff	50
Moenkopi formation:
Chocolate-brown sandy shale with a smaller amount of brown shaly and platy sandstone; forms steep slope	325
Brick-red sandy shale and earthy sandstone in even-bedded layers	55
Cream-colored cross-bedded massive sandstone; De Chelly (?) sandstone lentil	90
Brick-red sandy shale and a smaller amount of red earthy sandstone in even-bedded layers	450
Total thickness of Moenkopi formation	920
Moenkopi or Coconino ("transition beds"):
Heavy gray sandstone	5
Brown sandy shale and brown shaly sandstone. A bed of gray limestone 1 foot or more thick near top	45
Massive gray sandstone	6
Brown sandy shale	5
Massive gray sandstone	4
Brown sandy shale and brown earthy sandstone. Contains one or two thin beds of gray limestone	24
Total thickness of "transition beds"	89
Coconino sandstone: Massive cross-bedded cream-colored sandstone. Two beds of brown sandy shale aggregating 3 feet near the top. Exposure of sandstone extends down to San Juan River	55

Section on San Juan River north of Spencer Camp.
[Measured by H. D. Miser.]

	Feet.
Navajo sandstone: Cream-colored to yellow massive cross-bedded sandstone	200+
Todilto (?) formation:
Brown fine-grained shaly sandstone with lavender cast	170
Lenses of conglomerate as much as several feet thick; conglomerate composed of sandstone pebbles in sandy matrix
Lavender, brown, and buff fine-grained sandstone in comparatively thin layers	50
Total thickness of Todilto (?) formation	220
Wingate sandstone. Buff fine-grained cross-bedded sandstone; no conglomerate at base	330
Chinle formation: Variegated marly shale; concealed almost everywhere by landslides. Formation extends to river, and base is not exposed	510

Section on north side of San Juan River just above its junction with the Colorado.
[Measured by H. D. Miser.]

	Feet.
Navajo sandstone:
Gray thin-bedded very fine grained limestone; forms flat top of small mesa	4-1/2
Buff massive cross-bedded sandstone	310
Todilto (?) formation: Dark and light brown sandstone in comparatively thin beds	200
Wingate sandstone: Buff sandstone to water's edge of San Juan River	10+

Section on Colorado River near the mouth of Fremont River.
[Measured by C. R. Longwell. The canyons of Colorado and Fremont rivers are cut in the Coconino sandstone. Above the canyons there is a wide stripped bench on the Coconino, with scattered buttes of the Moenkopi formation.]

	Feet.
Moenkopi formation:
Conglomerate at base of upper member of formation. Contains angular pebbles of chert, with maximum length of 2 inches, also a few fragments of silicified wood. Firmly cemented by calcium carbonate	15
Unconformity.
Gray sandstone, medium to coarse, strongly cross-bedded throughout. Conspicuous by contrast with red sandstone below. De Chelly (?) lentil	40
Regular beds (a few with cross laminae) of red to maroon sandstone, averaging several feet in thickness, of fine, uniform grain. A few shaly layers, forming narrow benches in cliff	158
Heavy bed of cross-bedded pink to tan sandstone; persistent, good horizon marker; fine uniform grain	28
Heavy bed of reddish-brown sandstone, grading into gray at the base	6
Fine-grained maroon and red sandstone and sandy shale in regular beds from 6 to 30 inches thick; form steep interrupted slope	115
Red sandy shale, with some layers of cross-bedded fine-grained sandstone; forms slope; muscovite abundant	45
Massive white to gray sandstone, with medium grain	2
Gritty shale and fine-grained sandstone, red to light brown	22
Incomplete thickness of Moenkopi formation	431
Unconformity.
Coconino sandstone: Gray and tan sandstone, of fine to medium grain, in massive beds and with cross-bedding on large scale. Forms walls of Narrow Canyon and Dirty Devil Canyon. Base not exposed.

Section on Colorado River near mouth of Crescent Creek (""North Wash").
[Measured by C. R. Longwell.]

	Feet.
Wingate sandstone forms a sheer cliff at least 300 feet high, at top of the steep slope on which the Chinle formation is exposed	300+
Chinle formation:
Regular beds of pink sandstone, 6 inches to 2 feet thick	12
Coarse sandstone, pink to tan, cross-bedded	25
Gritty shale and fine-grained sandstone, in thin layers	10
Gray calcareous sandstone	1
Pink sandstone in thin beds	27
Massive layer of gray to buff sandstone	6
Calcareous shale in massive layers, containing more or less grit, with a few intercalated thin layers of fine-grained sandstone	155
Heavy bed of dense gray limestone, with chert lenses and nodules	4
Pink calcareous shale	24
Alternating layers of gray limestone and pinkish shale. Limestone layers average 2 feet in thickness and are dense, with abundance of chert	27
Gray, lavender, and yellow shale, banded, with a few thin sandy layers	102
Total thickness of Chinle formation	393
Shinarump conglomerate: Massive coarse-grained, cross-bedded sandstone, with lenses of conglomerate; contains abundance of silicified wood	35
Unconformity.
Moenkopi formation:
Lavender, pink, and greenish shale, with a few sandstone layers; green layers prominent near top	72
Gray and yellow sandy shale and fine-grained sandstone	6
Bright-red clay shale	22
Gray, lavender, and yellow shale, with a few bands of dense gray limestone	60
Red and pink sandy shale and fine-grained sandstone	70
Fine-grained cross-bedded red to pink sandstone	2
Alternating layers of gray sandstone and red shale; shale papery, sandstone ripple marked	17
Alternating layers of red and brown sandstone and sandy shale; sandstone layers have current and ripple marks, also a few rain prints; partings of brown paper shale	55
Single bed of massive cross-bedded light-brown sandstone	22
Alternating layers of red and brown sandstone and sandy shale; sandstone layers have current and ripple marks, also a few rain prints	65
Alternating thin beds of gray sandstone, with very thin partings of brown shale	6
Light-brown conglomeratic sandstone	2
Alternating thin beds of gray sandstone, with very thin partings of brown shale	2
Light-brown conglomeratic sandstone	2
Alternating thin beds of gray sandstone, with very thin partings of brown shale	4
Light-brown conglomeratic sandstone	3
Alternating thin beds of gray sandstone, with very thin partings of brown shale	9
Massive gray cross-bedded sandstone	3
Alternating thin beds of sandstone and shale, yellow, red, brown, and lavender	9
Firmly cemented conglomerate with angular pebbles of chert and hard sandstone; fragments of lustrous coal and of silicified wood also occur as pebbles	10
Total thickness of upper member of Moenkopi formation	441
Unconformity.
Massive gray sandstone, with marked cross bedding, loosely cemented with calcium carbonate. De Chelly (?) sandstone lentil	35
Typical red and maroon beds of lower member.

Section on Colorado River below mouth of Crescent Creek.
[Measured by C. R. Longwell.]

	Feet.
Navajo sandstone: Tan and buff sandstone, cross bedded on large scale. The sandstone of this locality is an isolated remnant capping a high point	300
Todilto (?) formation:
Alternating regular beds of calcareous sandstone and gritty shale, with a few layers of limestone conglomerate. Two of the sandstone layers are cross-bedded and tan. Other beds are pink, gray, and lavender. Form long slope	77
Thin layers of red and maroon sandstone, cross-bedded	60
Light-brown and gray cross-bedded sandstone; friable, forming slope; contains hard, concretionary nodules	22
Total thickness of Todilto (?) formation	159
Unconformity (?)
Wingate sandstone:
Tan and light-brown cross-bedded sandstone, forming cliff	85
Conglomerate, with pebbles and, boulders of sandstone as much as 2 feet in diameter, also pebbles of red clay; calcareous cement	0-4
Massive cross-bedded sandstone, forming almost unbroken cliff. Tan on fresh surfaces, reddish brown on weathered face	280
Total thickness of Wingate sandstone	369
Chinle formation: Forms a long slope below the cliff of the Wingate sandstone.

Section on Colorado River near mouth of Trachyte Creek.
[Measured by C. R. Longwell.]

	Feet.
Shinarump conglomerate: Coarse-grained gray conglomeratic sandstone, with abundance of silicified wood. Forms low cliff, with shelf above	5-15
Unconformity.
Moenkopi formation:
Alternating layers of gray sandstone and greenish shale	5
Lavender, gray, and pink calcareous shale	25
Fine-grained brown sandstone	3
Gray "marl," sandy near base	55
Gray cross-bedded sandstone	3
Greenish-gray and pink shale, paper-thin	4
Bright-red clay shale	5
Yellow, lavender, pink, and gray "marly" shale, in thick beds	60
Alternating chocolate-colored shale and gray to brown sandstone, in thin layers. Ripple marks abundant	60
Massive brown sandstone with strong current marks	2
Alternating chocolate-colored shale and gray to brown sandstone	8
Massive sandstone	2
Chocolate-colored sandy shale	6
Massive cross-bedded sandstone	2
Gray sandstone and chocolate-colored shale, in alternating thin layers	4
Massive gray to brown cross-bedded sandstone	8
Alternating chocolate-colored shale and gray to brown sandstone, with strong ripple marks	22
Light-brown cross-bedded sandstone	5
Chocolate-colored sandy shale	10
Thick layers of sandstone, with thin partings of chocolate-colored shale	11
Alternating gray sandstone and chocolate-colored shale	18
Heavy layers of cross-bedded current-marked sandstone, with thin shale partings; sandstone gray to brown, shale dark chocolate-colored	12
Brown fine-grained sandstone, with thin lamination	6
Heavy layers of pink cross-bedded sandstone, with shale partings	16
Alternating gray sandstone and brown shale; abundant ripple and current marks	22
Fine-grained sandstone with shaly lamination	9
Firmly cemented conglomerate containing angular pebbles of chert and hard sandstone	2
Total thickness of upper member of Moenkopi formation	385
Unconformity.
De Chelly (?) sandstone lentil (gray to pink cross-bedded sandstone	20
Typical red beds of the lower member.

Section on north side of Twomile Canyon, directly east of Mount Holmes, in the Henry Mountains.
[Measured by C. R. Longwell.]

	Feet.
Navajo sandstone: Massive tan sandstone, capping a rounded hill	250
Todilto (?) formation:
Massive fine-grained cross-bedded lavender and gray sandstone	18
Purple and gray shale; forms slope	10
Massive cross-bedded brown sandstone, medium to coarse	9
Red and brown sandy calcareous shale with thin layers of dense gray limestone; forms slope	40
Brown and gray heavy-bedded sandstone with calcareous cement	27
Pink sandy shale; forms slope	14
Gray sandstone and pink sandy shale in alternating beds	11
Reddish-brown and gray medium to fine grained sandstone in heavy layers, some with cross-bedding. Calcareous cement. Layers of unequal resistance, forming steep slope. All beds lenticular; a few lenses conglomeratic	120
Total thickness of Todilto (?) formation.	249
Unconformity.
Wingate sandstone: Tan to reddish-brown sandstone, chiefly in unbroken cliff. Large-scale cross-bedding	366
Unconformity (?).
Chinle formation:
Alternating layers of hard fine-grained sandstone and pink sandy shale	14
Pink shale, with a few layers of gray sandstone.	22
Gray conglomeratic sandstone, with small pebbles of chert and hard sandstone	2
Heavy bed of fine-grained pink sandstone, loosely cemented	8
Varicolored calcareous shale, with a few sandstone layers	40
Cross-bedded gray sandstone, conglomeratic at base; contains silicified logs	6
Pink and yellow calcareous shale, sandy near top	17
Hard gray limestone, containing chert nodules	2
Lenticular layers of gray sandstone with partings of shale	10
Pink and yellow gritty shale	20
Gray and lavender "marls" beds, jointed	34
Cross-bedded gray and lavender sandstone	15
Massive fine-grained sandstone, rich with calcium carbonate and containing cherty nodules	6
Brick-red gritty shale, with layers of gray sandstone	28
Pink and gray calcareous shale or "marl," appearing massive	80
Gray and purplish sandy shale in thin beds	16
Total thickness of Chinle formation	320
Shinarump conglomerate: Coarse conglomeratic massive and cross-bedded sandstone with lenses of conglomerate; abundance of silicified logs; plain impressions of plants on bedding surfaces. Forms vertical cliff	60-120
Unconformity.
Moenkopi formation: Greenish shale immediately below unconformity. Forms slope.

Section of Chinle formation at north end of prominent Wingate-capped outlier west of South Fork of Silver Falls Creek, in the Circle Cliffs.
[Measured by R. C. Moore.]

	Feet.
Wingate sandstone: Reddish-brown fine-grained cross-bedded, very massive sandstone, forming single vertical wall; prominently jointed; basal few feet horizontally bedded in thin layers, with ripple marks measuring about 6 inches from crest to crest; thickness estimated	250
Chinle formation:
Soft limestone, lavender mottled with light greenish blue, weathering in very irregular fragments; partly covered with debris; upper part oxidized and stained to dark purple beneath Wingate sandstone and along joints	5
Light-bluish conglomerate, mostly rather fine grained; pebbles consist almost entirely of limestone like the associated limestones of the Chinle formation, but there are some flint, quartz, and ironstone pebbles as much as 1-1/2 inches in diameter; upper part grades into very coarse limestone grit, with lines and lenses of fine conglomerate; very massive; crops out in prominent bench	28
Soft shaly limestone, light greenish blue and lavender, mottled; contains locally harder limestone in beds 6 to 10 inches thick which project; this division weathers in a slope	70
Very hard dense fine-grained limestone, light bluish in lower part with mottling of lavender, massive and uniform; locally contains calcite crystals; except for lower part, which is somewhat softer, this bed forms prominent cliff, which in places overhangs	5
Light-blue hard calcareous shale; forms land slide slope	15
Argillaceous limestone, impure, mottled light greenish blue and lavender; weathers in small angular fragments but forms at outcrop a massive vertical ledge; grades upward and downward into hard calcareous shale	3
Light-blue hard calcareous shale; forms slope	14-1/2
Hard dense nodular limestone, mottled light greenish blue and lavender; weathers in small irregular-shaped fragments; grades imperceptibly into shale above and below; forms bench	8
Hard calcareous light-blue shale, forming slope	38
Light-bluish shaly soft, very micaceous sandstone, grading into sandy shale	59-1/2
Light-bluish to brown limestone conglomerate, containing pebbles of limestone and chert 3 inches or less in diameter; grades into coarse limy sandstone	2-1/2
Yellowish-brown hard sandy shale grading to ash-gray and lavender shale	53
Grayish-blue to lavender calcareous, highly micaceous sandstone, grading upward into soft massive cross-bedded sandstone; lower part weathers in thin platy fragments	35-1/2
Purple shale, grading upward into yellow and blue shale; sandy, especially in lower part; contains abundant mica; weathers in rounded slopes	13
Brownish-gray thinly laminated to platy sandstone, weathering dark brown; lower part locally conglomerate, containing pebbles of ironstone and jasper as much as 1 inch in diameter	5-6
Sandy shale; upper part weathers to shades of lavender and purple; lower part darker; the proportion of sand increases toward the top; contains satin spar, crystals of gypsum, and mammillary concretions of ironstone with crystalline calcite; weathers in rounded slopes	91-1/2
Brown thin-bedded flaggy sandstone, grading laterally to burnt sienna slaggy ironstone, containing nodules of limonite; this bed forms a bench that weathers irregularly in crumbly fragments	2
Hard calcareous sandy shale, light greenish blue predominant in variegated coloring; weathers in rounded badland slopes	25
Total thickness of Chinle formatiom	474
Shinarump conglomerate: Grayish-brown irregularly bedded massive sandstone, showing thin cross lamination; some of the weathered surfaces are dark brown or black on account of a surface deposit of iron oxide; contains bluish sandy shale in middle part	85
Moenkopi formation.

Section of Kaibab limestone west of The Peaks, in the Circle Cliffs.
[Measured by R. C. Moore.]

	Feet.
Moenkopi formation. Kaibab limestone:
Yellow dolomitic limestone in massive evenly bedded ledges; weathers in large angular blocks pitted by solution; part contains numerous dendrites of manganese oxide and concretions of a mineral resembling wad; contains fossils; forms resistant cap of prominent bench	37
Light-yellow soft dolomitic massive limestone, filled with angular fragments of chert; weathers in smooth slope; exposed	15
Soft light creamy-yellow thin to medium bedded limestone; weathers in slope; partly concealed	37
White very sandy limestone, rounded sand grains scattered rather evenly; more lime than sand; weathers in thick ledges	34
White medium to coarse grained massive sandstone; rounded quartz grains in a lime matrix	19
White very sandy limestone, rounded sand grains scattered rather evenly; more lime than sand; weathers in thick ledges; forms bench	21
Total thickness of Kaibab limestone	163
Coconino (?) sandstone: White medium to coarse grained moderately soft massive sandstone; rounded quartz grains in a lime matrix; breaks into irregular blocks on weathering; exposed	73

Section of lower beds in front of Kaiparowits Plateau, south of Tenmile Spring, about 15 miles southeast of Escalante, in middle part of sec. 4, T. 37 S., R. 4 E.
[Measured by R. C. Moore.]

	Feet.
"Tununk shale": Bluish sandy shale, grading downward into soft fossiliferous sandstone	400+
Dakota (?) sandstone: Conglomeratic buff to almost white coarse to medium grained sandstone, containing lenses of conglomerate with pebbles as much as 3 inches in diameter; irregularly cross bedded; forms cliff and prominent bench	90
McElmo formation:
Red and light-brown sandy shale, interbedded with sandstone of similar color; forms slope partly concealed	55
Light-brown and yellow fine-grained sandstone, cross-bedded in part; occurs in massive layers and forms bench	70
Total thickness of McElmo formation	125
"Varicolored shales and sandstones"
Red and gray shale and sandstone, interbedded; mostly covered	12
Red, gray, and drab sandstone and shale, in thin alternating beds; considerable variation in color and texture	60
Yellow and buff soft, very massive sandstone; weathers in smooth round slopes, locally with caves and shallow depressions at outcrop	300+
Partial thickness of "varicolored shales and sandstones"	372

Section on Halls Creek about 8 miles above its mouth.
[Measured by R. C. Moore.]

	Feet.
McElmo formation: Reddish-brown and light greenish-gray massive hard, irregularly bedded conglomeratic sandstone; forms prominent escarpment; thickness reduced by erosion	76
"Varicolored shales and sandstones"
Thin-bedded red sandstone	123
Tan-brown massive soft cross-bedded sandstone, weathering in smooth rounded slopes, partly covered	850
Total thickness of "varicolored shales and sandstones	973
Gypsiferous shales and sandstones.
Light-red and greenish sandy shale; contains beds of white sandstone and gypsum	90
Maroon shale and hard fine-grained quartzitic sandstone; forms escarpment	50
Total thickness of "gypsiferous shales and sandstones"	140
Navajo sandstone: White medium-grained very massive cross-bedded sandstone; forms prominent ridge	600+

Section across Waterpocket Fold near southwest corner of T. 32 S., R. 8 E., at Bitter Creek divide, head of Halls Creek.
[Measured by R. C. Moore.]

	Feet.
Masuk sandstone: Light-yellow massive sandstone, weathering yellowish brown; forms very prominent escarpment; in lower part grades into medium-bedded sandstone	297
"Masuk shale": Yellowish-brown to drab sandy shale; upper part contains beds and lenses of soft sandstone; forms slope beneath escarpment of sandstone above	700
Blue Gate sandstone: Yellow to light-brown medium to massively bedded sandstone forming precipitous cliff; locally contains lignite	230
"Blue Gate shale": Bluish-drab sandy shale, very uniform in color and texture; upper part grades into soft shaly sandstone	1,200
Tununk sandstone: Yellowish-brown medium to massively bedded sandstone	50-75
"Tununk shale": Bluish-drab sandy shale, uniform in color and texture; includes very fossiliferous thin yellow sandstone at base	975
Dakota (?) sandstone: Light-yellow soft irregularly bedded sandstone, grading upward into sandy shale; contains two thin beds of impure lignite 9 and 20 inches thick	15
McElmo formation:
Grayish-blue, maroon, and purple banded soft sandy shale, weathering in valleys and badlands	415
Grayish-white to light bluish-green conglomerate and sandstone; contains pebbles as much as 2 inches in diameter; consists in part of thick beds and lenses of coarse conglomerate and in part of coarse gritty very irregularly bedded sandstone	150
Total thickness of McElmo formation	563
"Varicolored shales and sandstones":
Red and gray banded sandy shale grading to soft thin-bedded sandstone	90
Tan-brown massive soft cross-bedded sandstone, weathering in smooth rounded surfaces	260
Reddish-brown and bluish-gray very soft shaly sandstone, weathering readily, forming valley; partly covered	470
Tan-brown massive soft cross-bedded fine-grained sandstone, weathering in smooth rounded surfaces	340
Total thickness of "varicolored shales and sandstones"	1,160
"Gypsiferous shales and sandstones:"
Light-red and bluish-gray shale and sandstone; gray to white sandstone in alternating beds; contains several beds of bluish to white gypsum as much as 3 feet thick; the gypsum occurs also in numerous thin veins	400
Dark to light red sandy shale, containing two beds of very hard reddish and light green mottled dense siliceous massive and flaggy limestone that forms escarpments	50
Total thickness of "gypsiferous shales and sandstones"	450
Navajo sandstone: White to very light cream-colored sandstone, locally stained light orange red in middle and lower parts; capped by bed of coffee-brown sandstone, 10 feet, and light tan, highly cross-bedded sandstone, 8 feet. Very massive, highly cross-bedded on large scale; the cross-beds are etched in relief by weathering; crops out in high, prominent "reef" whose surface is marked by numerous conical tepees, mosques, and rounded domes	1,400
Todilto (?) formation: Dark-red to maroon cross-bedded sandstone, medium to coarse grained, thin to medium bedded; some beds hard, others soft; bedding very irregular; locally contains soft maroon sandy shale; thickness in part estimated.	160
Wingate sandstone: Red very massive hard fine-grained sandstone, of uniform color and texture, cross-bedded but bedding not prominent, much jointed; crops out as single ledge making a vertical cliff or palisade	340
Chinle formation:
Light-bluish hard calcareous shale, mottled with lavender; upper part stained purple; weathers in rough angular blocks; forms slope	48
Massive light greenish-blue limestone conglomerate, composed of pebbles of limestone, quartz, jasper, and sand in a lime matrix	2
Alternating beds of light bluish-green limestone and shale, mottled with lavender; the shale is hard and calcareous, forms slopes, and grades without demarcation into limestones that are nodular, hard, and massive and form projecting ledges	146
Sandy shale and sandstone, yellowish brown, yellow, dark brown, blue, purple, and ash gray, dark tones predominating; sandstone in part soft and massive, in part hard, dense, cross-bedded, and forming projecting ledges, locally conglomeratic	304
Total thickness of Chinle formation	500
Shinarump conglomerate: Hard very massive, irregularly bedded light bluish-gray to white sandstone, weathering yellowish white locally; forms prominent escarpment; at this place thickness ranges from 40 to 110 feet within a short distance, average	60
Moenkopi formation: Thin to medium-bedded ripple-marked micaceous sandstone; weathers in slopes and projecting ledges; base not exposed	250+

Section of Shinarump conglomerate and upper part of Moenkopi formation on west side of Circle Cliffs between Horse Creek and the Peaks.
[Measured by R. C. Moore.]

	Feet.
Shinarump conglomerate:
Light-gray coarse-grained very massive sandstone, forming almost unbroken vertical faced escarpment; weathers in large angular blocks	30-60
Massive cross-bedded light bluish-gray sandstone, mottled and streaked along irregular joints with purple; grades upward without demarcation into sandy limestone; weathers in single massive bed softer than overlying sandstone and therefore forming a reentrant in the cliff; upper surface uneven	16
Moenkopi formation:
Chocolate-brown very sandy shale, grading into shaly sandstone; more calcareous above	7
Chocolate-brown thin-bedded ripple-marked and cross-laminated sandstone	3
Chocolate-brown very micaceous sandy shale, grading into thin shaly sandstone	5
Chocolate-brown hard shaly to platy sandstone; forms slight projecting ledge	1
Brown sandy shale, grading into thin shaly sandstone; weathers as slope	8
Chocolate-brown hard platy sandstone, forming a ledge	1
Chocolate-brown sandy shale, grading into shaly sandstone	22-1/2
Chocolate-brown thin-bedded ripple-marked laminated sandstone, locally weathering massive and forming a prominent projecting ledge	5
Chocolate-brown sandy micaceous shale with thin seams and beds of soft sandstone; in upper part contains thin beds of shaly sandstone	46-1/2
Light greenish-gray platy fine-grained micaceous sandstone, with large asymmetrical ripple marks; produces a slight bench	1/3
Chocolate-brown sandy micaceous shale, containing abundant thin beds of shaly sandstone which weathers in thin chips and platy slabs; weathers in gentle rounded slope	27
Brown very micaceous ripple-marked sandstone, with thin light-gray bands, platy with thin shale beds between harder layers; top layer very hard and slabby	2-1/2
Chocolate-brown sandy shale, with thin yellow and brown sandstone beds that make slight benches	56
Light-yellow very massive hard sandstone; forms projecting wall	50
Light-yellow massive sandstone, weathering in thin plates; grades into shaly sandstone; forms bench	12
Chocolate-brown sandy micaceous shale	40
Light-yellow massive sandstone; locally stained red on outcrop; grades locally into shaly or thin-bedded sandstone; forms prominent bench	160
Yellow very shaly sandstone, grading to sandy shale	5
Yellow calcareous micaceous sandstone, massive but thinly laminated, with ripple bedding; grades to shaly sandstone	4
Partial thickness of Moenkopi formation	456
(Top of Kaibab limestone 25 to 40 feet below.)

Section of Moenkopi formation in canyon north of The Peaks, northwest of Wagonbox Mesa, in the Circle Cliffs.
[Measured by R. C. Moore.]

	Feet.
Shinarump conglomerate: Gray medium to fine grained massive sandstone, weathering yellowish in part, locally conglomeratic; weathers in large angular blocks; outcrop forms prominent cliff	50-150
Moenkopi formation:
Maroon sandy shale grading into yellow shale in upper 15 feet, with many paper-thin sandstone layers	50
Yellow fine-grained soft sandstone; weathers rather shaly	3
Maroon shale with thin shaly sandstone	39
Buff, brown, and gray fine-grained sandstone, in layers 1 to 4 inches thick	8
Yellowish-brown sandy shale	26
Pink to maroon sandstone, thin bedded, with a few massive layers as thick as 16 inches at intervals; interbedded with very sandy shale; upper part yellow-brown	48
Fine-grained hard gray and light-pink sandstone, weathering brown and light gray; weathers in beds 2 to 12 inches thick, but in fresh exposures beds appear very massive; upper part more reddish than lower; ordinarily well exposed	42
Red sandstone, with thin sandy shale interbedded, medium to massive bedding	31
Very thin bedded platy light-brown and yellow to pink sandstone, weathering reddish brown; abundant ripple marks; grades locally into shale; forms slopes	36
Pink to red sandy shale, containing thin beds of platy sandstone; weathers in slopes	21
Total thickness of Moenkopi formation	304
Kaibab limestone: Deep-yellow to buff very hard fine-grained dense dolomitic limestone, in massive beds 3 to 6 feet thick; weathers in large angular blocks; forms prominent bench; exposed thickness	20

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Last Updated: 08-Aug-2008