Stratigraphy and Environment of the Toroweap Formation (Permian) North of Ashfork, Arizona

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Stratigraphy and environment of the Toroweap Formation (Permian) north of Ashfork, Arizona

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Authors Mullens, Rockne Lyle, 1944-

Publisher The University of Arizona.

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Link to Item http://hdl.handle.net/10150/554040 STRATIGRAPHY AND ENVIRONMENT OF THE TOROWEAP

FORMATION (PERMIAN) NORTH OF

ASHFORK, ARIZONA

Rockne Lyle Mullens

A Thesis Submitted to the Faculty of the

DEPARTMENT OF GEOLOGY

In Partial Fulfillment of the Requirements For the Degree of

MASTER OF SCIENCE

In the Graduate C ollege

THE UNIVERSITY OF ARIZONA

19 67 STATEMENT BY AUTHOR

This thesis has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library.

Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author.

SIGNED:

APPROVAL BY THESIS DIRECTOR

This thesis has been approved on the date shown below:

Professor of Geology ACKNOWLEDGMENTS

The research, on which this paper is based, was supported by a research grant from the Museum of Northern Arizona and a Special

Master's Program grant from the Ford Foundation. Mr. William J.

Breed and Dr. Edward B. Danson, Museum of Northern Arizona, and

Dr. Stanley S. Beus, Northern Arizona University, generously placed the facilities of the Museum and University at the writer's disposal.

Their cooperation is greatly appreciated.

The writer is greatly indebted to Dr. Richard F. Wilson, who

directed the research, and Drs. Donald L. Bryant and Joseph F.

Schreiber. Their critical reading of the paper and many suggestions were invaluable.

The writer is as always greatly indebted to his parents for

their continual assistance and encouragement throughout his entire

education; to them he is forever grateful. TABLE OF CONTENTS

Page

ACKNOWLEDGMENTS...... iii

LIST OF ILLUST RATIONS...... vi

ABSTRACT...... v iii

INTRODUCTION...... 1

Purpose and Scope of Investigation ...... 1 Location and P h y sio g r a p h y ...... 1 Methods of S tu d y ...... 3 History of Nomenclature of the Toroweap Formation . . . 10 General G e o lo g y ...... 15

DISCUSSION OF LITHOLOGIC U N IT S ...... 17

Coconino S a n d s to n e ...... 17 Toroweap-Coconino C ontact...... 18 Toroweap F o r m a tio n ...... 18 Toroweap-Kaibab Contact ...... 21 Kaibab Form ation ...... 22

PALEO NTO LO G Y...... 32

Faunal L is t ...... 32 Quantitative Faunal Distribution ...... 34 "Patch R e e fs " ...... 39

MINERALOGY...... 40

Authochthonous M inerals ...... 40 Allochthonous Minerals...... 41

CONCLUSIONS...... 43

Paleogeography...... 43 Correlation with Type Section of Toroweap Formation . . 43

iv V

TABLE OF CONTENTS--Continued

Page

Environmental Interpretations...... 45 Faunal Interpretations...... 51 Suggestions for Future Research ...... 53

APPENDIX A--LOCATION AND DESCRIPTION OF MEASURED SECTIONS OF THE TOROWEAP FORMATION (PERMIAN) NORTH OF ASHFORK, ARIZONA...... 59

SELECTED REFERENCES 99 LIST OF ILLUSTRATIONS

Figure Page

•L Index map of the study a rea ...... 2

2. Classification system for terrigenous clastic rocks (Folk, 1959)...... &

3. M ineralogical classification of carbonate r o c k s...... 5

4. Textural classification of carbonate rocks (Folk, 1 9 5 9 )...... 6

5. G rain-size sca le for carbonate rocks (Folk, 1959)...... 7

6. Relative fossil-abundance diagram (slightly modified from Belden, 1954)...... 8

7. Calibration curve for the x-ray determination of the percent dolomite in a carbonate sample (Tennant and Berger, 1957) ...... 11

8. Isopach map of unit I ...... 23

9. Isopach map of unit II...... 24

10. Thickness map of unit III ...... 25

11. Isopach map of unit IV ...... 26

12. Isopach map of unit V ...... 27

13. Isopach map of unit VI ...... 28

14. Isopach map of unit VII...... 29

15. Isopach map of unit VIII ...... 30

16. Thickness map of unit IX ...... __ ...... 31

vi v ii

LIST OF ILLUSTRATIONS--Continued

Figure Page

17. "Ndrmal marine" faunal abundance distribution in unit VI ...... 35

18. Nautiloid faunal abundance distribution in unit VII ...... 36

19. Gastropod faunal abundance distribution in unit VII ..... 37

20. Pelecypod faunal abundance distribution in unit VII ..... 38

. 21. Paleogeographic map of the time of maximum transgression of the Toroweap Sea ...... 44

22. Selected thin sections...... 54

23. Gastropoda...... 55

24. Nautiloidea and Pelecypoda .■ ...... 56

25. Ostracoda ...... 57

26. Vertebrata ...... 58

27. GEOLOGIC MAP OF THE STUDY AREA NORTH OF ASHFORK, ARIZONA ...... Back Pocket ABSTRACT

The Toroweap Formation in the area north of Ashfork, Arizona, is in an area of transition from predominantly "normal marine" de position in the Aubrey Cliffs area to the west to predominantly non marine deposition to the east of Sycamore Canyon to the southeast.

The Toroweap in the study area is divisible into nine units, each repre

senting a different environmental setting. These changes in environ ments of deposition are best explained by climatic fluctuations in the

source area, affecting both the amount of sediment and fresh water

contributed to the sea. The main factors controlling deposition in the

study area are the position of the brackish-saline water interface,

turbidity, and energy.

Heavy minerals and clays show that the predominant sources

for units I through VIII and unit IX are probably different. Units I

through VIII contain rounded, super-mature heavy minerals and illite;

while unit IX contains angular sub-mature heavy minerals and mont-

m o rillonit e - ve rm ic ulit e.

The chief factors affecting the faunal distribution in the study

area are substrate, water depth, energy, turbidity, and salinity. The

most important of these seems to be the character of the substrate. ix

The Toroweap Formation in the area north of Ashfork is characterized by very nearshore, shallow-water fauna that lived near a desert coastline under conditions of climatically controlled alter nating brackish and saline water environments. INTRODUCTION

Purpose and Scope of Investigation

The Toroweap Formation cropping out north of Ashfork, Arizona, is in an area of transition from predominantly "normal marine" deposi tion in the Aubrey Cliffs area to the west (McKee, 1938; Belden, 1954) to predominantly non-marine deposition to the east of Sycamore Canyon to the southeast (McKee, 1938). The Toroweap Formation in the Ash fork area seemed promising to provide detailed evidence for the loca tion and nature of this transition. The exposures north of Ashfork are the nearest outcrops of Toroweap east of the Aubrey Cliffs, studied by

Belden (1954), and represent a logical next area in a detailed study of the environments of deposition of the Toroweap Formation.

Location and Physiography

The area investigated is about five miles north-northwest of

Ashfork, Arizona, on Fitzgerald Hill, Ferno Mesa, and the southern

end of Paradise Ridge, which collectively make up the southwestern

edge of an extensive plateau, the Coconino Plateau. Detailed examina tion was made of a strip about two miles wide and four miles long

parallel to the southwestern edge of the major structural and topographic

province, the Colorado Plateaus (Fig. 1).

1 Fig. 1. - -Index map of the study area (back pocket). 3 Fitzgerald Hill and Ferno Mesa rise about 800 feet above the

Chino Valley to the southwest, to an altitude of 6, 000 feet. About two miles north and west of Fitzgerald Hill and Ferno Mesa, Paradise

Ridge rises another 300 feet to an altitude of 6, 300 feet. The climate is. semi-arid; precipitation averages about 14 inches per year. Vegeta tion consists chiefly of juniper and pinyon forests.

The thesis area is accessible from Ashfork, Arizona, by sev eral roads, all of which are rough and rutted. From Williams, Arizona, to the east it may be reached by a good, unpaved road from the Williams

Country Club. This road joins the Atchison, Topeka, and Sante Fe right-of-way road near Double A, near the eastern edge of the thesis area.

Methods of Study

The geologic map of the study area (Fig. 27, in back pocket) was constructed from United States Forest Service aerial photographs and from field observations. This map is uncorrected for lateral dis tortion, but since a mosaic of photographs was used in the preparation, distortion is probably minimal.

Detailed lithologic sections were measured by Abney hand level and tape measure. These sections are divided into units which consist of a bed or series of beds that display continuous deposition under the same or similar depositional environments. For purposes of discussion 4 and interpretation, these units are grouped into three-dimensional environmental units. Each unit displays a single environmental or depositional setting that is interpreted to be the result of a particular water depth, salinity, relation to strand, climate, source areas, and faunal distribution.

The classification system used for terrigenous clastic rocks

(those containing less than 50 percent carbonate and evaporite minerals) is that of Folk (1965), (Fig. 2).

The classification system used for carbonate rocks (those con taining more than 50 percent carbonate minerals) is that of Folk (1959),

(Figs. 3-5).

Both qualitative and quantitative paleontological methods were used in the study of the fauna of the Toroweap Formation. Qualitative methods consisted of the collection of fossils from each unit, identifi cation of the taxa present, and interpretation of the environmental significance of the assembleges. Quantitative methods consisted of the determination of the relative abundances of each of the major fossil groups, plotting and contouring these abundance values, and interpre tation of environmental trends from the abundance values from . these contour maps. The relative abundance of fossil groups was de termined by the use of the number of diameters between members of the same group (Fig. 6); a method first used by Belden (1954, p. 7-8, pi. 1) on the Toroweap Formation in the Aubrey Cliffs. An average 5

Sand

S - Sandstone C - Claystone s - Sandy c - Clayey Z - Silt stone M - Mudstone z - Silty m - Muddy

Fig. 2. - -Classification system for terrigenous clastic rocks (Folk, 1965).

1 Limestone i Dolomitic Limestone i Calcareous Dolomite t Dolomite i 0 10 50 90 100 Percent Dolomite

Fig. 3. - - Mineralogical classification of carbonate rocks. 7

Allochthonous Autochthonous Constituents Constituents

Very Coarse Calcirudite 64 mm Coarse Calcirudite Extremely Coarsely 16 mm Crystalline Medium Calcirudite 4 mm Fine Calcirudite Very Coarsely Crystalline 1 mm Coarse Calcarenite 0. 5 mm Coarsely Crystalline Medium Calcarenite 0. 25 mm Fine Calcarenite 0.125 mm Medium Crystalline Very Fine Calcarenite 0. 062 mm Coarse Calcisiltite 0. 031 mm Finely Crystalline Medium Calcisiltite 0.016 mm Fine Calcisiltite 0. 008 mm Very Finely Crystalline 0. 004 mm Calcilutite Aphano c ry st alline

Fig. 5. - -Grain-size scale for carbonate rocks (Folk, 1959). 8

Rare (R)

Common (C)

Common (VC) Abundant (A)

Unit Fossil D iam eter Diameters from an Individual

Fig. 6. - -Relative fossil-abundance diagram (slightly modified from Belden, 1954). 9 diameter was determined for each of the faunal groups; the distance between as many individuals as possible and their nearest neighbor of the same group was determined. Each of these measurements was divided by the average diameter of the group and the resulting series of numbers were averaged to obtain a relative abundance value for a particular location. These values were plotted and faunal distribution maps made from them.

The use of this method of recording fossil abundance rather than a grid method corrects for the size and somewhat for the mode of life differences among taxa, and gives a more realistic quantitation of relative faunal abundance.

Mineralogical techniques worthy of special description here are the method used to determine the cal cite-dolomite ratio in a carbonate rock sample, and the identification scheme used to determine the clay minerals. A semi-quantitative determination of the calcite-dolomite ratio in a carbonate rock sample can be quickly made by the use of x-ray diffraction techniques. A polished slice or thin section is mount ed in the diffractometer, and the region between 28 and 32 degrees 20

scanned to obtain the (104) calcite reflection (3. 03 A) and the (104) dolo mite reflection (2. 88 A). Since, in general, the area under an x-ray

diffractometer peak is directly proportional to the percent of a mineral present by weight in a sample, the calcite-dolomite ratio: is equal to the area under the calcite 3. 03 A peak divided by the area under the 10 dolomite 2. 88 A peak multiplied by the appropriate constant. This im plies a linear relationship between relative x-ray intensities and the weight percent of a mineral in a sample, but in practice, machine

sensitivities greatly affect the extreme ends of the curve. For con venience and accuracy of determination, samples of known calcite- dolomite ratio were scanned, and the peak-area ratios plotted on

semi-log scale to obtain a standardized calcite-dolomite ratio curve

(Fig. 7).

Samples high in clay minerals were disaggregated, dispersed

(when necessary), allowed to settle, and the clay fraction drawn off.

Both oriented and random mounts were scanned by diffractometry through a series of treatments with Mg++, ethylene glycol, and various

degrees and lengths of heating. The identification and classification

scheme used is that of Wars haw and Roy (1961), augmented by reflec

tion-intensity curves from Brown (1961).

History of Nomenclature of the Toroweap Formation

The earliest reference to the strata in Northern Arizona that

include the Toroweap Formation is by Marcou (1856), who was a mem ber of the expedition of 1853-54, led by Lieutenant Whipple. By litho

logic correlations across the North American continent, he considered

that the magnesian limestone or dolomite (Kaibab Formation) was

equivalent to the Magnesian Limestone (Permian) of England. A few 11

- 6 . 0

- 4. 0

- 2. 0

- 0. 6

- 0. 4

9p 100

Percent Dolomite in a carbonate sample

Fig. 7. - -Calibration curve for the x-ray determination of the percent dolomite in a carbonate sample (after Tennant and Berger, 1957). 12 m iles west of Bill Williams Mountain, at Partridge and Clear Creeks, a lower magnesian limestone (Toroweap Formation) was considered by

Marcou, on the basis of a fossil brachiopod, to be similar to the

Mountain Limestone (Lower Carboniferous) of England.

Newberry (1861) examined the same area of Partridge and

Clear Creeks, while with the exploration party under Lieutenant Ives.

He recognized the two limestones separated by gypsum, but unlike

Marcou, considered them, on the basis of fossil evidence, to be of

Upper Carboniferous age rather than Permian and Lower Carboniferous.

The name "Aubrey limestone" was given to these two Upper

Paleozoic limestones by Gilbert (1875), but later the name "Aubrey" was adopted as a group name for all the Upper Paleozoic sandstones and limestones (Supai Formation to Kaibab Formation) of the Grand

Canyon region by the United States Geological Survey. In 1910, Barton changed the name of the limestones to the "Kaibab limestone" to re solve the conflict of terminology. The "Kaibab limestone" was named from its extensive outcrops on the Kaibab Plateau, but no type section was designated. A type section for the "Kaibab limestone" was desig nated by Noble (1928) in Kaibab Gulch, Utah, that included all of the strata between the Hermit Shale (the Coconino Sandstone is missing in

Kaibab Gulch) and the Moenkopi Formation.

During the late nineteenth and early twentieth centuries, many eminent geologists described the "Kaibab limestone" of Northern 13

Arizona; however, most of the references were to the uppermost of the two limestones.

McKee (1938) considered that the "Kaibab lim estone,11 as pre viously recognized, contained not one but two distinct formations. He proposed that the name Kaibab be retained for the upper of these two formations, and that the name be changed to Kaibab Formation to avoid confusion over the varied lithologies represented in the redefined Kai bab. For the lower of the two formations he proposed the name Toro- weap Formation.

McKee (1938) named three formal members of the Toroweap

Formation: the Alpha, Beta, and Gamma Members from top to bottom.

The Gamma Member is a red to yellow fine-grained sandstone.that grades vertically into limestones of the Beta Member.

The Beta Member of the Toroweap Formation is a massive gray limestone, which is 220 feet thick in the type section in Toroweap Val ley, thins regularly to the east and southeast, and is absent along the

Little Colorado Canyon and in Sycamore Canyon. The Beta Member is divisible laterally into two facies. Facies 1 occurs roughly west of a line joining Toroweap Valley and Seligman, Arizona, and consists of limestones containing "normal marine" brachiopods, crinoids, and echinoids. Facies 2 is a limestone with a molluscan fauna that occurs roughly to the east of the line joining Toroweap Valley and Seligman. 14

The Alpha Member of the Toroweap Formation is an interbedded unit of "red beds, " gypsum, and thin magnesian limestones that is divisible into two lithologic facies. Facies 1 is a unit of interbedded gypsum and thin magnesian limestone that occurs generally west of the

Toroweap Valley-Sellgman line. Facies 2 is a "red bed" unit without

evaporite deposits that occurs east of the Toroweap Valley-Seligman line.

The Gamma Member, and facies 1 and 2 of the Beta and Alpha

Members make up what is known as the western phase of the Toroweap

Formation. This western phase grades laterally to the east by inter- tonguing into beds of white cross-laminated sandstone of the eastern

phase of the Toroweap. This transition is completed over a short lateral distance that lies roughly on a line connecting Desert View

Point in the Grand Canyon and Sycamore Canyon on the Mogollon Rim.

The nomenclature used in this thesis includes the Toroweap

Formation as defined by McKee (1938), but rejects the use of the formal members. Alpha, Beta, and Gamma, because precise lateral relation

ships with the type Toroweap Formation in Toroweap Valley have not been determined. The use of the terms eastern and western phases, while useful at present, may require a redefinition of the Toroweap-

Coconino relationship in the eastern phase when detailed studies of this

transition are made. The Toroweap Formation, in this thesis, is di

vided into nine informal environmental units. The relationships of 15 these units to McKee's (1938) members will be discussed under inter pretations and conclusions.

General Geology

The formation exposed in the area north of Ashfork, Arizona, are, in ascending order, the Coconino Sandstone, Toroweap Formation,

Kaibab Formation, all of Permian Age, and pyroclastics and basalts of

Teritiary(?) Age.

The Coconino Sandstone is a very pale orange, fine-grained sandstone composed almost exclusively of very thick sets of cross laminae. Extensive outcrops of Coconino cover most of Fitzgerald Hill and Ferno Mesa, and form the lower half of the cliffs connecting the two. The Coconino Sandstone in the area north of Ashfork, Arizona, was considered to be of eolian origin by McKee (1934). The upper sets of cross-laminated sandstone in this area are quarried extensively as building material (flagstone).

The Toroweap Formation is made up of a lower unit of thin- bedded pale-red and orange sandstones and siltstones interbedded with gray sandy silty dolomites, a middle unit of massive very pale orange dolomite, and an upper unit of rqd sandstones and siltstones. The

Toroweap forms an extensive band of outcrops from Fitzgerald Hill to

Ferno Mesa, and forms the lower slope of Paradise Ridge, The 16

Toroweap Formation in this area is considered to be of marine origin

(McKee, 1938).

The Kaibab Formation is a light-gray, thin-bedded to massive limestone. The Kaibab crops out as the capping of two mesas between

Fitzgerald Hill and Ferno Mesa, and as the capping of Paradise Ridge.

The Kaibab Formation in this area is also considered to be of marine origin (McKee, 1938).

Pyroclastics of Tertiary(?) Age fill channels in the Kaibab and

Toroweap Formations and are overlain by massive basalts also of

Tertiary(?) Age.

The strata in the study area are broken by at least four north west-striking faults. These faults are nearly vertical, and most commonly have the northeast side upthrown with respect to the south west side; the faulting is post-Kaibab (Middle Permian) and pre-lava

(Tertiary?), and also of probable Tertiary Age. The strata are warped into a gentle synclinal structure, the limbs of which dip less than five degrees. The Toroweap Formation is beveled by post-warping and pre-lava erosion on both Fitzgerald Hill and Ferno Mesa. DISCUSSION OF LITHOLOGIC UNITS

The upper Coconino Sandstone, the Toroweap Formation, and the lower Kaibab Formation are divided into three-dimensional units in this section for the purpose of discussing the vertical and lateral succession of depositional environments. These units are discussed in relation to their lithologies, thickness, and fauna; and the vertical and lateral relationships of these parameters.

Coconino Sandstone

The upper Coconino Sandstone in the area north of Ashfork,

Arizona, is a very thickly cross-laminated,"*■ very pale orange (10YR 2 3 8/2) to moderate orange pink (SYR 8/4), fine-grained sandstone that is very well sorted, rounded, frosted, and well cemented by silica overgrowths (Fig. 22a). It weathers to form partially covered steep slopes and rounded hilltops, punctuated by numerous outcrops.

1. All stratification terminology is according to the classifica tion of McKee and Weir (1953).

2. All rock-colors are designated after comparison with the Rock-color chart, (Rock-Color Chart Committee, 1948).

3. All grain sizes are given according to the Wentworth Particle Size Classification (Wentworth, 1922).

17 p Toroweap-Coconino Contact 18

The Toroweap-Coconino contact in this area is a very flat, broadly undulating, stained surface that truncates the upper cross- laminae of the Coconino Sandstone.

Toroweap Formation

Unit I of the Toroweap Formation is a laminated, pale-red (5R

8/4) sandstone to siltstone. It consists of subangular, poorly sorted medium-grained silt to very fine grained sand; and rounded, frosted very fine to coarse-grained sand (Fig. 22b). Both sandstones and siltstones are cemented with dolomite and are friable. Unit I has a maxi mum thickness of 4. 6 feet in measured section 2 and a minimum of 3. 0 feet in measured section 4 (Fig. 8). This unit weathers to form a covered slope above the Toroweap-Coconino contact.

Unit II grades from a thin-bedded, pale red (5R 6/2), sandy silty dolomite at the base to a thin-bedded, pale yellowish brown (10YR

6/2) to grayish-orange (lOYR 7/4) dolomite at the top (Figs. 22c, d).

This transition takes place by a gradual reduction in terrigenous clastic content toward the top of the unit, and a reduction toward the west and northwest. The dolomite is finely crystalline with some porosity; the terrigenous grains are similar to those in unit I with some fine-grained, angular silt in the middle and upper portions of the unit. The unit has a maximum thickness of 30. 6 feet in measured section 7 and a minimum 19 of about 27 feet in measured section 6 (Fig. 9). Unit II weathers to form a slope composed of rounded benches and steps. Ostracods and fragmentary mollusks are locally abundant and scattered thoughout the unit. A three-foot-thick Paraparchites zone forms a good marker unit about 6~ feet above the base of the zone; Paraparchites sp., Jonesina sp., and Corvella sp. are very abundant.

Unit III is a laminated to thin-bedded, grayish-orange (10YR

7/4) sandy siltstone. It is composed of moderately well sorted, subangular, coarse-grained silt to very fine grained sand. The siltstone is cal cite cemented and is friable. The unit has a maximum thickness of 6. 7 feet in measured section 7 and a minimum thickness of 6. 5 feet in measured section 4 (Fig. 10). Unit III weathers to form a covered slope.

Unit IV is a thin-bedded, light to medium -gray (N7 to N5) dolo mite. The dolomite is finely crystalline with rare beds of very coarsely crystalline limestone (Fig. 22e). The unit has a maximum thickness of 11. 6 feet in measured section 2 and a minimum of 6. 5 feet in measured section 4 (Fig. 11). Unit IV weathers to form a slope composed of sharply defined steps. Fragmentary mollusks are abundant in some beds, especially in the upper part of the unit.

Unit V is a laminated to thin-bedded, grayish-orange (10YR7/4) sandy silstone similar to unit III. The unit has a maximum thickness 20 of 5. 7 feet in measured section 2 and a minimum of 4.1 feet in measur ed section 4 (Fig. 12). Unit V weathers to form a covered slope.

Unit VI is a massive, very pale orange (10YR 8/2) silty dolo mite, composed of finely crystalline dolomite and fine- to medium- grained, subangular, well-sorted quartz silt (Fig. 22f). The unit has a maximum thickness of 50. 4 feet in measured section 1 and a mini mum of 33. 6 feet in measured section 3 (Fig. 13). Unit VI weathers to form a prominent cliff. Crinoid, echinoid and brachiopod remains decrease in particle size from 30 to 50 millimeters in the western part of the area to about one-sixteenth of a millimeter in the central part. Taxa recognized in this unit include Squamaria ivesi, ?Archa- eocidaris sp., Bellerophon (Bellerophon) hilli, Bellerophon (B. ) cf.

B. (B.) deflectus. Glabrocingulum ( Glabrocingulum ) coronatum, and

Schizodus sp.

Unite VII is a thin-bedded, pale-brown (SYR 5/2) finely cry stalline dolomite to dolomitic limestone. This unit is variable in thick ness (Fig. 14) and grades laterally into the top of unit VI in the western part of the area. Unit VII weathers to form a slope composed of sharply defined steps above unit VI. Fossils include a rich mollusc an fauna in the main body of the unit, and a rich brachiopod-bryozoan fauna in rare "patch reefs. " Taxa recognized include Metacoceras bowmani. ? Cooperoceras sp., Euphemites sp., Bellerophon (Bellero phon) hilli, Goniasma geminocarinata, Straparolus (Euomphalus) 21 kaibabensis, Warthia sp., Knightites (Retispira) modesta, ?Orthonema

cf. O. Socorroense, ?Orthonema striatonodosa, Schizodus sp.,

Sanguinolites sp. . and Plagioglypta canna.

Unite VIII consists of thin-bedded grayish-pink (SYR 7/2) lim e

stone and dolomite, and pale-red (10YR 6/2) bedded chert. The lime

stone is coarsely crystalline, and the dolomite is finely crystalline

and silty. The unit has a maximum thickness of 6.4 feet in measured

section 5 but is absent over most of the study area (Fig. 15). Unit VIII

weathers to form a rounded outcrop band in a gentle slope above unit

VII.

Unit IX is a "red bed" sequence, consisting of orange to reddish-

orange sandstones to silt stones, and rare sandy limestone lenses. The

sandstones and siltstones consist of fine- to coarse-grained, angular

silt; very fine grained, subangular sand; and fine- to coarse-grained,

rounded, frosted, clear quartz sand. The unit is rather uniform in

thickness and varies from about 97 to 105 feet (Fig, 16). Unit IX

weathers to form a long, gentle, covered slope with rare outcrops near

the top of the unit. i . . ' ■ / ••

■ . ' 1 : : . ' ' ’ • , Toroweap-Kaibab Contact

The Toroweap-Kaibab contact is arbitrarily placed, in this v ■ ; thesis, at the color change from predominantly red siltstones below the

contact to predominantly yellow siltstones above it. Commonly 22 associated with this color change is a conglomeratic zone in the basal yellow siltstones of the Kaibab Formation. However, the contact, could also be placed between the yellow siltstones and the marine lim e stones of the Kaibab above them.

Kaibab Formation

The basal part of the Kaibab Formation is a laminated to faintly cross -laminated, pale yellow ish - o range (10YR 8/6) to moderate orange pink (SYR 8/4) siltsone that contains a thin, light brownish gray (SYR

6/1) limestone about five feet above the base of the unit. The siltstone consists of moderately well sorted, fine- to medium-grained, angular silt. The unit weathers to form a covered slope of friable siltstone beneath the massive limestones of the Kaibab Formation. This unit is commonly brecciated or conglomeratic. 23

1.0

Miles

Isopach interval = 0.5 feet

3 7 x * = Control point, thick ness of unit in feet Fig.:. 8 .- -Isopach map of unit I 24

Mile s

Isopach interval = 1 foot

x31. 6 _ Qoirtroi point, thick ness of unit in feet

Fig. 9. - -Isopach map of unit II. 25

s% i 1 - - % \ = * ,

<' % ;/,o5 r > \ VV SN ,,'l(x\Xvtl /V j "S unv^Z/IV^ ^

' 'nu"” «''' -- — ; i , ■*=» ^v, «u •..V$ / V ^•li«“ 6.5 / •> \X,'"Vfp- x % r \ / V k, 1 V>vl^ 5 5 < 6.7 -V "4 '•> \v xxxl//«« S-.'1"" ''' \ „ X I„."I\VV'U"' ,,l'V ^/IVV" vf / *•% V / -x" xXV X\ I,/ F 5 y 'n iv

V//IM 0

6 .7 Control point, thick ness of unit in feet

Fig. 10. --Thickness map of unit III. 26 x 9.5

f x"i, -- 0 0.5 1.0 - i i I Miles

Isopach interval = 1 foot

x10. 6 _ Qon^roj_ point, thick ness of unit in feet.

Fig. 11. - -Isopach map of unit IV. 27

% ",

Miles

Isopach interval =0.5 feet 4. 9 x ' = Control point, thick ness of unit in feet

Fig. 12. —Isopach map of unit V. 28

41.3 5

/ v\»/ ? 0 0.5 - I . 1.0

Miles

Isopach interval = 5 feet

5 Q 4 x ’ = Control point, thick ness of unit in feet

Fig. 13. --Isopach map of unit VI. 29

> ,0 .0

Miles

Isopach interval = 5 feet

4. 0 x * = Control point, thick ness of unit if feet

Fig. 14. --Isopach map of unit VII. 30

CAll'l' '

0 0.5 1.0 1 ______J______| % Miles

Isopach interval = 5 feet

0. 5 x * = Control point, thick ness of unit in feet

Fig. 15. --Isopach map of unit VIII. 31

: vi % \ s A 1 0 4 .6 ^ ^ 1/ 4'"^ c =L \ f '^, »tfvv\»*» QJ i %'mw01 1 3 =«' \ yic rr s u. ‘ r fQ ■f a . VN V ‘'•/ix" / \ 92.1 / ,-v'' r , \ ■ 'I t . '*

% .x' f

V \ t % / ' V'v ^s[<\ § i *>♦' ^Xx i f

iv , x ',"iti:7.:"''"'"'> 4? a\n' xV' / X' y / vS" //ylv 'Oil"'

/ XV // % 4' 4 1.0 Miles

100.7 x = Control point, thick ness of unit in feet

Pig. 16. - -Thickness map of unit IX PALEONTOLOGY

The fauna of the Toroweap Formation has been and is being described systematically in formal publications. Although several heretofore undescribed taxa were collected by the author and other workers in the Toroweap Formation, it is not within the scope of this thesis to describe this fauna systematically. The identification and interpretation of this fauna, however, is within the scope of this thesis and is presented in this part.

Faunal List

Bryozoa:

Septopora? sp.

Polypora? sp.

Ramose forms

Brachiopoda:

Squamaria ivesi (McKee, 1938)

Hustedia? cf. H. meekana (Shumard, 1860)

Phricodothyris ? cf. P. guadalupensis (Shumard, 1860)

Gastropoda:

Euphemites sp.

Warthia sp.

32 33

Bellerophon (Bellerophon) hilli (Yochelson, 1960)

Bellerophon (B .) cf. B. (B.) deflectus (Chronic, 1952) (Fig. 23a)

Knightites (Retispira) modesta (Girtv. 1909) (Fig. 23b, c)

Straparolus (Euomphalus)kaibabensis (Chronic. 1952) (Fig. 23d-f)

Glabrocingulum (Glabrocingulum) coronatum (Chronic, 1952)

Naticopsis sp.

Goniasma geminocarinata (Chronic. 1952)

Orthonema cf. O. socorroense (Girty, 1909)

Orthonema? striatonodosum (Chronic, 1952)

Scaphopoda:

Plagioglypta canna (White. 1874)

Cephalopoda:

Metacoceras bowmani (Miller and Breed, 1964) (Fig. 24a)

? Cooperoceras sp.

? Solenocheilus sp.

Gen. et sp. nov.

Pelecypoda:

Schizodus cf. S. texanus (Clifton, 1942) (Fig. 24b, c)

Palaeonucula levatiformis (Walcott. 1884) (Fig. 24d, e)

Sanguinolites sp. (Fig. 24f, g)

A start ell a sp.

Echinoidea:

?Archaeocidaris so. 34

Ostracoda:

Paraparchites cf. P. gibbosus (Upson. 1933) (Fig. 25a-e)

Coryella cf. C. stovalli (Harris and Laliker, 1932)(Fig. k, 1)

Jonesina sp. (Fig. f-j)

? Jonesina sp. (Fig. m-q)

V ertebrata:

Fish? ornaments, scales, and teeth (Fig. 26a-i)

Quantitative Faunal Distribution

Unit I was not observed to contain fossil remains. Unit II con

tains a very abundant to common ostracod fauna in its lower and middle

portions, and an abundant pelecypod fauna in its middle and upper por

tions. Unit III contains sparse fish ornaments, scales, and teeth.

Unit IV contains rare to abundant pelecypod and gastropod faunal re

mains. Unit V contains sparse fish remains as in unit III. Unit VI

contains a very abundant "normal marine" crinoid-brachiopod-echinoid

fauna in the western portion of the area (Fig. 17), and a sparse

pelecypod-gastropod fauna in the eastern and central portions. Unit VII

contains an abundant to sparse nautiloid-gastropod-pelecypod-scaphopod

fauna (Figs. 18, 19, 20). Unit VII contains rare, small biostromal

"patch reefs. " These "patch reefs" contain an abundant brachiopod- , i bryozoan-pelecypod fauna. Units VIII and IX were not observed to con-

tain fossil remains. • 35

*\V«' * % ..v .l\xv'-'vv, '"vvz//ll. Absent

r 4 0 0.5 1.0 J Mile $

Fig. 17. - -"Normal marine" faunal abundance distribution in unit VI /. A

I e s

Fig. 18. --Nautiloid faunal abundance distribution in unit VII 37

Fig. 19. - -Gastropod faunal abundance distribution in unit VII 38

K 0 0.5 1.0 \ ""** {______J ______| Miles

Fig. 20. --Pelecypod faunal abundance distribution in unit VII 39

"Patch Reefs"

One biostromal "patch reef" in unit VII crops out about i mile

southwest of measured section 7, and at least two more crop out along the west edge of Paradise Ridge to the north of the area of detailed

study. These "reefs" are small (about 15 feet in diameter), roughly

circular, undisturbed biostromes. Although they are encased in the finely crystalline dolomites of unit VII, these "reefs" are entirely limestone, and contain no species in common with the rest of unit VII.

Taxa recognized are Septopora? sp., Polypora? sp., a ramose bryozoan, Hustedia? cf. H. meekana, Phricodothyris ? cf. P. guadalu-

pensis, and an unidentified pelecypod. These "reefs" are essentially

undistrubed biocoenose communities. This is shown by the fact that

all of the bivalved shells are articulated, and by the gradation into

finely crystalline dolomites of unit VII> with a minimum of debris, over

a lateral distance of not more than two feet. MINERALOGY

Authochthonous Minerals

Dolomite and minor amounts of calcite are the most abundant authochthonous minerals in the Toroweap Formation in the study area.

The dolomite is of two types: type 1 is finely to coarsely crystalline and porous; type 2 is finely crystalline and dense, commonly interbedded with limestone. The calcite occurs as coarsely to very coarsely crystalline material interbedded with dolomites of type 2 and as cement in sandstones and silt stones. Units II, VI and VIII are pre dominantly of type 1 dolomite; units IV and VII are predominantly of type 2 dolomite and minor calcite.

Hematite and limonite form pseudomorphs after pyrite. These pseudomorphs are locally abundant in, and are restricted to unit'll.

The pseudomorphs occur as fracture fillings and replacement of dolo mite intraclasts in some locally brecciated zones, and as selective replacements of finely crystalline silty dolomite. The morphology of the crystals seems to be consistent within any one bed in an area, but is not consistent outside of that particular bed and local area. Forms observed were unmodified mirror cubes , mirror cubes modified by octahedrons, striated cubes, cubes modified by dodecahedrons.

40 41 pyritohedrons, octahedrons modified by cubes, octahedrons, and pyritohedrons modified by octahedrons.

Authigenic quartz occurs as small (50 microns) doubly-termi nated, free-growing crystals. These crystals are confined to unit II, becoming locally abundant near the middle of the unit.

Manganese oxides are locally abundant throughout the Toroweap

Formation in the study area. The only manganese mineral recognized

in units I through VIII is pyrolusite, which occurs as dendrites coating

fracture surfaces in dolomites and sandy siltstones. Lithiophorite

(LiMn^AlgOg- SH^O) is the only manganese oxide recognized in unit IX.

It occurs as minor amounts of spongy to colloform blebs in siltstones

and limestones, but in one locality just northwest of measured section

7 it forms as much as 40 percent by weight of silt stone beds near a

fault.

Allochthonous Minerals

Quartz silts and sands are the most abundant allochthonous

constituents in the Toroweap in the study area. Angular to subangular

very fine grained silt to very fine grained sand is abundant throughout

the formation; rounded, frosted fine- to coarse-grained sand is locally

abundant. 42

Heavy minerals in units I through VIII are entirely zircon, tourmaline, organic phosphates, and minor rutile; those in unit IX are zircon, tourmaline, leucoxene, apatite, and magnetite-ilmenite.

The clay minerals present in the Toroweap are illite, montmorillonite, and a random layer montmorillonite-vermiculite clay.

The principal clay mineral in units I through VIII is illite; the princi pal clay mineral in unit IX is a random layer montmorillonite-vermi culite with minor amounts of montmorillonite and illite.

In every sample examined the red color of the sediments was due to ferric iron oxides adsorbed onto the illite or vermiculite. In units I through VIII the major carrier of iron oxide is illite; in unit IX it is the clays high in vermiculite. The high montmorillonite clays are greenish white and carry little ferric iron. CONCLUSIONS

Paleogeography

The Toroweap Formation probably was deposited in a broad shallow sea on a stable shelf adjacent to an extensive desert to the east and southeast. The shoreline is marked by the transition from the marine western phase to the non-marine eastern phase of the Toroweap

(McKee, 1938). The shoreline (eastern phase-western phase transition) trended north-northeast to the north of Sycamore Canyon, Arizona, and possibly trended west to the southeast of Sycamore Canyon. The edge of the stable shelf was marked by the northwest trending Las Vegas

Hinge Line about 120 miles to the northwest of the study area. The Las

Vegas Hinge Line formed the boundary between the shelf facies to the southeast and the basinal facies to the northwest (Welsh, 1959). A hypothetical paleogeographic map (Fig. 21) was constructed to locate the study area with respect to supposed major paleogeographic pro vinces.

Correlation With Type Section of Toroweap Formation

A three-fold division of the Toroweap in the study area can be recognized as being generally correlatable with the three formal mem bers in the type area in Toroweap Valley, 100 miles to the northwest.

43 Approximate limit of the stable shelf

ColoradoUtah Arizona New M exico

D efiance Nevada P ositive A rea Toroweap Sea

Co conino -T oroweap

eastern phase desert A rea

Known shoreline

Inferred shoreline

Fig. 21. - -Paleogeographic map of the time of maximum transgression of the Toroweap Sea. 45

Unit I in the study area is probably equivalent to part of the Gamma

Member; units II through VIII are equivalent to the Beta Member; and unit IX is equivalent to the Alpha Member.

Environmental Interpretations

The Coconino Sandstone is a thick, eolian blanket sand deposited under arid desert conditions (McKee, 1934). To the west of the Desert

View-Sycamore Canyon line, eolian deposition was ended by the onlap of the Toroweap Sea; east of this line eolian sand deposition continued simultaneously with the deposition of marine sediments to the west of the lin e.

The Toroweap Formation in the area north of Ashfork, Arizona, was deposited in a shallow, nearshore embayment along an arid coast line. The embayment was bordered on the east and south by deserts in which sand dunes, driven by a prevailing southeasterly wind (Reiche,

1938), were active during the entire time of Toroweap deposition. The shore line makes a half circle around the embayment to the southeast

(Fig. 21).

Unit I of the Toroweap Formation is a thin sheet of sandstone and siltstone possibly formed as a low-energy beach deposit as the

Toroweap Sea transgressed onto the deserts to the southeast. The silts and sands were derived from the reworking of local Coconino sands and the influx of Toroweap eastern phase sands and angular silt probably 46 brought in from the south and northeast by river systems. This sand

and silt is a moderate energy deposit; but compared to normal beach

deposits, it is of much lower energy. This apparent lack of wave action may have resulted from a restriction between the study area and the

Aubrey Cliffs area, where a correlative of unit I is thicker and con tains low-angle cross-laminae suggestive of typical beach deposits

(Belden, 1954).

Unit II is a sequence of sandy dolomites formed very near the

shore under conditions of alternating brackish and hypersaline waters.

Seasonal high precipitation probably increased flow and competence in

rivers, producing turbid, brackish waters in which an abundant ostracod

fauna thrived; dry seasons reduced flow and competence of streams,

allowing conditions of low influx of fresh water and sediments, and high

evaporation, produce increased salinity and carbonate precipitation.

This is evidenced by the mixing of brackish water ostracod faunas and

fine-grained silt with thin laminae of secondary dolomite (type 1) after

limestone. In thin section, rare undisturbed samples contain alternating

very thin laminae of sandy silt and finely crystalline dolomite. Most

samples are, however, highly disturbed and contain random sand and

silt grains in a finely crystalline dolomite matrix.

Unit III is a thin, uniform sheet of sandy siltstone probably de

posited under brackish water conditions. Major climatic fluctuations

probably brought about increased precipitation that increased river 47 flow and competence, with the net result of moving the brackish-saline water interface and carbonate deposition farther seaward to the north w est.

Unit IV is a sequence of dolomites and interbedded limestones of low clastic content probably formed under conditions of high salinity

and low turbidity. Major climatic fluctuations may have caused de

creased precipitation, decreasing river flow, and competence; these

decreases would allow chemically precipitated lime muds to accumulate

under very near shore restricted conditions. Most of this lime mud

was altered to dolomite (type 2) penecontemporaneously before lithifi-

cation.

Unit V is identical in lithology to unit III and is probably also

identical to unit III environment of deposition.

Unit VI is a massive bed of silty dolomite that was probably

deposited under "normal marine" conditions on the extreme western

edge of the study area, and alternating brackish and saline conditions

in the central and eastern portions. The "normal marine" crinoid-

brachiopod-echinoid fauna thrived in abundance on a bioclastic calciru-

dite bottom made up of crinoid stems, echinoid plates and spines, and

whole and fragmentary brachipod shells. In the central part of the study

area, a pelecypod-Bellerophon (B .) deflectus fauna lived on a bioclastic

calcarenite bottom. In the eastern part, a sparse G1 abro cingulum-

Schizodus-Astartella fauna lived on a bioclastic calcisiltite bottom. 48

Conditions of low wave activity prevailed, but were punctuated by periods of high wave and current energy as evidenced by common thin well-sorted bioclastic calcirudite beds in a generally poorly sorted calcarenite and calcisiltite. The evidence for brackish-water condi tions prevailing sporadically in the central and eastern portions of the area is the great abundance of silt in unit VI (20 to 40 percent) which must have been carried to the sea by rivers or streams. This unit marks the farthest advance to the southeast of the "normal marine" environment, and probably the time of maximum transgression of the

Toroweap Sea.

Unit VII is a finely crystalline dolomite that was probably de posited under conditions of regression and low precipitation. This regression restricted the depositional environment, and caused the deposition of penecontemporaneous lagoonal dolomites (type 2). A sparce to abundant molluscan fauna lived on a carbonate -mud bottom, characterized by very low energy conditions. The extreme variability of this unit and its relationship to unit VI are not clearly understood and do not fit any of the models proposed by this author.

Unit VIE is a sequence of silty dolomites and bedded cherts restricted to the western portion of the study area. It is probably con temporaneous with and may intertongue with the lowermost "red beds" in the area. Since it was observed to contain no fauna and is only 49 represented on the extreme western edge of the study area, very little is known about its environment of deposition.

Unit IX is a "red bed" sequence deposited as a very wisespread clastic sheet. That unit IX is of marine origin is demonstrated by the unbanded nature of the very fine grained elastics. The clay minerals have the appearance of having been flocculated, indicating a probable saline environment of deposition. Although the source areas which supplied clastic sediments to units I through VIII were still active, the predominant source area had changed. This change is evidenced in the nature of the heavy minerals and clays. The only allochthonous heavy minerals noted in units I through VIII are tourmaline, zircon, and minor rutile; these are very well rounded and nearly spherical. The heavy minerals in unit IX include rare grains as in units I through VIII, but the preponderance of the grains are angular zircon, rutile, leucoxene, apatite, and magnetite-ilmenite. The predominant clay mineral in units

I through VIII is illite; the predominant clay mineral in unit IX is montmorillonite-vermiculite with only minor amounts of illite. The high montmorillonite-vermiculite content of this unit tends to indicate vol- canism in the source area, since in the Late Paleozoic and Early and

Middle Mesozoic Eras in the Colorado Plateaus area, high montmorillonite clays are almost invariably associated with known tuffaceous volcanic material. This is especially true in the Trias sic (Schultz,

1963). The nearest known Permian volcanic activity lay to the northwest 50 in the Cordilleran area in northern Nevada. West of the Toroweap

Valley-Segilman line, thick evaporite sequences were deposited in equivalents of unit IX, but in the study area to the east of the line, evaporite deposition was probably prevented by the influx of fresh waters from the same river systems that supplied sediment and fresh waters to the embayment throughout Toroweap time.

The basal part of the Kaibab Formation contains siltstones and sandstones with low-angle cross-lamination suggestive of a beach de posit formed by the reworking of Toroweap "red beds" by the trans gressing Kaibab Sea.

An alternate hypothesis to explain the variation in clastic- carbonate, calcite-dolomite ratio, type of dolomite, and fossil content of the Toroweap Formation in the study area is that the variations were caused by a series of minor transgressive and regressive cycles within the major Toroweap transgression. Although this author feels that the climatic hypothesis fits the data better and explains the observed varia tions more logically, the actual environmental model for the Toroweap in this area may be a complex function of both climate and transgressive-

regressive cycles, plus other physical phenomena not directly suggested by the preserved criteria. 51

Faunal Interpretations

The Permian of northern Arizona contains a markedly variable fauna, both vertically and laterally. Numerous statements have been made as to the paleoecological significance of these variations. McKee

(1938) divided the Beta Member of the Toroweap Formation into two facies on the basis of faunal content. Facies 1 is characterized by a

crinoid-echinoid-brachiopod fauna that the interpreted to be distinctive

of a "normal marine" environment; facies 2 contains a molluscan fauna / characterized by bellerophontid gastropods that he interpreted to be

distinctive of a brackish-water environment.

Nicol (1944) studied three faunal zones in the Alpha Member of

the Kaibab Formation, and concluded that the distribution of the mol

luscan fauna is strongly controlled by the substrate, turbidity and

energy, and salinity. He concluded that the anomalously high abundance

of nautiloids in a restricted environment characterized by mud-bottom

dwelling organisms was due to their having been washed into their pre

sent burial location.

Data from the present study indicate that the most important

factors controlling molluscan fauna distribution are substrate, energy,

depth of water, and salinity. The most important of these was probably

substrate; the least important may be salinity, but a complex interrela

tionship among all of these factors is indicated. 52

Bellerophon (Bellerophon) deflectus occurs only in association with the calcarenite bottom in unit VI, and Astartella sp ., Palaeonucula sp., Glabrocingulum sp., and Schizodus sp. occur only associated with the calcisiltite bottom. Unit VII contains a fauna characterized by such mud-bottom dwelling forms as Plagioglypta sp., Sanguinolites sp.,

Goniasma sp., and thin-shelled bellerophontid gastropods. Faunal abundance variations within this unit are probably due primarily to water depth. The nautiloids within unit VII may have floated into their present burial location.

This author believes that serious doubt has been cast on the validity of the use of the bellerophontid gastropods as indicators of a brackish-water environment. They seem to be much more sensitive to substrate, water depth, and energy of the environment than they are to

salinity. The occurrence of the "normal marine" crinoid-brachiopod-

echinoid fauna in the study area does not provide evidence on the relia bility of this fauna as an indicator of the "normal marine" environment;

however, studies of their variation in abundance in the Aubrey Cliffs

indicate that they are reasonably reliable as "normal marine" indicators

(Belden, 1954). They also seem to reflect substrate and possibly depth

of water to some degree. 53

Suggestions for Future Research

A redefinition of the members of the Tordweap Formation in the western phase, and of the Toroweap eastern phase-Coconino Sand

stone relationship in the eastern phase, are needed. The formal mem

ber names Alpha, Beta, and Gamma are not good terminology since

these names imply a vertical relationship, which is not strictly true;

and there are probably more than three distinct members in the

western phase.

A systematic detailed examination of the lithology and fauna on

which to base interpretative environments of deposition of the Toroweap

Formation is needed to determine the validity of interpretations made

in this thesis, and to propose alternative and additional interpretations. Fig. 22. - -Selected thin sections. a. Coconino Sandstone, showing secondary quartz overgrowths; 30X. b. Toroweap Formation, sandy siltstone from unit I immediately above Coconino-Toroweap contact; 4OX. c. Toroweap Formation, interlaminated dolomite and siltstone fr o m unit II; 2 OX. d. Toroweap Formation, silty dolomite from unit II; 40X. e. Toroweap Formation, finely crystalline dolomite from unit IV; 4QX f. Toroweap Formation, bioclastic fragments in silty dolomite from unit VI; SOX. 54

e f Fig. 22. - -Selected thin sections. Fig. 23. - -Gastropoda.

a. Bellcrophon (Bellerophon) dcflcctus Chronic, 1952; side view; IX.

b. Knightites (Retispira) modesta (Girty, 1909); side view; IX.

c. Knightites (Retispira) modesta (Girty, 1909); apertural view; IX.

d. Straparolus (Euomphalus) kaibabensis Chronic, 1952; um bilical view IX. e, f . Straparolus (Euomphalus) kaibabensis Chronic, 1952; top view; lx 55

Fig. 23. - -Gastropoda. Fig. 24. --Nautiloidea and Pelecypoda. a. Metacoceras bowmani Miller and Breed, 1964; side view; IX. b. Schizodus cf. S. texanus Clifton, 1942; interior view of left valve* —nxr c. Schizodus cf. S. texanus Clifton, 1942; exterior view of left valve; l£X .

d. Palaeonucula levatiformis (Walcott, 1884); interior view of left valve; 4X.

e. Sanguinolites sp .; interior view of right valve; l |X .

f. Sanguinolites sp .; exterior view of right valve; l &X. e

Fig. 24. - -Nautiloidea and Pelecypoda. Fig. 25. --Ostracoda.

a-e. Paraparchites cf. P. gibbosus Upson, 1933; 25X. f-k. Jonesina sp.; 25X.

1, m. Coryella cf. C. stovalli Harris and Laliker, 1932; 25X. n - r . ?Jonesina sp .; 25X. Fig. 25. - -Ostracoda Fig. 26. --Vertebrate, a, b. Fish ornaments; top view; 25X. c-e. Fish ornaments; bottom view; 25X. f. Fish ornament( ? ); 25X. g. Fish scale fragment (?); 25X. h,i. Fish teeth; 10X. 58

Fig. 26. --Vertebrata APPENDIX A

LOCATION AND DESCRIPTION OF MEASURED SECTIONS

OF THE TOROWEAP FORMATION (PERMIAN)

NORTH OF ASHFORK, ARIZONA

Toroweap Formation Section 1.

Sec+ion measured one-half way down canyon in NE 4 , SW 4 , SWi, Sec. 7, T. 22 N ., R. 1 W. about i mile southeast of a little used road that runs from the Sante Fe right-of way, down a prominent point, to Ashfork, Arizona. Tertiary(?): Basalts (unmeasured). Unconformity: Erosion and Channeling.

Perm ian: 1 Toroweap Formation (incomplete): F eet Unit VII: 22. Biogenic dolomite, very pale orange (10 YR 8/2), weathers pinkish-gray (5Y 8/1); finely crystalline; thin- to thick-bedded; weathers to form a step- slope above massive cliff; fossiliferous, Schizodus sp., Sanguinolites sp., Astartella sp., Palaeo- nucula sp ., Bellerophon (B. ) hilli, Euphemites sp., Knightites (Retispira) modesta, Goniasma sp., Metacoceras bowmani. ------4. 0 Total of unit VII.------4. 0

Unit VI: ; 21. Silty dolomite, very pale orange (10 YR 8/2), wea thers pinkish-gray (5Y 8/1); finely crystalline; contains fine- to medium-grained silt, well-sorted.

59 60

composed of angular quartz grains; thick- to massive-bedded; weathers to form a massive cliff. ------4 6 .4 20. Silty dolomite, very pale orange (10 YR 8/2), weathers slightly grayer; finely crystalline; con tains fine- to medium-grained silt, moderately well sorted, composed of angular quartz grains; thin-bedded; weathers to form a rounded bench at base of cliff; small white mega-quartz pods com mon. ------4. 0 Total of unit VI. ------:------50. 4

Unit V: 19. Covered. ------6. 0 Total of unit V . ------6. 0

Units III and IV; 18. Biogenic dolomite, pale-brown (5 YR 5/2), weathers pale yellowish brown (10 YR 6/2); coarsely to finely crystalline; thick-bedded; weathers to form a sharp bench; fossiliferous, pelecypod.fragments common. - - 2.9 17. Recrystallized limestone, pale-brown (5 YR 5/2), weathers pale yellowish brown (10 YR 6/2); coarsely crystalline; thin-bedded, with some laminae near middle of unit; weathers to form a sharp bench.------2 .9 16. Covered.------10.0 Total of units III and IV.------15.8

Units I and II; 15. Silty dolomite, grayish-orange (10 YR 7/4), lam inated with pale yellowish brown (10 YR 6/2), weathers very pale orange (10 YR 8/2); finely crystal line; contains fine- to medium-grained silt, moderately well sorted, composed of angular quartz grains; laminated to thinly laminated; weathers to form a partially covered step-slope.------2. 6 14. Silty biogenic dolomite, pale-red (10R 6/2), weathers grayish-orange (10YR 7/4); finely cry stalline; contains fine- to medium-grained silt, fair-sorting, composed of angular quartz grains; thin-bedded; weathers to form a rounded bench; fossiliferous.------1.1 61

13. Silty biogenic dolomite, pale yellowish brown (10 YR 6/2), weathers very pale orange (10 YR 8/2); finely to coarsely crystalline; contains fine- to medium- grained silt, fair-sorting, composed of angular quartz grains; thin-bedded; weathers to form a rounded bench; fo ssilife r o u s. ------1. 6 12. Silty dolomite, grayish-orange (10 YR 7/4), weathers slightly lighter; finely crystalline; con tains fine- to medium-grained silt, moderately well sorted, composed of angular quartz grains; thick-bedded; weathers to form a rounded bench; patchy limonite staining; fossiliferousf ?).------2 .8 11. Silty dolomite, pale-red (10 YR 8/2), weathers very pale orange (10 YR 9/2); finely crystalline; contains fine- to medium-grained silt, fair-sort ing, composed of angular quartz grains; thin- bedded; weathers to form a pitted and ridged bench. - - 1.6 10. Silty dolomite, light brownish gray (SYR 6/1), weathers very pale orange (10YR 8/2); finely cry stalline; contains fine- to medium-grained silt, fair-sorting, composed of angular quartz grains; thin-bedded; weathers to form a rounded bench.------2.1 9. Silty dolomite, light olive gray (5 Y 6/1), weathers yellowish-gray (5 Y 8/1); finely crystalline; contains fine- to medium-grained silt, well-sorted, com posed of angular quartz grains; thin-bedded; wea thers to form a rounded step.------1.3 8. Silty dolomite, light olive gray (5 Y 6/1), weathers grayish orange pink (SYR 7/2); finely crystalline; contains fine-to medium-grained silt, well-sorted, composed of angular quartz grains; thin-bedded; weathers to form a rounded step.------0. 9 7. Silty dolomite, pale-red (SR 6/2), weathers gray ish orange pink (SYR 7/2); finely crystalline; con tains fine- to coarse-grained silt, poorly sorted, composed of angular to subangular quartz grains; thin-bedded with some thin laminae near top of unit; weathers to form a rounded bench.------2 .3 6. Silty dolomite, pale-red (10R 6/2), weathers pink ish-gray (SYR 8/1); finely crystalline, contains fine- to coarse-grained silt, poorly sorted. 62

composed of angular quartz grains; thin-bedded; weathers to form a pitted bench.------1.1 5. Silty dolomite, pale-red (10 R 6/2), weathers light- brown (5 YR 6/4); finely crystalline; containes fine- to coarse-grained silt, poorly sorted, composed of angular quartz grains; thin-bedded; weathers to form a distinct bench.------1. 0 4. Silty dolomite, pale-red (5 R 6/2), weathers pale yellowish brown (10 YR 6/2); finely crystalline; con tains, fine- to coarse-grained silt, poorly sorted, composed of angular to subangular quartz grains; thin-bedded; weathers to form a rounded bench.------1. 0 3. Sandy silty dolomite, grayish-orange (10 YR 7/4), weathers pale yellowish brown (10 YR 6/2); finely crystalline; contains coarse-grained silt to very fine-grained sand, moderately well sorted, com posed of subangular quartz grains; thin-bedded; weathers to form a rounded bench.------1.4 2. C o v e r e d .------13. 8 Total of units I and II.------34. 6 Total of incomplete Toroweap Formation.------110. 8

Unconformity: Toroweap-Coconino contact is a flat surface truncating the cross strata of the Coconino Sandstone.

Coconino Sandstone (unmeasured):

1. Sandstone, grayish orange pink (SYR 7/2); fine grained, very well sorted; composed of rounded, frosted quartz grains; well-cemented, silica-over growth cementation; very thick sets of cross laminae; weathers to form a steep, partially covered slope. 63

Toroweap Formation Section 2.

Section measured up cliff and small wash on cliff face, and up a narrow ridge connecting two buttes about 200 yards to the west, in SE*, NE^, Sec. 12, T. 22 N ., R. 2 W. Measured section is about 50 to 100 yards west of and parallels a little used road that from the Sante Fe right-of-way, down a prominent point, to Ashfor, Arizona

Permian: Kaibab Formation (incomplete): F eet 39. Siltstone and sandstone: Silt stone, pale yellowish orange (10 YR 8/6); very fine to fine-grained, poorly sorted; composed of subangular quartz grains; calcareous, friable; laminated; weathers to form a friable slope beneath a resistant lime stone in the Kaibab Formation; heavy minerals common. Sandstone, very pale orange (10 YR 8/2); fine-grained, well-sorted; composed of rounded, frosted quartz grains; calcareous, friable; lamina ted; weathers to form a covered to friable slope.------11. 0 38. Re crystallized limestone, light brownish gray (5 YR 6/1), weathers grayish-orange (10 YR 7/4); coarsely crystalline; thin-bed of laminae; weathers to form a resistant outcrop band in a friable and covered slope; calcite vugs common; lithiophorite( ?) c o m m o n .------0. 3 37. Siltstone, moderate orange pink (5 YR 8/4); medium grained silt, well-sorted; composed of subangular quartz grains; calcareous, friable; laminated to thin-bedded; weathers to form a friable sloping outcrop below limestone band; muscovite common.----- 5 .3 Total of incomplete Kaibab Formation.------16. 6

Toroweap Formation: Unit IX: 36. Interbedded sandstone, siltstone, mudstone, claystone, and limestone: Sandstone, very pale orange (10YR 8/2); fine-grained, well-sorted; composed of subrounded quartz grains; calcareous, friable; thin-bedded. 64

Siltstone and mudstone, moderate reddish orange (10R 6/6) to grayish-red (10 R 4/2); very fine- to fine-grained silt and clay; poorly sorted; com posed of angular, iron-stained quartz grains and clay; calcareous, friable. Cl ay stone, yellowish-gray (5 Y 8/1); calcareous binding, friable; thinly laminated. Re crystallized limestone and calcite-cemented breccia, light-gray (N7); coarsely crystalline; thin-bedded; clasts of sandstone, same as sand stone in this unit; calcite lined vugs, abundant; manganese oxide dendrites common.------12.8 35. Sandstone and conglomerate: Sandstone, very pale orange (10YR 8/2); very fine- to medium grained, fair-sorting; composed of rounded, frosted, iron-stained quartz grains; calcareous, friable; thin-bedded. Pebble conglomerate, matrix of sandstone as in unit 34; clasts of siltstone, pale reddish brown (10 R 5/4) as in unit 33, and green clay stone; unit weathers to form a covered slope.------2 .0 34. Sandstone, moderate reddish orange (10 R 6/6); fine- to medium-grained, well-sorted; composed of rounded, frosted, slightly iron stained quartz grains; calcareous, friable; thin-bedded; weathers to form a friable b e n c h .------9. 6 33. Sandy siltstone and sandstone: Sandy siltstone, pale reddish brown (10R 5/4); medium-grained silt to very fine grained sand, fairly well-sorted; composed of sub angular to subrounded, iron stained quartz grains; slightly calcareous, friable, some thin lensy laminae of clay stone, grayish-red (10R 4/2); laminated. Sandstone, pale reddish brown (10R 5/4); very fine to coarse-grained, fair sorting; composed of subrounded to rounded, frosted, iron stained quartz grains; rounded, frosted, floating, coarse-grained quartz sand grains common; calcareous, friable; thin-bedded; unit weathers to form a covered slope.------4. 8 32. Sandstone, very pale orange (10YR 8/2), medium- to fine-grained, very well sorted; composed of rounded, frosted quartz grains; non-calcareous, veins and stringers, friable; weathers to form a 65

friable pod; forms sandstone lense about twelve to fifteen feet long and three feet thick in the thickest p ortion .------3 .0 31. Siltstone, moderate reddish orange (10 R 6/6); fine-grained, well-sorted; composed of subangular to subrounded quartz grains; non-calcareous, friable; thin-bedded to thinly laminated; weathers to form a covered slope; some sandstone laminae as in unit 30, and silty claystone, yellowish-gray (5 Y 8/l) laminae present;, muscovite and phlogopite( ?) com mon in claystone.------? - 8 .0 30. Siltstone, pale reddish brown (10R 5/4); very fine and fine-grained, well-sorted; composed of subangular, iron stained quartz grains; calcareous, friable; laminated to thinly laminated; weathers to form a covered slope; two four-inch-thick lenses, one near the base and one near the middle of unit, of sandstone, very pale orange (10 YR 8/2); fine- and coarse-grained sand, bimodal, moderately well-sorted; composed of rounded, frosted quartz grains; slightly calcareous, friable; thin-lense.------4. 8 29. Very calcareous sandstone to very sandy recrystal lized limestone, grayish orange pink (10 R 8/2); coarsely crystalline; fine- to coarse-grained sand, fairly well-sorted, composed of rounded, frosted quartz grains; coarsely crystalline calcite cement, vugs and seams, well-cemented; weathers to form a resistant outcrop bench in a covered slope; unit is traceable for about fifty feet'along outcrop, pinching out in a feather-edge; unit is domed and bent, undulatory, with as much as three feet of relief; somewhat brecciated and recemented with c a lc ite .------1.5 28. Sandstone, very pale orange (10 YR 8/2); fine- to very fine-grained, moderately well-sorted; com posed of rounded, frosted quartz grains; calcareous, friable; thin-bedded; manganese dendrites, abundant; somewhat brecciated in p la c e s.------: - 2 .0 27. Sandy siltstone: Upper sandy siltstone, moderate orange pink (10R 7/4); medium-grained silt to fine grained sand, poorly sorted; composed of sub rounded to rounded quartz grains; calcareous. 66

friable; thin-bedded; weathers to form a covered slope; heavy minerals common. Lower sandy silt stone, moderate reddish orange (10R 6/6) with interlaminated siltstone and claystone, grayish-yellow green (5 GY 7/2); medium- to coarse-grained silt and very fine-grained sand, well-sorted; composed of subrounded to rounded quartz grains; orange siltstone calcareous, green siltstone, slightly calcareous, and clay stone, non- calcareous, all are friable; weathers to form a covered s lo p e .------9 .6 26. Sandstone, moderate reddish orange (10R 6/6) with small white (N9) spots common; very fine to fine grained, moderately well-sorted; composed of sub rounded quartz grains; rounded, frosted, floating, med ium -grained quarts sand "grains rare; non-calcareous, friable; laminated to thinly laminated; weathers to form a covered slope; small clasts of claystone, grayish-red (10 R 4/2), rare.------4 .3 25. Covered (200 yard gentle slope). Top of covered unit: Silty sandstone, moderate orange pink (10R 7/4) with white (N9) blotches; coarse-grained silt to medium-grained sand, poorly sorted; composed of rounded, frosted quartz grains; rounded, frosted, floating medium-grained quartz sand grains common; calcareous, friable; laminated to thin-bedded; weathers to form a covered slope; heavy minerals common.------37. 3 Total of unit IX.------100. 7

Unit VII: 24. Biogenic dolomite, pale yellowish brown (10 YR 6/2); weathers slightly lighter to very pale orange (10 YR 8/2); finely to coarsely crystalline; thin-bedded; weathers to form a step slope above cliff; fossiliferous, Schizodus sp. Sanguinolites sp., Euphe- mites sp., Bellerophon (B .) hilli, Bellerophon (JB.) sp ., Goniasma sp., Straparolus (Euomphalus) kaibabensis, M etacoceras bowm ani. ------1 7 .4 Total of unit V II.------1 7 .4 67

Unit VI: 23. Silty dolomite, very pale orange (10 YR 8/2), weathers same; finely crystalline; contains fine- to medium- grained silt, fair-sorting, composed of angular quartz silt; thick- to massive-bedded; weathers to form a major cliff; fossiliferous, gastropods rare, Glabrocingulum (G. ) coronatum. ----- 39. 2 22. Silty dolomite, very pale orange (10 YR 8/2), weathers grayish orange (10 YR 7/4); finely crystalline; contains fine- to medium-grained silt, well-sorted, composed of subrounded quartz grains; thick-bedded; weathers to form a rounded bench below cliff; small white mega-quartz pods co m m o n .------3.8 Total of unit VI.------43. 0

Unit V: 21. Covered.------5.7 Total of unit V.------5.7

Unit IV: 20. Biomicrite, brownish-gray (SYR 4/1), weathers light brownish gray (5 YR 6/1) speckled with small white spots; thick-bedded; weathers to form a sharp bench; fossiliferous, molds filled with sparry calcite.------2 .3 19. Silty dolomite, light brownish gray (5 YR 6/1), weathers pale yellowish brown (10 YR 6/2); finely crystalline; contains fine- to medium-grained silt, well-sorted, composed of subangular quartz grains; thin-bedded; weathers to form a rounded bench; thin veins of sparry calcite com m on .------0 .8 18. Dolomite, very pale orange (10 YR 8/2), weathers pinkish gray (5 YR 8/1); finely crystalline; laminated to thinly laminated; weathers to form a rounded step; thin veins of sparry calcite common.------0 .4 17. Dolomite, brownish-gray (5 YR 4/1), weathers pale yellowish brown (10 YR 6/2); finely crystalline; thin- bedded; weathers to form a sharp bench; sparry calcite veins common; fossils rare.------1 .8 68

16. Calcareous dolomite, pale yellowish brown (10 YR 6/2), weathers grayish-orange (10 YR 7/4); finely crystalline; contains rare rounded, frosted, floating, very fine-grained quartz sand grains; thick-bedded; weathers to form a rounded bench.------3 .0 15. Dismicritic dolomite, pale-brown (SYR 5/2), weathers pale yellowish brown (10 YR 6/2); finely crystalline; thin-bedded; weathers to form a rounded step; sparry calcite veins; fossiliferous.------3. 3 Total of unit IV.------11.6

Unit III: 14. Covered.------6.7 Total of unit III.------6. 7

Unit II: 13. Silty dismicritic and biogenic dolomite, light-brown (5YR 6/4), weathers light brownish gray (SYR 6/l); finely to coarsely crystalline; contains fine- to medium grained silt, well-sorted, composed of subangular quartz grains; thin-bedded; weathers to form a rounded bench; dusky red sparry calcite crystals common; fossiliferous.------3.9 12. Biogenic dolomite, pale yellowish brown (10 YR 6/2), weathers same; finely crystalline; thin-bedded; weathers to form a flat rounded bench; fossiliferous. - 1.7 11. Sandy dolomite, pale yellowish brown (10 YR 6/2), weathers grayish-orange (10 YR 7/4); finely crystal line; contains fine- to very fine grained sand, fair sorting, composed of subangular quartz grains; thick-bedded; weathers to form a pitted bench; calcite crystals common.------3 .0 10. Silty dolomite, variegated moderate orange pink (10YR 7/4), grayish orange pink (5 YR 7/2), and pale yellowish brown (10 YR 6/2), weathers very pale orange (10 YR 8/2); finely crystalline; con tains fine- to medium-grained silt, fair-sorting, composed of angular quartz grains; thin-bedded; weathers to form a rounded bench; authigenic quartz crystals abundant.------3.3 69

9. Silty dolomite, pale yellowish brown (10 YR 6/2), weathers very pale orange (10YR 8/2); finely crystalline; contains fine- to medium-grained silt, well-sorted, composed of sub angular quartz grains; thin-bedded; weathers to form a rounded b e n c h .------5 .4 8. Sandy silty biogenic dolomite, light-brown (SYR 6/4), weathers grayish-orange (10 YR 7/4); finely crystalline; contains coarse-grained silt to fine grained sand, poorly sorted, composed of subangular quartz grains; thin-bedded; weathers to form a rounded bench; hematite blebs common; fossiliferou s, ostracods, r a r e .------1 .0 7. Sandy silty biogenic dolomite, moderate reddish orange (10R 6/6), weathers moderate orange pink (10R 7/4); finely crystalline; contains coarse grained silt and very fine grained sand, well- sorted, composed of subangular quartz grains; thin- bedded; weathers to form a rounded bench; fossili ferous, ostracod fragments( ?).------2.1 6. Sandy silty micrite, pale yellowish orange (10 YR 8/6) to pale yellowish brown (10 YR 6/2), weathers pale-red (10R 6/2); finely crystalline; contains medium-grained silt to fine-grained sand, poorly sorted, composed of subangular quartz grains; thin-bedded; weathers to form a rounded bench; hematite blebs common.------2.1 5. Sandy dolomite, light - br own (SYR 6/4), weathers moderate orange pink (10R 6/4); finely crystalline; contains fine- to very fine grained sand, fair sorting, composed of subangular quartz grains; thin-bedded; weathers to form a rounded bench; hematite blebs common.------1.5 4. Sandy silty dolomite, grayish orange pink (10R 8/2) to moderate orange pink (5 YR 8/4); finely crystalline; contains coarse-grained silt to very fine grained sand, well-sorted, composed of angular quartz grains; thin-bedded; weathers to form a rounded step s l o p e . ------2. 6 3. Sandy dolomite, moderate orange pink (10 R 7/4), weathers same; finely crystalline; contains very fine to medium-grained sand, moderately well 70

sorted, composed of rounded, frosted, quartz grains; rounded, frosted, floating, coarse grained quartz sand common; laminated; weathers to form a rounded step slo p e. ------2.5 Total of unit I I . ------29. 1

Unit I: 2. C overed.------4 .6 Total of unit I . ------4. 6

Total of Toroweap F o r m a tio n .------218. 8

Unconformity; Toroweap-Coconino contact is a slightly undulating stained surface.

Coconino Sandstone (unmeasured):

1. Sandstone, grayish orange pink (SYR 7/2); fine grained, very well-sorted; composed of rounded, frosted quartz grains; well-cemented, silica- overgrowth cementation; very thick sets of cross laminae; weathers to form a steep, partially covered slope. 71

Toroweap Formation Section 3.

Section measured in SWi, SEi, Sec. 1, T. 22 N ., R. 2 W. in a small canyon about & mile southeast of a faint road that runs from the Sante Fe right of way to the bottom of the cliffs.

Permian:

Toroweap Formation (incomplete): F eet 20. Covered slope that extends well into the lower part of the Kaibab Formation (unmeasured).

Unit VII: 19. Biogenic dolomite, very pale orange (10 YR 8/2), weathers pinkish-gray (5 Y 8/1); finely crystalline; thin- to thick-bedded; weathers to form a step slope above massive cliff; fossiliferous, Schizodus sp., Sanguinolites sp., Metacoceras bowmani. ?Cooperoceras sp., Plagioglypta canna. ------2 .0 Total of unit VII...... JjQ

Unit VI: 18. Silty biogenic dolomite, very pale orange (10 YR 8/2), weathers same; finely crystalline; contains fine- to medium-grained silt, moderately well-sorted, com posed of angular quartz grains; massive; weathers to form a major cliff; fossiliferous, Squamaria ivesi, crinoids, echinoids abundant. ------30.6 17. Silty dolomite, very pale orange (10 YR 8/2), weathers same; finely crystalline; contains fine- to medium grained silt, moderately well-sorted, composed of subangular quartz grains; thick-bedded; weathers to form a rounded bench below cliff; small white mega quartz pods common. ------3 .0 Total of unit V I...... 33. 6

Units IV and V : 16. Covered.------6.2 15. Biogenic dolomite, light brownish gray (5 YR 6/1), weathers pale yellowish brown (10 YR 6/2); finely 72

crystalline; thin-bedded; weathers to form a sharp bench; sparry cal cite veins abundant; slightly fetid; fossiliferous, fragments.------2 .0 14. Dolomite, pale yellowish brown (10 YR 6/2), weathers same; finely crystalline; thin-bedded; weathers to form a sharp step; cal cite veins and blebs common; flecked with tiny limonite stains.------1.0 13. Silty biogenic dolomite, grayish orange pink (5 YR 7/2), weathers very pale orange (10 YR 8/2); finely crystalline; contains fine- to medium-grained silt, well-sorted, composed of angular quartz grains; thin-bedded; weathers to form a sharp step; fossili ferous, pelecypod molds filled with sparry cal cite.----- 1 .0 12. Recrystallized limestone, pale-brown (SYR 5/2), weathers pale yellowish brown (10 YR 6/2); coarsely crystalline; thin-bedded; weathers to form a sharp step; calcite veins common. ------0.3 Total of units IV and V. — ------10. 5

Units I, II, and III: 11. Covered.------15.9 10. Silty dolomite, moderate-red (5 R 5/4) to grayish- orange (10 YR 7/4); finely crystalline; contains fine- to medium-grained silt, fair-sorting; com posed of angular quartz grains; thin-bedded; weathers to form a rounded b en ch .------••••------0. 9 9. Sandy silty biogenic dolomite, moderate-red (5 R 5/4) to grayish-orange pink (5 YR 7/2); finely crystalline; contains fine-grained silt to fine-grained sand, poorly sorted, composed of subangular quartz grains; thin-bedded; weathers to form a rounded bench; fossil molds. ------1.5 8. Silty dolomite, pale-red (10 R 6/2), grayish- orange (10 YR 5/2), and pale-brown (5 YR 5/2), weathers grayish orange pink (SYR 7/2); to light brownish gray (5 YR 6/l); finely crystalline; con tains fine- to medium-grained silt, fair-sorting, composed of sub-angular quartz grains; thin- bedded; weathers to form a rounded bench.------0. 7 73

7. Silty sandstone, banded grayish-orange (10 YR 7/4), very pale orange (10 YR 8/2), with some streaks of moderate reddish orange (10 YR 6/6); coarse grained silt to fine-grained sand, moderately well sorted; composed of rounded, frosted quartz grains; non-calcareous, friable; laminated; weathers to form.a minor covered interval between dolomites.----- 0 .4 6. Silty dolomite, pale yellowish brown (10 YR 6/2), weathers yellowish-gray (5 Y 8/1); finely crystalline; contains fine-grained silt, well-sorted, composed of angular quartz grains; thin-bedded; weathers to form a rounded s t e p . ------0.9 5. Silty biogenic dolomite, light-brown (SYR 6/4), weathers grayish-orange (10 YR 7/4); finely crystal line; contains fine- to medium-grained silt, well- sorted, composed of subangular quartz grains; thin- bedded; weathers to form a rounded step fossiliferous, ostracods( ?) co m m o n .------0. 9 4. Intraclastic dolomite; Matrix of silty dolomite, moderate orange pink (SYR 8/4), weathers grayish orange pink (SYR 7/2); finely crystalline; contains fine- to medium-grained silt, fair-sorting, com posed of angular quartz grains; intraclasts of siltstone, sandstone, and silty dolomite, light-brown (SYR 6/4) and grayish-orange (10YR 7/4); cobbles of eight to ten inch maximum diameter, poorly sorted; composed of subangular to sub rounded Toro- weap. fragm ents.------13.2

Erosion Surface; The contact between units three and four is a channeled surface with relief locally as much as one foot.

3. Sandy silty dolomite, light-brown (SYR 6/4), weathers grayish-orange (10 YR 7/4); finely crystalline; contains coarse-grained silt to very fine-grained sand, moderate ly well sorted, composed of subangular quartz grains; thin-bedded; weathers to form a partially covered step slo p e.------6 .4 2. Dolomitic siltstone to silty dolomite, grayish-orange (10YR 7/4), weathers grayish orange pink (SYR 7/2); finely crystalline; contains fine- to coarse-grained 74

silt, poorly sorted, composed of subangular to angular quartz grains; thin-bedded; weathers to form partially covered step slope.------19. 3 Total of units I, II, and III. ------60.1

Total of incomplete Toroweap Formation.------106. 2

Unconformity; Toroweap-Coconino contact is a slightly undulating surface which truncates the upper cross-beds of the Coconino Sandstone.

Coconino Sandstone (unmeasured):

1. Sandstone, grayish orange pink (SYR 7/2); fine-grained, very well sorted; composed of rounded, frosted quartz grains; well-cemented, silica-overgrowth cementation; very thick sets of cross-laminae; weathers to form a steep, partially covered slope. 75

Toroweap Formation Section 4.

Section measured up the west-facing cliff and the butte at the top of the cliff in Ne £, Se £, NW i, Sec. 1, T. 22 N ., R. 2 W. Section measured about fifty yards north of a faint road that runs from the Sante Fe right-of-way to the bottom of the cliffs.

Perm ian:

Kaibab Formation (incomplete): F eet 40. Silty sandstone to sandy siltstone, pale yellowish orange (10 YR 8/6); coarse-grained silt to very fine-grained sand, moderately well sorted; com posed of angular quartz grains; calcareous, friable; faint, unmeasureable cross - laminae visible in some places; weathers to form a covered to friable slope; small calcite crystal lined cavities and seams ab u n d an t.------4 .8 39. Breccia: Matrix of silty sandstone, pale yellowish orange (10 YR 8/6); coarse-grained silt and very fine grained sand, poorly sorted; composed of rounded to subrounded, frosted quartz grains; rounded, frosted, floating, coarse-grained quartz sand common; calcareous, moderately well cemen ted; clasts of recrystallized limestone, pale red purple (5RP 4/2); medium crystalline; dense, almost clastic free; and siltstone, laminated moderate orange pink (10 YR 8/2) and grayish orange pink (5 YR 7/2); fine- to medium-grained silt, moderately well sorted; composed of angular quartz grains; clasts of one to four inch maximum diameter, poorly sorted, angular; unit weathers to form a friable slope; small calcite crystal lined cavities in m atrix co m m o n .------1 .0 Total of incomplete Kaibab Form ation.------5 .8

Unit IX: 38. C overed.------1 1 .6 37. Sandstone, light-brown (5 YR 6/4); very fine to coarse grained, poorly sorted; composed of rounded, frosted 76

quartz grains; calcareous, friable; thin-bedded to laminated; weathers to form a covered slope; heavy m inerals com m on.------5 .8 36. Sandstone, moderate reddish orange (10R 6/6); very fine to fine-grained, moderately well sorted; composed of subrounded, limonite stained quartz grains; slightly calcareous, friable; thin-bedded; weathers to form a covered slope or a small friable bench in some washes; heavy minerals abu nd ant.----- ;------3 .0 35. Silty sandstone, light-brown (5YR 5/6); coarse grained silt to coarse-grained sand, poorly sorted; com posed of rounded, frosted quartz grains; rounded, frosted, floating, coarse-grained quartz sand abun dant; calcareous, friable; thin-bedded; weathers to form a covered slope; heavy minerals common.------2 .5 34. C overed.------11.6 33. Sandy siltstone, moderate reddish orange (10R 6/6); medium-grained silt to very fine grained sand, poorly sorted; composed of angular quartz grains; rounded, frosted, floating, coarse-grained quartz sand rare; calcareous, friable; thin-bedded; weathers to form a covered slope heavy minerals common; muscovite rare. ------5 .8 32. Micrite(?), pinkish-gray (SYR 8/1); slightly oolitic(?); slightly sandy, rounded, frosted, floating, coarse grained quartz sand common, and limonite-stained fine-grained quartz sand rare; friable; thin- and gnarly-bedded, tufa-like texture; weathers to form a covered slo p e.------5. 8 31. C overed.------4 0 .6

Unit VIII: 30. Silty dolomite, pinkish-gray (SYR 8/1), weathers yellowish-gray (5 Y 8/1); finely crystalline inter spersed with some coarsely crystalline dolomite; contains fine- to medium-grained silt, fairly well- sorted, composed of angular quartz grains; thin- bedded; weathers to form a thin outcrop line in a covered slope; cherty, thin, nodular to platy chert com m on.------0 .3 Total of unit VIII.------073 77

Unit IX continued: 29. C overed.------5. 4 Total of unit IX. - 92.1

Units VII and VI: 28. Silty dolomite, very pale orange (10 YR 8/2), weathers yellowish-gray (5 Y 8/1); finely crystalline; contains fine- to medium-grained silt, well-sorted, composed of angular quartz grains; thick-bedded; weathers to form a rounded bench at top of cliff; cherty, light-brown (5 YR 6/4), nodular to irregular plates in bands; small white megaquartz pods common; fossils rare, M etacoceras bowmani.------5 .8 27. Silty biogenic dolomite, very pale orange (10 YR 8/2), weathers pinkish-gray (5 YR 8/l); finely cry stalline; contains fine- to medium-grained silt, well-sorted, composed of angular quartz grains; massive-bedded; weathers to form the upper part of a major cliff; cherty, bands of nodular chert common; fossiliferous; Squamaria ivesi, crinoids, and echinoids very abundant at base of u n it.------17.4 26. Silty biogenic dolomite, yellowish-gray (5 Y 8/1), weathers pinkish-gray (SYR 8/1); finely crystalline; contains fine- to medium-grained silt, well-sorted, composed of angular quartz grains; thick-bedded to massive; weathers to form the lower portion of a major cliff; small, white mega-quartz pods common; fossiliferous, Squamaria ivesi, crinoids, and echi noids very abundant. ------15.9 25. Silty dolomite, very pale orange (10 YR 8/2), weathers moderate orange pink (SYR 8/4); finely crystalline; contains fine-grained silt, poorly sorted, composed of angular quartz grains; thin-bedded; weathers to form a pitted bench at base of cliff; small white mega quartz pods common. ------1.1 Total of units VII and VI. ------40. 2

Unit V: 24. Sandy siltstone to silty sandstone, grayish-orange (10 YR 7/4); coarse-grained silt to very fine grained sand, well-sorted; composed of subangular quartz 78

grains; calcareous, friable; laminated to thinly laminated; weathers to form a partially covered slope; red and white liesagang banding com m on.------4.1 Total of unit V . ------4.1

Unit IV: 23. Biogenic dolomite, brownish-gray (5 YR 4/1) to pale yellowish brown (10 YR 6/2), weathers very pale orange (10 YR 8/2); finely crystalline; thin-bedded; weathers to form a sharp bench; very small limonite stains common; fossiliferous at top of unit, fragmentary, molds.------2 .7 22. Recrystallized limestone, pale-brown (SYR 5/2), weathers grayish orange pink (SYR 7/2); coarsely crystalline; thin-bedded; weathers to form a sharp bench; fetid; calcite crystals common; fossiliferous, fragmentary, pelecypods.------:------2 .9 21. Dolomite, brownish-gray (SYR 4/1), weathers very pale orange (10YR 8/2); finely crystalline; thin- bedded; weathers to form a sharp step; fetid; calcite vugs common; fo ss il fragm ents r a re .------0 .9 Total of unit IV.------6. 5

Unit III: 20. Siltstone, grayish-orange (10YR 7/4); coarse-grained with some very fine grained sand, moderately well sorted; composed of sub angular quartz grains; calcer- eous, friable; laminated to thinly laminated; weathers to form a partially covered slope; red and white liesagang banding common.------6. 5 Total of unit III. ------6. 5

Unit II: 19. Dolomite, pale-red (10R 6/2), weathers grayish orange pink (SYR 7/2); finely to coarsely crystal line; thick-bedded; weathers to form a sharp bench; calcite crystals, abundant; fossil fragments rare, o stra co d s.------2 .4 18. Silty dolomite, pale yellowish brown (10 YR 6/2) to dark yellowish brown (10 YR 4/2), weathers grayish- 79

orange (10 YR 7/4); finely crystalline; contains fine-grained silt, well-sorted, composed of angular quartz grains; thin-bedded, four to six inch thick beds; weathers to form a sharp step- slope; slightly fetid.------2 .7 17. Dolomite, dark yellowish brown (10 YR 4/2) to pale yellowish brown (10 YR 6/2), weathers grayish- orange (10 YR 7/4) to yellowish-gray (5Y 8/1); finely to coarsely crystalline; thin-bedded; weathers to form a sharp bench; slightly fetid; cal cite crystals com m on.------2 .8 16. Sandy siltstone to silty sandstone, grayish-orange (10YR 7/4); coarse-grained silt to very fine grained sand, fairly well sorted; composed of subangular quartz grains; calcareous, friable; laminated to thinly laminated; weathers to form a covered slope; heavy m inerals com m on.------0. 4 15. Silty biogenic dolomite, mottled pale-red (10R 6/2), to grayish-orange (10 YR 7/4), weathers very pale orange (10 YR 8/2); finely crystalline; contains fine grained silt, poorly sorted, composed of angular quartz grains; rounded, frosted, floating, fine- to coarse-grained quartz sand, rare; thin-bedded; weathers to form a rounded bench; fossil fragments, ostracod s.------0 .8 14. j Biogenic dolomite, pale-red (5R 6/2), moderate-red (5R 5/4), and medium dark gray (N4), weathers from grayish orange pink (5 YR 7/2) to light brownish gray (5 YR 6/1); finely crystalline; thin-bedded, four to eight inch thick beds; weathers to form a series of sharp steps; calcite in small cavities; fossil frag ments in gray d o lo m it e .------2 .3 13. Silty dolomite, pale yellowish brown (10 YR 6/2), weathers grayish-orange (10 YR 7/4); finely crystal line; contains fine- to medium-grained silt, poorly sorted, composed of angular quartz grains; thin- bedded; weathers to form a small rounded bench.------1.4 12. Silty biomicrite, pale-red (5 R 6/2), weathers grayish orange pink (5 YR 7/2); contains fine- to medium-grained silt, poorly sorted, composed of angular quartz grains; thin-bedded to laminated; weathers to form a rounded step; pseudo morphs of 80

hematite after pyrite; authigenic quartz crystals; fossil fr a g m e n ts .------0. 8 11. Silty dolomite, pale-red (5R 6/2), weathers grayish orange pink (SYR 7/2); finely crystalline; contains very fine grained silt, well-sorted, composed of angular quartz grains; thin-bedded; weathers to form a rounded bench; small authigenic quartz crystals common; ostracods(?)------1.8 10. Silty dolomite, moderate-red (5R 5/4) to pale-red (5R 6/2), weathers pale-red (10R 6/2); finely cry stalline; contains very fine to medium-grained silt, poorly sorted, composed of angular quartz grains; thin-bedded; small aughigenic quartz crystals com m on.------1.2 9. Sandy siltstone, moderate orange pink (SYR 8/4), weathers very pale orange (10 YR 8/2); coarse grained silt and very fine grained sand, moder ately well sorted; composed of angular quartz grains; non-calcareous, friable to moderately well cemented; laminated to thin-bedded; weathers to form a slope: small manganese oxide blotches; large scale liesagang banding, red and white, somewhat controlled by minor jo in tin g .------1.6 8. Silty dolomite, pale-red (SR 6/2), weathers grayish orange pink (SYR 7/2); finely crystalline; contains very fine grained silt, well-sorted, composed of angular quartz grains; thin-bedded; weathers to form a rounded bench; small manganese oxide blebs both form a rounded bench; small manganese oxide blebs both follow and cut across bedding in thin stringers. - 1. 1 7. Silty dolomite, moderate reddish orange (10 R 6/6) and light-brown (SYR 6/4), weathers grayish-orange (10 YR 7/4); finely crystalline; contains very fine grained silt, well-sorted, composed of angular quartz grains; thin-bedded; weathers to form a rounded bench.------1. 5 6. Silty dolomite, pale-red (SR 6/2), weathers moder ate orange pink (10 R 7/4); finely crystalline; con tains medium- to coarse-grained silt, moderately well-sorted, composed of angular quartz grains; thick bed of laminae; weathers to form a rough bench; manganese oxide filling fine fractures.------1. 1 81

5. Silty dolomite, grayish-red (10R 4/2); finely cry stalline; contains very fine grained silt, well-sorted, composed of angular quartz grains; thin-bedded; weathers to form a lime-coated bench; hematite pseudomorphs after pyrite common; fossil frag- m ents( ? ) . ------0. 9 4. Covered.------1.9 3. Silty sandy dolomite, pale-red (5R 6/2), weathers pale-red (10 R 6/2); finely crystalline; contains coarse-grained silt to fine-grained sand, fair- s or ting, composed of rounded, frosted quartz grains; thin-bedded; weathers to form a rounded bench in a slo p e .------1.0 Total of unit II. 25. 7

Unit I:

2. Sandy siltstone, pale-red (5R 6/2), weathers pale- red (10 R /2); medium-grained silt to very fine grained sand, moderately well-sorted; composed of subrounded to subangular quartz grains; calcareous, moderately well cemented; thin bed of thin laminae; weathers to form a slope; muscovite common; lower portion covered.------3. 0 Total of unit I. ------3. 0

Total of Toroweap Form ation.------178.4

Unconformity: Toroweap-Coconino contact is a stained slightly undulating surface with a local relief of not more than a few centimeters. Coconino Sandstone (unmeasured):

1. Sandstone, moderate orange pink (SYR 8/4); fine grained, very well sorted; composed of rounded, frosted quartz grains; well-cemented, silica- overgrowth cementation; very thick sets of steeply dipping cross-laminae; weathers to form a steep partially covered slope. 82

Toroweap Formation Section 5

Section measured in SEi, NWi, NE^, Sec. 36, T. 23 N ., E. 2 W. about i mile west of the Bowman Quarry. Section measured up the northeast side of canyon and up the northeast wall of the Sante Fe cut at the top of the canyon.

Tertiary(?):

Volcanic ash overlain by basalt (unmeasured).

Unconformity: Erosion surface with channeling displaying several feet of relief locally.

Permian:

Toroweap Formation (incomplete): F eet Unit IX (incomplete): Units 28 to 33 measured up northeast wall of Sante Fe cut in the southeast end of the cut.

33. Sandy siltstone to silty sandstone, very pale orange (10 YR 8/2) to moderate orange pink (10 R 7/4); coarse-grained silt to very fine grained sand, well- sorted; composed of subrounded quartz grains; non- calcareous, friable; laminated to thin-bedded.------14.0 32. Siltstone, mud, and recrystallized limestone: Siltstone, very pale orange (10 YR 8/2); very fine to fine-grained silt, moderately well-sorted; com posed of angular quartz grains; slightly calcareous to non-calcareous, friable; thin-bedded to laminated; phlogopite( ?) common; manganese oxide dendrites common. Mud, dark yellowish brown (10 YR 4/2), drys to pale yellowish brown (10 YR 6/2); very fine grained silt and clay, poorly sorted; composed of angular quartz grains and montmor illonite - vermi - culite; non - calcareous, unindurated; forms a dis continuous bed of four to six inch diameter pods near top of unit; muscovite rare, phlogopite( ?) common. Recrystallized limestone, pale-brown (5 YR 5/2); coarsely to very coarsely crystalline; 83

forms a one foot thick, fifty foot long, undulatory lense near top of unit; lenses of fine grained sand rare; calcite-lined vugs common, clear calcite c r y sta ls.------11.6 31. Sandy silts tone and siltstone: Sandy siltstone, moderate reddish orange (10 R 6/6); coarse grained silt to very fine grained sand, fairly well sorted; composed of subangular quartz grains; calcareous, friable; laminated. Siltstone, very pale orange (10 YR 8/2); medium- to coarse grained, well-sorted; composed of angular quartz grains; slightly calcareous, friable; laminated.------4. 4 30. Sandy siltstone to silty sandstone, very pale orange (10 YR 8/2), moderate orange pink (5 YR 8/4), and moderate reddish orange (10 R 6/6); medium-grained silt to very fine grained sand, poorly sorted; composed of angular quartz grains; rounded, frosted, floating, coarse-grained quartz sand abundant; calcareous, friable; thin-bedded to lam inated.------4. 5 29. Sandy siltstone to silty sandstone, very pale orange (10 YR 8/2) to moderate orange pink (10 R 7/4); coarse-grained silt to very fine grained sand, well- sorted; composed of subrounded quartz grains; cal careous, friable; thin-bedded to laminated.------4. 8

Total of incomplete unit IX .------39. 3

Unit VIII: 28. Recrystallized limestone, dolomite, and chert: Re- crystallized limestone, grayish orange pink (SYR 7/2); very coarsely crystalline; forms thin beds near top of unit. Dolomite, very pale orange (10 YR 8/2), finely crystalline; thin-bedded. Chert, pale-red (10R 6/2); thin beds in dolomite near top of u n it.------6. 4 Total of unit V III.------6. 4

Units 1 to 27 measured up northeast side of canyon below Sante Fe cut. 84

Unit VI:

27. Silty dolomite, very pale orange (10 YR 8/ 2), weathers same to pale yellowish brown (10 YR 6/2); finely crystalline; contains fine- to medium- grained silt, fair-sorting, composed of angular quartz grains; thick-bedded to massive; weathers to form a prominent cliff; chert bands common, light- brown (5 YR 6/4), weathers moderate reddish orange (10 YR 6/2), forms three to four inch thick nodular bands in top ten feet of unit; insoluble resi due = 37.7%; fossiliferous, Metacoceras bowmani, and a very large nautiloid, abundant in top four feet of u n it.------43. 1 Total of unit V I.------43.1

Unit V:

26. C overed.------4. 6

Total of unit V . ------4. 6

Unit IV: 25. Biogenic dolomite, light brownish gray (SYR 6/1), weathers pale yellowish brown (10 YR 6/2); finely crystalline; thin-bedded; weathers to form a pitted bench; calcite crystals abundant; orange chert band and orange siltstone form basal 0. 2 feet of u n it.------2. 3 24. Silty calcareous dolomite, light brownish gray (SYR 6/1), weathers pinkish-gray (SYR 8/1); finely crystalline; contains fine-grained silt, well- sorted, composed of angular quartz grains; thin- bedded to laminated; weathers to form a rounded bench; insoluble residue = 12. 0% .------1.3 23. C overed.------0 .6

22. Dolomite, light olive gray (5 Y 6 / 1), weathers yellowish gray (5 Y 8/1), finely crystalline; thin- bedded; weathers to form a sharp bench; slightly fetid; insoluble residue = 4. 8% ------2. 3

21. Silty calcareous dolomite, pale yellowish brown (10 YR 6/2), weathers same; finely crystalline; con tains fine-grained silt, poorly sorted, composed of 85

angular quartz grains; thick-bedded; weathers to form a pitted bench; calc it e vugs common; insoluble residue = 16. 2%.------2. 2 20. ' Dolomite, medium-gray (N5), weathers yellowish- gray (5 Y 8/1); finely crystalline; thin-bedded, four to six inch thick beds; weathers to form a rounded, veined bench; slightly silty; calc it e vugs common; slightly fetid; insoluble residue = 9. 4% .------1.0 Total of unit IV .------9. 7

Units II and III; 19. Covered. Silty biomicrite (2. 0 feet from base of unit), dark yellowish brown (10 YR 4/2), weathers yellowish-gray (5 Y 8/1); contains fine-grained silt, moderately well-sorted, composed of angular quartz grains; thin-bedded; weathers to form a rounded bench in a covered slope; insoluble residue = 15. 1%; fossil fragments abundant, ostracods com m on.------11.3 18. Silty calcareous dolomite, pale yellowish brown (10 YR 6/2), weathers yellowish-gray (5 Y 8/1); finely to coarsely crystalline; contains fine-grained silt, well-sorted, composed of angular quartz grains; thin-bedded; weathers to form a pitted bench; insoluble residue = 19. 4%; top 0. 3 feet fossiliferous, pelecypods, gastropods, and ostracods; ostracods very abundant.------3.1 17. C overed.------2.3 16. Silty dolomite, grayish-orange (10 YR 7/4), weathers grayish orange pink (5 YR 7/2); finely crystalline; contains fine- to coarse-grained silt, poorly sorted, composed of angular quartz grains; thin-bedded; weathers to form a prominent ledge, rounded; insolu ble residue = 17. 6%; fossiliferous; ostracods common to r a r e . ------1. 3 15. Silty biogenic dolomite, grayish orange pink (5 YR 7/ 2), weathers slightly grayer; and biogenic dolomite, medium -gray (N5), weathers pinkish-gray (5 YR 8/1); finely crystalline; fine- to coarse-grained silt, poorly sorted; composed of angular to subangular quartz grains; thin-bedded; weathers to form a sharp step; insoluble residue =15. 1%; fossiliferous, pelecypods abundant, ostracods r a r e . ------1.0 86

14. Biogenic dolomite, pale yellowish brown (10 YR 6/2), weathers very pale orange (10 YR 8/2); finely cry stalline; fine- to medium-grained silt, poorly sorted; composed of angular quartz grains; thin-bedded; weathers to form a rounded step; insoluble residue = 8. 2%; fossiliferous, pelecypod fragments abundant. 1.0 13. Silty dolomite, grayish orange pink (5 YR 7/2), weathers slightly lighter; finely crystalline; contains fine- to coarse-grained silt, poorly sorted, com posed of angular to subangular quartz grains; thin- bedded; insoluble residue = 23. 5%; fossiliferous, ostracods common, pelecypod fragments common. - - 0. 4 12 Sandy silty biogenic dolomite, mottled pale yellowish brown with spots of dark yellowish orange (10 YR 6 / 6), weathers grayish orange pink (5 YR 7/2); finely crystalline; contains medium-grained silt to coarse grained sand, poorly sorted, bimodal, composed of rounded, frosted quartz grains; rounded, frosted, floating, coarse-grained sand abundant; thin-bedded; weathers to form a rounded step; fossil fragments and ostracods r a r e . ------0. 4 11. Dolomite, finely crystalline, and intraclastic dolo mite, almost all of the colors of the Toroweap are represented in this unit; intraclasts, i to 4 inches in diameter, poorly sorted; composed of angular to subangular fragments of dolomite; thin-bedded; weathers to form a slope; insoluble residue = 9. 4%. - 4. 3 10. Silty sandy dolomite, light-brown (5 YR 6/4), weathers grayish orange pink (SYR 7/2); finely crystalline; contains fine- to very fine grained sand, fair-sorting, composed of subangular to subrounded quartz grains; thin-bedded; weathers to form a rounded bench; insoluble residue = 24.0% .------1.1 9. C overed.------4 .0

8. Silty biogenic dolomite, moderate yellowish brown (10 YR 5/4), weathers grayish-orange (10 YR 7/4); finely crystalline; contains fine-grained silt with rare very fine grained sand, poorly sorted, com posed of angular to subangular quartz grains; thin- bedded; weathers to form a rounded ledge; insoluble residue = 11. 7%; fossiliferous, ostracods very abundant. Paraparchites sp., Jonesina sp., 87

Coryella s p . ------3.1

7. Silty biogenic dolomite, moderate yellowish brown (10 YR 7/4), weathers pale yellowish orange (10 YR 8/ 6); finely crystalline; contains fine- and coarse grained silt, well-sorted, bimodal, composed of angular to subangular quartz grains; thin-bedded; weathers to form a rounded bench; insoluble resi due = 14. 4%; fossiliferous, fragments, ostracods(?). 1.5

6. Sandy dolomite, grayish-orange (10 YR 7/4), weathers very pale orange; finely crystalline; con tains very fine-grained sand, poorly sorted, com posed of subangular quartz grains; thin-bedded weathers to form a sharp bench.------2. 0 5. Silty sandy dolomite, dark yellowish orange (10 YR 6 / 6) to light-brown (5 YR 6/4), weathers grayish orange pink (5 YR 7/2); finely crystalline; contains fine-grained silt to very fine grained sand, moderately well sorted, composed of subrounded quarts grains; thin-bedded; weathers to form a rounded step; insoluble residue = 24. 9%; manganese oxide dendrites; fossil fragments( ? ) ------0 .4

4. C overed.------1.4 3. Sandy dolomite, grayish orange pink (5 YR 7/2), weathers yellowish gray (5 Y 8 / 1); finely crystalline contains very fine grained sand, well-sorted, com posed of rounded, frosted quartz grains; thin beds of laminae; weathers to form a rounded bench; in soluble residue = 35. 1%; calc it e vugs common; pockets of non-calcareous sand common.------1.4 Total of units II and III.------40. 0

Unit I; 2. Covered. Upper: Silty sandstone, very pale orange (10 R 8/ 6), fine-grained sand, poorly sorted; composed of subangular quartz grains, some grains polished; calcareous, friable; thin sets of laminae; weathers to form a covered slope; iron oxide staining on some bedding planes; insoluble residue = 62.2%. Lower: Very sandy siltstone, pale reddish brown (10 R 5/4); coarse-grained silt to very fine grained sand, poorly sorted; composed of subangular quartz grains; 88

rounded, frosted, floating, coarse-grained quartz sand rare; calcareous, friable; lamina ted; weathers to form a covered slope; insol uble residue = 56. 4%. ------3. 8 Total of unit I . ------3 .8 Total incom plete Toroweap F o r m a tio n .------146.9

Unconformity; Toroweap-Coconino contact is a stained, flatly undulating surface with very little relief.

Coconino Sandstone (unmeasured):

1. Sandstone, moderate orange pink (5 YR 8/4); fine grained, very well sorted; composed of rounded, frosted quartz grains; well-cemented, silica- overgrowth cementation; very thick sets of steeply dipping cross-laminae; weathers to form a partially covered slope. 89

Toroweap Formation Section j>.

Section measured up the east side of a wash located near • the east end of the Bowman Quarry in N e £, NW5, Sec. 31, T. 23. N ., R. 1 W. and up butte about 200 yards to the east.

Permian:

Kaibab Formation (unmeasured): F eet 38. Sandstone, very pale orange (10 YR 8/2); fine grained, well-sorted; composed of rounded, frosted quartz grains; calcareous, friable; laminated; weathers to form a covered slope.

Toroweap Formation:

Unit IX: 37. Silty sandstone, slightly browner than moderate reddish orange (1 0 R 6/ 6); medium- to fine grained sand and coarse-grained silt, fair to poorly sorted; composed of rounded, frosted quartz grains; calcareous, friable; laminated to thin-bedded; weathers to form a steep friable ou tcrop .------6. 0

36. Sandy siltstone, moderate reddish orange (10R 6/ 6); coarse-grained silt and fine-grained sand, fair sorting; composed of sub angular to subrounded quartz grains; calcareous, friable; laminated to thinly laminated; weathers to form a friable slope; insol uble residue - 77. 8% .------3 .0 35. Sandy siltstone and silty sandstone, very pale orange (10 YR 8/ 2); coarse-grained silt to fine grained sand, poorly sorted; composed of rounded, frosted quartz grains; rounded, frosted, floating, coarse-grained quartz sand common; calcareous, friable; laminated to thin-bedded; weathers to form a frothy slope.------0.8

34. Siltstone, moderate reddish orange (10R 6/ 6); coarse-grained, fair-sorting; composed of sub rounded quartz grains; calcareous, friable; laminated to thinly laminated; weathers to form 90

a friable slope; heavy minerals present; insoluble residue = 84.9% .------7 .8 33. Micrite( ?), pinkish-gray (SYR 8/1); tufa-like texture; gnarly-bedded; w eathers to form a frothy s l o p e .------5 .8 32. C overed.------81.2

Total of unit IX .------104. 6

Unit VIII:

31. Silty micrite, pinkish-gray (5 YR 8/ 1), w eathers light olive gray (5 Y 6/ 1); contains medium-grained silt, well-sorted, composed of sub angular quartz grains; thin-bedded; weathers to form a rounded platey outcrop in a slope; insoluble residue = 25. 5%.- - 0. 3 Total of unit VIII.------073 Unit VII:

30. Biomicrite, very pale orange (10 YR 8/ 2), weathers same; slightly silty, fine-grained silt, well-sorted, composed of angular quartz grains; thin-bedded; weathers to form the top of a prominent ledge; chert nodules near middle of unit, light-gray (N7), weathers lichen-covered black and orange; fossiliferous, Metacoceras bowmani. ------2.2 29. Recrystallized limestone, pale-brown (5 YR 5/2) weathers grayish orange pink (5 YR 7/2); coarsely crystalline; thin-bedded; weathers to form a sharp bench above massive unit; insoluble residue = 8. 5%.- - 1.9 Total of unit V I I .------471

Unit VI:

28. Silty dolomite, very pale orange (10 YR 8/ 2), weathers pinkish-gray (SYR 8/1); finely crystalline; contains fine- to medium- grained silt; fair-sorting, composed of subangular quartz grains; massive; weathers to form the upper part of a prominent cliff; cherty; sm all white m ega-quartz pods com m on.------10.8 27. Silty biogenic dolomite, very pale orange (10 YR 8/2), weathers pinkish-gray (SYR 8/1); finely crystalline; contains fine- to coarse-grained silt, poorly sorted, composed of subangular quartz 91

grains; thick-bedded; weathers to form a series of rounded ledges which make up the base of the pro minent cliff; insoluble residue = 19.5%; calcite crystals common; fossil fragments, trilobite p ygid iu m .------16.4 26. Silty dolomite, very pale orange (10 YR 8/2), weathers yellowish-gray (5 Y 8/1); finely crystalline; contains fine- to coarse-grained silt, poorly sorted, composed of subangular quartz grains; thick-bedded; weathers to form rounded ledges; insoluble residue = 17.7%; some calcite crystals; fossil fragments, productid brachipod fragm ents.------10.2 25. Sandy silty biogenic dolomite, very pale orange (10YR 8/2); weathers pinkish-gray (SYR 8 / 1); finely crystalline; contains fine-grained sand and coarse-grained silt, fair-sorting, composed of subangular quartz grains; thin-bedded; weathers to form a ragged bench; fo ssil fragm ents c o m m o n .------1.5 24. Silty dolomite, very pale orange (10 YR 8/2), w eathers yellow ish -gray (5 Y 8 /l); finely crystalline; contains fine-grained silt, fair-sorting, composed of subangular quartz grains; thick-bedded; weathers to form a rounded bench; insoluble residue = 26.1%; chert nodules near center of unit, pale yellowish brown (10 YR 6/ 2), weather moderate reddish orange (10R 6/ 6).------3 .3 Total of unit VI.------42. 2

Unit V:

C overed.------5. 8 Total of unit V . ------5 .8

Units II, III, and IV: 22. Silty biogenic dolomite, dark yellowish brown (10 YR 4/2) to pale yellowish brown (10 YR 6/ 2 ), weathers yellowish-gray (5 Y 8 /l); finely crystalline; contains fine- and coarse-grained silt, fair-sorting, composed of subangular quartz grains; thick-bedded; sparry calcite; fossiliferous; insoluble residue = 14.2%. 2.0 21. Dolomite, pale yellowish brown (10 YR 6/2), weathers grayish-orange (10YR 7/4); finely crystalline; thin- 92

bedded; weathers to form a sharp bench; slightly fetid. 1.1

20. Recrystallized limestone, brownish-gray (SYR 4/ 1), weathers dark yellowish brown (10 YR 4/2); coarsely crystalline; thin-bedded; weathers to form a sharp step; slightly fetid.------0.3 19. Biogenic dolomite, pale yellowish brown (10 YR 6/2), weathers slightly grayer; finely crystalline; thin- bedded; weathers to form a sharp bench; slightly fetid; insoluble residue = 9.3%; fossiliferous.------2.1 18. C overed.------14.2 17. Silty biogenic dolomite, light-brown (SYR 6/4), weathers pale yellowish brown (10 YR 6/2); finely crystalline; contains fine- and coarse-grained silt, fair-sorting, composed of subangular quartz grains; thin-bedded; weathers to form a sharp bench; insol uble residue = 15.4%; fossiliferous, gastropods, ostracods( ?).------1.2 161 Sandy silty biogenic dolomite, pale yellowish brown (10YR 6/2), weathers very pale orange (10 YR 8/2); coarsely crystalline; fine- to medium-grained silt, fairly well sorted, composed of subangular quartz grains; rounded, frosted, floating, coarse- and medium quartz sand common; thin-bedded; weathers to form a rounded step; fossiliferous.------0 .4 15. Silty dolomite, light-brown (SYR 5/6), weathers light-brown (5 YR 6/4); finely crystalline; contains fine- and coarse-grained silt, fair-sorting, thin- bedded; weathers to form a rounded bench; fossils(?). 1.1 14. Silty dolomite, grayish orange pink (SYR 7/2), weathers slightly lighter; finely crystalline; con tains fine- and coarse-grained silt, fair-sorting, composed of subangular quartz grains; thin-bedded; weathers to form a rounded bench; fossil frag- m ents( ?). ------0.9 13. C o v e r e d .------2.7 12. Sandy silty biogenic dolomite, banded from grayish- orange (10YR 7/4), light-brown (SYR 6/4) to grayish- red (10R 4/2); weathers grayish orange pink (SYR 6/4); coarsely crystalline; contains coarse-grained silt and very fine grained sand, fair-sorting; com posed of subrounded quartz grains; rounded; frosted. 93

floating, coarse-grained quartz sand common; thin-bedded; weathers to form a rounded bench; fo ssilifero u s, sm all ostracods com m on.------1.2 11. Silty dolomite, pale yellowish brown (10 YR 6/2), weathers grayish orange pink (5 YR 7/2) and pale yellowish brown (10 YR 6/ 2); finely crystalline; con tains fine-grained silt, well-sorted; composed of angular quartz grains; thin-bedded; weathers to form a sharp bench; fossils( ?), ostracods( ?).------1.3 10. Silty calcareous dolomite, grayish-orange (10 YR 7/4), weathers pale yellowish orange (10 YR 8/ 6); finely crystalline; contains coarse- and fine-grained silt, poorly sorted; composed of angular to subangular quartz grains; thin-bedded; weathers to form a rounded bench; insoluble residue = 18. 8% tiny white pellets common in parts; fossiliferous, ostracods common.------0.9 9. Silty dolomite, light-brown (SYR 6/4), weathers moderate orange pink (SYR 8/4); finely crystalline; coarse- and fine-grained silt, moderately well sorted,bimodal; composed of subangular quartz grains; thin-bedded; weathers to form a rounded bench; insoluble residue = 26.5%; pyrolusite(?) dendrites common.------1.2

8. Silty dolomite, mottled light-brown (SYR 6/4) to grayish-orange (10 YR 7/4); finely crystalline; con tains coarse- to fine-grained silt, moderately well sorted, composed of subangular quartz grains; thin-bedded; weathers to form a rounded step; in soluble residue = 26.2%; calcite crystals and veins c o m m o n .------0. 5 7. C overed.------2 .9

6. Silty biogenic dolomite, grayish-orange (10 YR 7/4) to light-brown (SYR 6/4), weathers pale yellowish brown (10 YR 6/2); finely crystalline; contains fine grained silt, fair-sorting, composed of angular quartz grains; thin-bedded; weathers to form a rounded bench; insoluble residue = 17.8%; calcite veins abundant; fossiliferous, Paraparchites sp ., Jonesina s p ., C oryella sp .------2 .5 5. Silty dolomite, light-brown (SYR 6/4), weathers grayish orange pink (SYR 7/2); finely crystalline; 94

contains fine- and coarse-grained silt, poorly sorted, composed of subangular quartz grains; thin-bedded; weathers to form a rounded bench.------0.9 4. C overed.------5 .4 3. Silty sandy dismicritic dolomite, pale-red (10R 6/2), weathers grayish orange pink (SYR 7/2); finely crystalline; contains very fine-grained sand and coarse grained silt, poorly sorted, composed of rounded, frosted quartz grains; rounded, frosted, floating, coarse-grained quartz sand rare; thin-bedded; weathers to form a rounded bench; brown sparry calcite blebs and eyes abundant; pyrolusite( ?) dendrites common.------1.2 Total of units II, III, and I V . ------4 4 .0 Unit I:

C overed.------3. 6

Total of unit I. ------3. 6

Total of Tor owe ap F o r m a tio n .------203. 8

Unconformity: Toroweap- Coconino contact very flat and only slightly undulatory.

Coconino Sandstone (unmeasured): 1. Sandstone, moderate orange pink (SYR 8/4); fine grained, very well-sorted; composed of rounded, frosted quartz grains; well-cemented, silica-over growth cementation; very thick sets of steeply dipping cross-laminae; weathers to form a partially covered slope. 95

Toroweap Formation Section 7.

Section measured at the northwest end of the deepest cut on the Sante Fe Line in SE?, SE4, Sec. 6, T. 22 N ., R. 1 W. Section was measured up southwest side of cut.

Recent:

Soil on Toroweap Formation (unmeasured).

Perm ian:

Toroweap Formation (incomplete): F eet Unit VI (incomplete): 24. Silty dolomitic recrystallized limestone, very pale orange (10 YR 8/2); coarsely crystalline; contains fine- to medium-grained silt, moderately well-sorted, composed of angular quartz grains; m a ssiv e .------17. 0

Total of incomplete unit V I.------TtT o

Unit V:

23. Sandy siltstone, pale yellowish orange (10YR 8/ 6); coarse-grained silt to very fine grained sand, moderately well sorted; composed of angular quartz grains; calcareous, friable; thin-bedded to laminated; large scale liesagang banding runs through unit at random, bands moderate pink (5R 7/4).------4 .9 Total of unit V . ------479

Unit IV: 22. Biogenic dolomite, light-gray (N7) to medium light gray (N6); finely crystalline; thick-bedded; calcite vugs common; fossiliferous, mollusks abundant near top of u n it.------4. 6 21. Dolomite, medium-gray (N5) to pinkish-gray (SYR 8/ 1); finely crystalline; thin-bedded; siltstone, pinkish-gray (5 Y 8 / 1), laminae between beds of d o lo m ite .------6.2 Total of unit IV. 10.8 96

Unit III: 20. Sandy siltstone, grayish-orange (10 YR 7/4) with moderate yellowish brown (10 YR 5/4); coarse grained sand, moderately well sorted; composed of angular quartz grains; calcareous, friable; laminated to thin-bedded; sparry calcite cement.------6. 7 Total of unit III.------6.7

Unit II:

19. Dolomite, very pale orange (10 YR 8 / 2 ); finely crystalline; thin-bedded; forms bed at top of second road bench.------2.2 18. Dolomite, mottled pinkish-gray (5Y 8/1) to very pale orange (10 YR 8/2); finely crystalline; thin- bedded.------2 .3 17. Inter laminated sandy siltstone and micrite, pinkish-gray (SYR 8/ 1); siltstone, coarse-grained silt to very fine-grained sand; composed of sub angu lar quartz grains; thin-bedded, laminated near top of u n it.------1.0 16. Silty sandstone, grayish-orange (10YR 7/4); very fine-grained, fair-sorting; composed of angular quartz grains; laminated to thinly laminated.------0.7 15. Sandy silty dolomite, pale yellowish brown (10 YR 6/ 2) interbedded with silty sandstone, grayish- orange (10YR 7/4); finely crystalline; contains coarse-grained silt to very fine grained sand, mod erately well-sorted composed of angular quartz grains; form s seven thin b e d s .------5. 2 14. Silty sandstone, grayish-orange (10 YR 7/4); very fine grained, well-sorted; composed of angular quartz grains; non-calcareous, friable; laminated to thinly laminated; liesagang banding along frac tures pale-red (5 R 6/2). ------0.7 13. Silty sandy dolomite, very pale orange (10 YR 8/2); finely crystalline; contains coarse-grained silt to very fine grained sand, moderately well sorted, composed of angular quartz grains; very thick bed.----- 4. 0

12. Sandy silty dolomite, pale yellowish brown (10 YR 97

6/ 2); finely crystalline; contains coarse-grained silt to very fine grained sand, moderately well sorted, composed of angular quartz grains; thin- bedded; fossiliferous, ostracods common.------1.4 11. Sandy siltstone to silty sandstone, yellowish-gray (5 Y 8/1); coarse-grained silt to very fine grained sand, moderately well sorted; composed of angular quartz grains; calcareous, friable; laminated to thin-bedded.------0.5 10. Silty dolomite, pale-red (10R 6/2), mottled; finely crystalline; contains medium-grained silt, moder ately well-sorted, composed of angular quartz grains; th in -b ed d ed .------0. 6 9. Sandy siltstone, interlaminated pale reddish brown (10R 5/4), and grayish-orange (10 YR 7/4); coarse grained silt to very fine-grained sand, moderately well sorted; composed of angular quartz grains; non- calcareous, friable; lam inated.------0 .3

8. Silty dolomite, grayish orange pink (SYR 7/2); finely crystalline; contains coarse-grained silt, fair- sorting, composed of angular quartz grains; thin-bedded; fossiliferous, ostracods.------1.0 7. Silty dolomite, pale-red (10R 6/2); finely crystal line; contains coarse-grained silt, composed of angular quartz grains; th ick -b ed d ed .------3. 2

6. Sandy silty dolomite, pale-red (5 R 6/2); finely crystal line; contains coarse-grained silt and some very fine grained sand, moderately well sorted, composed of angular quartz grains; thin-bedded.------1.2 5. Silty biogenic dolomite, light-brown (SYR 6/4); finely crystalline; contains fine-grained silt, poorly sorted, composed of angular quartz grains; thick- bedded; fossiliferous, ostracods very abundant, Paraparchites sp., Jonesina sp., Coreyella s p . ------3.1 4. Sandy silty dolomite, pale-red (10R 6/2); finely crystalline; contains coarse-grained silt to very fine grained sand, moderately well sorted, com posed of angular quartz grains; thick-bedded; locally conglomeratic, with clasts of local origin.----- 3.2

Total of unit I I . ------30. 6 98

Unit I:

3. Sandstone, moderate reddish orange (10R 6/ 6); very- fine grained, well-sorted; composed of rounded, frosted quartz grains; rounded, frosted, floating, coarse-grained quartz sand common; slightly cal careous, fairly well indurated; thick-bedded.------3.2 2. Sandstone to silty sandstone, pale-red (10R 6/2); very fine grained, well-sorted; composed of rounded, frosted quartz grains; calcareous, fairly well indurated; thick-bedded; heavy minerals c o m m o n .------0. 5 Total of unit I. ------3. 7 Total of incomplete Toroweap Formation.------73. 7

Unconformity: The Toroweap-Coconino contact is a flat surface that truncates the steeply dipping cross-laminae of the Coconino Sandstone.

Coconino Sandstone (unmeasured):

1. Sandstone, grayish orange pink (SYR 7/2); very fine to fine-grained, well-sorted; composed of rounded, frosted quartz grains; well-cemented, silica-overgrowth cemen tation; very thick sets of cross-laminae. SELECTED REFERENCES

Belden, W. A ., 1954, The stratigraphy of the Toroweap Formation, Aubrey Cliffs, Coconino County, Arizona: Univ. of Arizona M. S. thesis (unpub.).

Brown, G. (editor), 1961, The x-ray identification and crystal structures of clay minerals, 2d. edition: Mineralogical Society (British), London, 544 p.

Chronic, H ., 1952, Molluscan fauna from the Permian Kiabab For mation, Walnut Canyon, Arizona: Geol. Soc. America Bull., v. 63, p. 95-165.

Darton, N. H ., 1910, A reconniassance of parts of northwestern New Mexico and northern Arizona: U. S. Geol. Survey Bull. 435, 84 p.

Folk, R. L ., 1959, Practical petrographic classification of limestones Am. Assoc. Petroleum Geologists Bull., v. 43. p. 1-38.

______, 1965, Petrology of Sedimentary Rocks, 2d edition: Hemphill's Austin, Texas.

Gilbert, G. K ., 1875, Report on the geology of portions of Nevada, Utah, California, and Arizona, examined in the years 1871, 1872, and 1873: U. S. Geog. and Geol. Surveys W. 100th Meridian Rept., v. 3, p. 17-187, 503-567.

Girty, G. H ., 1909, Paleontology of the Manzano Group of the Rio Grande Valley, New Mexico: U. S. Geol. Survey Bull. 389, p. 41-136.

Marcou, J ., 1856, Resume and field notes: U. S. Pacific Railroad Expl., v. 3, pt. 4, Geological Report, p. 165-171.

McKee, E. D ., 1934, The Coconino Sandstone--its history and origin: Carnegie Inst. Washington Pub. No. 440, p. 77-115.

99 100

______, 1938, The environment and history of the Kaibab and Toroweap Formations of.northern Arizona and southern Utah: Carnegie Inst. Washington Pub. 492.

______, and Weir, G. W., 1953, Terminology for stratification and cross-stratification in sedimentary rocks: Geol. Soc. America Bull., v. 64, p. 381-390.

Miller, H. W., and Breed, W. J ., 1964, Metacoceras bowmani, a new species of nautiloid from the Toroweap Formation (Permian) of Arizona: Jour. Paleo^ , v. 38, p. 877-880.

Newberry, J. S., 1861, Geological Report, pt. 3, 154 p;, in Report upon the Colorado River of the west, explored in 1857-58 by Lieut. J. C. Ives: Washington, Government Printing Office.

Nicol, D ., 1944, Paleoecology of three faunules in the Permian Kaibab Formation at Flagstaff, Arizona: Jour. Paleo., v. 18, p. 553-557.

Noble, L. F ., 1938, A section of the Kaibab Limestone in Kaibab Gulch, Utah: U. S. Geol. Survey Prof. Paper 150-C, p. 41-60.

Reiche, P ., 1938, An analysis of cross-lamination; the Coconino Sandstone: Jour. Geol., v. 46, p. 905-932.

Rock-Color Chart Committee, 1948, Rock-color chart: Nat. Res. Council, Washington, D. C.

Schultz, L. C ., 1963, Clay minerals in Trias sic rocks of the Colorado Plateau: U. S. Geol. Survey Bull. 1147-C, p. 1-71.

Tennant, C. B ., and Berger, R. W., 1957, X-ray determination of dolomite-calcite ratio of a carbonate rock: American Mineral ogist, v. 42, p. 23-29.

Upson, M. E ., 1933, The Ostracoda of the Big Blue series in Nebraska: Nebr. Geol. Survey Bull. 8, 2d ser. 54 p.

Warshaw, C. M ., and Roy, R ., 1961, Classification and scheme for the identification of layer silicates: Geol. Soc. America Bull., v. 72, p. 1455-1492. 101

Welsh, J. E ., 1959, Biostratigraphy of the Pennsylvanian and Permian Systems in southern Nevada: Univ. of Utah Ph. D. thesis (unpub.).

Wentworth, C. K ., 1922, A scale of grade and class terms for clastic sediments: Jour. Geol, v. 30, p. 377:392.

Yochelson, E. L ., 1960, Belle r op ho ntacea and Patellae ea, Pt. 3 of Permian Gastropoda of the southwestern United States: Am. Mus. Nat. History Bull., v. 119, art. 4, p. 207-294. 3ChdL^1’Z> 2

112*30'

Fig. 1. --Index map of the study area. 0UA0PANGLE LOCATION z F f 2 7 / / ? c 7 3 VOLUMETRIC ALLOCHEM COMPOSI l>efore the main rock name (e.g., fossiliferous intrasparite, oolitic pelmicrite, pelletiferous oosparite, or intraclastic biomicrudite). This ran be shown symbol mary dolomite” to the rock nameT)Lr” or and “DLa" use for“Dr" the or symbol “Da” for (ethe g.,symbol dolomitized (e.g., primary intrasparite, dolomite Ii:DLa). intramicrite, If the rock IIi:Da). Instead contains “primary of dolomiteoxer 10 micrite" percent dolomite of uncertain origin, prefix the term “dolo- smaller than 1.0 mm. Grain size and quantity of ooze matrix, cements, or terrigenous grains are ignored. m a y a l s o b e ping r e f on i x which e d . is dominant (e.g., sandy biosparite, TsIb:La,or silty dolomitized pelmicrite, TzIIp:DLa). Glauconite, cellophane, chert, pyrite, or other modifiers ically as Ii(b), Io(p), respectively.llb(i), microsparite," etc., can be used instead of “micrite" or “biomicrite.” mitic” to the rock name and use“dLr” or “dLa" for the symlwl (e.g., dolomiticpelsparite, Ip:dl>e). If the rock consists of primary dolomite, prefix the term “pri (IIIm:D), the term “dolomicrite" may be used. a vC. £ V l 6 . If4. the rock contains other allochems in significant quantities that are not mentioned in the main rock name, these should be prefixed as qualifiersimmediately 3 . If5.the fossils are ofrather uniform type, this fact should . Upper2. name in each box refers to calcirudites (median allochem size larger than 1.0 mm) and lower name refers to all rocks with median allochem size . Specify7. crystal size as shown on the examples (see table 5). 1 ifthe rock contains over If the. rock was originallymicrocrystalline and can be shown to have recrystallized to microspar (5- to 10-micron, clear calcitet, the terms “microsparite," “bio- Names. and symbols refer to limestone. If the rock contains over 10 percent replacement dolomite, prefix the term “dolomitized"’ to the rock name and use n u Z2 n Ei-b 0 = 5 £ # A3:1 1

? / ? ? 7 (b) | Microcrystalline ooze matrix Pelsparite (Ip:La) Oosparrudite* (Io:Lr) S P A R R Y A L L O C H E M I C A L Biopelsparite (Ibp:La) Biopelsparrudite* (Ibp:Lr) Biosparrudite (Ib:Lr) Oosparite (Io:l a) Intrasparrudite (Ii:Lr) Intrasparite L I M E S T O N EPA , R T I A L L YD O L O M I T I Z E DLI M E S T O N EA . N DPR I M A RDO Y L O M I T E Biosparite (Ib:La) ROCKS”(I) Sparry calcite cement > A L L O C H E M I C A LR O C K S 1 10 1 i: La) percent terrigenous material, prefix “sandy," Tilly," or “clayey" to therock name and“Ts," “Tz," or “To” to the symbol, depend 10% > Allochems Microcrystalline ooze matrix > M I C R O C R Y S T A L L I N EA L L O Biomicrite (Hb:I

Kaibab Formation

c C3

> E t— Toroweap Formation

Coconino Sandstone

Fault

We^Wi^d Sw tion

1 550 000 FEET

(ASH FORK) R. 1 W . 378 112° 30'

4 MILES x=jjrT 3 0 0 0 3 0 0 0 6 0 0 0 9 0 0 0 12000 1 5000 18000 2 1 0 0 0 FEET ~E 1 ,5 0 1 5 KILOMETERS i—i i—i i—i i—i t-=r~F CONTOUR INTERVAL 40 FEET DATUM IS MEAN SEA LEVEL

QUADRANGLE LOCATION

Topographic base from U. S. G. S. Hearst Mtn. Quadrangle Fig. 2 7 . - GEOLOGIC MAP OF THE STUDY AREA NORTH OF Geology by R. L. Mullens, 1967 ASHFORK, ARIZONA 7 0 S .