GEOLOGICAL SURVEY CIRCULAR 635 

Stratigraphic Sections and 

Chemical Analyses of 

Phosphatic Rocks of Permian 

And Mississippian Age in 

Weber County, Utah 

Stratigraphic Sections and 

Chemical Analyses of 

Phosphatic Rocks of Permian 

And Mississippian Age in 

Weber County, Utah 

By E. M. Schell and K. P. Moore 

GEOLOGICAL SURVEY CIRCULAR 6 3 5 

Washington 1970 
United States Department of the Interior 

WALTER J. HICKEL, Secretary 

Geological Survey 

William T. Pecora, Director 

Free on application to the U.S. Geological Survey, Washington, D.C. 20242 
CONTENTS 

Page 

Abstract ------------------------------------------------------------------------------------------------------------------------------------ 1 

Introduction _ ___ _________ _ ___________ __ ________ _____ ___ _ ____ __ ____ _________________ ___ ____ ______ _______ __ _____________________ ___________ 1 

Personnel and acknowledgments_____________ _______________ ___ __ _______________ ____________________ ____________ 1 

Previous work ______________________________ ------------------------------------------------------------------------------------ 3 

Field and laboratory procedures----------------------------------- __ ------------------------------------------------- 3 

References cited ____________________________________________________ ---------------------------------------------------------- 3 

Stratigraphic sections and analyses------·---------------·----- _______ ---·------------ ---------·-------------- 4 

South Sheepherd Creek, CP-35 ____ _____ _ _________________________ ___ __________________ ____________________ 4 

North Sheepherd Creek, CP-36·-------------------------------------------·--------------------------------------- 5 

Hardy Hollow, CP-37 ______ -------------------------------·------------------------------------------------------------ 5 

Ogden Canyon, CP-38 ________ ------------------------------------------------------------------------------------------- 10 

Wheat Grass Creek, CP-44 _____________________________ -------------------------------------------------------------- 11 

ILLUSTRATION 

Page 

FIGURE 1. Index map of trench localities in Weber and 

Morgan Counties, Utah _______ ------------------------------------------------------------------------ 2 

III 

STRATIGRAPHIC SECTIONS AND CHEMICAL ANALYSES OF 

PHOSPHATIC ROCKS OF PERMIAN AND MISSISSIPPIAN 

AGE IN WEBER COUNTY, UTAH 

By E. M. SCHELL and K. P. MOORE 

ABSTRACT 

Stratigraphic sections and chemical anlyses of phosphatic rocks from five trench localities in Weber County, 

Utah, are presented. Four of the trenches are in Mississippian rocks, and one is in Permian rocks. Of the 

Mississippian rocks, the highest grade phosphatic interval is at the Wheat Grass Creek locality. Here the 

phosphatic rocks are 14.9 feet thick, and a 5.8-foot-thick 

zone has an average of 22.1 percent P205. Three localities of Mississippian rocks have 1.1 or less feet of 

phosphate rock that contains 24+ percent P205. The 

Permian Park City Formation and related strata, where 

measured in Hardy Hollow, are 675 feet thick and consist of a 10.9-foot-thick phosphatic interval in the 

Grandeur Member of the Park City; the Meade Peak 

Phosphatic Shale Tongue of the Phosphoria Formation 

is 171 feet thick, but it is cut by numerous faults. 

INTRODUCTION 

This report presents stratigraphic sections 

and chemical analyses of phosphatic rocks from 

five trench localities in vVeber County, Utah. 

The localities are from 6 to 25 miles east of 

Ogden, Utah in the Ogden River drainage 

system (fig. 1). 

Four trenches ( CP-35, CP-36, CP-38, CP44) are in the upper part of the Lodgepole 

Limestone and the basal part of the Deseret and 

Humbug Formations, all of Mississippian age. 

The highest grade phosphatic rocks of the Mississippian are at the Wheat Grass Creek locality 

(CP-44). The phosphatic rocks there are 14.9 

feet thick, and a 5.8-foot zone contains an average of 22.1 percent P.z05. The three other localities of Mississippian rocks have 1.1 or less feet 

of phosphate rock that contains 24 + percent 

P 205. The phosphatic intervals in the Mississippian rocks are considered to be one phosphatic zone. Because of facies changes, the 

phosphatic intervals are assigned to three mappable formations. A discussion of the details 

1 

of the Mississippian stratigraphy is beyond the 

scope of this report. 

One trench (CP-37) is in the Park City 

Formation and related strata of Pern1ian age. 

Where measured in Hardy Hollow, the Park 

City and related strata are 675 feet thick and 

contain a 10.9-foot-thick phosphatic interval in 

the Grandeur lVIember of the Park Cit:r Formation. The Meade Peak Phosphatic Shale Tongue 

of the Phosphoria Formation is 171 feet thick, 

but it is cut by numerous faults. 

The field study is part of a geologic program 

of the Conservation Division, U.S. Geological 

Survey, begun in 1964, to support mineral land 

classification of phosphate withdrawals on Federal lands. Trenching and sampling of the phosphatic intervals were done in August 1964 and 

July 1966 to augment geologic mapping projects 

in the general area. This report supplements 

stratigraphic and analytical data of previous 

investigators (Blackwelder, 1910; Cheney and 

others, 1953; Cheney, 1957; Mullens and Laraway, 1964; Schell and Gere, 1964; Mullens, 

1969). The manner of investigation w~.s similar 

to the procedure described by McKelve:T, Davidson, O'Malley, and Smith (1953, p. 1-6). The 

analytical data and condensed descriptions of 

the rocks are presented for each trench, and 

detailed descriptions of the rocks exposed in 

the trenches follow the analytical data. No interpretation of the data is presented e:r:cept for 

interpretation of some of the faulting in the 

Hardy Hollow trench ( CP-37). 

PERSONNEL AND ACKNOWLEDGT:fENTS 

Field studies and geologic mapping in the 

northwest quarter of the Morgan 15-minute 

quadrangle by R. J. Hite specifically outlined 

for the first time the topographic expr~ssion of 
112° 00' 

---

41° 15' 

BOX ELDER 

) COUNTY 

UTAH 

R 1 W. 

111°45' 

R. 1 E. R 2 E. 

CP-30 X 

Dry Bread Hollow trench T. 

CP-44X 

Wheat Grass Creek trench 

EXPLANATION 

X 

7 

N. 

T 

5 

N 

CP-35 T. 

Trench locality and number 4 

N. 

R. 3 E 

0 2 3 4 MILES 

FIGURE 1.-Trench localities in Weber and Morgan Counties, Utah. 

the phosphatic rocks from which three trench 

localities were selected. Field studies and geologic mapping in the Causey Dam quadrangle 

by T. E. Mullens (1969) delineated phosphatic 

rocks of Mississippian age. R. J. Hite and T. E. 

Mullens also participated in sampling and describing one trench each in Sheepherd Creek 

(CP-35) and Wheat Grass Creek (CP-44). 

R. K. Stewart and Byron Walke did the hand 

2 

trenching in the North and South Sheep herd 

Creeks localities in 1964; Lynn Walker and 

S. A. Wilbur did the hand trenching at the 

Wheat Grass Creek locality in 1966. E. M. 

Schell described and sampled the stratigraphic 

sections, and K. P. Moore made the chemical 

analyses. Permission by the land owners to 

trench and to sample the rocks is gratefully 

acknowledged. 
PREVIOUS WORK 

The Mississippian phosphatic rocks of the 

general area were first described by Blackwelder (1910, p. 547-550). Cheney (1957, p. 37) 

published a measured section of the Ogden 

Canyon (CP-38) locality but considered the 

P20s content too low to warrant sampling. Mullens (1969) showed the outcrop pattern of the 

Humbug Formation in the Causey Dam quadrangle and gave a synopsis of the data from 

the Wheat Grass Creek (CP-44) locality. 

Preliminary data on the Permian phosphate 

deposits in the Hardy Hollow area were presented by Blackwelder (1910, p. 547-548, fig. 

44) . Blackwelder published a few analyses of 

phosphate rock float and the general outcrop 

pattern of the Park City Formation. The two 

nearest trench sections of the Park City Formation and related strata to the Hardy Hollow 

(CP-37) locality are the Devils Slide and Dry 

Bread Hollow localities (fig. 1). The Devils 

Slide locality is about 12 miles southeast in 

sec. 26, T. 4 N., R. 3 E. A stratigraphic section 

and chemical analyses of the phosphatic rocks 

in the Devils Slide locality were published by 

Cheney, Smart, Waring, and Warner (1953, 

p. 11-17). The geology of the Devils Slide area 

was mapped by Mullens and Laraway (1964). 

The Dry Bread Hollow locality is about 11 miles 

northeast of the Hardy Hollow locality. Geologic and trench ·data of the Dry Bread Hollow 

area were presented by Blackwelder (1910, p. 

548-550, fig. 44) and, more recently, by Schell 

and Gere (1964) and Mullens (1969). 

FIELD AND LABORATORY PROCEDURES 

Three of the trenches, CP-35, CP-36, and 

CP-44, were hand excavated to a maximum 

depth of about 8 feet. The uppermost beds of 

the phosphatic interval at these localities were 

not sampled because of excessive overburden. 

The Hardy Hollow trench ( CP-37) was bulldozed to a maximum depth of about 15 feet. 

Little additional excavation was necessary at 

the Ogden Canyon trench (CP-38) because the 

phosphatic interval is well exposed in an abandoned roadcut. Although well exposed, the rocks 

sampled at Ogden Canyon are overturned in a 

sharp fold. All the trenches described and sampled are in the weathered zone ; therefore, the 

thickness and the analyses may not be representative of the units at depth. In general, 

3 

weathered phosphatic rock is slightly enriched 

in P20s as compared to underlying unvreathered 

phosphatic rock (Cheney, 1957, p. 3f-35). At 

the Hardy Hollow ( CP-37) locality numerous 

fault zones and some repetition of t ~ds were 

noted in the trenched intervals. No data on the 

thickness of strata deleted by faulting are available, and the interpretation of repetition of 

beds is the sole responsibility of the senior 

author. 

Separate numerical designations were made 

for lithologic units and channel samples. Except in the units low in P20s content, a channel 

sample rarely exceeded 2 feet in thickness. At 

least one chip sample was collected from each 

bed, and the samples were later studied under 

a binocular microscope to supplement or modify 

the field descriptions. 

Rock names and adjectives and the terms for 

hardness and thickness of bedding ar~ similar 

to those described by Sheldon (196a:, p. 57). 

Color names and numerical designations are 

from the Munsell color charts. The Wentworth 

scale for size classification was used for sandstone, phosphorite, limestone, and de 1omite. 

Channel samples, which averaged about 10 

pounds, were crushed in the field to I'linus lisinch mesh by a jaw crusher. A Jone::o splitter 

was used to obtain two splits of about half a 

pint each. One split was stored for. future use, 

and one split was forwarded to the laboratory 

for analyses. 

The methods of P20s and acid-insoluble analyses are similar to those described by Hoffman 

and Lundell (1938). Interpretation of chemical 

data of phosphatic rocks was pres~nted by 

McKelvey, Davidson, O'Malley, anq Smith 

(1953, p. 3-4). 

REFERENCES CITED 

Blackwelder, Eliot, 1910, Phosphate deposits east of 

Ogden, Utah: U.S. Geol. Survey Bull. 430-H, p. 

536-551. 

Cheney, T. M., 1957, Phosphate in Utah and an analysis 

of the stratigraphy of the Park City and the Phosphoria formations, Utah-a preliminary report: 

Utah Geol. and Mineralog. Survey Bull. 59, 54 p. 

Cheney, T. M., Smart, R. A., Waring, R. G., and Warner, 

M. A., 1953, Stratigraphic sections of the Phosphoria formation in Utah, 1949-51: U.S. Geol. Survey Circ. 306, 40 p. 

Hoffman, J. I., and Lundell, G. E. F., 1938, Analysis of 

phosphate rock: U.S. Natl. Bur. Standards Jour. 
Research, v. 20, no. 5, Research Paper 1095, p. 

607-626. 

McKelvey, V. E., Davidson, D. F., O'Malley, F. W., and 

Smith, L. E., 1953, Stratigraphic sections of the 

Phosphoria formation in Idaho, 1947-48, Pt. 1: 

U.S. Geol. Sm·vey Circ. 208. 49 p. 

Mullens, T. E., 1969, Geologic map of the Causey Dam 

quadrangle, Weber County, Utah: U.S. Geol. Survey 

Geol. Quad. Map GQ-790. 

Mullens, T. E., and Laraway, W. H., 1964, Geology of 

the Devils Slide quadrangle, Morgan and Summit 

Counties, Utah: U.S. Geol. Survey Mineral Inv. 

Field Studies Map MF-290. 

Schell, E. M., and Ge:re, W. C., 1964, Preliminary report 

on the phosphate deposits and stratigraphy of Permian rocks in Dry Bread Hollow, Weber County, 

Utah: U.S. Geol. Survey open-file report, 36 p. 

Sheldon, R. P., 1963, Physical stratigraphy and mineral 

resources of Permian rocks in weEtern Wyoming: 

U.S. Geol. Survey Prof. Paper 313-B, p. 49-273. 

STRATIGRAPHIC SECTIONS AND 

ANALYSES 

SOUTH SHEEP HERD CREEK, CP -35 

Trench ~P-35 is at South Sheepherd Creek, 

SE1Jt,SE14 sec. 34, T. 6 N., R. 2 E., Salt Lake 

n1eridian, Weber County, Utah. T~·'.e phosphatic 

section near the top of the Lodgep1le Limestone 

was sampled and described in a hand-excavated 

trench by E. M. Schell and R. J. Eite. Chemical 

analyses were by K. P. Moore. 

Abst?·act section of only the uppe·r pa·rt of Lodgepole Limestone, CP-35 

Cumulative Chemical analyses (percent) Thickness 

Sample Unit Thickness Rock description thickness Acid Ignition X percent 

(ft) (ft) PzO;; V205 Cr203 insoluble loss Pz05 (cumulative) 

Top of trench -------- ------------------ -------------------- ------------------------------------------

CP-35-5 M-llb 3.1 Mudstone, slightly 

phosphatic ----- ------------------ 3.1 2.61 0.12 0.06 63.18 1.1.72 8.09 

4 M-lla 2.8 Mudstone, calcareous, 

slightly phosphatic --------------- 5.9 4.23 .26 .04 50.99 14.25 19.93 

3 M-10 .3 Phosphorite --------------------- 6.2~ 7.47 .11 .01 26.22 21.55 ~ 22.17 

3 M-9 .7 Mudstone, calcareous ---------------- 6.9 27.40 

2 M-8 .1 Phosphorite, calcareous ------------ 7.0~ 4.33 .25 .06 58.76 1.0.03 ~ 27.83 

2 M-7 .9 Mudstone, silty ---- --------------------- 7.9 31.73 

1 M-6 .2 Phosphorite -------------------------------- B.lt J37.29 

1 M-5 .2 Mudstone -------------------- --------------- 8.3 42.85 

1 M-4 .3 Phosphorite ------------------------------- 8.6, 27.79 .05 .02 6.44 9.53 l51.19 1 M-3 .1 Mudstone, phosphatic ---------------- 8.7 53.97 

1 M-2 .5 Phosphorite -------------------------------- 9.2 67.86 

----------------------- Base of trench ------------------------------ ---------------- ------------------- ------------------------ ------------------------------

M-1 7.0 Dolomite, cherty ----

Detailed desc1·iption of only the uppe?' part of 

Lodgepole Limestone, CP-35 

Unit Rock description 

Cumu- Thick- lative ness thick- (ft) ness 

(ft) 

-----------·-- Top of trench ___________________ ----------------------------------- -------------------------- M-llb Mudstone, slightly phosphatic, calcareous, silty, 

soft; upper part is moderate brown (7.5YR 

4/4), lower part is grayish brown. ( 5YR 

3/2); indistinct bedding; contains calcite 

pods. Basal contact is sharP----.-------------------------- 3.1 lla Mudstone, slightly phosphatic, calcareous, silty, 

soft; upper 2.4 ft is pale brown (lOYR 5/2), 

10 

8 

7 

6 

lower 0.4 ft is moderate yellowish brown {lOYR 4/5); indistinct bedding; contains cal- cite pods. Basal contact is sharp _____________________ _ 

Phosphorite, very dark gray ( 2.5 Y 3/0), very coarse to fine-pelletal, calcareous, hard, thin- bedded; contains a 0.01-ft-thick mudstone layer 0.1 ft above base. Basal contact is sharp 

Mudstone, moderate-brown (51' R 4/4) , calcar- eous, soft; indistinct bedding, highly weath- ered; contains calcite veinlets and small pods. 

Basal contact is sharp ------------·--·------------------------ Phosphorite, fine- to medium-pelletal, very cal- careous, hard; single bed. Basal contact is 

sharp -----------------·------------------------------------------------------ Mudstone, dark-grayish-brown (10YR 3/2), silty 

soft, laminated; lower 0.1 ft contains phosphorite pellets. Basal contact is sharp ___________ _ 

Phosphorite, dark-gray ( 2.5 Y 4/0), very coarse to fine-pelletal, calcareous, hard, thick-bedded; contains reworked dolomite pebbles. Basal 

con tact is sharp------------------------------------------------------

2.8 

.3 

.7 

.1 

.9 

.2 

3.1 

5.9 

6.2 

6.9 

7.0 

7.9 

8.1 

4 

16.2---- ------------------------------- -------------------------------

Unit 

M-5 

4 

3 

2 

Deta£led desc1·iption of only the upper pwrt of 

Lodgepole Limestone, CP-35-Continued 

Rock description 

Cumu- Thick- lative ness thick- (ft) ness 

Mudstone, grayish-brown (lOYR 4/3). slightly 

phosphatic, slightly calcareous, soft; indis- tinct bedding, highly weathered; contPins a 0.05-ft-thick fine- to coarse-pelletal phos- phorite layer. Basal contact is sharp________________ .2 

Phosphorite, dark-gray (2.5YR 4/0), fi'1e- to coarse-pelletal and oolitic, calcareous, hard, thick-bedded. Most oolites consist of calcite and a phosphatic outer rim. Basal contact is 

sharp -------------·------------------------------------------------.. ----------- .3 

Mudstone, grayish-brown (7.5YR 4/2), phosphatic, calcareous, soft; indistinct beiding; 

contains fine to coarse pellets of phosphorite. 

Basal contact is sharP-----------------------------·----------- .1 

Phosphorite, gray (N 5/0), pelletal and OQ}itic 

(fine to 5 mm) , calcareous, hard, thickbedded. Some oolites contain a calcite center 

and a phosphorite rim. Sharp irregular basal 

contact contains dolomite pebbles front unit 

below ----------------------------------------------------------------------·-- .5 

(ft) 

8.3 

8.6 

8.7 

9.2 

-------------·Base of trench. ______________ ·-------------------------------------------------------------------------

1 Dolomite, gray ( 2.5 Y 5/0), fine- to mediumgrained, cherty, hard, massive; contains irregular lenses and pods of dark-gray chert, 

and gastropods and crinoids (?). Forms ledge. Base not exposed____________________________________________________ 7.0 16.2 
NORTH SHEEPHERD CREEK, CP--36 

Trench CP-36 is at North Sheepherd Creek, 

NEl;iSEl;i sec. 34, T. 6 N., R. 2 E., Salt Lake 

meridian, Weber County, Utah. The phosphatic 

section near the top of the Lodgepole Lin1estone 

was sampled and described in a hand-excavated 

trench by E. M. Schell. Chemical analyses were 

by K. P. Moore. 

Abst1·a.ct section of only the upper pm·t of Lodgepole Limestone, CP-36 

Sample Unit Thickness 

(ft) Rock description 

Cumulative ____ C_h_em_ic_a_l_a_n_al..:.y_se_s ___ ( p=--e_r_c_en_t_;_)___ Thickness 

thickness A 'd I n •t• >' percent Pz05 V205 Cr20.~ 1

·nsoclu1ble g 1 Ion Pz05 (ft) loss (cumulative) 

M-10 16.0 Concealed, overlain by limestone ledge ___ _ ___________ ____________ _____ _ _____________________________________________________________________________ _ 

Top of trench _____________________ _ 

M-9 5.0 Mudstone, calcareous ____ _ 5.0 

CP-36-5 M-8 .3 Phosphorite, calcareous 5.3t 2.54 0.4 0.01 17.90 30.46 ~ 0.76 

5 M-7 1.1 Limestone, argillaceous 6.4 ~ 3.55 

4 M-6 .1 

4 M-5 .9 ~~o;~~~:~t~a~~~-~~~~-~--------:::::::::: ~:~~ 5.06 .18 .05 56.53 14.76 ~ 4.05 

8.60 

3 M-4 .4 Phosphorite and mudstone 7.8 25.13 .05 .02 8.45 11.58 18.65 

2 M-3 .7 Phosphorite and mudstone ______ 8.5 25.44 .02 .01 4.11 14.38 36.45 

1 M-2 .4 Phosphorite -------------------------------- 8.9 26.29 .01 .01 5.23 11.69 46.95 

--------------- ---------------- --------------- Base of trench -------------------------------- ___________________________________ _ -----------------------------------------------

M-1 15.0 Dolomite, cherty _ _____ ___ ___ _______ _ ____________________________________ -------------------------------

Detailed desc1·iption of only the upper part of 

Lodgepole Limestone, CP-36 

Unit Rock description 

Cumulative Thick- thick- ness ness 

(ft) (ft) 

M-10 Concealed, probably mudstone. Overlain by darkgray massive limestone ledge---------------------------- 16.0 ____________ Top of trench --------------------------------------------------------------------------------------

9 Mudstone, dark-yellowish-brown (10YR 4/2), very calcareous, soft; indistinct bedding. Con- tains two pho~phorite beds about 0.1 ft thick about 0.6 and 3.5 ft above base; phosphorite is pale brown (lOYR 5/2), fine to coarse pelletal, 

argillaceous, calcareous, and hard. Basal con- tact is sharp_____________________________________________________________ 5.0 5.0 

8 Phosphorite, light-brownish-gray (5Y R 5/1), 

fine-pelletal to very coarse pelletal and oolitic, 

hard, thick-bedded; matrix dolomitic. Basal 

contact is sharp------------------------------------------------------- .3 5.3 

7 Limestone, grayish-brown (2.5Y 5/2), very argillaceous, soft, thick-bedded; contains calcite veinlets. Basal contact is sharp____________________________ 1.1 6.4 

6 Phosphorite, gray (N 6/0), fine- to medium- pelletal, hard; matrix dolomitic; contains cal- cite veinlets; single bed. Basal contact is sharp .1 6.5 

Mudstone, pale-brown (10YR 5/2), calcareous, 

soft; indistinct bedding, laminated in part. Basal contact is sharp____________________________________________ .9 7.4 

4 Phosphorite and mudstone. Upper 0.3 ft is phosphorite, dark-grey (N 4/0), fine-pelletel to very coarse pelletal and oolitic, hard, thickHARDY HOLLOW, UTAH, CP--37 

Trench CP-37 is in Hardy Hollow, lot 9, sec. 

2, T. 5 N., R. 2 E., Salt Lake meridian, Weber 

County, Utah. The Meade Peak Phosphatic 

Shale Tongue of the Phosphoria Formation and 

the phosphate zone of the Grandeur Member of 

5 

Detailed desc1·iption of only the upper pa'ti of 

Lodgepole Linwstone, CP-36-Continued 

Unit Rock description 

Cumu- Thick- lative n~s thick- (f~) ness 

bedded; matrix dolomitic; oolites contain a cal- cite core. Lower 0.1 ft is mudstone, grayish- brown (10YR 4/3), soft, fissile; contains fine to very coarse pellets of phosphorite. Basal 

(ft) 

con tact is sharp --------------------------------------------------- .4 7. 8 

M-3 Phosphorite and mudstone. Upper 0.6 ft is phosphorite, gray (N 5/0), fine-pelletel to very coarse pelletal and oolitic, hard, thick-bedded; matrix dolomitic; oolites contain a calcite core. Basal 0.1 ft is mudstone, moderate-yellowish- brown (lOYR 5/4), phosphatic, soft; indistinct bedding, highly weathered; contains fine to coarse pellets of phosphorite. Basal contact is 

sharp --,----------------------·---------------------------------------------- • 7 8.5 

2 Phosphorite, dark-gray (N 4/10), pelletal, cal- careous, fossiliferous, hard, thick-bedded; con- tains oolites and nodules ranging from fine to 10 mm in diameter. Upper part contains re- worked phosphorite nodules and calcite-filled phosphorite oolites. Lower part contains re- worked dolomite pebbles. Basal contact is 

sharp and irregular ------------------------------------------------ .4 8.9 

______________ Base of trench. ________________________________________________ --------------------------------------

Dolomite, gray (2.5Y 5/0), fine- to medium- grained, cherty, hard, massive; contains dark- gray chert pods and lenses. Forms ledge_______ 15.0 

the Park City Formation was described and 

sampled on the ridge between Hardy Hollow 

and Sheepherd Creek by E. M. Schell in bulldozer trenches ; the remaining interval was described by E. M. Schell along a Brunton and 

tape traverse. Chemical analyses were l~y K. P. 

Moore. 
Sample Unit 

D-1 

Thickness 

(ft) 

Abstract section, CP-S7 

Rock description 

Cumulative ____ C_h_em_ic_al_a_n_a_::ly_se_s_(;..:.p_er_·c_en_t __ ) ___ Thickness 

thickness A "d Ignition X pp2e

0

rc

5

ent ( f ) P::!Os V:!Os Cr203 •"nsoclulble t loss (cumulative) 

DINWOODY FORMATION-BASAL UNIT ONLY 

5.0+ Limestone, silty _ _____ 5.0 _ 

PARK CITY FORMATION AND RELATED STRATA Rex Chert Tongue of Phosphoria Formation 

P-83 43.0 Chert, carbonatic ________ _ 43.0 .. 

Franson Member of Park City Formation 

P-82 34.0 Limestone ------------------------- 77.0----- ------------------------------------------------------------ P-81 7.0 Dolomite _____ _ ------------------------- 84.0 ___________________________________________________________ ---------------------------------

P-80 120.0 Limestone -------------------------- 204.0 ----- -------------------------------------------------------- __ Top of trench -------------------------

P-79 80.0 Dolomite ___ - ----------------- 284.0 ----

Meade Peak Phosphatic Shale Tongue of Phosphoria Formation 

CP-37-66 P-78 

65 P-77 

64 P-76 

63 P-75 

62 P-74 

61 P-73 

60 P-72 

59 P-71 

58 P-70 

57 P-69 

56 P-68 

55 P-67 

54 P-66 

53 P-65 

52 P-64 

51 P-63 

50 P-62 

49 P-61 

48 P-60 

47 P-59 

46 P-58 

45 P-57 

44 P-56 

43 P-55 

42 P-54 

41 P-53 

40 P-52 

39 P-51 

38 P-50 

37 P-49 

36 P-48 

35 P-47 

34 P-46 

33 P-45 

32 P-44 

2.8 

2.7 

4.0 

5.0 

6.0 

5.0 

5.0 

5.0 

5.0 

5.0 

5.0 

5.0 

5.0 

3.0 

2.8 

3.0 

5.0 

5.0 

5.0 

4.0 

4.5 

5.0 

2.3 

1.8 

.6 

5.0 

5.0 

.5 

2.2 

2.0 

1.7 

1.7 

3.0 

2.5 

2.5 

Phosphorite; top of unit 

is faulted; P-77 and P-78 

range from 5.5 ft thick 

to about 13 ft thick ______________ 286.8 

Phosphorite _____ _ _________ 289.5 

Fault zone _ _ ________________ 293.5 

Fault zone ___________________ 298.5 

Sandstone, calcareous ______________ 304.5 

Sandstone, similar to 

unit P-74 ____________________________ 309.5 

Sandstone, similar to 

unit P-74 ___________________________ 314.5 

Sandstone, similar to 

unit P-74 ____________________________ 319.5 

Sandstone, similar to 

unit P-74 ______________________________ 324.5 

Sandstone, similar to 

unit P-74 ______________________________ 329.5 

Fault zone ______ __ _ _____________________ 334.5 

Fault zone, similar to 

unit P-68 _____________________________ 339.5 

Fault zone, similar to 

unit P-68 ______________________________ 344.5 

Fault zone, similar to 

unit P-68 -------------------------------- 347.5 

Chert __________________________________________ 350.3 

Siltstone __ ___ _ ___________________________ 353.3 

Siltstone, similar to 

unit P-63 ______________________ _ 358.3 

Siltstone, similar to 

unit P-63 ______________________________ 363.3 

Siltstone, similar to 

unit P-63 _______________________________ 368.3 

Siltstone _ _ ________________________________ 372.3 

Siltstone, similar to 

unit P-59 _______________________________ 376.8 

Fault zone ______________________________ 381.8 

Siltstone _______ _ __________________________ 384.1 

Siltstone, dolomitic ____________________ 385.9 

~R~~;~;~lt~ __ :::::::::-:::::::::::::::::::::::: ~~t~ Siltstone, similar to 

unit P-53 _____________________ 396.5 

Phosphorite, siliceous _ 397.0 

Siltstone, micaceous _____________ 399.2 

Siltstone, dolomitic 401.2 

Mudstone and phosphorite, 

interbedded 402.9 

Mudstone and phosphorite, 

similar to unit P-48 404.6 

Dolomite, argillaceous, silty _ _ 407.6 

Dolomite, similar to 

unit P-46 ------------------------------ _ 410.1 

Dolomite, similar to 

unit P-46 ______ ___ ___________________ 412.6 

6 

28.59 

28.80 

9.51 

12.36 

2.40 

1.68 

0 

0 

0 

0 

0 

.08 

2.77 

4.57 

4.43 

4.91 

5.41 

4.39 

0 

1.44 

.59 

0 

.01 

0 

0 

0 

1.26 

27.28 

.01 

.90 

16.51 

10.85 

4.69 

0 

6.00 

0.06 

.06 

.03 

.03 

.02 

.04 

.03 

.05 

.03 

.03 

.04 

.04 

.10 

.11 

------

.03 

.08 

.04 

.04 

.03 

.04 

.04 

.04 

0.11 

.13 

.03 

.06 

.01 

.01 

.01 

.04 

.02 

.03 

.02 

.07 

.07 

.02 

.14 

.03 

.04 

.16 

.12 

.12 

.03 

.17 

13.74 

12.37 

61.97 

44.68 

46.44 

61.98 

10.98 

28.23 

68.53 

64.03 

64.71 

89.28 

84.28 

53.21 

84.08 

80.65 

80.92 

78.79 

91.72 

88.94 

87.22 

89.96 

89.01 

57.87 

74.77 

76.26 

82.29 

17.99 

86.72 

66.71 

40.19 

42.33 

54.93 

65.99 

42.87 

5.64 

6.23 

13.33 

5.78 

4.74 

13.15 

6.78 

13.02 

12.88 

14.22 

15.54 

80.05 

157.81 

195.85 

257.65 

272.05 

280.45 

280.45 

280.45 

280.85 

280.85 

280.85 

280.85 

294.70 

308.41 

320.81 

335.54 

362.59 

384.54 

384.54 

390.30 

392.95 

392.95 

392.97 

392.97 

392.97 

392.97 

399.27 

412.91 

412.93 

414.73 

442.79 

461.23 

475.30 

475.30 

490.30 
Sample Unit 

CP-37-31 P-43 

30 P-42 

29 P-41 

28 P-40 

27 P-39 

26 P-38 

25 P-37 

24 P-36 

23 P-35 

22 P-34 

21 P-33 

20 P-32 

19 P-31 

18 P-30 

17 P-29 

16 P-28 

15 P-27 

14 P-26 

13 P-25 

12 P-24 

11 P-23 

------------------

---------------- P-22 

CP-37-10 P-21 

9 P-20 

8 P-19 

P-18 

---------------- P-17 

---------------- P-16 

--------------- --

---------------- P-15 

----·------------ ----------------

---------------- P-14 

P-13 

CP-37-7 P-12 

6 P-11 

5 P-10 

4 P-9 

3 P-8 

2 P-7 

1 P-6 

---------------- P-5 

---------------- P-4 

---------------- P-3 

---------------- P-2 

----------------------------

---------------- P-1 

Thickness 

(ft) 

2.5 

2.5 

2.5 

2.5 

2.5 

2.5 

1.4 

1.5 

1.4 

1.8 

1.5 

.5 

1.8 

1.9 

.7 

.7 

.5 

2.3 

2.2 

2.5 

2.5 

(29.5) 

2.0 

1.2 

.4 

.2 

.4 

20.0 

17.0 

121.0 

2.0 

2.4 

2.0 

2.0 

2.0 

.4 

2.0 

1.2 

1.3 

3.0 

2.5 

2.0 

4.2 

35.0 

--------------- ------------------------

Abstract section, CP-37-Continued 

Cumulative ___ _:C_h--em_ic_al_a_n_al..::..y_se_s....:(..:..p..:....er_ce_n_t.:....) ___ Thickness 

Rock description thi(cfktn)ess V 205 Cr?03 I·nsAocluidble Iglnition X PzeO~ent Pz05 - - oss (cumulative) 

PARK CITY FORMATION AND RELATED STRATA-Continued 

Meade Park Phosphatic Shale Tongue of Phosphoria Formation-Continued 

Dolomite, similar to 

unit P-46 __ 415.1 2.90 .04 .20 41.62 18.86 497.55 

Dolomite, simila1· to 

unit P-46 417.6 6.74 .03 .19 41.76 16.62 514.40 

Dolomite, similar to 

unit P-46 ___ 420.1 7.20 .04 .14 53.56 10.58 532.40 

Dolomite, similar to 

unit P-46 422.6 0 .01 .05 25.68 32.02 532.40 

Dolomite, similar to 

unit P-46 ---------------- 425.1 0 .004 .01 24.05 35.77 532.40 

Dolomite, similar to 

unit P-46 ------------------- 427.6 0 .02 .04 37.42 27.06 532.40 

Chert, carbona tic --------------- 429.0 0 .007 .006 63.79 532.40 

Dolomite, argillaceous -- 430.5 0 .004 .006 20.69 36.91 532.40 

Fault zone ------------------------------- 431.9 0 .06 .08 69.74 532.40 

Mudstone, silty -------------------- 433.7 0 .10 .14 73.53 7.68 532.40 

Siltstone, argillaceous ------------ 435.2 6.34 .08 .08 69.56 6.03 541.91 

Mudstone, silty -------------------------- 435.7 8.98 .08 .14 55.76 7.04 546.40 

Dolomite -------------------------------------- 437.5 .02 .01 .01 13.64 39.38 546.43 

Dolomite, similar to 

unit P-31 -------------------------------- 439.4 .02 .01 .01 11.64 41.37 546.46 

Siltstone ------------------------------------- 440.1 4.78 .04 .04 65.72 7.74 549.80 

Mudstone, phosphatic, silty _______________________________________ 440.8 14.93 .04 .17 46.86 6.86 560.25 

Phosphorite -------------------------------- 441.3 32.31 .02 .09 7.53 5.09 576.40 

Siltstone, phosphatic ---------------- 443.6 17.04 .04 .16 35.92 8.81 615.59 

Siltstone, similar to 

unit P-26 -------------------------------- 445.8 13.72 .03 .13 40.55 9.55 645.77 

Mudstone, phosphatic, silty ---- 448.3 12.80 .05 .27 45.78 8.80 677.77 

Mudstone, similar to 

unit P-24 -------------------------------- 450.8 12.77 .04 .16 49.21 7.26 *699.69 

Faulted and folded zone _________________ ___ _ __ -----------------------------------------------------------

Chert -------------------------------------------- 452.8 --------------------------------------------------------------------------------------------

Siltstone, phosphatic, 

argillaceous ---------------------------- 454.0 15.85 .05 .25 42.91 7.27 19.02 

Phosphorite ------------------- 454.4 28.35 .02 .05 18.01 3.65 30.36 

Siltstone, phosphatic __________ _ ___ 454.6 12.85 .004 .04 58.21 2.97 *32.93 

Fault zone --------------- 455.0------- ---------------------- --------------------------------------

Grandeur Member of Park City Formation 

Dolomite -------------------------------------- 475.0 _________________________ ------------------------------------------------------------------

Dolomite -------------------------------------- 492.0 _______ ------------------------------------------------------------------------------------ Base of trench __________________________________________________________________________________________________________________________________ _ 

Dolomite, limestone, and 

chert float ------------------------------ 613.0 -------------------------------------------------------------------------------------------- Top of trench ___________________________________________________________________________________________________________________________________ _ 

Chert -------------------------------------------- 615.0 ____ --------------------------------------------------------------------------------------- Dolomite -------------------------------------- 617.4 __________________________ --------------------------------------------------------------- Phosphorite _______________________________ 619.4 27.90 .05 .06 9.97 8.58 55.80 

Phosphorite, similar to 

unit P-12 _ _ _ ______________________ 621.4 26.77 .06 .07 7.35 8.83 109.34 

Phosphorite, similar to 

unit P-12 ____________________________ 623.4 25.80 .06 .07 7.59 11.18 160.94 

Phosphorite ________________ 623.8 17.34 .02 .03 8.85 20.25 167.87 

Phosphorite ____________________________ 625.8 26.88 .03 .04 8.97 8.89 221.63 

Siltstone, dolomitic ________ 627.0 1.38 .01 .01 66.68 13.49 223.28 

Phosphorite -------------------------------- 628.3 21.19 .03 .05 13.42 13.48 *250.82 

Fault zone ---------------------------------- 631.3 ______________ ------------------------------------------------------------- Dolomite _ _________ ____________ __ ______________ 633.8 ________________________________________________________________________ -------------------- Limestone __ ______________ ____ ________________ 635.8 ______________________________________________________________________ ----------------------

Limestone ------------------------------------ 640.0 -------------------------------------------------------------------------------------------- Base of trench ----------------------------------------------------------------------------------------------------------------------------------- Limestone and dolomite, 

mostly float _____________________________ 675.0 _ ------------------------------------------------------------------------------------------ Contact with Weber Quartzite_________________ -------------------------------------------------------

below ----------------------------- ______________________ ------------------------------------------------------------------------------------------

*Cumulative data incomplete. Computations start with zero after interruption. 

7 
Detailed desc1~i1Jtion, CP-37 

Unit Rock description 

Cumu- Thick- lative ness thick- (ft) ness 

(ft) 

D-1 

DINWOODY FORMATION-BASAL UNIT ONLY 

Limestone, light-brownish-gray (5YR 6/1}, very 

fine grained, silty, hard, thick-bedded; con- tains gastropods and bioclastic debris________________ 5.0 + 

PARK CITY FORMATION AND RELATED STRATA Rex Chert Tongue of Phosphoria Formation 

P-83 Chert, medium-light-gray ( N 6/0), spicular, car- bona tic, hard, massive, brecciated, concretion- ary; grades into a cherty limestone in upper 

5.0 

part of unit._ ____________________________________________________________ 43.0 43.0 

Franson Member of Park City Formation 

P-82 Limestone, very light gray (N 8/0), very fine grained, hard, massive; contains abundant bio- clastic debris; contains fine-grained, sandy 

dolomite near middle of unit------------------------------- 34.0 77.0 81 Dolomite, medium-light-gray (N 6/0), very fine grained, hard; indistinct bedding; contains some light-gray spicular chert beds____________________ 7.0 84.0 

80 LimEStone, light-gray (N 7/0), fine- to coarse- grained, hard, massive; brecciated and rece- mented by calcite; includes chert and dolomite float; exposures are poor; ledge former in parL120.0 204.0 

____________ Top of trench----------------------------------------------------------------------------------------- P-79 Dolomite, dark-grayish-brown (2.5Y 4/2), very fine grained, silty, hard, thin-bedded to mas- sive, brecciated; contains sparse phosphorite 

pellets and chert pods and lenses; contains several small gouge zones ______________________________________ 80.0 284.0 

Meade Peak Phosphatic Shale Tongue of Phosphoria Formation 

P-78 Phosphorite, very dark gray (N 3/0), fine- to medium-pelletal, silty, calcareous, argillaceous, 

medium-hard, thin- to thick-bedded, brecciated; 

top of unit is faulted; this unit combined with the underlying unit was measured as 5.5 ft thick on north wall of trench; these two units are about 10 ft thick on south wall of trench, whereas they are about 13 ft thick north of the 

north wall ---------------------------------------------------------------- 2. 8 286.8 77 Phosphorite, smilar to unit P-78; has sharp con- tact with unit below________________________________________________ 2.7 289.5 

76 Fault zone, variegated; dominant colors are dark 

red (lOYR 3/6), pale brown (2.5Y 6/2), and light brownish gray (lOYR 5/1); unit consists mainly of sandstone and phosphorite frag- ments in an unconsolidated sand matrix____________ 4.0 293.5 

75 Fault zone, similar to unit P-76; has gradational contact with unit below________________________________________ 5.0 298.5 

74 Sandstone, yellowish-gray (lOYR 7/1), fine- to coarse-grained, subangular to subrounded, cal- careous, hard, thick-bedded to massive; con- tains argillaceous material, bioclastic debris, and sparse phosphorite pellets; upper part is brecciated and iron stained ________________________________ _ 

73 Sandstone, similar to unit P-74 ----------------------------- 72 Sandstone, similar to unit P-7 4 _____________________________ _ 71 Sandstone, similar to unit P-74 ___________________________ _ 

70 Sandstone, similar to unit P-7 4 ----------------------------- 69 Sandstone, similar to unit P-74; basal part is brecciated and iron stained and contains some cherty beds; has gradational contact with unit 

below -------------------------------------------------------------------------- 68 Fault zone, dark-red (lOR 3/6) to reddish-yellow 

(5YR 6/8) to pale-yellowish-orange (lOYR 

8/6); consists of argillaceous calcereous sand- stone and chert fragments; upper part consists of gouge containing spicular chert fragments __ 67 Fault zone, similar to unit P-68 ____________________________ _ 

66 Fault zone, similar to unit P-68 ----------------------------- 65 Fault zone, similar to unit P-68; primarily gouge containing chert fragments; has gradational contact with unit below _________________________________________ _ 

64 Chert, brownish-gray (5YR 4/1), silty, spicular, 

hard, thick-bedded; contains phosphorite pellets; highly fractured and stained dark red (lOR 3/6); chip sample contains a gastropod; has gradational contact with unit below ___________ _ 

6.0 304.5 

5.0 309.5 5.0 314.5 5.0 319.5 5.0 324.5 

5.0 329.5 

5.0 334.5 5.0 339.5 5.0 344.5 

3.0 347.5 

2.8 350.3 

8 

Detailed description, CP-37-Continued 

Unit Rock description 

Cumu- Thick- lative ness thick- (ft) ness 

(ft) 

PARK CITY FORMATION AND RELATED STRATA-Continued 

Meade Peak Phosphatic Shale Tongue of Phosrltoria Formation- Continued 

P-63 Siltstone, weak-red (lOR 5/3) to dark-brownish- gray (5YR 3/2), siliceous, hard, thin-bedded; contains numerous chert beds about 0.2 ft thick; this unit and underlying unit are highly 

fractured -------------------------------------------------------------------- 3.0 62 Sil'stone, similar to unit P-63 ------------------------------ 5.0 61 Siltstone, similar to unit P-63 -------------------------------- 5.0 60 Siltstone, similar to unit P-63; has grar\ational contact with unit below________________________________________ 5.0 

59 Siltstone, light-yellowish-brown ( lOYR 6/4), 

slightly calcareous, hard, thick-bedde<J, laminated in part ------------------------------------------------------------ 4.0 58 Siltstone, similar to unit P-59; contains a 0.4-ft- thick brecciated chert bed 2 feet below top of unit; has gradational contact with unit below____ 4.5 

57 Fault zone, moderate-yellowish-brown ( lOYR 5/4) stained to yellowish-red (5YR 5/6); con- sists of brecciated siliceous slightly ca.Icareous siltstone fragments; has sharp cont~r.t with 

unit below ---------------------------------------------------------------- 5.0 56 Siltstone, very pale brown (1 0 Y R 7/2), hard, 

thick-bedded; contains slight iron oxirle stain- ing; contains a 0.1-ft-thick phosphorite bed at upper contact; has sharp contact with unit 

below ------------------------------------------------------------------------- 2.3 55 Siltstone, pale-brown (lOYR 6/2), dolomitic, ar- gillaceous, siliceous in part, medh•m-hard, 

thick-bedded; has sharp contact w'th unit 

below ----------------------------------------------------------·-------------- 1.8 54 Chert, light-brown (2.5YR 6/4). calcareous, 

silty, hard, thick-bedded; has sharp contact 

with unit below ------------------------------------------------------ .6 53 Siltstone, pale-brown (10YR 5/2) to b-ownish- black (lOYR 2/1), medium-hard, thic1-bedded; colors are light because of weatherirg____________ 5.0 

52 Siltstone, similar to unit P-53; has grFdational contact with unit below_______________________________________ 5.0 

51 Phosphorite, very dark gray (N 3/0), fine- to coarse-pelletal, siliceous, slightly silty and cal- careous, hard, thick-bedded; has shari' contact with unit below_______________________________________________________ .5 

50 Siltstone, moderate-yellowish-brown (lOYR 5/4), 

micaceous, medium-hard, thick-bedd<o>d; has 

sharp contact with unit below ------------------------- 2.2 

49 Siltstone, pale-brown (lOYR 5/3}, dolomitic, 

slightly calcareous, medium-hard, thid--bedded; has sharp contact with unit below____________________ 2.0 

48 Mudstone and phosphorite, interbeddd. Mud- stone, pale-brown (5YR 5/2), phosphatic, silty, 

calcareous, medium-hard, thin-bedded. Phos- phorite, grayish-brown (7.5YR 4/2), fine- to coarse-pelletal, argillaceous, silty, medium- hard, thin-bedded; contains calcite-fired chert 

pods --------------------------------------------------------------------------- 1. 7 47 Mudstone and phosphorite, similar to unit P-48; has sharp contact with unit below_____________________ 1.7 

46 Dolomite, dark-yellowish-brown (10YR 4/2), very fine grained, argillaceous, silty, medbm-hard, 

thick-bedded; contains sparse phosphorite pellets, calcite and chert pods, and rumerous small gouge zones; contains a less th::.n 0.1-ft- thick phosphorite bed near base__________________________ 3.0 

45 Dolomite, similar to unit P-46 ------------------------------ 2.5 44 Dolomite, similar to unit P-46; contains a 0.1-ftthick phosphorite bed near base ------------------------ 2.5 43 Dolomite, similar to unit P-46; contains a 0.1-ft- thick phosphorite bed near base_________________________ 2.5 

42 Dolomite, similar to unit P-46; contains a 0.1-ft- thick phosphorite bed near middle______________________ 2.5 41 Dolomite, similar to unit P-46________________________________ 2.5 

40 Dolomite, similar to unit P-46 ------------------------------- 2.5 39 Dolomite, similar to unit P-46 ------------------------------- 2.5 38 Dolomite, similar to unit P-46; has sharp contact 

with unit below -----·----------------------------------------------- 2.5 37 Chert, very dark gray (N 3/0) to med'um-gray 

(N 6/0), calcareous, hard, brecciatei, nodular; indistinct bedding; contains calcite rods; has sharp contact with unit below____________________________ 1.4 

353.3 

358.3 

363.3 

368.3 

372.3 

376.8 

381.8 

384.1 

385.9 

386.5 

391.5 

396.5 

397.0 

399.2 

401.2 

402.9 

404.6 

407.6 

410.1 

412.6 

415.1 

417.6 

420.1 

422.6 

425.1 

427.6 

429.0 
Detailed description, CP-37-Continued 

Unit Rock description 

Cumu- Thick- lative ness thick- (ft) ness 

(ft) 

PARK CITY FORMATION AND RELATED STRATA-Continued Meade Peak Phosphatic Shale Tongue of Phosphoria Formation- Continued 

P-36 Dolomite, pale-brown ( 2.5 Y 6/2), very fine grained, argillaceous, medium-hard, brecciated; indistinct bedding; contains sparse chert nod- ules; has indistinct contact with unit below.... 1.5 430.5 35 Fault zone, light-ye'lowish brown ( lOYR 4/2); consists of calcareous soft unconsolidated mud- stone; has indistinct contact with unit below 1.4 431.9 34 Mudstone, brownish-black (lOYR 2/1) (weath- ers moderate yellowish brown (10YR 4/4) ), 

slightly calcareous, silty, soft, fissile; contains sparse chert pods; has sharp contact with unit 

below ···-·---------------------------- ----·----------------------·--------·--- 1.8 433.7 33 Siltstone, pale-brown (2.5YR 5/2), argillaceous, 

slightly calcareous, soft, thick-bedded; contains fine to coarse phosphorite pellets and irregular 

phosphorite lenses; has gradational contact 

with unit below --------·-------·------------------------------------ 1.5 435.2 32 Mudstone, pale-brown ( 2.5 Y 6/2), slightly calca- reous, silty, soft, thick-bedded; contains phosphorite that ranges from finely pelletal to nod- ules as much as 1 in. in diameter; has sharp 

contact with unit below--------------------------------------- .5 435.7 31 Dolomite, grayish-brown (2.5Y 5/2), very fine grained, slightly argillaceous, medium-hard, 

massive ------------------------------------------------------------ _________ 1.8 437.5 30 Dolomite, similar to unit P-31; has gradational contact with unit below_________________________________________ 1.9 439.4 

29 Siltstone, light-yellowish-brown (10YR 6/4), 

slightly calcareous and argillaceous, medium- hard, thick-bedded; contains fine to medium phosphorite pellets and numerous calcite-lined chert geodes; has gradational contact with unit 

below -------------------------------------------------------------------------- . 7 440.1 28 Mudstone, dark-yellowish-brown (lOYR 4/2), 

phosphatic, slightly calcareous, silty, medium- hard, thin- to thick-bedded; contains fine to coarse phosphorite pellets and several thin phosphorite beds; has gradational contact with 

unit below ---------------------------------------------------------------- . 7 440.8 27 Phosphorite, very dark gray (N 3/0), fine- to coarse-pelletal, slightly calcareous and silty, 

medium-hard, thick-bedded; contains sparse phosphorite nodules; has sharp contact with unit below __________________ ---······-·········-························ .5 441.3 26 Siltstone, grayish-brown (10YR 4/3), phosphatic, 

slightly argillaceous and calcareous, medium- hard, thin-bedded; contains fine to medium phosphorite pel'lets, and chert nodules ............... 2.3 443.6 25 Siltstone, similar to unit P-26; has gradational 

contact with unit below .... -----·-····-······················-- 2.2 445.8 

24 Mudstone, grayish-brown (7.5YR 4/2), phosphatic, slightly calcareous, silty, soft, thin- bedded, brecciated; contains fine to coarse phosphorite pellets, and chert concretions ...... __________ 2.5 448.3 

23 Mudstone, similar to unit P-24; has indistinct 

contact with unit below ..... ·---···--··-···-·-···-···---------- 2.5 450.8 

_____________ Faulted and folded zone; contains several fault 

gouge zones and highly concorted zones; con- sists primarily of dolomite rubble and some chert and phosphorite rubble. Interval meas- ured with Jacob staff set at 30°. Attitude of beds above and below unit interval is nearly 

parallel ----------·---------·--------------·----------··---------------------·- ( 29.5) 

P-22 Chert, very dark gray (N 3/0), hard, massive, 

brecciated; has sharp contact with unit below.. 2.0 452.8 21 Siltstone, light-brownish-gray (lOYR 5/1 ), phosphatic, argillaceous, soft; indistinct bedding; contains fine to coarse phosphorite pellets; contains a 0.1-ft-thick phosphorite bed in upper part; upper half is stained pale red (lOR 6/2); has sharp contact with unit below) 1.2 454.0 20 Phosphorite, medium-gray (N 5/0), fine-pelletal to nodules as much as 5 mm in diameter, 

slightly calcareous and argillaceous, hard, 

thick-bedded; contains abundant phosphatic bioclastic debris; has sharp contact with unit 

below ----·--------·----·-·-------·-·--·----------------------·-------------- .4 454.4 

9 

Detailed description, CP-37-Continue~"i 

Unit Rock description 

Cumulative T'tick- thick- ness ness (ft) (U) 

PARK CITY FORMATION AND RELATED STRATA-Continued Meade Peak Phosphatic Shale Tongue of Phosphoria For"'ltation- Continued 

P-19 Siltstone, very pale brown (lOYR 7/2), phosphatic, argillaceous, medium-hard, thick-bed- dPd; contains phosphorite consisting of fine to coarse pellets, sparse reworked nodules, lami- nae, and phosphatic bioclastic debris; has 

sharp contact with unit below ------------·-----·------- .2 454.6 18 Fault zone, weak-ye!lowshi-orange (lOYR 7/6); consists of gouge and fragments of dolomite and siltstone; appears to be a near-beddingplane fault _______ ------------·- ____ -----·------·----------·---------·-- .4 455.0 

Grandeur Member of Park City Formation 

P-17 Dolomite, light-brownish-gray (lOYR 5/1), very fine grained, hard, thick-bedded to massive; fracture is conchoidal; contains brachipods 

( orbiculoids) -----------------------·---------·-------------------------· 21.0 475.0 16 Dolomite, brownish-gray (lOYR 4/1), very fine grained, hard, thick-bedded to massive; frac- ture is conchoidal; contains small calcite pods, 

dark-gray chert pods and lenses, and sparse very fine phosphatic debris; contains brachio- pods (orbiculoids). Similar to unit P-17 ___________ 17.0 492.0 

_____________ Base of trench·-----------·----··--·-----------·-·-----------------------·--------·------------------ P-15 Dolomite, 'limestone, and chert float; dark-gray 

(weathers light gray) ·--------------·----··-----·-----------121.00 613.0 ______________ Top of trench-----------·-----------------------------·--··--------·---·-----·----·-------·------------ P-14 Chert, dark-gray (N 4/0),. hard, massive, brec- ciated, possibly lenticular; contains calcareous pods; has sharp contact with unit below____________ 2.0 615.0 

13 Dolomite, pale-brown (7.5l'R 6/2), very fine grained, hard, thick-bedded; contains chert pods; has gradational contact with unit below__ 2.4 617.4 12 Phosphorite, light-brownish-gray (lOYR 6/1), fine- to coarse-pelletal, slightly calcareous and silty, hard, thin- to thick-bedded; c~ntains calcite veinlets -----·--··-----------------------------------------------··--- 2.0 619.4 11 Phosphorite, similar to unit P-12 ---------------------·---·- 2.0 621.4 10 Phosphorite, similar to unit P-12; has sharp con- tact with unit below________________________________________________ 2.0 623.4 

9 Phosphorite, light-brownish-gray ( lOYR 6/1), 

fine-pelletal, calcareous, slightly argillaceous, 

hard, thick-bedded; has sharp contact with unit 

below --··-----------------------------·-----------·---------------------------- .4 623.8 8 Phosphorite, dark-gray (N 4/0), fine- to medium- pelletal, slightly calcareous, medium-hard, thin- to thick-bedded; has gradational contact with 

unit below --------------·--·-----------------------------·------------------ 2.0 625.8 

7 Siltstone, strong-brown (7.5YR 5/6) dolomitic, 

medium-hard, thick-bedded; contains sparse dark grains; has gradational contact with unit 

below -------·---------------------------·------------------------------------ 1.2 627.0 

6 Phosphori~e. medium-gray (N 5/0), fine- to coarse-pelletal, calcareous, slightly silty and argillaceous, medium-hard, thin- to thick-bed- ded; has sharp contact with unit below____________ 1.3 628.3 

5 Fault zone; consists of a limestone breccia, light- red (2.5l'R 6/1) to moderate-orange (7.5YR 

6/6), very fine grained, argillaceous, medium- hard, thick-bedded; upper and lower parts are in place and only partially brecciated; appears 

to be a near-bedding-plane fault-------------·------·---- 3.0 631.3 

4 Dolomite, light-brownish-gray (lOYR 5/1), very fine grained, slightly argillaceous, hard, mas- sive; has sharp contact with unit below____________ 2.5 633.8 

3 Limestone, moderate-orange (7.5YR 6/6), very fine grained, slightly argillaceous, medium- hard, thick-bedded; unit may be faulted; has 

sharp contact with unit below ----·-·----------·---------· 2.0 635.8 

2 Limestone, pale-brown (2.5Y 6/2), very fine grained, hard, massive; contains calcite vein- lets and sparse phosphatic bioclastic debris____ 4.2 640.0 

_____________ Base of trench.-----·---------------------------------··-------------------·---------·--------------· 

P-1 Limestone and dolomite, mostly float; light-gray 

( N 7/0), very fine grained, hard, thick-bedded to massive; contains cherty carbonate rock beds 33.0 675.0 ______________ Contact with Weber Quartzite below ____________________________________________ _ 
OGDEN CANYON, CP-38 rocks was described and sampled by E. M. Schell 

in an old roadcut on the north side of Ogden 

Trench CP-38 is in Ogden Canyon, NW~-i- Canyon. The section is overturn€.d, and the surSW14 sec. 16, T. 6 N., R. 1 E., Salt Lake meri- rounding area is highly folded and faulted. The 

dian, Weber County, Utah. The phosphatic shale description is from stratigraphic top to base. 

member of the Deseret Limestone and adjacent Chemical analyses were by K. P. Moore. 

Abst,ract section of only the phosphatic shale membe'r of the Dese1·et Limestone and adjacent rocks, CP-38 

Sample Unit Thickness Rock description (ft) 

M-15 4.0+ Limestone -------------------

CP-38-1 M-14 3.3 Limestone, argillaceous, 

siliceous ---------------------------

2 M-13 .2 Phosphorite 

3 M-12 1.9 Limestone, argillaceous, 

siliceous _ 4 M-11 .94 Limestone and phosphorite, 

interbedded -----------------------

5 M-10 1.81 Limestone and phosphorite, 

interbedded ----------------------------

6 M-9 1.29 Limestone and phosphorite, 

interbedded 

7 M-8 .8 Limestone, argillaceous 

8 M-7 1.0 Phosphorite, argillaceous, 

calcareous -----------------------

9 M-6 1.3 Limestone, argillaceous --------

10 M-5 1.8 Limestone, argillaceous 11 M-4 2.0 Mudstone and phosphorite, 

interbedded ----------------------------

M-3 .8 Limestone, siliceous 

M-2 .2 Limestone, argillaceous ----------

M-1 10.0+ Limestone ------ -----------------------

Detailed desc,ri1Jtion of only the phosphatic shale nwmber 

of the Deseret Lhnestone and adjacent rocks, CP-38 

Unit Rock description 

Cumu- Thick- lative ness thick- (ft) 

M-15 Limestone, black (N 2/0), very fine grained, 

hard, massive; contains calcite veinlets ____________ 4.0+ 

14 Limestone, black (N 2/0), very fine grained, ar- gillaceous, siliceous, sooty, hard, fissile to thin- bedded; contains phosphorite pellets __________________ 3.3 

13 Phosphorite, black (N 2/0), fine- to coarse- pelletal, calcareous, hard, thin-bedded______________ .2 

12 Limestone, black ( N 2/0), very fine grained, ar- gillaceous, siliceous, sooty, hard, massive _______ 1.9 

11 Limestone and phosphorite, interbedded. Lime- stone, black ( N 2/0), very fine grained, argillaceous, hard, fissile to thick-bedded. Phosphorite, black (N 2/0), fine- to coarse-pelletal, 

calcareous, hard, thin-bedded. From top to base, unit consists of the following sequence: 

Ft 

Limestone, fissile ----------------------------------0.07 Phosphorite __________ ---------------------------------- . 05 

Limestone, thick-bedded -------------------- .33 Limestone, fissile --------------------------------- .05 Limestone, thick-bedded ______________________ .32 

Limestone, fissile ---------------------------------- .12 

ness 

(ft) 

4.0 

7.3 

7.5 

9.4 

Total, unit M-11 _________________________________________ 0.94 10.34 

10 Limestone and phosphorite, interbedded. Limestone black (N 2/0), very fine grained, phosphatic, fissile to thin-bedded; some beds are argillaceous and fissile, others are hard single beds. Phosphorite, black (N 2/0), fine- to coarse-pelletal, calcareous, hard, thin-bedded. Unit consists of the following sequence from top to base: 

Ft 

Phosphorite _______ ------------------------------------0.07 Limestone, fissile ------------------------------- _ .02 Limestone, thin-bedded ______________________ .10 

Limestone, fissile ---------------------------------- .04 Phosphorite ___________________________________________ .09 

Limestone, fissile ---------------------------------- .02 

Phosphorite -------------------------------------------- .08 Limestone, thin-bedded _____________________ .18 

Phosphorite -------------------------------------------- .05 Limestone, fissile ---------------------------------- .02 Limestone, thin-bedded ______________________ .15 

Cumulative Chemical analyses (pe':cent) 

thickness Acid Ignition 

( ft) P205 V205 Cr:,:03 insoluble loss 

4.0 -------------------------------- ------------------

7.3 4.12 0.10 0.04 30.08 27.12 

7.5 24.71 .02 .02 6.56 13.46 

9.4 2.35 .04 .01 30.44 27.95 

10.34 8.57 .06 .04 27.71 24.94 

12.15 11.17 .03 .03 30.42 19.99 

13.44 3.55 .02 .02 14.58 35.31 

14.24 0 .01 .02 34.75 29.98 

15.24 17.76 .08 .10 21.76 19.88 

16.54 0 .02 .01 39.21 25.45 

18.34 0 .03 .02 41.70 27.94 

20.34 13.87 .08 .10 30.60 18.07 

21.14 --- --------------- ---------------------------------------- -------------------------------

21.34 --------------------- --------------------------------------------------------

31.34 --- ------------------------------------------------------------

Detailed clesc,ri11tion of only the phosphatic shale member 

of the Dese'ret Limestone and adjacent rocks, CP-38 

-Continued 

Unit 

M-9 

8 

7 

4 

2 

Rock description 

Cumu- Thick- lative ne<>s thick- (ft) ness 

(ft) 

Phosphorite -------------------------------------------- .12 Limestone, fissile --------------------------------- .30 

Phosphorite -------------------------------------------- .15 Limestone, fissile --------------------------------- .12 Limestone, thin-bedded ---------------------- .22 Limestone, fissile ---------------------------------- .02 

Phosphorite ------------------------------------------- .06 Total, unit M-10 ------------------------------------------ Limestone and phosphorite, interbedded: similar to unit M-10. Unit consists of the following 

sequence from top to base: Ft 

Limestone, fissile ---------------------------------0.18 Limestone, thin-bedded ______________________ .80 

Limestone, fissile ---------------------------------- .12 Phosphorite -------------------------------------------- .15 Limestone, fissile ---------------------------------- .04 

1.81 

Total, unit M-9 ------------------------------------------- 1.29 Limestone, black (N 2/0), very fine grained, 

argillaceous, sooty, hard, thin-bedded; fracture is platy _________________________ -------------------------------------------- .8 

Phosphorite, black (N 2/0), fine-to ccarse-pel- letal argillaceous, calcareous, sooty, fissile; 

weathered rock is soft, unweathered rock is hard; contains limestone laminae and a 0.3-ft- thick limestone bed 0.1 ft below top __________________ 1.0 

Limestone, black (N 2/0), very fine gra.ined, argillaceous, hard, massive -------------------------------------- 1.3 Limestone, dark-yellowish-brown ( lOYR 4/2), very fine grained, argillaceous. hard, massive; 

contains a 0.2-ft-thick fissile limestone bed at 

top ----------------------------------------------------------------------------- 1.8 Mudstone and phosphorite, interbeddro, Mud- stone, black (N 2/0), calcareous, ph-:>sphatic, 

soft, fissile. Phosphorite, fine- to ccarse-pelletal; consists of laminae less than 0.1 ft thick __ 2.0 Limestone, black (N 2/0), sublithographic, siliceous, hard, thick-bedded --------------------------------------- .8 Limestone, brownish-gray (5YR 4/1), very fine grained, argillaceous, soft, fissile ---------------------- .2 Limestone, dark-gray, very fine grained, hard, 

massive; contains chert pods and lenses ____________ 10.0+ 

12.15 

13.44 

14.24 

15.24 

16.54 

18.34 

20.34 

21.14 

21.34 

31.34 

10 
WHEAT GRASS CREEK, CP-44 

Trench CP-44 is at Wheat Grass Creek, 

SE1;4NW1;4NE1;4 sec. 26, T. 7N., R. 3 E., Salt 

Lake meridian, Weber County, Utah. The phosphatic section at the base of the Humbug Formation was sampled and described by E. M. 

Schell and T. E. Mullens in a hand-excavated 

trench. Chemical analyses were by K. P. Moore. 

Abst·ract section, CP-44 

Sample Unit Thickness 

(ft) Rock description Cumulative 

thickness (ft) 

Chemical analyses (percent) Thickness 

Acid X percent V 205 Cr203 · P20:> msoluble (cPmulative) 

Humbug Formation-basal part only 

M-15 _____ Limestone ----------------------------------------------- ----------------------- ------------------------- -------------------------------------

Top of trench ------------------------- ----------------- ----------------- -----------------------------------

CP-44-14 M-14 5.5 Mudstone, dolomitic 5.5 3.83 0.11 0.09 50.09 21.06 

13 M-13 1.1 Phosphorite, argillaceous, 

calcareous 6.6 18.34 .09 .03 15.84 41.23 

12 M-12 .6 Mudstone and phosphorite 7.3 15.03 .19 .13 33.63 50.25 

11 M-11 .3 Phosphorite, calcareous 7.6 23.50 .06 .03 8.62 57.30 

10 M-10 1.5 Limestone and mudstone ______ 9.1 4.68 .08 .03 24.54 64.32 

9 M-9 .1 Phosphorite, dolomitic 9.2 19.72 .05 .03 11.96 66.29 

8 M-8 .5 Phosphorite, argillaceous 9.7 15.86 .15 .11 33.06 74.22 

7 M-7 .6 Phosphorite, calcareous 10.3 24.20 .09 .05 13.98 88.74 

6 M-6 .7 Phosphorite and mudstone 11.0 21.65 .14 .09 21.54 103.89 

5 M-5 .6 Phosphorite 11.6 27.74 .09 .06 6.34 120.53 

4 M-4 .9 Phosphorite and mudstone 12.5 19.44 .16 .08 24.88 138.03 

3 M-3 1.5 Phosphorite --------------------- 14.0 28.69 .05 .04 4.12 181.06 

2 M-2 .4 Mudstone, phosphatic, 

calcareous -------------------------------- 14.4 13.54 .11 .. 24 37.23 186.48 

1 M-1 .5 Clay and mudstone (fault 

zone) ----- ----------------------- 14.9 12.20 .12 .36 28.90 192.58 

Lodgepole Limestone 

-------------------------- __________ 3.0+ Limestone, sandy ------------------------------------ ------------------------------------------------------------------------------------ Base of trench ___________________________________________________________ -------------------------------------------------------------------

Detailed desc1-iption, CP-44 

Unit Rock description 

Humbug formation-basal part only 

Cumu- Thick- lative ness thick- (ft) ness 

(ft) 

M-15 Limestone, very dark gray (N 3/0), very fine grained, hard, massive; contains sparse chert 

nodules about 1 in. long -------------------------------------------------------------- __________________ Top of trench ----------------------------------------------------------------------------------- 14 Mudstone, brownish-gray (51' R 4/1), dolomitic, 

soft, thin- to thick-bedded, concretionary, 

hackly- to shaly-weathering; contains a 0.2- ft-thick phosphatic mudstone 0.4 ft above base; has gradational basal contact __ -------------------------- 5.5 5.5 13 Phosphorite, brownish-gray (5YR 4/1), fine-pelletal, argillaceous, calcareous, soft, thin- to 

thick-bedded; contains hard poorly formed very fine grained dolomitic argillaceous concretions _ 1.1 6.6 12 Mudstone and phosphorite, interbedded. Mud- stone, black ( N 2/0), slightly calcareous, soft, fissile to thin-bedded; appears to be non- phosphatic. Phosphorite, black (N 2/0), fine- to medium-pelletal, calcareous, argillaceous, 

soft, thin-bedded; contains sparse phosphorite nodules. Has sharp basal contact ________________________ .6 7.3 

11 Phosphorite, black ( N 2/0), fine- to coarse- pelletal, calcareous, hard, thin-bedded; contains some shaly interbeds; has gradational basal 

contact --------------------------------------------------------------------- .3 7.6 10 Limestone and mudstone. Bulk of unit made up of massive very fine grained limestone concre- tions as much as 0.9 ft in diameter. Mudstone. dark-grayish-brown (lOYR 3/2), thin-bedded to fissile. Upper part of unit contains a 0.05- ft-thick phosphatic mudstone. Has sharp basal 

contact ----------------------------------------------------------------------- 1.5 9.1 9 Phosphorite, brownish-gray ( 10YR 4/1), fine- pelletal, dolomitic, hard, thin-bedded; has gradational basal contact --------------------------------------------- .1 9.2 8 Phosphorite, brownish-black ( 5YR 2/1), fine- to very coarse-pelletal, argillaceous, slightly cal- careous, soft, thin-bedded; has gradational basal 

contact ---------------------------------------------------------------------- .5 9. 7 7 Phosphorite, brownish-black (51' R 2/1), fine- to coarse-pelletal and some very coarse pelletal, 

11 

Detailed description, CP-44-Continued 

Unit Rock description 

Cumu- Thick- lative ne.;s thick- (ft) ness 

(ft) 

Humbug Formation-basal part only-Continued 

calcareous, medium-hard, thin- to thick-bedded; contains sparse nodules of phosphatic limestone; has gradational basal contact ---------------- M-6 Phosphorite and mudstone, brownish-black (5l'R 

2/1), medium-hard, thin-bedded. Phosphorite, fine- to medium-pelletal, calcareous. Mudstone, 

fine-pelletal, slightly calcareous and phos- phatic. Has gradational basal contact ___________ _ 

5 Phosphorite, black (N 2/1), very coarse to fine- pelletal, slightly calcareous, medium-hard, thin- bedded; contains thin phos11hatic limestone beds and four mudstone laminae; has gradational basal contact ---------------------------------------------- 4 Phosphorite and mudstone, brownish-black (5l'R 

2/1), thin-bedded. Phosphorite, very coarse to fine-pelletal. slightly calcareous, soft to med- ium-hard. Mudstone, phosphatic and slightly 

calcareous, soft. Basal contact is gradational 

Phosphorite, brownish-black (5YR 2/1), very coarse to fine-pelletal, slightly calcareous and argillaceous, medium-hard, massive; contains nodules as much as 0.2 ft in diameter near middle and top; basal contact is gradational ___ _ 

2 Mudstone, very dark gray (N 6/0), phosphatic, 

calcareous, soft, fissile to platy; has gradational 

basal contact --------------------------------------------------------- Clay and mudstone, reddish-brown, dark-brown, and medium- to light-gray, phosphatic, slightly 

calcareous, soft, shaly-weathering. Unit ap- pears to be a fault zone that locally crushes 

underlying bed ----------------------------------------------------

Lodgepole Limestone 

______________ Limestone, light-brownish-gray ( 5l'R 6/1), very 

fine grained, sandy, hard, massive; contains thin irregular chert beds, and fossil spines 

.6 

.7 

.6 

.9 

1.5 

.4 

.5 

10.3 

11.0 

11.6 

12.5 

14.0 

14.4 

14.9 

and hash. Base not exposed ---------------------------------------------------·---- ______________ Base of trench -----------------------------------------------------------------------------------

'ku 5. GOVERNMENT PRINTING OFFICE: 1970 0-3'37-587