Lower and Middle Cambrian Stratigraphy in Northern Utah and Southeastern Idaho

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 69. PP. 647-688. 3 FIGS. JUNE 1958

LOWER AND MIDDLE CAMBRIAN STRATIGRAPHY IN NORTHERN UTAH AND SOUTHEASTERN IDAHO

BY GEORGE B. MAXEY

ABSTRACT The stratigraphic succession of Lower and Middle Cambrian sediments in northern Utah and southeastern Idaho as determined from 13 measured sections includes the basal medium- to coarse-grained Prospect Mountain Quartzite overlain by interbedded fine- and coarse-grained clastic rocks (Pioche Formation) that in turn are overlain by several hundred to a few thousand feet of carbonate rocks with a few thinly interbedded layers of fine elastics. The carbonate sequence includes the Langston Formation, Ute Limestone, Blacksmith Dolomite, and Bloomington Formation. Known occurrences of fossils are listed for the formations. Seventeen faunal groups are identified, and a sequence of faunizones is proposed. Cambrian deposits may be separated into (1) orthoquartzite; (2) greenish-brown, micaceous and arenaceous shale; (3) brown-weathering, calcareous sandstone; (4) rusty- brown-weathering dolomite; (5) green and buff fissile shale; (6) calcareous black shale; (7) mottled, silty, aphanitic, thinly bedded limestone; (8) Girvanella limestone; (9) intraformational conglomerate; (10) oolitic limestone; (11) "undifferentiated limestone"; and (12) "undifferentiated dolomite" facies. All these sediments probably were deposited in a shallow, chiefly transgressive, though oscillating, sea. This sea transgressed a low-lying but mature topography eastward to western Utah by earliest Cambrian (pre-Olenellus?) time and to eastern Utah by the end of Early Cambrian time. The area remained submerged during Medial Cambrian and much of Late Cambrian time.

CONTENTS

„ Langston Formation (Lower and Middle , . Fage Cambrian) ...... 669 Introduction ...... 648 Ute Formation ...... 671 Location and general description of sections Blacksmith Dolomite ...... 672 studied ...... 649 Bloomington Formation ...... 672 General statement ...... 649 Early an(j Medial Cambrian faunules in Utah Portneuf and Bannock ranges, Idaho ...... 649 and southeastern Idaho ...... 673 Malad Range, Idaho ...... 649 ZonatiOn of the faunules ...... 676 Bear River Range, Utah and Idaho ...... 650 General statement ...... 676 General description ...... 650 Olenellus zone ...... 676 High Creek section ...... 651 Glossofleura-Zacanlhoid.es zone ...... 677 Section on the North Fork of Mill Creek Bathyuriscus-Elrathina zone ...... 678 and Spence Gulch section^ ...... 655 Thompsonaspis zone ...... 678 Section in the Left Fork of Blacksmith Asaphiscus-Bolaspidella, zone ...... 678 Fork Canyon ...... 656 Discussion ...... 678 South Cottonwood Canyon section, Early and Medial Cambrian sedimentation Blacksmith Fork ...... 658 and paleogeograPhy ...... 679 Blacksmith Fork section ...... 658 Description of the lithofacies ...... 679 North part of the Wasatch Range, Utah. . . 659 Interpretation and paleogeography ...... 685 General statement ...... 659 Selected references ...... 686 Calls Fort section ...... 659 Willard Peak section ...... 662 Ogden Canyon section ...... 664 ILLUSTRATIONS Big Cottonwood Creek and Neffs Canyon sections ...... 664 Fisure Pa«e Summary ...... 666 1. Location of the stratigraphic sections Promontory Range, Utah ...... 666 studied and outcrops of Cambrian rocks Lower and Middle Cambrian formations in in the region ...... 648 northeastern Utah and southeastern 2. Lithologic variations within some Lower Idaho and their regional relationships .... 667 and Middle Cambrian formations in Prospect Mountain Quartzite (Lower Cam- northern Utah and southeastern Idaho. . 670 brian) ...... 667 3. Regional correlation and Early and Me- Pioche Formation ...... 668 dial Cambrian faunules and faunizones. . 673 647

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FIGURE 1.—LOCATION OF THE STRATIGRAPHIC SECTIONS STUDIED AND OUTCROPS OF CAMBRIAN ROCKS IN THE REGION

INTRODUCTION plex and partly in error on the basis of modern principles and concepts of regional stratig- As part of a regional investigation of the raphy. Many of the conclusions here presented Cambrian rocks of the Great Basin which has are tentative because the field and laboratory been conducted sporadically since 1939, the study is still in progress. Additional informa- writer studied several sections of Lower and tion and more dependable conclusions will be Middle Cambrian rocks in northeastern Utah made available as the study progresses. and southeastern Idaho (Fig. 1). New informa- The writer gratefully acknowledges the tion resulting from this study constitutes the advice and assistance of Dr. Charles Deiss main body of this paper. Suggestions are also and Dr. J. Stewart Williams, both of whom included for simplifying and correcting Cam- encouraged him to begin and continue these brian formational and biostratigraphic nomen- studies. Dr. B. F. Howell consistently and clature which seems to be unnecessarily com- patiently advised the writer throughout the

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study; assisted him with many problems, Porlneuf and Bannock Ranges, Idaho chief among these the identification of most of the fossils; and finally read the manuscript. Detailed descriptions of sections of Cambrian Without this advice and assistance the study rocks in the north part of the Bannock Range would probably have never been completed, have been published by Ludlum (1943, p. 973- and for this the writer is sincerely grateful. 986). In the vicinity of Pocatello and Inkom, Dr. Erling Dorf and Dr. Franklin Van Houten Idaho, he found that 3200 feet of Prospect also read the manuscript and offered helpful Mountain ("Brigham") Quartzite unconform- suggestions. Thanks are extended to Dr. ably overlies the Precambrian Blackrock Lime- Norman Denson, Mr. Donald Duncan, Dr. stone. This is one of the few localities in Idaho Franco Rasetti, the late Dr. Charles E. Resser, and northern Utah, outside the Wasatch Range, Dr. John F. Mason, and the late Mr. Frank where the base of the Prospect Mountain For- Beckwith, all of whom contributed much time mation is exposed. The formation is pink to and many ideas. red, thick-bedded, vitreous, medium-grained Funds to finance the field and laboratory quartzose sandstone interbedded with beds work were furnished in part by the Depart- of coarse sandstone and pebble conglomerate. ments of Geology of Princeton University and The upper 600 feet of the formation as de- Utah State Agricultural College. The Univer- scribed by Ludlum is thin-bedded and contains sity of Connecticut also contributed funds for much green or buff siltstone and shale. The laboratory equipment and freed the writer lower part of this shaly and silty sequence may from excessive academic tasks during 1949 and be the lithogenetic equivalent of the Pioche 1950. Field assistants included John W. Wetz- Shale, and the upper part the equivalent of the ler (Summer, 1939), Kent O. Bushnell, and Spence Shale Member of the Langston Forma- Arthur Reimer (Summer, 1950). To these tion. The quartzite is conformably overlain by organizations and individuals the writer is 4250 feet of sparsely fossiliferous limestones indebted and extends his warmest thanks. interbedded with a little shale and sandstone. All sections described for the first time by In the vicinity of Scout Mountain about 10 the writer were measured with a Brunton com- miles south of Pocatello, Idaho, the writer pass and steel tape; adjustments were made to identified lithologic equivalents of the Lang- obtain the correct thicknesses of stratigraphic ston, Ute, and Bloomington Formations which units where necessary. These adjustments were also crop out in adjacent areas of Idaho and usually made by reference to Mertie's chart northern Utah. Time did not allow detailed (1922, PL VI). Rock colors were determined in measurement of this section, but several litho- the field by use of a standard rock color chart logic units and formations were recognized, (Goldman and Merwin, 1928). The color names including the Spence Shale Member of the corresponding to the color chips on the chart Langston Formation and the Hodges and Calls are from Ridgway (1912, p. 1-53). Fort Shale Members of the Bloomington For- mation. An equivalent of the Blacksmith Dolo- LOCATION AND GENERAL DESCRIPTION OF mite probably is absent in this locality. SECTIONS STUDIED A section in the south part of the Bannock Range, about 3 miles north of Malad City, General Statement Idaho, was also examined. Lithologic equivalents of the above-mentioned formations, ex- Most of the outcrop areas (Fig. 1) in north- cept the Blacksmith Dolomite, were also rec- eastern Utah and southern Idaho were visited ognized in this area. by the writer during the period 1940-1951 when he measured one or more detailed sections of Malad Range, Idaho rocks of Early and Medial Cambrian age in several of the areas. When detailed sections, The Two Mile Canyon section is exposed described by other geologists were available, approximately 2 miles southeast of Malad City, they were carefully studied in the field. Col- Idaho (Fig. 1), in a small canyon in the Malad lections made from these sections were accu- Range, a northward extension of the Wasatch rately located within the sections. Significant Range of Utah. The Cambrian rocks that crop lithologic variations were likewise noted and out in the vicinity of Two Mile Canyon were carefully checked in the field. Detailed de- first studied in detail by Walcott in 1898 and scriptions are given here for only those sections 1906 (Resser, 1939b, p. 4, 9-11). Meek had which have not been published. earlier made collections and notes. Walcott Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 650 G. B. MAXEY—LOWER AND MIDDLE CAMBRIAN STRATIGRAPHY

measured and described in detail a partial sec- Canyon are identical with those in the same tion of the Prospect Mountain ("Brigham") formation in closely adjacent areas. Quartzite and a complete section of the formations of Medial Cambrian age. The description Bear River Range, Utah and Idaho of this section was not published until 1939 when Resser (1939b, p. 10-11) included it in General description.—The Bear River Range his discussion of the "Ptarmigania strata" is an eastward prong of the Wasatch Range (Naomi Peak Limestome Member of the Lang- and extends northward nearly 95 miles from ston Formation). Sharp's Mountain, east of Brigham City, Utah, The writer visited the Two Mile Canyon sec- to Soda Point, 45 miles north of the Utah-Idaho tion several times between May 1939 (accom- boundary. The southern part of the range in panied by Deiss) and June 1941. The rocks are Logan quadrangle, Utah, is underlain by a complexly faulted in Two Mile Canyon, and a broad syncline, broken on the west along the careful search for a place to measure an undis- range front and near the center of the range by turbed sequence of rocks of Medial Cambrian normal faults of considerable throw. Rocks of age was unsuccessful. However, an undisturbed Cambrian age crop out along the west front of but incomplete section from well down in the the range nearly as far south as Logan, Utah, Prospect Mountain Quartzite ("Brigham") to and, in the center and east parts of the Range, high in the Spence Shale Member of the Lang- to its southern extremity. The northern part of ston Formation was carefully measured and the range in Idaho has not been completely described, and fossils were collected from sev- mapped, and the boundaries of the outcrops eral horizons. The lower part of Walcott's of Cambrian rocks are not accurately known. section described by Resser (1939b, p. 10-11), However, much of the northern part of the including the Prospect Mountain ("Brigham") range is underlain by rocks of this age. Quartzite, Walcott's "Langston" limestone, and The Cambrian rocks in the Bear River Range the Spence Shale, corresponds very closely in were probably first studied by Hague and Em- lithologic detail to the section measured by the mons (1877, p. 340-417) during the Fortieth writer. Therefore the section is not described Parallel Survey (1867-1877). Peale (1879, p. here. 598-600), with the Green River Division of the Walcott's description of the Two Mile Can- Hayden Survey, also worked in the range in yon section may be correct as far as sequence of 1877. Many of the data collected by these field lithologic types is concerned, but his assign- parties were later studied and described by ment of those types to the Middle Cambrian Walcott, who first visited the area in 1898. He formations which occur in adjacent areas does followed this work with extended studies of not appear to be accurate. The Spence Shale the Blacksmith Fork and Mill Creek areas in and some overlying units are now known to 1906 and published the original Blacksmith occur low in the Langston Formation rather Fork Cambrian section in 1908 (Walcott, 1908a, than at the base of the Ute Formation (Wil- p. 5-9; 1908b,p. 191-200). Walcott was assisted liams and Maxey, 1941, p. 276-285). Probably by Burling and others in the later study. the Spence Shale and the three overlying units Further results of these studies were published in Walcott's description of the Ute Formation in 1912 (Walcott, 1912, p. 148-153). (Resser, 1939b, p. 10) should be referred to the Richardson described the Cambrian rocks Langston Formation. Moreover, the basal beds in the eastern part of the range in the Randolph of the Nounan Formation contain fossils of quadrangle in 1913 (p. 406-409) and in 1941 Late Cambrian age. Accurate measurement of (p. 7-14). He noted that the section is similar the thickness of the various lithologic units may to the Blacksmith Fork section and described not be possible in an unmapped area of such and named the Hodges Shale Member at the complex structure. For example, the apparent base of the Bloomington Formation and the thinness of the Bloomington Formation and the Worm Creek Quartzite Member at the base of apparent thickness of the Blacksmith Dolomite the St. Charles Formation (Upper Cambrian). in Walcott's Two Mile Canyon section may be Mansfield (1927, p. 52-56), on the basis of work the result of cutting out and duplication of beds of geologists of the United States Geological by faulting. However, the section in Two Mile Survey between 1909 and 1916, gave detailed Canyon contains the lithogenetic equivalents descriptions of sections of the Cambrian rocks of the section in adjacent areas in northern in southeastern Idaho, chiefly east of the Bear Utah and southern Idaho. The faunas con- River Range. He adopted the formational tained in the Langston Formation at two Mile names of Walcott's Blacksmith Fork section Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 LOCATION AND GENERAL DESCRIPTION OF SECTIONS STUDIED 651

and recognized the Hodges Shale and Worm especially along the high ridges between the Creek Quartzite of Richardson. larger streams. The base of the measured section Deiss (1938) remeasured and emended the is at the contact of the Pioche (?) shale and the Blacksmith Fork section and designated type Langston Formation on the main ridge be- localities for the formations of Medial Cam- tween the North and South forks of High Creek brian age. He also described the Glossopleura in section 11, T. 14 N., R. 2 E., approximately horizon at the base of the Ute Formation and 7 miles northeast of Richmond, Utah (Fig. 1). correctly stated that "the shale at the base The line of the section follows northeasterly of the Ute Formation cannot be correlated up the ridge, on the South Fork side of the ridge. with the Spence shale of Idaho" (1938, p. 116). Resser (1939a; 1939b) described the faunas High Creek Section, Bear River Range of the lower part of the Langston Formation. He recognized the Spence Shale Member but UPPER CAMBRIAN incorrectly assigned it to the base of the Ute Nounan Formation Formation, and he described in the detail the Feet "Ptarmigania fauna" at the base of the Lang- 45. Dolomite and limestone: neutral- ston. These descriptions were based chiefly on gray, thin-bedded medium-crystal- unpublished field notes and undescribed mate- line dolomite interbedded with rial collected by the Walcott expeditions of dark-gray thin-bedded, finely 1898 and 1906. crystalline limestone in first 20 Williams and Maxey (1941, p. 276-285) feet of unit overlain by neutral- showed that the Spence Shale Member occurs gray, thin- to medium-bedded (1 near the base of the Langston Formation and inch to 6 inches), finely crystal- is not a member of the Ute Limestone. Most line dolomite; weathers to speckled of the detailed field date collected during those white and gray surfaces; poorly field seasons is incorporated in the present re- exposed outcrops 60 port. On the basis of these data and later study, Total thickness of Nounan Forma- Williams (1948, p. 1131-1135) briefly de- tion 1125 scribed the Cambrian formations of the Logan quadrangle and discussed lithologic and faunal MIDDLE CAMBRIAN variations within that area. Benson (1942) described and named the Calls Bloomington Formation Fort Shale Member of the Bloomington Forma- Calls Fort Shale Member tion and, on the basis of fossils, showed that 44. Limestone: dark blackish gray, thin- the top of the Bloomington Formation was de- bedded, finely crystalline, platy; posited in latest Medial Cambrian time. He weathers to blue-gray and colonial- described three new and important faunules buff-stained plates; some arenace- in the Bloomington Formation and showed that ous, shaly, dolomitized layers in these faunules were present in uppermost top 60 Middle Cambrian rocks in Wyoming, Montana, 43. Limestone: dark gray, thin-bedded, British Columbia, and Alberta. conglomeratic with very small, The sections given below were measured by well-rounded, limestone pebbles the writer during the field seasons of 1939 and and much limonite; weathers to 1940 and were checked and emended by him lighter-gray and limonite-stained in the summer of 1950. rough-surfaced plates 1-2 feet High Creek section.—Rocks of Early and square. Fossil locality 101 s24 at Medial Cambrian age are well exposed from base (of this unit; 30 far down in the Prospect Mountain Formation Fossils: to the contact of the Bloomington and Nounan Homagnostus cf. pisiformis pater (Upper Cambrian) Formations. Exposures of (Holm and Westergard) the Spence Shale Member and the Prospect Elrathia dubia Denson Mountain, Ute, Blacksmith, and Bloomington Unidentified and undescribed Formations are as good as any in northern trilobite genera Utah and southern Idaho. More fossil zones Hyolithes were found in this section than in any other Stenotheca measured or observed section in the Bear River 42. Limestone and shale: neutral-gray, and Wasatch ranges. Outcrops are numerous, thin-bedded, finely crystalline Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 652 G. B. MAXEY—LOWER AND MIDDLE CAMBRIAN STRATIGRAPHY

Feet Feet shaly limestone interbedded with limonitic blobs on weathered sur- thin beds of dark-gray limestone; faces; weathers to lighter-bluish- near deep-olive, thin-bedded, finely gray rough chunks and plates. chunky to fissile shale. Limestones Nonfossiliferous 15 weather to light bluish-gray, 34. Covered interval: float indicates beds colonial-buff-stained J^- to 1- similar to unit 35 70 foot quadrangular plates; shales 33. Limestone: similar to unit 34 except weather to tea-green chunks and fossiliferous at the base. Fossil very thin small plates. Poorly ex- locality 101 alO 55 posed outcrops 90 Fossils: Total thickness of Calls Fort Olenoides, sp. Shale 180 Undescribed and unidentified 41. Limestone: dark blue gray, medium trilobite genera crystalline, oolitic; has very few Hodges Shale Member dark-gray bands and spots; 32. Limestone and shale: dark-bluish- weathers to lighter bluish-gray gray, thick-bedded finely crystal- chunks 40 line, oolitic limestone interbedded 40. Limestone: neutral gray, irregularly with three 4- to 6-foot phases of and thinly bedded, finely crystal- andora-green, very thin-bedded line; contains many buff clay (beds y\(,-y^ mcn thick), calcareous partings; slightly nodular, some shale that weathers to small tea- beds more nodular and darker gray green chips. Fossil locality 101 s7 than others especially toward top; in basal oolite layers of this unit. . 40 weathers to very light-bluish-gray Fossils: chunks; at base is very thin- Olenoides, sp. bedded and weathers to colonial- Undescribed and unidentified buff plates; few beds of more finely trilobite genera crystalline, thicker-bedded, slightly 31. Limestone, shale, and sandstone: 2 darker limestone toward center of feet of vinaceous-pink, very thin unit which form good 4- to 5-foot and unevenly bedded, micaceous, outcrops 155 calcareous, shaly, very finely- to 39. Limestone: dark neutral gray, thick- medium-grained sandstone at base; bedded, finely crystalline oolitic. . 50 this sandstone overlain by dark- 38. Limestone: dark neutral gray with neutral-gray, thin-bedded, com- tannish tinge, thick-bedded finely pact nodular, arenaceous, unevenly crystalline, oolitic; smaller oolites bedded limestone with many shale and lighter color than above 70 partings, overlain by andora-green, 37. Limestone: dark neutral gray, thick- very thin-bedded calcareous shale bedded, finely crystalline, oolitic. . 165 that weathers to small tea-green 36. Limestone: dark bluish gray, thick- chips; shale and limestone thinly bedded, finely crystalline, oolitic; interbedded on top part. Much of contains few small limestone peb- the unit poorly exposed 100 bles J^-l inch in diameter; 30. Limestone and shale: mouse-gray, weathers to lighter-bluish-gray, thin-bedded, finely crystalline limonite-stained low outcrops; in- limestone with some clay partings; terbedded with very dark-bluish- some shale as described in unit 31 gray, very compact limestone interbedded; 2 feet of graphalium- which contains few small crystals green, thin-bedded, very pure, of calcite and few small splotches of compact limestone in center of tan limonite, and which weathers unit; all outcrops poorly exposed. . 55 to limonite-stained, lighter-blue- 29. Covered interval: probably inter- gray, low outcrops 100 bedded shale and limestone is indi- 35. Limestone: dark bluish gray, thin- to cated by float, animal burrows, and thick-bedded (beds 2 inches to 2 few very poor outcrops 70 feet thick), compact, brittle, 28. Limestone and shale: dark-grayish- nodular; contains some buff to tan olive, thin-bedded, micaceous, cal-

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Feet Feet careous shale which forms low, even 21. Dolomite: very light gray, thick- light-buff slopes; interbedded with bedded; contains many small cal- thin beds of dark-gray, thin-bedded, cite crystals and some limonite finely crystalline, arenaceous, shaly flakes and pseudomorphs after limestone that weathers to light pyrite; weathers to drab, very light- bluish gray in thin, platy, low out- buff sugary surface; some beds with crop; bedding planes uneven; dark-gray streaks and mottles in poorly exposed outcrops 130 them 95 27. Limestone: dark neutral gray, thin- Total thickness of Blacksmith bedded, finely crystalline, at bot- Formation 485 tom of unit bedding is in thin Ute Formation laminations (Ke~l inch thick); 20. Limestone: light-neutral-gray, thick- bedding becomes thicker and there bedded, finely crystalline, slightly are chert layers 1 inch thick toward arenaceous limestone containing the middle of the unit; one 4-foot many small crystals of calcite; bed of oolitic, finely crystalline, weathers to high light-neutral-gray thin-bedded limestone near middle ledges with rough sugary surfaces of unit; limestone tends to become at base of unit; middle part of unit nodular with uneven bedding weathers to light lavender-tinged planes toward top. Fossiliferous gray surface; upper part is darker at top. Fossil locality 101 s 200 gray and weathers to dark-gray Fossils: ledges 225 Olenoides, sp. 19. Limestone and sandstone: dark-blue- cf. Clypkaspidella gray, thin-bedded, finely crystal- Blainia gregaria Walcott line limestone interbedded with Hdcionella, sp. light-blue-gray, thin-bedded, fine- Undescribed and unidentified grained calcareous sandstone. trilobite genera "Girvanella," J^-lJ-

Feet Feel inch which weather to light tan tan to buff on weathered surfaces; yellow; limestone weathers to light some beds slightly nodular; "Gir- blue gray. In upper part of unit a vanella" in upper part of unit but very few "Ginanella" appear. ... 85 not numerous 155 13. Shale: dull-greenish-citrine, thin- 6. Covered interval: much limestone bedded, micaceous, arenaceous float; bank in lower part as well as shale which weathers to a duller, scarcity of limestone float indicate drabber color 15 contact of shale (described below) 12. Limestone and shale: citrine-yellow, and limestone in lower part of thin-bedded micaceous, arenaceous interval 35 shale interbedded with amber- Spence Shale Member brown to light-gray thin-bedded 5. Shale: dark grayish olive to olivaceous arenaceous finely crystalline lime- black, calcareous; weathers to stone containing much limonite... 20 small deep-olive-buff to olive-buff 11. Limestone and shale: dull-citrine to chips, fossiliferous; forms smooth citrine-yellow, thin-bedded, fine- low slopes 185 grained, arenaceous, micaceous 4. Limestone and shale: vinaceous- shale intercalated with thin layers fawn-colored, thin-bedded, cal- of dark-bluish-gray thicker-bedded, careous, fossiliferous shale con- finely crystalline, oolitic limestone, taining lenses of finely crystalline, both of which are interbedded with dark-gray limestone. Fossil locali- 1-2-foot layers of dark-livid-brown ties 101 a2d and 101 a2c at top of to warm-blackish-brown, thick- this unit 7 bedded, finely crystalline, oolitic Fossils: (101 a2d and 101 a2c) limestone 10 "Agnostus" 10. Sandstone and limestone: citrine- Alokistocare, sp. yellow, thin-bedded, fine-grained, Bathyuriscus calcareous, shaly, micaceous sand- Chancia stone interbedded with mottled Clappaspis neutral-gray and deep-livid-brown, Clavaspidella thin-bedded, finely crystalline, Elrathia silty limestone which weathers to Kochina dull mahogany red and which is Olenoidcs overlain by a bed of purer dark- Oryctocephalus green-blue-gray finely crystalline, Pachyaspis slightly arenaceous limestone which Pagetia shows shadows of oolitic struc- Spencia ture 15 Taxioura (Ogygopsis) Total thickness of the Ute Forma- Total thickness of Spence Shale Member 192 tion 745 Naomi Peak Limestone Member Langston Formation 3. Limestone, shale, and calcareous 9. Limestone: medium bluish gray, sandstone: dark-bluish-gray, thick- thick-bedded, finely crystalline; to thin-bedded, finely crystalline to weathers to very light bluish gray, medium-crystalline, fossiliferous, lined with very light-gray streaks slightly arenaceous limestone inter- parallel to bedding 35 bedded and intercalated with 8. Dolomite: mottled, neutral gray to vinaceous-fawn-colored, calcareous, dark neutral gray, thick-bedded, fossiliferous shale. Few feet of finely crystalline; becomes less dark-neutral-gray, medium-bedded, mottled, lighter in color, and medium-grained, very calcareous arenaceous toward top of unit; sandstone at base: sandstone weathers to reddish-buff, sugary- weathers to between deep olive surfaced chunks 35 buff and olive buff low outcrops; 7. Limestone: dark neutral gray to calcareous cement leaches out bluish gray, thick-bedded, finely easily on weathered surfaces and is crystalline; some small veins light not present J^-l inch from outside

Feet soil. The Spence Shale, however, can be traced surface. Fossil localities 101 a2,101, northward along the strike to excellently ex- a2a, 101 a2b. posed outcrops of the lower Middle Cambrian Fossils: ("Ptarmigania" strata) formations in sec. 2, T. 13 S., R. 42 E., on the Albertella divide between Mill Creek and the North Fork Clavaspidella of Mill Creek. Here, a partial section, including Dolichometopsis the lower part of the Ute Formation, the Lang- Kochaspis ston Formation, and the upper part of the Kochidla Prospect Mountain Quartzite, was measured Kochina and described by the writer in 1940. This lo- Oryctocephalus cality is probably the same as, or very close to, Poitlsenia the locality where Walcott described the Middle Prozacanthoides Cambrian formations on "Mill Creek, west of Ptarmigania Liberty" (Resser, 1939b, p. 13-14) in 1906. Thickness of Naomi Peak Member 32 Walcott's descriptions, especially of the Lang- Total thickness of Langston Formation.. 484 ston Formation, do not agree with the observations of the writer, whose Mill Creek section is LOWER CAMBRIAN AND PRECAMBRIAN (?) given here.

Pioche (?) Shale North Fork of Mill Creek Section, Bear River Range 2. Shale and quartzite: greenish-buff, micaceous, fucoidal, sandy, and MIDDLE CAMBRIAN silty shale in beds 2-4 feet thick interbedded with thin- to medium- Feel bedded, fine- to medium-grained, Ute Formation dark-reddish-brown, purple, green, 7. Limestone and shale: poorly exposed and pink sandstone and quartzite outcrops of light-green to greenish- in beds 10-20 feet thick. Weathers tan fissile shale interbedded with darker brown than underlying dark-gray, compact, thin- to quartzite and contains much more medium-bedded argillaceous lime- shale. Thickness of formation not stone not measured measured but estimated to be about Langston Formation 150 feet on south side of High 6. Dolomite: light gray to dark gray, finely Creek Canyon at forks. to coarsely crystalline, compact to Prospect Mountain Quartzite porous with much limonite along 1. Quartzite: pink to red, medium- joint cracks and bedding planes, grained, cross-bedded thick-bedded medium-bedded to massive; weath- units interbedded with few purple ers to bright orange-tan slopes and and green units. Not measured, but to dull, dark-tan, blocky, sugary- estimated to exceed 3000 feet. surfaced outcrops 155 (Thickness in south part of Preston 5. Limestone: dark neutral gray, finely quadrangle, about 10 miles north crystalline, thin- to medium- of High Creek, given by Williams bedded; some beds contain silty (1948, p. 1132) as 4800 feet with partings and mottles 170 base not exposed). 4. Limestone and shale: very poorly exposed outcrops of unit 5 shale in Section on the North Fork of Mill Creek and lowe % of unit 80 Spence Gulch section.—Spence Gulch, the type Spence Shale Member locality of the Spence Shale Member of the 3. Shale: fuscous black and light tea Langston Formation, is a tributary of the Left green poorly exposed, argillaceous, Fork of Mill Creek. It joins this fork in sec. f ossilif erous 65 12, T. 13 S., R. 42 E. (Boise Base and Merid 2. Covered interval: contact of the shale ian), and extends about 1 mile southeastward with "Plarmigania strata", and con- from the junction before it opens into a rather tact of Naomi Peak member with wide basin. Only parts of the Prospect Moun- Prospect Mountain quartzite (?) tain Quartzite and Spence Shale are well ex- probably concealed by soil in this posed, and other formations are covered with interval 20 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 656 G. B. MAXEY—LOWER AND MIDDLE CAMBRIAN STRATIGRAPHY

Feel Feel Total thickness of Spence Shale and Clappaspis Hyolithes Naomi Peak Member 85 Covered interval ... 20 Total thickness of Langston Formation. . 490 Total thickness of Spence Shale...... 70

LOWER CAMBRIAN AND PRECAMBRIAN (?) LOWER CAMBRIAN AND PRECAMBRIAN (?)

Prospect Mountain Quartzite (?) Prospect Mountain Quartzite (?) 1. Sandstone: army brown, medium- 1. Sandstone and quartzite: poorly ex- grained, slightly calcareous, mica- posed outcrop of white, medium- ceous, medium-bedded.... not measured grained, medium-bedded sandstone with flecks of limonite which over- The writer also measured, described, and lies purplish to maroon, medium- collected from the Spence Shale at the type grained, medium-bedded quartzite locality. R. A. Spence, son of the discoverer not measured of the Spence Shale at Spence Gulch, showed the writer the exact place in Spence Gulch Section in the Left Fork of Blacksmith Fork where he recalled that Walcott measured and Canyon.—This section is on the north side of collected from the Spence Shale Member. the canyon (Fig. 1); the base of the measured Spence Gulch is a strike valley cut in the Spence section is in the NW y± sec. 23, T. 11 N., R. Shale; the east side of the valley is a dip slope 3 E., on the prominent spur about a quarter of of the more resistant Prospect Mountain a mile east of the Lucky Star mine. The line quartzite, and the west side is formed of the of the section runs northerly up the spur. limestone and dolomite overlying the Spence Outcrops of lower Middle Cambrian forma- shale. Most of the shale member is covered, tions are well exposed from the Prospect Moun- but, midway between the head and mouth, the tain-Langston contact upward to the Black- stream has undercut the west side of the gulch smith-Bloomington contact. The Spence Shale and removed the soil, thus exposing a steep Member is absent at this locality as at Black- outcrop which Walcott designated the type smith Fork and at Temple Ridge, and the lower locality of the Spence shale. The writer re- dolomite of the Langston is thicker and measured and collected from the Spence at this conformable with the Prospect Mountain locality (Fig. 1). Quartzite.

MIDDLE CAMBRIAN MIDDLE CAMBRIAN Feet Feel Langston Formation Bloomington Formation not measured 5. Dolomite: very light to dark gray, Blacksmith Formation finely to coarsely crystalline, com- 23. Dolomite: between medium and dark pact to porous with much limonite neutral gray, finely crystalline, thin- along joint cracks and bedding to medium-bedded; many beds are planes, medium-bedded to massive; oolitic; one bed near the top of the weathers to bright orange-tan unit is light mouse gray, compact, slopes not measured saccharoidal 85 4. Limestone: dark neutral gray, com- 22. Dolomite: banded neutral gray and pact, thin- to medium-bedded dark gray, darker bands approxi- not measured mately 6 feet thick, light bands ap- Spence Shale Member proximately 20 feet thick; light 3. Covered interval not measured band composed of very compact, 2. Shale; fuscous black and light tea very dolomitic limestone and green; argillaceous, fossiliferous SO dolomite which is laminated and Fossil locality Ilia weathers to smoke-gray surfaces; Fossils: (Ilia) contains splotches of limonitic, silty "Agnostus" Elrathia material; dark-gray bands are com- Alokistocare Zacanthoides posed of coarsely crystalline, Bythicheilas Acrotrela medium-bedded dolomite. Mud Bathyuriscus A crothele cracks observed in the basal light Cl/ancia Iphidella band 45

Feet 21. Dolomitic limestone: neutral gray, stone interbedded with dark-olive laminated, very compact; laminae shale; few interbedded layers of show very plainly on smoke-gray dark-gray, very finely crystalline, weathered surfaces; laminae slightly thin- to medium-bedded, pure lime- silty at base of unit, sillier and stone. Outcrops poorly exposed. ... 15 sandy up section 45 11. Limestone: light gray, finely crystal- 20. Dolomite: light neutral gray, finely line, thin-bedded, silty; interbedded crystalline, thick-bedded; sac- with dark-gray, very finely crystal- charoidal 25 line, compact, thin- to thick-bedded 19. Dolomite: blackish gray, very finely limestone with many silty-concen- crystalline, compact, thin- to trated layers and areas which stand medium-bedded; very uneven bed- in relief on weathered surfaces and ding planes; contains veinlets of which weather light tan 85 calcite and limonite; slightly fetid; 10. Siltstone and shale: very light-bluish- weathers to low outcrops slightly gray, laminated, calcareous siltstone darker 15 which grades into, and is interbedded 18. Dolomite: light neutral grav, finely with, very pure, dark-olive to crystalline, thick-bedded; sugary- citrine-drab shale 15 textured 80 9. Limestone: dark gray, finely crystal- 17. Dolomite: dark neutral gray, very line, thin- to medium-bedded; silty; finely crystalline, medium-bedded; contains siltier mottles and streaks weathers to sugary-surfaced, slightly which weather to dull light tan and lighter-gray, prominent outcrops; stand in relief on weathered surfaces; banding due to slightly different outcrops poorly exposed; some lime- grain size of lighter and darker stone very pure 80 shades of gray at the base 30 8. Covered interval: talus-covered slope; Total thickness of the Blacksmith talus resembles unit 9 30 Formation 325 7. Shale: citrine drab, laminated; Ute Formation weathers to argus-brown; fissile; 16. Limestone: dark gray, finely crystal- outcrops on well-exposed slopes. . . 10 line, compact, brittle, thin- to Fossils: (105 F) medium-bedded; weathers to tan- Elrathina? surfaced, blocky ledges; silty part- Total thickness of Ute Formation. . 675 tings or relatively even bedding Langston Formation planes; some bedding planes very 6. Dolomite: dark gray, finely crystal- uneven; fossiliferous in middle part line, medium-bedded to massive, of unit 85 weathers to dark-tan, sugary-sur- 15. Oolitic limestone: light-gray matrix faced, high ledges 65 with dark-gray oolites approximately 5. Limestone: dark gray, finely crystal- 1 mm. in diameter; thick to thin- line, thick-bedded, many flecks of bedded 70 limonite disseminated throughout 14. Limestone: dark gray, very finely rocks; few beds of intraformational crystalline, compact, thin- to conglomerate and algal limestone; medium-bedded, very pure; fos- fossiliferous. Fossil locality 105 D 20 siliferous at base of unit; some algal feet from base of unit 40 and intraformational conglomerate Fossils: (105 D) beds; some beds sandy 235 Glossopleura Fossil locality 105 k Glyphaspis'i Fossils: (105 k; 4. Limestone: light neutral gray, very Olenoides finely crystalline, compact, lami- Alokistocare nated, saccharoidal; weathers to Acrotrela smooth light-tan surfaces 8 13. Covered interval: float indicates that 3. Dolomite: light neutral gray, medium unit is similar to unit 14 50 crystalline, massive; weathers to tan, 12. Silty limestone and shale: very light- sugary-surfaced, high ledges 125 bluish-gray, laminated, silty lime- 2. Dolomite: medium gray, finely crystal- Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 658 G. B. MAXEY—LOWER AND MIDDLE CAMBRIAN STRATIGRAPHY

Feet Feet line, compact, medium-bedded to locality 97 b 25 feet from base of massive; very sandy at base, less unit 50 sandy upward in section; weathers Fossils: (97 b) to dark-tan, sugary-surfaced out- Glossopleura crops 100 Clavaspidella? Total thickness of Langston Forma- 2. Dolomite: dark-gray, finely crystalline, tion 338 pact, limonitic dolomite, unfos- siliferous 55 LOWER CAMBRIAN AND PRECAMBRIAN (?) Total thickness of Langston Forma- tion 390 Prospect Mountain Quartzite (?) LOWER CAMBRIAN AND PRECAMBRIAN (?) 1. Sandstone and shale: brownish-white, Prospect Mountain Quartzite (?) medium-bedded to massive, 1. Sandstone: brownish white, medium- medium- to fine-grained sandstone bedded to massive, medium- to fine- of speckled appearance due to fine grained; characteristic speckled ap- limonite grains disseminated pearance due to fine grains of throughout; thin layers of inter- limonite shot through the sandstone; bedded, tawny-olive, micaceous, weathers to dark reddish-tan, poorly limonitic shale not measured exposed outcrops not measured

South Cottonwood Canyon section, Blacksmith Blacksmith Fork section.—This section was Fork.—South Cottonwood Canyon is approx- measured by Walcott (1908a, p. 5-9) and was imately 11 miles east of Hyrum, Utah, and is established by him as one of the most important a tributary to Blacksmith Fork. The following Cambrian sections in the Western Cordillera. section was measured on the west side of the All the formations named by him have been canyon in SE ^ sec. 18, T. 10 N., R. 3 E. The recognized throughout northeastern Utah and base of the section is approximately 1 mile southeastern Idaho. Adoption and use of the south of the base of the section Deiss measured formational names by geologists of the U. S. in 1937. Geological Survey (Mansfield, 1927; Black- In this section, as in the sections in Black- welder, 1909; Richardson, 1913; 1941) and smith Fork, in the Left Fork of Blacksmith, Deiss' (1938, p. 1105-1124) excellent redefini- and on Temple Ridge, the Spence Shale Mem- tion of them bolstered their validity and greatly ber is not present, and the lower dolomites of extended the area in which they were used. the Langston Formation are thicker and con- Resser's (1939b, p. 6-7) discussion of the formable with the Prospect Mountain Quartz- Cambrian section in the area further influenced ite (?). geologists to accept the Blacksmith Fork section as the standard for northern Utah and southern Idaho. MIDDLE CAMBRIAN The observations of the writer coincide with Langston Formation Deiss' (1938, p. 1105-1124) descriptions. There- Feet fore, the section is not redescribed in this report. 4. Dolomite: light to dark gray, finely to The Blacksmith Fork section (Fig. 1) is not the coarsely crystalline, compact to most representative or "typical" of Cambrian porous with much limonite along stratigraphy in the Bear River Range. Two joint cracks and bedding planes, near-by sections, the High Creek and Calls medium-bedded; weathers to bright Fort sections, are better exposed and more orange-tan slopes and to dull tan, easily accessible, and contain more typical blocky, sugary-surfaced outcrops; formations and more faunal horizons. The nonfossiliferous 285 prominent lithofacies change in the Langston 3. Limestone: dark neutral gray, com- Formation where the Spence Shale and Naomi pact, thin- to medium-bedded, nodu- Peak Limestone Members pinch out to the lar; contains many buff to tawny- southeast begins only a few miles north and olive limonitic partings; several beds west of Blacksmith Fork, and these two mem- of intraformational conglomerate; bers are missing in the Blacksmith Fork section. few algal and oolitic beds; fos- They are important markers throughout the siliferous at center of unit. Fossil rest of the area from the Logan River to the

Bannock Range and from the east side of the of the St. Charles Formation (Upper Cambrian) Bear River Range to west of the Wasatch with the Garden City Limestone (Ordovician). Range and Wellsville Mountain. Thus the The west side of the mountain is steep, and the High Creek section, which is thicker and more rock outcrops occur chiefly as cliffs and high centrally located within the area of outcrop ledges. These excellently exposed outcrops ex- of the formations, contains formations with tend from the latitude of Brigham City to a few more typical facies and more numerous fauna! miles north of the Calls Fort monument, a dis- horizons. For these reasons, the High Creek tance of more than 8 miles. section is considered the "standard" for north- Field parties of the 40th Parallel Survey eastern Utah and southeastern Idaho in this (1867-1877) were probably the first geologists paper. to examine and collect fossils from the Cam- brian rocks in this area. During this period, North Part of the Wasatch Range, Utah Meek collected fossils from the formations between the Prospect Mountain ("Brigham") General statement.—The Wasatch Range ex- Quartzite and the Blacksmith Formation tends from Mt. Nebo, just northeast of Nephi, (Resser, 1939b, p. 8, 12), and Resser and others Utah, northward approximately 140 miles to collected from a near-by locality in 1926 the north end of Wellsville Mountain, about 20 (Resser, 1939b, p. 8, 12). Although this section miles north of Brigham City, Utah. Northward is one of the most extensive, best exposed, and from Wellsville Mountain is a broad low gap most readily accessible of the Cordilleran Cam- through which Bear River has cut a deep can- brian sections, none of these workers measured yon. This gap is bounded on the north by the and described it in detail. Walcott (1908a, south end of the Malad Range. The Bear p. 8-9) named it the type locality for the River Range is an east prong of the Wasatch Brigham quartzite and published an estimated Range which branches eastward from the main thickness of 2000 feet for it. Resser (1939b, range in the latitude of Brigham City and then p. 12) described former work in the vicinity parallels it on the opoosite side of Cache Valley of Brigham City, published an incomplete de- for early 30 miles. The Wasatch Range is scription of part of the Ute Formation, and complexly folded and faulted, and outcrops of listed fossils which are from mixed collections rocks of Cambrian age are common especially but presumably came from the Naomi Peak along the west front. Well-known exposures Limestone Member (his ''Ptarmigania strata"). occur on Wellsville Mountain, especially east He had previously (1939a, p. 2-3) listed the of the Calls Fort monument, about 7 miles same fossil localities for collections of specimens north of Brigham City, Utah; in the vicinity which he said were presumably from the Spence of Ogden Canyon east of Ogden, Utah; and in Shale Member. Big Cottonwood Canyon, east of Salt Lake Williams and Maxey (1941, p. 276-285) City, Utah (Fig. 1). The formations in Wells- briefly mentioned the significance of the se- ville Mountain are all lithogenetic equivalents quence of Cambrian formations in the Calls of the formations in the Bear River Range, and Fort section. Denson (1942, p. 23-27) measured the Cambrian section near Calls Fort is prob- the upper part of the Middle Cambrian section ably as nearly complete as any section in in 1941 and collected from three important northern Utah. South of Brigham City, Utah, fossil zones. He also described the Calls Fort the Cambrian section is incomplete, and evi- Shale Member of the Bloomington Formation dence presented in the following paragraphs and designated the west side of Wellsville suggests that most of Medial Cambrian and Mountain, near the Calls Fort monument, as all of Late Cambrian time is unrepresented by its type locality. Williams (1948, p. 1131-1135) rocks in most of the Wasatch Range. Cambrian mentioned the Cambrian rocks in Wellsville sediments similar to those in the Bear River Mountain and briefly described the relation- Range were probably deposited but were re- ships between the formations there and in the moved by erosion before Late Devonian time, Logan quadrangle. although the Medial Cambrian-Devonian The following section was measured and hiatus in the Wasatch Range may, in part, also described by the writer in 1940. The lower part represent a period of nondeposition. was further examined and remeasured in 1950. Calls Fort section.—Cambrian rocks are well The base of the section is on the ridge between exposed in the Calls Fort area on the west side the second and third canyons south of a point of Wellsville Mountain from far down in the due east of the Calls Fort monument (Fig. 1) Prospect Mountain Formation to the contact and is in the SE y± of sec. 14, T. 10 N., R. 2 W. Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 660 G. B. MAXEY—LOWER AND MIDDLE CAMBRIAN STRATIGRAPHY

The line of the section follows the ridge upward Feet and northeastward. The upper part of the sec- crystalline limestone shot through tion (from the top of the middle member of with very thin shaly partings and the Bloomington Formation to the top of the specks and veinlets of calcite. Top Bloomington Formation) was measured on the of unit contains a few oolitic beds second spur to the north, on the north side of which have sandy and silty partings which weather in relief to very light Precipice Canyon. buff 515 The best and most readily accessible exposures of the Spence Shale Member and the Hodges Shale Member Bloomington Formation in northern Utah and 27. Shale and silty limestone: dark- southeastern Idaho occur on Wellsville Moun- mouse-gray, micaceous shale which weathers to drab (when well ex- tain. Walcott's type locality of the Brigham posed weathers to between army quartzite is approximately 5 miles south on the brown and natal brown); limestone first prominent spur of the Mountain, north of is dark neutral gray, finely crys- Brigham City. talline, thin-bedded; irregularly interbedded and intermingled with Calls Fort Section, Wasatch Range thin beds and irregular masses of fawn-colored siltstone and shale UPPER CAMBRIAN which stand in relief on weathered Nounan Formation surfaces. In weathered outcrops Feel units is tawny olive. Fossiliferous, 31. Dolomite: neutral gray, finely crys- brachiopods throughout upper part talline, thin-bedded to laminated; of unit. Fossil locality 103 cc at weathers to lighter-gray sugary- top of unit 335 outcrops 85 Fossils: (103 cc) Olenoides MIDDLE CAMBRIAN Hyolithes Weslonia Bloomington Formation Lingulella 30. Limestone: dark neutral gray, finely Obolus crystalline, medium- to thick- Fossils locality 103 ccl is 125 feet bedded; fossiliferous; contains two from top of unit. oolitic beds near top of unit 35 Fossils: (103 ccl) Calls Fort Shale Member Olenoides 29. Shale and limestone: neutral-gray, Undescribed genera slightly calcareous shale; contains Fossil localities 103 cc2 and 103 nodules of slightly lighter-gray cc3 are 175 feet from top of unit. limestone which tend to weather Fossils: (103 cc2) (103 cc3) out, leaving holes on the faces of Olenoides well-exposed outcrops; shale weath- Undescribed genera ers to dark-olive-buff, blocky out- Total thickness of Hodges Shale crops. Few interbedded thin layers Member 335 of oolitic dark-gray limestone and Total thickness of Bloomington dark-neutral-gray, finely crystalline Formation 1085 thin-bedded limestone throughout 200 Blacksmith Formation Total thickness of Calls Fort Shale 26. Dolomite and dolomitic limestone: Member 200 mostly light neutral gray with few- 28. Limestone: dark neutral gray, finely beds of dark neutral gray, compact crystalline, thin-bedded; irregularly to medium crystalline; not re- interbedded and intermingled with markably banded in contrast to thin beds and irregular masses of unit 25; some laminated beds; fawn-colored siltstone and shale weathers to pale smoke gray. which stand in relief on weathered Dolomitic limestone chiefly in surfaces at base of unit; this is upper fourth of unit 395 overlain by dark-neutral-gray to 25. Dolomite: neutral gray and dark neu- neutral-gray, thin-bedded, finely tral gray, fine to medium crystal- Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 LOCATION AND GENERAL DESCRIPTION OF SECTIONS STUDIED 661

Feet Feet line, massive; cliffs banded by alter- 17. Limestone; dark neutral gray, finely nating lighter and darker shades; crystalline, thin-bedded, sandy; cross-bedding common; some oo- bedding marked by very conspicu- litic beds 410 ous laminae of fine sand and silt, Total thickness of the Blacksmith between natal and bone brown that Formation 805 weather into relief; gray layers Ute Formation weather to much lighter gray 30 24. Limestone: dark neutral gray, finely 16. Shale; citrine drab, laminated, weath- crystalline, thin-bedded, sandy; ers to argus brown on well-exposed silty and sandy partings surfaces 3 present but not conspicuous; 15. Limestone: dark neutral gray, finely upper third of unit notable for crystalline, thin-bedded, sandy; irregular streaking of dark neutral bedding marked by very conspicu- and light neutral gray; grades into ous laminae of fine sand and silt, dolomite 90 natal and bone brown that weather 23. Sandstone: dark neutral gray, fine- into relief; gray layers weather to grained, thin-bedded, calcareous, much lighter gray 26 micaceous; silty and sandy partings 14. Shale: citrine drab, laminated; and sandier beds weather to tawny- weathers to argus brown on well- olive surfaces; some cross-bedding. 113 exposed surfaces 3 22. Shale: citrine drab, laminated, 13. Limestone: dark neutral gray, algal micaceous, weathers to argus brown (Ginanella?}, oolitic, finely crys- on well-exposed surfaces 5 talline; thin- to medium-bedded, 21. Limestone: dark neutral gray, finely sandy; characterized by silt and crystalline, thin-bedded, sandy; clay partings which weather to bedding marked by very conspicu- tawny olive and stand in relief on ous laminae of fine sand and silt weathered surfaces; upper part of that weather into relief to between unit is thin-bedded 80 natal and bone brown; gray layers 12. Shale; citrine drab, laminated, weath- weather to much lighter gray 30 ers to argus brown on well-exposed 20. Shale: citrine crab, laminated; surfaces 7 weathers to argus brown on well- 11. Limestone: dark neutral gray, oolitic, exposed surfaces; fossiliferous. thin-bedded, some cross-bedded; Fossil locality 103 t at base of this lower and upper quarters of unit unit 40 characterized by conspicuous silty Fossils: (103 t) partings which weather to tawny Olenoides olive and stand in relief. Girvanella? Ehmaniella (?) conspicuous in upper part 40 Obohis 10. Shale: citrine drab, laminated; weath- 19. Limestone: neutral gray to dark ers to argus brown on well-exposed neutral gray, oolitic and finely surfaces 3 crystalline; lower compact phase 9. Limestone: dark neutral gray, mas- thin-bedded; upper oolitic phase sive, oolitic; upper third of unit medium-bedded to massive; con- lighter color and thinner-bedded spicuous beds of edgewise-con- with conspicuous silt partings 35 glomerate at base of unit; 8. Shale: citrine drab, laminated; weath- conglomerate contains pebbles ers to argus brown on well-exposed 1-1% inches long. Oolitic bed 50 surfaces; fossiliferous. feet from top of unit is fossiliferous. Fossil locality 103 F 4 Fossil locality 103 s 80 Fossils: (103 F) Fossils: (103 2) Glossopleura, sp. Olenoides Kootenia Alokislocare Zacanlhoides 18. Shale: citrine drab, laminated; Acrolrela weathers to argus brown on well- Acroihele exposed surfaces 6 Iphidella

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Feel Feet Hyolithes sandy throughout, some sand con- Total thickness of Ute Formation. . 621 centrated in wavy, discontinuous Langston Formation partings that stand in relief on 7. Dolomite: light gray, fine to medium weathered surfaces. These are crystalline, massive; weathers to Resser's "Ptarmigania strata". buff-brown, sugary surfaces; middle Fossil locality 103 A 25 portion characterized by irregular Fossils: (103 A) banding due to slightly different Ptarmigania crystal size expressed in color on Albertella weathered surfaces, the finely crys- Taxioura (Ogygopsis) talline parts appearing slightly Clavaspidella darker 90 Kochaspis 6. Limestone and siltstone: dark- Prozacanthoides neutral-gray, finely crystalline, Oryctocephalus nodularly bedded limestone with Total thickness of Langston irregular partings of silty lime- Formation 310 stone which stand in relief on weathered surfaces and weather to LOWER CAMBRIAN between natal and bone brown. Siltstone is smoke gray, calcareous, Pioche (?) formation laminated; forms upper three 2. Quartzite and shale: reddish-brown, quarters of unit 20 medium-grained and purple quartz- Spence Shale Member ite interbedded with a few dark- 5. Shale: neutral gray, laminated, cal- green, medium-grained quartzite careous; weathers to citrine olive layers; all quartzite thin- to and, on well-exposed outcrop sur- medium-bedded and interbedded faces and edges; to mahogany red; with numerous thin (2 inches to 4 unit remarkably uniform; fossilif- feet thick) beds of green and tan, erous; lower 15 feet fuscous-black, micaceous, fucoidal shale 125 laminated shale which weathers to light-drab surfaces. Fossil locality LOWER CAMBRIAN AND PRECAMBRIAN (?) 103 c 125 Prospect Mountain Quartzite Fossils: (103 c) 1. Quartzite: red and pink, generally Bathyuriscus Spencia medium-bedded to massive me- Alokistocare Clavaspidella dium-grained quartzite flecked "Agnostus" Acrolhde with limonite pseudomorphs and Elrathia Iphidella some beds containing a few pebbles Chancia Wimanella interbedded with a few thin beds of Glossopleura Hyolithes dark-green, medium-bedded, me- Taxioura-Ogy- dium-grained quartzite; weathers gopsis to brownish-red and pink slopes, 4. Silty limestone and shale: thin-bedded much lighter in hue than overlying to laminated silty limestone; lami- Pioche (?) formation. Not meas- nations marked by clay-rich ured, but estimated by Walcott to laminae, between natal and bone be 2000+ feet thick. Base not brown that stand in relief on weath- exposed. ered surfaces; lower half of unit with 2 layers of fuscous-black, Willard Peak section.—Willard Peak is about laminated, calcareous, fossiliferous 10 miles south of Box Elder Canyon and 4 miles shale 50 southeast of the town of Willard, Utah (Fig. 1). Total thickness of Spence Shale It is the nearest point south of Wellsville Moun- Member 175 tain at which a sequence of Cambrian quartzite, Naomi Peak Limestone Member shale, and limestone is exposed, because be- 3. Limestone: saccharoidal, light neutral tween Brigham City and Willard the range is gray, finely to medium crystalline, complexly faulted, and exposures consist chiefly porous, some oolites; massive, of poorly exposed, brecciated quartzite. No-

where on the long north-south ridge of which Feel Willard Peak is the highest point is there a 7. Limestone: similar to limestone unit complete section of Lower and Middle Cam- 8 but with no phyllitic shale 75 brian formations. However, a considerable 6. Shale: green, phyllitic or slaty, thickness of sediments, including the Prospect arenaceous with many micaceous Mountain Quartzite, Pioche (?) shale, and part layers 58 of the Langston Formation, are exposed as 5. Limestone and dolomite: dark-gray, part of a thrust sheet near the top of the moun- finely crystalline thin- to medium- tain. The upper part of the Langston Forma- bedded argillaceous limestone with tion is cut off by a thrust fault, and along the many silty partings; weathers to trace of this fault Prospect Mountain Quartzite light-grey ledges and is interbedded overlies the limestone. This incomplete section with a few 1- to 4-foot thick units is of considerable significance in the Cambrian of steel-gray, finely crystalline, stratigraphy of the Wasatch Range because medium-bedded dolomite which the complete section of the Prospect Mountain weathers to tan and dark-brown Quartzite is exposed, lying unconformably on blocky ledges 95 Precambrian gneiss and schist. The section 4. Shale: greenish brown, phyllitic or has been briefly mentioned by Blackwelder slaty; weathers to light-gray-green (1909, p. 519-526) and by Eardley and Hatch ledges 62 (1940, p. 835-837). 3. Limestone and dolomite: similar to The base of the section is about 2000 feet limestone and dolomite of unit 5 down from the crest of the ridge near the head but with considerably more dolo- of Willard Canyon and at the contact of the mite and a few sandy limestone Precambrian gneiss and the Prospect Mountain beds near base of unit 18 Quartzite. The line of the section runs eastward Total thickness of Langston For- and up the cliffs to within about 300 feet of the mation measured 408 crest of the ridge, where the trace of an over- thrust mass of Prospect Mountain Quartzite LOWER CAMBRIAN cuts off the upper part of the Langston Forma- Pioche Shale tion. 2. Shale, sandstone, and quartzite: greenish-brown phyllitic and slaty Willard Peak Section, Wasatch Range shale units ranging from a few LOWER CAMBRIAN AND PRECAMBRIAN (?) inches to 30 feet thick interbedded with brown and red, fine- to Prospect Mountain Quartzite medium-grained, medium-bedded Feet sandstone and quartzite in units 10. Quartzite: red, yellow, and white, 1-3 feet thick; forms slope at base medium-grained, medium-bedded of limestone cliffs and top of quartz- to massive, much shattered and ite cliffs (see below) 140 deformed. Thickness not measured. Total thickness of Pioche Shale 140 Trace of thrust fault 9. Poorly exposed interval covered with LOWER CAMBRIAN AND PRECAMBRIAN (?) small shattered fragments of Prospect Mountain Quartzite quartzite and mylonitic material. 1. Quartzite: pink and light reddish MIDDLE CAMBRIAN tan, medium- to coarse-grained, thin-bedded to massive, with little Langston Formation interbedded shale. Estimated thick- 8. Limestone and dolomite: dark-gray, ness 1200 feet, but thickness esti- finely crystalline thin- to medium- mated to range from 700 to 1500 bedded limestone with silty and feet along strike within a mile shaley partings; weathers to light- north and south of line of section. gray ledges and cliffs; interbedded Unconformably overlies Precam- with several 4- to 10-foot thick brian gneisses and schists. Esti- green, phyllitic or slaty shale units mated thickness 1200 with few beds of green micaceous Total thickness of Cambrian strata fine- to medium-grained sandstone. 100 measured and estimated 1750 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 664 G. B. MAXEY—LOWER AND MIDDLE CAMBRIAN STRATIGRAPHY

Ogden Canyon section.—Ogden Canyon runs overlying limestone or the underlying quartzite. eastward from Ogden and is about 10 miles He considered the basal Cambrian quartzite south of the Willard Peak area (Fig. 1). The conformable with the great thickness of quartz- same Cambrian formations are exposed in the ites and slates underlying it, which he called Ogden Canyon area and between Willard and Algonkian (1890, p. 549-550). Only the Pioche Ogden Canyon as are exposed in Willard Peak. Shale, which contains Olenellus gilberti, did he These formations are parts of thrust sheets consider Cambrian. Blackwelder (1909, p. and in most places are only incompletely ex- 520-523) discovered the angular unconformity posed and somewhat metamorphosed. The rocks between the quartzite of Cambrian age and the of Cambrian age exposed in this area have been Algonkain (?) quartzite and slate, and pointed briefly discussed by Blackwelder (1909) and out that the Cambrian quartzite ranges from Eardley and Hatch (1940). 1000 to 1500 feet in thickness and is conform- The Prospect Mountain Quartzite ranges able with the overlying Pioche Shale. Hintze from 1000 to 1500 feet in thickness. It uncon- (1913, p. 103-105) discussed the Big Cotton- formably overlies a thick series of gneisses, wood Canyon section and the unconformity at schists, quartzites, and argillites that have been the base of the quartzite and suggested the referred to the Proterozoic and "Archean" by name "Alta shale" for the shale between the Blackwelder (1909, p. 520-526) and Eardley basal quartzite and the limestone of Medial and Hatch (1940, p. 834-840). It is conformably Cambrian age. He postulated an unconformity overlain by a thin (125- to 175-foot thick) shale at the top of the shale, suggested that the lime- and quartzite unit, the Pioche Formation, stone be called the Maxfield limestone, and which, in turn, is overlain by the limestone recognized, as had Walcott and others, the and shale beds of the Langston Formation. unconformity between the top of the limestone Probably nowhere in this part of the Wasatch and beds of Mississippian age. Burling (1914, Range is more than 500 or 600 feet of shale or p. 111-112) pointed out that the term "Alta limestone of Cambrian age exposed above the shale" was not necessary and that there was Prospect Mountain Quartzite. The writer has probably no hiatus between the Pioche Shale found unidentifiable fossil fragments only in and the "Maxfield limestone" because both these shales and limestones. Both Blackwelder contained faunas of early Medial Cambrian (1909, p. 523) and Eardley and Hatch (1940, age. Since 1913, the U. S. Geological Survey p. 835-837) reported that the limestone was (Calkins and Butler, 1943, p. 9-18) has applied fossiliferous, but published no fossil lists. the term "Ophir formation" to the shale and Big Cotton-wood Creek and, Neffs Canyon sec- has accepted Hintze's "Maxfield limestone". tions.—Cambrian rocks are poorly exposed in Most workers have referred the quartzite at the Wasatch Range from just south of Ogden the base of the section to the "Tintic quartzite". Canyon to Neffs Canyon, about 6 miles south- The writer measured the Cambrian shale east of Salt Lake City, Utah, but in this canyon and part of the limestone in Big Cottonwood and in Big Cottonwood Creek Canyon, ap- Canyon (Fig. 1) in 1950 when he collected fossils proximately 5 miles southeast, Cambrian forma- from about the middle part of the limestone. tions are exposed as a part of a large fold which The base of the measured section is at the top also contains older and younger rocks. As in of the Prospect Mountain Quartzite in sec. 13, Ogden Canyon and at Willard Peak, the rocks T. 2 S., R. 2 E. (Salt Lake Base and Meridian) have been considerably folded and faulted and and about 800 feet west of the Maxfield Mine. are somewhat metamorphosed. The line of the section is northeasterly up the Descriptions of the Cambrian formations in slope. The formations are poorly exposed in Big Cottonwood Canyon were published in the this area, and many of the thicknesses are only reports of the Fortieth Parallel Survey (Hague estimates. However, the sequence of units is and Emmons, 1877, p. 366-378). The Cambrian correct. rocks were divided into (1) Cambrian quartzites and slates, (2) primordial slates, and (3) "Ute" Section in Big Cottonwood Creek Canyon, limestone. Fossils and lithologic samples col- Wasatch Range lected by members of the surveys were further MIDDLE CAMBRIAN described by Walcott (1886, p. 38-39; 1890, p. 549-550; 1891, p. 156-160; 1908a, p. 12). Langston Formation Walcott (1908, p. 12) recognized that the "Pri- 6. Covered interval: drift suggests bedrock mordial slates" were the equivalent of the is limestone as in unit 5. Not Pioche Formation, but he did not describe the measured. Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 LOCATION AND GENERAL DESCRIPTION OF SECTIONS STUDIED 665

Feet Neffs Canyon Section. Wasalch Range 5. Limestone: black gray to steel gray, finely crystalline thin-bedded, fossilif- MISSISSIPPIAN erous; with shaly and silty partings. Feet Fossil locality CC1-50, about 20 feet 7. Limestone: massive, gray to dark gray above base 50 finely to coarsely crystalline. Forms Fossils: prominent ledges and cliffs. Not Glossopleura cf. producla (Hall and measured. Whitfield) Spencia, sp. 4. Quartzite: brownish tan, very fine- Unconformity grained, laminated, somewhat calcareous; interbedded with a few beds MIDDLE CAMBRIAN of siltstone; weathers to blocky, dark- brown ledges 20 Langston Formation 3. Limestone: light gray, finely crystalline 6. Dolomite: steel gray, finely crystalline, to porcellaneous-textured, contains thin and irregularly bedded; weath- some silty and shaly flecks and ers to light-gray ledges and forms top partings 35 of cliffs above shale slopes; contains Total thickness of Langston Forma- many shaly and silty partings 62 tion measured 105 5. Quartzite and sandstone: pinkish- \vhite, fine- to coarse-grained, LOWER AND MIDDLE CAMBRIAN thin- to medium-bedded quartzite interbedded with tan fine-grained, Pioche Shale calcareous sandstone and quartzite 2. Shale: greenish black, phyllitic shale which weathers into thin brown and slate with many fucoidal mark- plates; top of unit is pinkish-white ings on bedding planes 175 pebble conglomerate about 4 feet thick 14 LOWER CAMBRIAN AND PRECAMBRIAN (?) 4. Limestone: light gray, very finely crystalline (some beds porcellaneous- Prospect Mountain Quartzite textured), thin-bedded to laminated 1. Quartzite: brown, pink, and red, with many shaly and silty partings; medium- to coarse-grained, thin- weathers to light-gray and tan ledges bedded to massive quartzite inter- at base of cliffs above shale slopes. bedded with a few thin (1-2 feet) Limestone becomes arenaceous and layers of dark-green and brown irregularly bedded toward top of phyllitic shale with many fucoidal unit 66 markings. Not measured, but ap- Total thickness of Langston Forma- proximately 1000 feet thick. tion 142 Unconformable with underlying Pre- cambrian slate and quartzite. LOWER AND MIDDLE CAMBRIAN

In Neffs Canyon the Cambrian rocks are Pioche Formation better exposed than in Big Cottonwood Canyon, 3. Shale and quartzite: greenish-brown and a stratigraphic section from the uncon- and olive-green, laminated, sandy, formity at the base of the Prospect Mountain micaceous fucoidal shale interbedded Quartzite to the unconformity at the base of with a few thin (1-4 inches) layers the Mississippian rocks was observed and of thin-bedded, fine- to medium- measured in part. The base of the measured grained, brown micaceous quartzites 98 section is at the contact of the Pioche Shale 2. Shale, quartzite, and sandstone: green- and Prospect Mountain Quartzite on the first ish-brown and olive-green, lam- small south tributary of Neffs Canyon (Fig. 1) inated, arenaceous, micaceous, in sec. 6, T. 2 S., R. 2 E. (Salt Lake Base and fucoidal shale interbedded with Meridian). The line of the section is north- brown and greenish-brown, fine- to westerly up the slope to the top of the ridge, medium-grained, thin- to thick- where the Mississippian limestones crop out bedded micaceous sandstone and as prominent ledges and cliffs. quartzite. Much shale and little Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 666 G. B. MAXEY—LOWER AND MIDDLE CAMBRIAN STRATIGRAPHY

Peel (3) a thin limestone and/or dolomite unit coarser material at top of unit; con- with some intercalated and interbedded siderably more coarsely clastic to- shale and sandstone, the Langston ward base of unit 100 Formation, which is truncated by an Total thickness of Pioche Formation 198 erosional unconformity or by a thrust fault. This unit is overlain unconform- LOWER CAMBRIAN AND PRECAMBRIAN (?) ably either by older beds in faulted contact or by dolomite and limestone of Prospect Mountain Quartzite Devonian (Calkins and Butler, 1943, 1. Quartzite: white and pinkish white, p. 18; Baker, 1947, chart) age or lime- medium- to coarse-grained (some stone of Mississippian age (Williams, beds of small pebble conglomerate), 1943, p. 599-600). medium-bedded with some cross- From these characteristics, the Big Cotton- bedding; interbedded with a few thin wood Creek section is considered the "stand- (1-2 feet) layers of greenish-brown ard" section for most of the Wasatch Range. shale in upper 100 feet of formation. Not measured, but estimated to be Promontory Range, Utah 1000 feet thick. Total thickness of Prospect Moun- Early and Middle Cambrian rocks in the tain Quartzite 1000 Promontory Range have been mentioned briefly Total measured and estimated thick- by Butler and Heikes (Butler et al, 1920, p. ness of rocks of Cambrian age 1340 499-501), Resser (1939b, p. 6), and Eardley and Hatch (1940, p. 801-802), all of whom The units in these sections compare closely recognized that the sequence on Promontory with those described by Hintze (1913, p. 103- Point at the south end of the range was similar 105), and the general sequence is the same as to that in the Bear River Range. Resser (1939b, other published descriptions (Walcott, 1890, p. 6) reported Early Cambrian fossils from p. 549-550; Blackwelder, 1909, p. 520-527; these rocks but did not give the species or Calkins and Butler, 1943, p. 9-18). Also the locate the zones. In 1950 the writer examined formations are lithologically similar to those the section in Miner's Canyon, about 3 miles recognized by the writer in the Ogden Canyon northwest of the Crystal Lake Salt Company and Willard Peak areas except that the un- buildings at the southwest end of Promontory conformity at the top is not recognized in those Point. areas. The strata in Miner's Canyon are much dis- Summary.—The data presented indicate that turbed by thrusts and small normal faults and the Cambrian sequence in the north part of the by folds. It was possible, however, to recognize Wasatch Range, north of Boxelder Canyon the entire sequence of the Bear River Range. (Wellsville Mountain), is essentially the same Because of complex faulting, and because only as the sequence in the Bear River Range in a few fossil-bearing zones were found, no de- Utah and in southeastern Idaho. South of tailed study was made. Estimates of thickness Boxelder Canyon, only the lower part of the indicate that the Langston Formation and the sequence is known, and the upper part was Blacksmith Dolomite may be thinner here than either never deposited or was removed by ero- at Calls Fort or in Blacksmith Fork Canyon; sion. Thus, the "standard" Cambrian sequence the Ute Formation may be considerably thicker, in this part of the Wasatch Range consists of: and the Bloomington Formation is less shaly (1) a basal quartzite unit of variable thick- but is about the same thickness. As at Calls ness, here referred to the Prospect Moun- Fort and High Creek, the shale and quartzite tain Quartzite, unconformably overlying beds between the Prospect Mountain Quartzite the Precambrian gneiss, schist, slate, and the Langston Formation are doubtfully and quartzite and conformably overlain referred to the Pioche Formation. The Prospect by Mountain Quartzite is approximately 1000 feet (2) a thinner sequence of predominantly thick and unconformably overlies Precambrian shaly beds with considerable intercalated strata. The Pioche (?) formation, the Spence and interbedded coarser elastics, here Shale Member of the Langston. and the shale referred to the Pioche Shale, ranging at the base of the Ute Formation contain frag- from about 150 to 200 feet in thickness, ments of fossils. Forms characteristic of the and conformably overlain by Spence Shale fauna elsewhere in Utah and

southeastern Idaho were recognized in the to more than 6000 feet in the Tintic district, Utah. Spence Shale Member at Miner's Canyon. However, the thickness in the Tintic district may be the result of duplication by folding and LOWER AND MIDDLE CAMBRIAN FORMATIONS faulting, or an unconformity may be present IN NORTHEASTERN UTAH AND SOUTHEASTERN within the quartzite. The largest well-exposed IDAHO AND THEIR REGIONAL and unquestioned thickness in the area under RELATIONSHIPS discussion is in the Bear River Range near the Utah-Idaho boundary, where Williams (1948, Prospect Mountain Quartzite (Lower Cambrian) p. 1132) and Church measured 4800 feet of DEFINITION AND DISTRIBUTION: The Prospect quartzite beds (probably includes approxi- Mountain Quartzite was first defined by Hague mately 150 feet of the Pioche (?) formation), (1883, p. 27; 1883, p. 254), who designated the and the base of the formation is not exposed. west side of Prospect Peak near Eureka, The maximum known thickness of the forma- Nevada, as the type locality. In the type area, tion is more than 7855 feet (Humphrey, 1945, the formation consists chiefly of reddish-brown p. 25-26) in the Groom district, Nevada. to pink, medium-grained, thick- to thin-bedded Wheeler (1948, p. 20) reported thicknesses of quartzite interbedded and intercalated with 4750 feet in the Deep Creek Range, Utah, and a few thin layers and lenses of micaceous are- 4128 feet in the Nopah Range, California. naceous shale and, near the base of the exposed Nolan (1929, p. 463) reported a thickness of section, with quartzitic conglomerate. Hague 3700 feet of Prospect Mountain Quartzite gives the thickness as 1500 feet at the type (Stirling quartzite) in the Spring Mountains, locality, where the base is not exposed and the Nevada, and the writer has observed approxi- quartzite is conformably overlain by the Pioche mately 4000 feet in the Desert Range, 20 miles Formation. Detailed descriptions of the forma- northeast of the Spring Mountains. tion are given in another part of this paper. Within the area of this study the rocks The formation has been recognized in sections previously assigned to the "Tintic quartzite" throughout Nevada, Utah, eastern California, belong in the Prospect Mountain Formation, northern Arizona, and southeastern Idaho in as do rocks assigned to all but the uppermost an area roughly the same as the Great Basin shaly units of the so-called "Brigham quart- province, but which extends northward and zite". The uppermost shaly units are here southward beyond its boundaries. The doubtfully referred to the Pioche Formation. Prospect Mountain Quartzite is unusually AGE: As far as the writer knows, diagnostic uniform and in nearly all areas is conformably fossils have not been found in the Prospect overlain by shales containing late Early Cam- Mountain Quartzite. The only fossils found in brian or early Medial Cambrian fossils. The the formation are numerous worm borings, base of the formation has been positively recog- fucoids (?), annelid and trilobite trails, and one nized in only a few localities in Utah and common phoronid (?) boring (Skolithos), none of southeastern Idaho. It unconformably over- which indicates the age of the formation. lies Precambrian formations in the Bannock Fossils from the overlying Pioche Shale show Range (Ludlum, 1943, p. 973), in the central that that formation is partly within the Olenel- southern parts of the Wasatch Range, and on lus zone in western Utah and in the central Promontory Point. In the Sheeprock Moun- and southern Wasatch Range, and here the tains, Utah, the quartzite is questionably un- Prospect Mountain Quartzite certainly is Early conformable upon Precambrian rocks. Else- Cambrian or older. In the northern Wasatch, where in Utah and Idaho the base of the in the Bear River Range, and in southeastern Prospect Mountain quartzite is covered or has Idaho the oldest known diagnostic fossils occur not been recognized. The quartzite is 3200 in the Langston Formation and belong within feet thick in the Bannock Range, approxi- the earliest Middle Cambrian zone (Albertella- mately 1000 feet thick on Promontory Point, Kochaspis subzone). Thus here also the quart- and ranges from approximately 700 feet to zite is probably Early Cambrian or older. 1200 feet in the Wasatch. Eardley and Hatch Wheeler (1947, p. 157-159) proposed that (1940, p. 825-826) report 3500 feet of quartzite the base of the Olenellus zone be recognized as above a questionable unconformity in the the base of the Cambrian system in western Sheeprock Range. Known thicknesses of the North America. This suggestion may be highly quartzite in the other areas of outcrop in Utah satisfactory for the Cambrian of the Cordillera and Idaho range from 300 feet near Ophir, Utah, for the reasons that Wheeler has so ably pre- Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 668 G. B. MAXEY—LOWER AND MIDDLE CAMBRIAN STRATIGRAPHY

sented. However, two important difficulties tions, "the Pioche shale (restricted)" and the arise: (1) although the top of the Olenellus "Comet shale". Wheeler and Lemmon (1939, zone is well defined and easily recognized in p. 34-35) restored the formation to its proper many areas, its base is not accurately defined status. Wheeler (1943, p. 1781-1982) indicated and apparently has not been recognized in the wide geographic occurrence of the Pioche western North America; (2) in eastern North Formation in Utah, Nevada, and Arizona and America and northwestern Europe well-defined in 1948 (p. 25) stated that, among other terms, and easily recognized faunal zones older than the "Ophir" and "Cabin" shales were synonyms the Olenellus zone have been found. In those of Pioche. regions the base of the Cambrian system has Data presented here prove the presence of been defined so as to coincide with the base of the Pioche Formation throughout most of the lowermost (Obolella) zone (Howell et al., west-central and northern Utah and suggest 1944, chart). its presence in the northern Wasatch, in part On the basis of physical characteristics, in- of the Bear River Range, and in southeastern cluding lithologic features, conformity with the Idaho. In the two last-named areas, the beds overlying Pioche Shale, etc., Wheeler (1948, lithogenetically equivalent to the Pioche For- p. 20, Fig. 5) doubtfully included the upper mation seem to pinch out to the east and were part of the quartzites in the Lower Cambrian not observed at Spence Gulch or in the Black- series in three western Utah sections, even smith Fork drainage area (Figs. 2, 3). Else- though diagnostic fossils of the Olenellus zone where in the Wasatch and southeastern Idaho do not occur in the quartzite. Probably in these beds have heretofore been included in Utah and Idaho, where the quartzites nearly the "Brigham formation". In the central everywhere conformably underlie the Pioche Wasatch Mountains the basal shales of the Shale and where Olenellus occurs in that forma- "Ophir formation" constitute the Pioche For- tion, the Prospect Mountain Quartzite is of mation. In Utah and southeastern Idaho it is Early Cambrian age. The formation was ap- composed of arenaceous and argillaceous shales, parently deposited during part, or all, of the generally interbedded and intercalated with time when faunas that antedate the Olenellus quartzite and sandstone layers and lenses. The fauna were thriving in other regions. Further quartzite and sandstone beds are lithologically study of the quartzite and other Lower Cam- similar to those of the underlying Prospect brian formations in the Great Basin may yield Mountain Formation. Only a few carbonate evidence allowing a more precise definition of layers or lenses are interbedded with the shales. Lower Cambrian faunal zones and thus permit Sparseness or lack of carbonate beds is the a more accurate age assignment of the forma- chief criterion used in many places to distin- tion. guish the Pioche Formation and the conformably overlying carbonate beds of the Langs- Pioche Formation ton Formation. Further, the Pioche shales are predominantly argillaceous and micaceous, DEFINITION AND DISTRIBUTION: The Pioche whereas the overlying shales are mostly cal- Shale was first described at the type locality careous. The formation thins eastward and near Pioche, Nevada, by Walcott (1908a, p. northward from the type locality (Wheeler, 11-12) as 210 feet of "arenaceous and argil- 1943, PI. 1; 1948, Fig. 5), and in at least one laceous shaly layers with some thin layers and section in northeastern Utah (Blacksmith Fork) bands of limestone more or less irregularly it is not present. In northeastern Utah and interbedded and limited in horizontal dis- southeastern Idaho the arenaceous beds contribution". He correctly pointed out that the stitute so much of the formation at the expense formation crops out in the House and Wasatch of the argillaceous shale that it is only arbi- ranges, in Utah, where it also lies conformably trarily distinguishable from the underlying between the Prospect Mountain Quartzite and Prospect Mountain Quartzite. The Pioche the overlying Cambrian limestones. Westgate ranges in thickness from 265 feet in the House and Knopf (1927, p. 8-10) redescribed the Range to approximately 100 feet in the Ophir formation, emended the original definition, and Canyon section. pointed out that the true thickness of the for- AGE : Fossils of Early Cambrian age belonging mation is approximately 1120 feet at the type to the Olenellus zone have been found in the locality. Deiss (1938, p. 1152-1160), on pale- Pioche Formation in Utah. Fossil localities in- ontological evidence, incorrectly divided this clude the House Range, Ophir Canyon, and Big lithogenetic and mappable unit into two forma- Cottonwood Creek Canyon. Olenellus has been Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 LOWER AND MIDDLE CAMBRIAN FORMATIONS 669

reported from the Pioche Shale of the Wasatch and limestone members. The sections upon Mountains east of Provo (P. E. Dennis, per- which Williams and Maxey's (1941) paper was sonal communication) and in rocks now as- based are detailed in the present paper. signed to the Pioche Shale of the Promontory The writer has recognized the Langston For- Range (Resser, 1939b, p. 6). The Langston mation in all areas described in this paper and Formation conformably overlies the Pioche suggests that the north side of the High Creek Shale and contains fossils belonging to the Canyon is the best and most nearly typical ex- Albertella-Kochaspis subzone, which contains posure of the Langston Formation. The forma- the earliest Medial Cambrian fossils in the tion is characteristically developed with all Great Basin. Thus, the fossils indicate that the members present, whereas to the southeast Pioche Formation is of late Early Cambrian (toward Blacksmith Fork) the Spence Shale and early Medial Cambrian age throughout and Naomi Peak Members pinch out into the northern Utah and southern Idaho. Like the thick basal dolomite (Fig. 2), and to the south overlying Langston Formation, it transgresses and west they finger into a maze of thinly the Early-Medial Cambrian boundary. interbedded and intercalated shale and limestone beds. Langston Formation (Lower and In the Wasatch Range, from Willard Peak Middle Cambrian) south and west to beyond the central Wasatch, the formation consists of these interbedded DEFINITION AND DISTRIBUTION: The Langston limestones and shales and a few sandy beds. formation was named by Walcott (1908a, p. 8; Throughout most of Utah and southern Idaho 1908b, p. 198-199) who described it as "mas- the Langston Formation marks the beginning sive-bedded, bluish-gray limestone with many of the long period of deposition of predomi- round concretions" and gave its thickness as nantly carbonate rocks which characterize the 107 feet in Blacksmith Fork Canyon, Utah, its Middle and Upper Cambrian Series, whereas probable type locality (1908a, p. 8). Later, he the underlying formations are predominantly (Walcott, 1908b, p. 188-199) redescribed it and detrital and arenaceous. Thus the base of the included 390 feet of "massive-bedded, dark formation is usually drawn at the first distinc- arenaceous limestone, passing at about ISO feet tive limestone bed above the Prospect Moun- down into a calcareous sandstone, and then a tain Quartzite. gray sandstone". In the later description he Beds formerly assigned to the upper part of listed fossils and made Blacksmith Fork Canyon the "Ophir formation" and to the "Maxfield" the type locality, although Langston Creek formation are here assigned to the Langston (where the formation is also exposed) is some Formation. distance from Blacksmith Fork. In both papers Two units within the Langston Limestone he states that the Langston Limestone conform- are locally distinct lithologic markers. Resser ably overlies the Prospect Mountain Quartzite (1939b) described a fauna from the basal lime- ("Brigham") and comfortably underlies the stone beds of the Langston Formation super- Spence Shale, which he considered the basal iacent to the shaly quartzite beds of the Pioche member of the Ute Formation. Walcott's defi- (?) Formation (Brigham) and subjacent to the nition was generally accepted, and Deiss (1938, Spence Shale Member. He called this the p. 1112-1119) remeasured and redescribed the Ptarmigania fauna, and the limestone in which formation and designated a new "type" locality it occurs he referred to as the "Ptarmigania in Blacksmith Fork Canyon. In 1941, Williams strata". He neither adequately defined the and Maxey (1941, p. 279) stated that the member nor designated a type locality, prob- Langston Formation is ably because he was not aware of its exact "a sequence of shales, limestone, and dolomites stratigraphic position. Further, the term that, though changing laterally to some extent, "Ptarmigania strata" is likely to become con- constitutes a satisfactory mappable (lithologic) fused with the term Ptarmigan Formation, an unit. The Spence shale is a member of the Langston already accepted name for a Middle Cambrian formation separated in normal sequence from the Brigham quartzite by only a few feet of crystalline formation in Canada. The detailed descriptions limestone." of sections in the northern Wasatch Mountains, in the Bear River Range, and in southeastern They pointed out that the Langston Formation Idaho indicate that these limestones are a at the "type" localities in Blacksmith Fork distinctive rock unit. In the field this unit is an consists of an abnormal development of the excellent stratigraphic marker or "key bed", dolomite members at the expense of the shale because (1) it is the first limestone in the sec- Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 on 02 October 2021 by guest Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf

AHdvaoixvaxs Nvraawvo aiaaiiM ONV >iaMoi—AHXVW -a ' LOWER AND MIDDLE CAMBRIAN FORMATIONS 671

tion above the arenaceous sediments of the locality, it consists of black and olive-green, Pioche (?) and Prospect Mountain formations, fissile, somewhat calcareous shale with numer- (2) it contains in all known outcrops the dis- ous fossils in the lower beds and with some tinctive, easily recognized fossils of the Ptar- interbedded thin layers of tan siltstone and migania fauna, and (3) it is nearly always silty shale in the upper part. The area of out- excellently exposed because it forms the first crop of the Spence Shale is somewhat larger ledges under the slopes formed on the Spence than that of the Naomi Peak Member because Shale and caps the prominent cliffs and ledges it crops out in the Promontory and Bannock of the underlying resistant arenaceous sedi- ranges and may extend northward beyond the ments. This unit is here designated the Naomi Snake River in Idaho. However, it was not Peak Limestone Member of the Langston recognized in Utah south of the latitude of Formation. Brigham City or west of Promontory Point ORIGINAL DESCRIPTION: The Naomi Peak (Fig. 2). Member is composed of light- to medium- AGE: The faunas of the Naomi Peak Lime- neutral-gray, finely crystalline, arenaceous stone and Spence Shale Members are assigned limestone with numerous lenses of coarsely to the Albertella-Kochaspis subzone and unques- crystalline, very fossiliferous, pure limestone. tionably show that the basal Langston was de- In many places few thin beds of gray, medium- posited in earliest Medial Cambrian time. The grained, brown-weathering, calcareous or dolo- "Ptarmigania fauna" contains several forms mitic sandstone occur near the base of the that have Early Cambrian affinities. The Lang- member. It conformably overlies the Pioche (?) ston Formation in the House Range contains Shale and underlies the Spence Shale Member only these early forms or their ancestors and, of the Langston Formation. It constitutes the in so far as known, no typically Medial Cam- basal 32 feet of the Langston in the excellent brian types. This fauna in the House Range is section on the north side of the North Fork of tentatively placed in the Antagmus-Oncho- High Creek, approximately 6}^ miles north- cephalus zone of late Early Cambrian age. This east of Richmond, Utah. The known outcrop suggests that the sedimentary environment of area of the Naomi Peak Limestone Member the Langston transgressed slowly eastward and extends from the Left Fork of Blacksmith Fork that the Langston Formation may transgress River northward beyond Spence Gulch and the Early-Medial Cambrian boundary in the Malad, Idaho, and from the east side of the western Great Basin. The upper beds of the Bear River Range to Wellsville Mountain. The Langston are everywhere clearly Medial Cam- member is 40 feet thick at the North Fork of brian, for they contain fossils belonging to the Mill Creek, 2>^ miles north of Spence Gulch, Glossopleura-Zacantkoides zone or they are Idaho; 32 feet thick at Two Mile Canyon, conformably overlain by beds assigned to that Idaho; 32 feet thick at High Creek, Utah; 25 zone. feet thick at Wellsville Mountain; and 40 feet thick at Temple Ridge, in the central part of Ute Formation the Bear River Range. It is not recognized in the Left Fork of Blacksmith Fork, in Black- DEFINITION AND DISTRIBUTION: The name smith Fork, in the Promontory Range, or in Ute Limestone was applied by King (1878, p. central or western Utah. 232-233) to the 2000 feet of limestones over- The Spence Shale was designated by Walcott lying the Cambrian quartzites. Walcott (1908a, (1908a, p. 8) as the basal member of the Ute p. 7) redescribed the lower 759 feet in Black- Formation. He described it as 30 feet of argil- smith Fork and restricted the name to these laceous shales in the type locality at Spence lower beds. This restricted usage has been Gulch, Idaho. Williams and Maxey (1941, p. followed, and Deiss (1938, p. 1120-1121) re- 276-285) redescribed the member as part of measured the thickness and emended the de- the Langston Formation immediately super- scription of the beds in the Blacksmith Fork jacent to the Naomi Peak Limestone. As section. Deiss retained Blacksmith Fork Can- Williams and Maxey (1941, p. 280) state, the yon as the type locality of the emended Ute formation is not wholly exposed at Walcott's Limestone. Williams and Maxey (1941, p. 281) type locality, but approximately 1 mile north- defined the Ute Formation as the "thin-bedded, northwest along the strike, on the west side of silty limestone and green shales" conformably the Left Fork of Mill Creek, it is well exposed overlying the Langston Formation and under- and is 125 feet thick. Here, as at the type lying the Blacksmith Dolomite, both persistent

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and readily recognized. This definition and the Palella-Thompsonaspis zone of authors Deiss' description are here recognized as es- (Howell et al, 1944, Chart). sentially correct. Outside the Bear River Range the Ute Formation has been readily recognized Bloomington Formation throughout northern Utah and southern Idaho. DEFINITION AND DISTRIBUTION: The Bloom- According to Deiss (1938, p. 1113-1114) the ington Formation conformably overlies the Ute Formation is 685 feet thick in Blacksmith Blacksmith Dolomite throughout northern and Fork. Its maximum measured thickness (745 northeastern Utah and in most of southern feet) in northern Utah and southeastern Idaho Idaho. It was named by Walcott (1908a, p. 7), is at High Creek, Utah. An estimate of its who designated the type locality as "Bear thickness at Promontory Point, Utah, is 790 River Range, about 6 miles west of the town feet. AGE: The basal shales of the Ute Formation of Bloomington, Bear Lake County, Idaho. A second easily accessible locality is in Blacksmith in southeastern Idaho and northern Utah con- Fork Canyon, east of Hyrum, Cache County, tain fossils assigned to the Glossopleura-Zacan- Utah." thoides zone. In central Utah the basal beds He described the formation as "bluish gray, conformably overlie rocks containing similar more or less thin-bedded limestones and argil- fossils. Olenoides, Ehmaniella (?), Alokistocare, laceous shales. Small rounded nodules of calcite and Obolus, all typical Medial Cambrian forms occur scattered regularly through many of the characteristic of the Bathyuriscus-Elrathina layers of limestone." Richardson (1913, p. 406) zone, occur approximately 400 feet above the described the basal shale beds of the Blooming- base of the formation in northern Utah. Fur- ton Formation as the Hodges Shale Member in ther, elements of the Bathyuriscus-Elrathina the Randolph quadrangle, Utah. Mansfield zone are reported from near the base of the (1927, p. 55) redescribed the formation in conformably overlying Blacksmith Dolomite. southeastern Idaho, recognized the Hodges Thus, the Ute Formation is Medial Cambrian. Shale Member at the base, and changed the type locality to Mill Creek, near Liberty, Blacksmith Dolomite Idaho. Deiss (1938, p. 1121-1132) redescribed the Bloomington in the Blacksmith Fork area Walcott (1908a, p. 7) designated "Blacksmith and pointed out that the Hodges Shale Member Fork Canyon, about 8 miles above its mouth was thinner there. Williams and Maxey (1941, and 15 miles east of Hyrum, Cache County, p. 381) described the formation in the Logan Utah," as the type locality of the Blacksmith quadrangle and vicinity as 1200 feet of thin- Dolomite. He incorrectly described the forma- bedded limestone and shale with the Hodges tion as 570 feet of "gray arenaceous limestone Shale Member at the base and a thick shale in massive layers." Deiss (1938, p. 1112-1113, member at the top. This upper thick shale 1121) emended this definition and correctly member was designated by Denson (1942, p. 24) stated that the formation was essentially all as the Calls Fort Shale. Thus, the Bloomington thick-bedded gray dolomite and interbedded Formation consists of (1) a basal tawny-olive magnesian limestones. These beds are approxi- shale and interbedded thin layers of light- to mately 450 feet thick at the type locality in dark-gray limestone (the Hodges Shale Mem- Blacksmith Fork and about 485 feet thick at ber), overlain by (2) a middle unit of thinly to High Creek. The formation thins northward thickly bedded, light- to dark-gray limestone and is not recognized in the northern extremity which weathers to slopes strewn with thin of the Bear River Range near Lava Hot Springs. plates of limestone, overlain by (3) an upper Walcott (1908a, p. 8) reports that it is only 23 tawny-olive shale unit with some interbedded feet thick in the section west of Liberty, Idaho. platy limestone, the Call's Fort Member. It apparently thickens westward and south- The Bloomington Formation crops out ward because it is more than 500 feet thick on throughout southeastern Idaho and north- Promontory Point and is thicker at Calls Fort eastern Utah as far south as the northern mar- than at High Creek. gin of Great Salt Lake and Brigham City. It The only fossils reported from the Blacksmith has been recognized in the Lakeside Range, on Dolomite are forms belonging to the "Thomp- the west margin of Great Salt Lake. In the sonaspis faunule" of Denson (1942, p. 26) and Wasatch Range it was probably removed by to the Bathyuriscus-Elrathina zone. Denson's late or post-Cambrian erosion, or it may never Thompsonaspis faunule is probably the same as have been deposited.

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AGE: Benson (1942 p. 24) places the Bloom- I'IOCHE SHALE ington Formation in the latest Medial Cam- brian zones on the basis of faunules, as yet not Wasatch Range, Big Cottonwood Canyon; base published, which occur in the Calls Fort and of the formation (Walcott, 1891, p. 319; Hintze, Hodges Shale Members. The writer tentatively 1913, p. 104-105; Burling, 1914, p. 8)

CALLS FORT SECTION HIGH CREEK SECTION WASATCH RANGE BEAR RIVER RANGE

FIGURE 3.—REGIONAL CORRELATION AND EARLY MEDIAL CAMBRIAN FAUNULES AND FAUNKONES

places these members in the Asaphiscus-Bolas- 1. Olenellus gilberti (Meek) pidella zone. The top of the Tkompsonaspis Cruziana, sp. zone occurs just below the base of the formation, Same: 100 feet above base of formation (Walcott, in the top of the Blacksmith Dolomite, at High 1890, p. 319; Hintze, 1913, p. 104-105; Burling, Creek, Utah. The base of the Lower Cedaria 1914, p. 3) zone (Upper Cambrian) is drawn near the base 2. Obolus (Westonia) ella (Hall and Whitfield) of the Nounan Formation, which lies conform- Micromitra (Iphidella) pannula (White) ably on the Calls Fort Member of the Bloom- Hyolithes billingsi (Walcott) ington Formation. Tuzoia argenta (Walcott) Ehmaniella (?) quadrans (Hall and Whit- EARLY AND MEDIAL CAMBRIAN FAUNULES IN field) UTAH AND SOUTHEASTERN IDAHO Glossoplei/ra producta (Hall and Whitfield) The writer here lists all reported occurrences of diagnostic Lower and Middle Cambrian LANGSTON FORMATION fossils in the region. The zones in which these faunules occur are designated on Figure 3 by Wasatch Range, Big Cottonwood Canyon; 70 the numbers heading each list. Zonation of the feet above base of formation faunules is discussed. Since no diagnostic fossils 3. Spencia, sp. undet. are known from the Prospect Mountain quartz- Glossopleura utaliensis (Resser) ite, this formation is not included. Anoria utaliensis (Resser)

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Promontory Range; 15 to 100 feet above base K. -iieslita Resser of formation K. U'asalchensis Resser 4. Many species from the Spence Shale, Koolenia acicularis Resser including Taxioura, sp. undet. Hyolithes, K. bearensis Resser sp.; and Elrathia, sp. undet. K. brevispina Resser Bear River and Malad ranges and Wellsville K. conwlula Resser Mountain; basal 32 to 40 feet of formation K. germana Resser (Naomi Peak Limestone Member) (Resser, K. granulosa Resser 1939b, p. 20-72) K. libertyensis Resser 5. Brachiopoda K. maladensis Resser Acrothele artemis Walcott K. mendosa Resser A. parilis Resser K. iienusla Resser Acrothyra minor Walcott Olenoides maladensis Resser Acrotreta eucharis Resser Oryctocephaliles typicalis Resser A. sulcala Walcott Oryctocephalus maladensis Resser Iphidella maladensis Walcott Pachyaspis lypicalis Resser Lingulella eucharis Resser Pagelia dytia Walcott Micromitra haydeni Walcott P. maladensis Resser Palerina hirta Resser Poliella dignata Resser Wimandla maladensis Resser P. germana Resser Gastropoda P. Sabrina Resser Helcionella aequa Resser P. wasatchensis Resser H. argula Resser P., sp. undet. E. burlingi Resser Poulsenia bearensis Resser Hyolithes prolixus Resser P. granosa Resser Agnostia P. occidens Resser Agnostus lautus Resser Prozacanthoides aequus Resser Trilobita P. alatus Resser Albertella, sp. undet. P. decorosus Resser Alokistocare brighamensis Resser P. exilis Resser A. euchare Resser P. libertyensis Resser Alokistocare euzona Resser P. optatus Resser Alokistocarella occidens Resser Ptarmigania agrestis Resser Bathyuriscus politus Resser P. altilus Resser Clavaspidella excatata Resser P. aurita Resser C. wasatchensis Resser P. exigua Resser Dolichometopsis alia Resser P. natalis Resser D. comis Resser P. ornala Resser D. communis Resser Tazioura magna Resser (Ogygopsis} D. grams Resser T. lypicalis Resser (Ogygopsis) D. gregalis Resser Tonkinella idahoensis Resser D. lepida Resser D. mansfieldi Resser Unidentified species and genera of D. media Resser trilobites and brachiopods D. potena Resser Same: beds between approximately 40 feet and D. poulseni Resser 230 feet above base of formation (Spence D. propinqua Resser Shale Member). The fossils occur chiefly in D. Stella Resser the basal 60 feet of the member (Resser, 1939a, Ehmaniella maladensis Resser p. 3-24). Inglefieldia idahoensis Resser 6. Algae Kochaspis dispar Resser Morania, sp. undet. K. maladensis Resser Echinoderma Kochiella arenosa Resser Eocrinus longidaclylus (Walcott) K. mansfieldi Resser Worms Kochina (?) elongata Resser Selkerkia spencei Resser K. (?) liberty

Acrotreta definila Walcott Spencia plena Resser A . levala Resser 5. typicalis Resser Iphidella grata Resser Taxioura, sp. undet. (Ogygopsis) Lingulella eucliaris Resser Ulio, curio Walcott Micromitra lepida Resser Vistoia (?) minuta Resser Wimanella nautes (Walcott) Zacanthoii.es abbreviates Resser W. rara (Walcott) Zacanthoides adjunct™ Resser W. spencei (Walcott) Z. gradatus Resser Gastropoda Z. holopygus Resser Hyolithes cecrops Walcott Z. idahoensis Walcott H. ornaiellus Resser Z. serratus Resser "Orthotlieca" sola Resser Agnostia Several unidentified species and genera Agnoslus bonnerensis Resser of trilobites; many embryonic forms A. brighamensis Resser Bear River Range and Wellsville Mountain; Trilobita 85 feet below top of formation in the Left Albertella, sp. undet. Fork of Blacksmith Fork Canyon Alokistocare brighamense Resser 7. Glossopleura, sp. undet. A. idahoense Resser Glyphaspis (?), sp. undet. A . laticaudum Resser Same: approximately 220 feet below top of A. punctatum Resser formation in Blacksmith Fork Canyon A . septum Resser 8. Glyphaspis (?), sp. undet. (Deiss, 1938, A. spencense Resser p. 1115) A lokistocarella spencei Resser Same: approximately 310 feet below top of Bathyuriscus atossa Walcott formation in Blacksmith Fork Canyon B. brighamensis Resser 9. Glossopleura, sp. undet. Bythicheilus alveatum Resser Clavaspidella (?), sp. undet. B. typicum Resser Chancia augusta Resser UTE FORMATION C. ebdome Resser C. evax Resser Promontory Range; at base of the formation Clappaspis coriacea Resser 10. Glossopleura cf. producta (Hall and Whit- C. dotis Resser field) C. idahoensis Resser Elrathina (?), sp. C. lanata Resser Bear River Range and Wellsville Mountain; C. spencei Resser basal 4 to 15 feet of the formation (Deiss, Clavaspidella anax (Walcott) 1938, p. 1114) C. bithus (Walcott) 11. Alokistocare, sp. Elrathia spencei Resser Elrathina (?), sp. Ehmaniella quadrans (Hall and Whit- Glossopleura producta (Hall and Whitfield) field) Glossopleura, n. sp. Glossopleura bion (Walcott) Kochina, n. sp. G. gigantea Resser Kootenia, sp. G. similaris Resser Zacanthoides, sp. G. utahensis Resser Micromitra, sp. Kootenia idahoensis Resser Acrotrela, sp. K. mathewsi Resser Acrothele, sp. K. spencei Resser Iphidella, sp. Olenoides brighamensis Resser Hyolithes, sp. O. evansi Resser Same: 105 to 109 feet above the base of the O. wasatchensis (Hall and Whitfield) formation Oryctocare geikei Walcott 12. Anomalocephalus , n. sp. Oryctocephalus walcotli Resser Ehmaniella, n. sp. Pagetia clytia Walcott Same: 275 to 375 feet above the base of the Poliella anteros (Walcott) formation P. ceranus (Walcott) 13. Olenoides, sp. Stauroholcus typicalis Resser Ehmaniella (?), sp. Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 676 G. B. MAXEY—LOWER AND MIDDLE CAMBRIAN STRATIGRAPHY

Alokistocare subcoronalum (Hall and Whit- Olenellus Zone field) Kootenia quadriceps (Hall and Whitfield) The oldest diagnostic fossils recognized in Utah and southern Idaho are members of the trilobite genus, Olenellus, chiefly Olenellus BLACKSMITH DOLOMITE gilberti (Meek), and the brachiopod species Obolus (Westonia) ella (Hall and Whitfield). Bear River Range and Wellsville Mountain; These forms are sparse in the Pioche Shale of near the base of the formation the Wasatch Range. Olenellus fossils are un- 14. See Howell et al. (1944, Chart) known in any other sections in the area and in Same: near top of formation (Denson, 1942) most areas are confined to the lower beds of the 15. Anomocare Pioche, but Obolus occurs higher in the section Patella in most parts of the area. Genera of the Olenellidae occur in many BLOOMINGTON FORMATION Lower Cambrian rocks in North America and northwest Europe. Howell et al. (1944, chart) Bear River Range and Wellsville Mountain; indicate that the Olenellus zone is underlain by 160 to 335 feet above the base of the formation three zones in Europe and northeastern North (Hodges Shale Member) America and by two zones in the Appalachian 16. Bolaspidella region of the United States. Further, a section Blainia cf. gregaria Walcott of Lower Cambrian rocks in the Inyo Range of Blainia gregaria Walcott California and Nevada, not shown on the chart, Olenoides contains fossils of Early Cambrian age which Solenopleura probably antedate the forms in the Pioche Helcionella, sp. Shale. The Olenellus zone in western Utah Undescribed genera of trilobites and (House Range) is immediately subjacent to brachiopods and conformable with strata containing ele- Same: 10 feet above top of Hodges Shale Member ments of the Antagmus-Onchocephalus zone 16a. Olenoides, sp. (Syspacephalus zone of Howell's chart) which Undescribed genera of brachiopods and has not been recognized in northeastern Utah trilobites and Idaho and is of latest Early Cambrian age. Same: 90 to 110 feet below the top of the forma- Lochman (1953, p. 487-488) states that on tion near top of Calls Fort Member the basis of present knowledge "... the entire 17. Asaphiscus Lower Cambrian should be correctly labeled Pachyrhachis oweni Walcott the Olenellus zone ..." She also describes two Parehmania subdivisions of the zone: (1) a lower subzone Bolaspis (?) characterized not only by Olenellidae but by Howellaspis (?) primitive nontrilobitic forms including the Acrocephalops (?) cf. A. gracilis Resser brachiopod, Obolella, and (2) an upper subzone Elralhia characterized by Olenellidae associated with Homagnostus cf. pisiformis pater (Holm Eodiscidae, general of the Corynexochidae, and and Westergaard) primitive opisthoparian genera. Presumably Undescribed genera of trilobites and this upper subzone would correspond with the brachiopods Syspacephalus zone of Howell et al. (1944, chart) and with the Antagmus-Onchocephalus zone. The Bonnia-Olenellus zone of Rasetti ZONATION OF THE FAUNULES (1951, p. 81-83, 109) apparently is essentially synonymous with the Olenellus zone of Loch- General Statement man. Five faunal zones are recognized in the Lower In northern Utah and southeastern Idaho and Middle Cambrian strata of Utah and the Olenellus zone as defined above is recogniz- southeastern Idaho, of which one, the Olenellus, able and of stratigraphic value, although it is of Early Cambrian age. The zones are appears that we are dealing with fossils that discussed in detail and compared with zones of appear in the upper part of the zone in other comparable age recognized in other areas.

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Glossopleura-Zacanthoides Zone that interval. Further, Anoria has been reported from only the interval in question. Therefore, it Faunas in those beds of the Langston and is suggested that this sequence of beds be Pioche Formations which directly overlie the tentatively referred to as the Anoria subzone beds containing Early Cambrian fossils char- of the Glossopleura-Zacanthoides zone in Utah acteristically contain the trilobite genera and Idaho. Glossopleura and Zacanthoides. One, and usually The beds in the upper part of the Glosso- both, genera occur commonly in the strata of pleura-Zacanthoides zone, between the upper- the Langston and basal Ute Formations of most Langston or basal Ute Formations and central and northern Utah and southeastern the base of the Blacksmith Dolomite, commonly Idaho. Numerous distinctive forms belonging contain the trilobite genera Glossopleura, to both trilobite and inarticulate brachiopod Zacanthoides, Solenopleura, Kootenia, Kochina, genera occur with them in some areas (see Elrathina, Ehmaniella, Dolichometopsis, Clap- fauna numbers in the preceding section and in paspis, Anomalocephalus, and Alokistocare. Figure 3). Neither form has been observed in Howell et al. (1944, p. 995) listed the trilobite strata overlying the topmost rocks of the Ute genus Solenopleurella as a fossil common to the Formation. On the basis of the distinctly "Glossopleura-Kootenia zone." Since this is the limited range of these two genera, it is here only form that does not commonly occur else- proposed that the beds in which they occur be where in the Glossopleura-Zacanthoides zone in designated the Glossopleura-Zacanthoides zone. Utah and Idaho it may be tentatively referred Trilobite genera most common near the base to as the Glossopleura-Solenopleurella subzone. of this zone include Dolichometopsis, Ptarmi- This zonation agrees with the zones proposed gania, Chancia, Clavaspidetta, Oryctocephalus, by other authors. Lochman (1952, p. 79-81) Kootenia, Kochina, Kochaspis, Taxiowra, Oryc- has recognized two zones, the Albertella and the tocare, Alokistocare, Ehmaniella, Clappaspis, and Glossopleura-Kootenia which closely compare in Albertella. Of these, Albertella is one of the more range, faunule succession, and faunal content uncommon trilobite genera. Only a few speci- to the interval here proposed as the Glosso- mens of this genus are known from Utah and pleura-Zacanthoides zone. Presumably an inter- Idaho. However, Albertella occurs at or near val containing elements of the Anoria subzone the base of the Middle Cambrian in many is not present in Sonora, or these elements are localities in the Western Cordillera. Because of blended with one or the other or both of Lcoh- this widespread occurrence, members of the man's zones and are not recognizable there, genus are Middle Cambrian guide fossils. Simi- perhaps as a result of facies differences in the larly, some species of Kochaspis are guide corresponding parts of the stratigraphic section. fossils in the lowest Middle Cambrian beds in Rasetti (1951, p. 93-99, 109) also recognizes Utah, Nevada, Idaho, and Canada. In Utah and two zones, the Albertella and the Glossopleura Idaho, species of Kochaspis occur in the same which again closely correspond with the basal Middle Cambrian beds with Albertella Glossopleura-Zacanthoides zone, and differ in (the Naomi Peak and Spence shale members). perhaps the same manner and for the same It is here proposed that the basal beds of the reasons given above. Rasetti, however, recog- Glossopleura-Zacanthoides zone be placed in the nizes two zones beneath his A Ibertella zone and Albertella-Kochaspis subzone. above the Olenellus zone (his Bonnia-Olenellus The beds between the Albertella-Kochaspis zone), the Wenkchemnia-Stephenaspis zone and subzone and the uppermost Langston strata in the Plaguira-Kochaspis zone. Lochman (1953, northern Utah and southern Idaho are only p. 486-487), who did not recognize these zones sparsely fossiliferous. Members of the trilobite in Sonora (Lochman, 1952, p. 80), suggests genera Glossopleura, Zacanthoides, Kootenia, that they may merge in other areas. Rasetti Kochina, and Glyphaspis have been observed (1951, p. 80) also suggests this possibility. occasionally. These forms are common in beds Lochman further states that faunas which in a similar stratigraphic position in other areas, should be assigned to a merged zone may have where they are usually referred to as the been collected several places in the western "Zacanthoides-Anoria zone" (Howell et al., 1944, United States and Sonora but that adequate Chart). Zacanthoides occurs in Utah throughout evidence is not yet available to assign them to a considerably thicker interval and may be this z,)ne. Many forms found in the Naomi most practicably utilized as a guide fossil for Peak Limestone associated with Kochaspis and

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Albertella are similar to those listed by Rasetti Thompsonaspis Zone from his zones. Thus, more extensive collection and study of the fossils may result in recogni- In the Bear River Range Denson (1942, p. tion of these zones or of a merging of the two 26) and the writer collected trilobites from the zones in Utah and Idaho. uppermost beds of the Blacksmith Dolomite which are the same forms as those Denson Bathyuriscus-Elrathina Zone refers to a Thompsonaspis faunule that occurs in Wyoming. Deiss (1938, p. 1018-1019) recog- Trilobite genera related to Ehmania and nizes in sections in the Cordilleran and Cana- Ekmaniella have been reported by Howell et al. dian Rocky regions a faunule composed of (1944 chart) from the base of the Blacksmith essentially the same forms which he calls the formation in northern Utah. They are included Olenoides-Thompsonaspis fauna. In all these in the Bolaspis-Glyphaspis zone of Howell. A areas this faunule is found in rocks which over- fauna consisting of genera of "Agnostus", El- lie strata of the Bathyuriscus-Elrathina zone rathia, and Bolaspidella was found by Denson and underlie rocks containing elements of the in the lower part of the upper beds of the distinctive Asaphiscus-Bolaspidella zone. This Blacksmith Dolomite and was assigned by interval containing Thompsonaspis and asso- Howell to the Elrathiella-Triplagnostus-Clap- ciated forms is here referred to as the Thomp- paspis zone (Howell et d., 1944, chart). The sonaspis zone. writer found only fragmental fossils not subject to accurate identification in the upper beds of Asaphiscus-Bolaspidella Zone the Ute Limestone and in all but the uppermost interval of the Blacksmith Dolomite. The beds constituting the Bloomington Although Deiss (1938, p. 1105-1124, 1161- Formation in northern Utah and southern 1163) did not find fossils in this interval of the Idaho contain genera of trilobites including Blacksmith Fork section he found faunules Asaphiscus, Bolaspidella (Deissella of some comparable to those mentioned above in Mon- authors), Blainia, Olenoides, Solenopleura, tana and in the House Range and later (1939, Parehmania, Bolaspis (?), Acrocephalops, El- p. 1016-1022; 1940, p. 731-794) in the Canadian rathia, Homagnostus, and several undescribed Rockies. He included these forms in his Eh- genera (see fauna numbers 16, 16a, and 17 in mania, "Agnostus"-Bathyuriscus, Bathyuriscus- the preceding section). Similar faunas occur in Elrathia, and Bathyuriscus-Elrathina faunas. the lower and middle parts of the Marjum These faunas succeeded his Glossopleura fauna Formation in the House Range of Utah and in and preceded his Thompsonaspis or Olenoides upper Middle Cambrian formations in Mon- (Neolenus) fauna. The interval in which he tana. Asaphiscus and closely allied forms and found these fossils corresponds stratigraphically Bolaspidella (Deissella of Denson and others) and in sequence of faunules to the interval be- are common elements in all these faunas and tween the Glossopleura-Zacanthoides zone and seem to be restricted to this interval of the the Thompsonaspis zone of this paper. Cambrian system. Therefore it is proposed that Rasetti (1951, p. 99-109) has studied this these beds be designated the Asaphiscus- stratigraphic interval in the Canadian Rockies Bolaspidella zone. and has proposed that it be called the Bathy- Denson (1942, p. 26) divided this zone into uriscus-Elrathina zone. two "faunules," basing his evidence for this On the basis of present knowledge it appears subdivision on genera for which descriptions proper to apply Rasetti's zone name in north- have not yet been published. Preliminary work eastern Utah for the interval between the in this and other areas indicate that such a Glossopleura-Zacanthoides and Thompsonaspis division will probably prove satisfactory. zones even though Rasetti does not find The Asaphiscus-Bolaspidella zone is the Ehmania or Bolaspis-Glyphaspis zone forms in uppermost zone of the Middle Cambrian and the Canadian Rocky sections. Thus, the is conformably overlain by beds (Nounan Bathyuriscus-Elrathina zone as used in this Formation) containing the Lower Cedaria zone paper includes the Bolaspis-Glyphaspis zone of of Late Cambrian age. Howell et al. and of Lochman; the Elrathiella- Triplagnostus-Clappaspis zone of Howell et al., Discussion the Elrathiella-Clappaspis zone of Lochman; it is essentially equivalent to the Bathyuriscus- The names of some of the faunal zones de- Elrathina zone of Rasetti. scribed here do not conform with those sug- Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 ZONATION OF THE FAUNULES 679

gested by the Cambrian subcommittee (Howell common and varied in the upper part of the el al., 1944, chart) nor with those described by Asaphiscus-Bolaspidella zone, especially in the Lochman (1952, p. 73-78) for northwestern Marjum Formation of the House Range and in Sonora in Mexico. The writer firmly believes the Bloomington Formation of northern Utah that, wherever possible, a faunal zone should and southern Idaho rather than before Thomp- be named for a diagnostic fossil or assemblage sonaspis. In Utah and Idaho, beds containing of fossils and, further, that, where practicable, Thompsonaspis underlie beds containing the it should include all beds in which that diag- late Medial Cambrian forms of Olenoides, nostic fossil or fossil assemblage occurs. Such a Ortia, and Bolaspidella, and Bolaspidella occurs procedure will undoubtedly render faunal zones throughout the interval in which Orria, Asa- far more usable. For example, the Cambrian phiscus and allied forms, and Olenoides are subcommittee lists four faunal zones (the found. Kochaspis liliana, Albertella, Zacanthoides- The sequence of zones for the Lower and Anoria, and Glossopleura-Kootenia zones), and Middle Cambrian given by the Cambrian sub- Lochman lists two (the Albertella and Glosso- committee (Howell et al., 1944), Lochman pleura-Kootenia zones) in which the two trilo- (1952, p. 80; 1953, p. 486-488), Rasetti (1951, bite genera Glossopleura and Zacanthoides p. 109), and the sequence proposed in this commonly occur. To the writer's knowledge the paper for Utah and Idaho are as shown on two genera do not occur in any other zones in p. 680. Utah and southern Idaho. Two of the zones of the subcommittee, the Kochaspis liliana zone EARLY AND MEDIAL CAMBRIAN SEDIMENTATION and the Albertella zone, appear to be a single AND PALEOGEOGRAPHY unit, as was suggested by Williams and Maxey (1941, p. 284) and as was later recognized by Description of the Lithofacies Lochman (Wheeler, 1948, p. 46). One other zone, the Glossopleura-Kootenia zone, is named Several lithofacies of Early and Medial for one genus that commonly occurs well below Cambrian age are common throughout Utah the designated lower boundary of the zone and and southeastern Idaho. Many of these litho- for another genus that occurs both above and facies are distinctive and are easily identified below the designated boundaries of the zone. by common macroscopic methods. The distin- The writer, therefore, has described and pro- guishing characteristics are valuable clues to posed the Glossopleura-Zacanthoides zone, which their origin. The fades include: (1) the ortho- includes all the beds in which the two genera quartzite facies, composed chiefly of medium to for which it is named are known to occur. Fur- coarse quartz particles with some interbedded ther, he has suggested subdivisions of the zone, lenses of quartz pebbles; (2) greenish-brown, or subzones, named after guide fossils within micaceous, and finely arenaceous shale, nor- the zone. mally interbedded with layers of the ortho- Fossil evidence does not indicate the same quartzite; (3) brown-weathering calcareous sequence of forms for Utah that is suggested by sandstone; (4) rusty-brown-weathering dolo- the zones proposed by the Cambrian subcom- mite; (5) green and buff fissile shale; (6) highly mittee (Howell et al., 1944, chart), especially calcareous, dark-gray to black shale and dark- the zones of late Medial Cambrian age. The gray, shaly, platy, aphanitic limestone; (7) available published material indicates that mottled, silty, aphanitic and thin-bedded lime- Thompsonaspsis and associated forms occur stone; (8) the Girvanella limestone; (9) intra- before Marjumia and with forms closely re- formational conglomerate; and (10) oolitic lated to early-appearing members of the writer's limestone. Certain other lithofacies are com- Asaphiscus-Bolaspidella zone. For example, posed of nondescript types, all carbonate, which Howell's chart (1944) shows Marjumia appear- are here placed in one of two groups—the ing before Thompsonaspsis. Actually Marjumia "undifferentiated limestones" and "undiffer- has been found only in the top of the Asaphis- entiated dolomites." cus-Bolaspidella zone and in overlying Upper Recognition of the lithofacies is based chiefly Cambrian strata. Also Bolaspidella (Deissella) upon their macroscopic features. Undoubtedly appears in the lower part of the Asaphiscus- sedimentological or statistical studies would Bolaspidella zone and has not been found with reveal evidence which might provide a basis Marjumia and related elements. Although for revision in both the recognition and the Olenoides occurs throughout the Middle Cam- interpretation of the lithofacies; however, the brian section, members of the genus are most writer believes that the presently recognized Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 680 G. B. MAXEY—LOWER AND MIDDLE CAMBRIAN STRATIGRAPHY

Cambrian Correlation Chart Lochman Rasetti This paper (Howell et al., 1944) (19S2; 1953) (1951)

Late Cambrian Lower Cedaria zone Medial Cambrian Deisella-Centropleura vermontensis zone Palella-T horn psonas pis } Asaphiscus-Bolaspidella zone zone Olenoides-Orria-Marjumia Thompsonaspis zone Elralhiella- Triplagnostus Elralhiella Clappaspis j Clappaspis zone zone \ Batltyuriscits Elrathina Bathyuriscus-Elraihina Bolaspis-Glyphaspis zone Bolaspis-Glyphaspis J zone zone zone I Glossopleura-Koolenia zone Glossopleura Kootenia Glossopleura zone zone Glossopleura-Zacan- Zacanthoides-A noria thoides zone zone Albertella zone Albertella zone Albertella zone Kochaspis liliana Plagiura-Kochaspis zone W enkchemnia- Stephenaspis zone Medial Cambrian

Early Cambrian Syspacephalus zone Olenellus zone Bonnia Olenellus zone Olenellus zone Olenellus zone Bonnia zone Obelella zone

facies and the interpretations based upon them Mountain Quartzite and a considerable part of add considerably to the understanding of Early the Pioche Formation. It consists of quartz and Medial Cambrian sedimentation and paleo- particles most of which are subangular and geography. In many instances the facies cor- firmly cemented with silica or, only occasion- respond closely to those recognized by McKee ally, with iron oxide. When iron-oxide cement (1945, p. 1-168) in the Grand Canyon region predominates the rock is somewhat friable. where the excellently exposed, continuous out- Labile mineral particles, mostly feldspar, occur crops of the Cambrian formations allow oppor- locally. The pink, red, purple, and green of the tunity for far more detailed study than do the various strata are probably due to dissemina- widely separated outcrops in the Great Basin tion of iron oxide. Most of the strata are region. Much of McKee's evidence and inter medium- to thick-bedded (4-12 inches thick), pretation is here recognized as the best available but many are massive (more than 12 inches explanation for many lithologic and strati- thick). Some syngenetic structures, such as graphic phenomena observed during the present common and characteristic cross-lamination study. and current ripple marks, are of inorganic ORTHOQUARTZITE : The dominant facies of the origin. Probable organic structures which Lower Cambrian strata in the area is medium- commonly occur, especially as casts on bedding to coarse-grained "clean" orthoquartzite (rarely planes, are burrows, tracks, and trails which containing lenses of quartz conglomerate) which may indicate the passage of trilobites, phoro- constitutes the principal part of the Prospect nids, and worms. Most of these markings have

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been described under the generic terms of composed of greenish-brown and gray-green, Cruziana (trail-like markings) and Skolithos micaceous, finely arenaceous, hard shale much (worm or phoronid burrows) and are the only of which is flaggy but seldom fissile. Some beds fossils reported from this facies. contain a little calcareous cement. In many The conglomeratic phases of the facies appear places the bedding planes are covered with ordinarily at the base of the Porspect Moun- worm-burrow castings, trails, and fucoidal tain Formation. Lenses of the conglomerate at structures. In Utah a few inarticulate brachio- this horizon in the few outcrops where the pod shells and the remains of one poorly pre- formational base is exposed are commonly served trilobite are the only fossils reported. composed of unusually coarse, in places very Inorganic syngenetic structures include ripple angular particles as large as boulders. The marks, occasional cross-lamination, and crater- writer has noted such outcrops in the central like pits on the bedding planes. In most locali- part of the Wasatch Range, and Eardley (1933, ties the shale is interbedded with strata of the p. 315-316) has reported them in the southern orthoquartzite facies in the transitional beds part of the Wasatch. Conglomeratic lenses are near the top of the Prospect Mountain Quartz- not confined to the basal part of the formation ite and throughout the Pioche Formation. It but also occur occasionally throughout its rarely occurs higher in the section in those thickness and in the orthoquartzite facies of the areas where it is interbedded with limestones of Pioche Formation. Most of the particles in the Langston, Ute, and Bloomington Forma- these upper lenses are small, well-rounded tions. It apparently is one of several lithologic quartz pebbles in a medium- to coarse-grained types deposited seaward from the orthoquartz- sand matrix. ite facies and nearer shore than the carbonate Inasmuch as the orthoquartzite facies com- facies. It may well have been deposited near poses most of the Prospect Mountain Quartzite, shore in place of the orthoquartzite facies when it is widespread in the Great Basin and locally coarse clastic material was lacking. is several thousand feet thick. In many sections BROWN-WEATHERING CALCAREOUS SANDSTONE it is interbedded with green, micaceous, and AND SANDY LIMESTONE : This facies is character- silty shale in the Pioche Formation and in the istic of the basal part of the Langston Forma- upper transitional beds of the Prospect Moun- tion in the Wasatch and Bear River ranges. It tain Quartzite. Therefore, the environment appears higher in the Langston and Ute For- which it represents apparently returned for mations where very thin beds and lenses of it several brief periods after the main deposition are intercalated between relatively great thick- of the orthoquartzite. The orthoquartzite was nesses of the limestone facies. In most places it not observed in formations overlying the is composed of angular and subangular, fine Pioche Formation. quartz grains embedded in calcareous or dolo- At the base of the Cambrian section in the mitic cement. In some places it is quartzitic Grand Canyon area McKee reports a con- and hard but it is usually friable. Calcareous or glomerate and a coarse sand facies that resemble dolomitic cement is predominant and forms a this orthoquartzite facies. However, the Grand finely to medium-crystalline, steel-gray to dull Canyon facies is less quartzitic, occurs in thin- neutral-gray matrix which may be flecked with ner layers, and contains much less silica and small irregular limonitic stains. The strata of much more iron-oxide cement. After a detailed this facies are usually irregularly bedded and study McKee (1945, p. 38, 47-51) concluded channeled; the channels are filled with frag- that the Grand Canyon conglomerate facies ments of trilobite cranidia and pygidia and was deposited in a near-shore marine environ- inarticulate brachiopods. Although it is gray ment and that the coarse sand facies was on fresh fracture, it weathers to rusty-brown or probably deposited in waters less than a mile orange-brown outcrops and is valuable as a to 15 or 20 miles from shore ranging in depth marker. The brown-weathered surfaces result from 20 to 60 feet. The writer believes these from concentration of silt and iron stain when interpretations more or less accurately describe the calcareous material is leached. In most the environment of deposition of the ortho- places the calcareous sandstone and sandy quartzite facies in the Great Basin area. limestone overlies and interfingers with the GREENISH-BROWN, MICACEOUS AND FINELY upper part of the greenish-brown, micaceous ARENACEOUS SHALE: Most of the Lower Cam- shale facies and underlies and interfingers with brian strata in Utah and southeastern Idaho the lower part of one of the carbonate facies. except the orthoquartzite facies are normally These relationships suggest that it was probably

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deposited seaward from the shale and landward and (p. 62): from the carbonates. However, the writer deems interpretations of environment based on exist- "The following events and factors are believed by the writer to have led up to the development ing evidence afforded by the facies rather un- of the rusty-brown dolomite facies in the Cam- satisfactory. It was probably deposited in an brian deposits of Grand Canyon: environment similar to that in which the rusty- Periodic rapid sinking of the basin caused the brown dolomite was formed. In many places sea to advance eastward relatively rapidly, from time to time, for distances of 25 to 100 miles, and this latter facies replaces the calcareous sand- as a result of each transgression, the zone of clastic stone in the stratigraphic sequence in the south deposition likewise shifted far eastward. Mean- part of the Bear River Mountains in north- while, conditions favorable to calcium carbonate eastern Utah. The rusty-brown dolomite seems accumulation apparently did not move shoreward a corresponding amount, so a specialized facies to occur only eastward from the sandstone in developed, intermediate in position between the this area. McKee (1945, p. 59-62) studied areas of clastic and pure-lime deposition. This rusty-brown dolomites in the Grand Canyon facies was controlled by waters of fairly high con- region and concluded they were the depositional centration, as indicated by dolomitic sediments and as suggested by the near-shore position. Fur- product of a transgressng sea in a specialized thermore, it was an area of less deposition than environment. to seaward, as is shown both by the abundance RUSTY-BROWN DOLOMITE: A steel-gray to of glauconite and by the accumulation of a far dull-gray, silty and sandy, finely to coarsely smaller amount of nonclastic sediment there than in the corresponding or synchronous limestone crystalline, medium- to thick-bedded dolomite facies to the west." is common in the Langston Fromation in the northern part of the Wasatch Range and in The writer believes this interpretation is prob- the Bear River Range. It also occurs sparingly ably accurate in regard to the rusty-brown in the Cambrian rocks in other parts of Utah dolomite facies of Utah and that the brown- and Idaho. It forms lenses and tongues which weathering calcareous sandstone and sandy interfmger with the brown-weathering calcare- limestone facies was perhaps deposited seaward ous sandstone and sandy limestone. Both facies from the dolomite in an otherwise similar en- weather to buff-tan, rusty-brown, or red-brown, vironment. limonite-stained, silty surfaces and are com- GREEN AND BUFF FISSILE SHALE: Green and monly indistinguishable in the field unless buff argillaceous and in places micaceous, fresh surfaces are carefully examined and fissile shale beds ranging from a few inches to treated with dilute acid. The rusty-brown dolo- several tens of feet thick are commonly inter- mite of the Langston Formation occurs in thin, bedded with the various limestone facies of the irregularly bedded lenses and tongues in the Ute and Bloomington Formations and with the Spence Shale and Naomi Peak Limestone on greenish-brown arenaceous shale facies of the Wellsville Mountain, Willard Peak, and Prom- Pioche Shale. Generally, this facies occurs in ontory Point. Because these intervals thicken very thin layers intercalated between relatively eastward the dolomite constitutes most of the thick coarser clastic and limestone beds. The lower part of the Langston in Blacksmith Fork green fissile shale contains calcareous nodules where it is thickly interbedded with units of and small (about 1-10 feet long and a few inches crystalline and algal limestone and other dolo- thick), thin, crystalline, commonly fossiliferous mitic facies. limestone lenses. Trilobite and inarticulate McKee (1945, p. 59-62), who described a bracbiopod fossils are abundant in the shale similar rock type from the Grand Canyon beds, and the bedding planes are marked by region, concluded that (p. 60): many fucoidal structures, worm burrows, and "The distribution of the various tongues of trails. rusty-brown dolomite in the Grand Canyon shows In most instances, these shale beds seem to be that they are developed, without exception, regressive clastic tongues deposited as a result among the deposits formed at times of a trans- of minor oscillations of the sea. In other out- gressing sea and not among those of regression. Furthermore, they are all located on the eastern crops they appear to be the product of mud margins of limestone facies and between these deposition between the coarser elastics which and areas of clastic sediments. They are asso- were deposited landward and the carbonate ciated almost everywhere with iron oxides and in deposition far from shore. most places with glauconite. Algal or Girvanella limestones, wherever present, form a facies be- BLACK TO DARK-GRAY, HIGHLY CALCAREOUS tween the dolomites and aphanitic, mottled lime- SHALE OR SHALY LIMESTONE: This facies makes stones to the west." up much of the Spence Shale Member of the

Langston Formation. It also occurs sparingly as ledges with yellow-brown or reddish-brown thin intercalations in the Naomi Peak Lime- mottling or irregular, wavy, thin ridges on the stone Member of the Langston Formation. As weathered surfaces. Thin layers and partings its name implies, the facies consists chiefly of of greenish-gray shale and tan silt are generally highly calcareous, thin-bedded to fissile shale intercalated with the thin beds of limestone. or very shaly thin-bedded, aphanitic limestone. Flakes and nodules of the silt and clay are It contains many well-preserved trilobite fos- irregularly distributed throughout the lime- sils, much pyrite and limonite (usually in stone matrix and are seldom distinguishable pseudomorphs after pyrite), and generally except on weathered surfaces. The mottled weathers to low, light- to medium-gray ledges thin-bedded limestone facies is commonly in- and plate-strewn slopes. Commonly the ledges terbedded with oolitic limestone and algal beds. weather to light-brown or tan surfaces. Inter- The intervals of the mottled facies are normally vals ranging from a few inches to 100 feet of much thicker than the other facies. Although the calcareous shale are interbedded with inter- numerous poorly preserved fossils, especially vals of the shaly limestone of approximately trilobites, are found on weathered surfaces, the same thickness. Thin intercalations and well-preserved fossils are rare in the un- beds of buff or greenish shales are commonly weathered rock. Better preserved and more interbedded with this facies. easily recoverable fossils are generally found in These black shales and black shaly limestones the thin intercalations and layers of shale be- do not correspond lithologically with most tween the limestone beds. Structures resembling black shales because they contain relatively the casts of worm burrows and trails are com- large amounts of calcium carbonate, numerous mon in these beds. benthonic fossil remains, and are not inter- As McKee (1945, p. 71-77) has suggested, bedded or associated with coarser elastics these silty limestone beds seem to be indurated (Twenhofel, 1950, p. 333-337; Pettijohn, 1949, calcareous ooze mixed with fine clastic material p. 289). It appears that occurrences of this which was deposited too far from shore to be lithologic type are relatively rare. Perhaps the diluted with large amounts of coarser clastic black, calcareous, pyritic shales and limestones material. He indicates that the dolomitic of the Upper Cretaceous rocks of the Black mottled rock may have originally been lime- Hills region resemble this facies more than stone which was replaced by dolomite before other described black shales. Rubey (1930, p. and during lithification. 13) concluded that Girvanella LIMESTONE: McKee (1945, p. 62- 64) described a limestone characterized by ". . . the conditions most favorable for the formation and preservation of calcium carbonate, spherical and ovoid nodules scattered through- organic material, and pyrite together would be out a finely crystalline matrix. The nodules relatively shallow water and a rapid rate of accu- have concentric structure and are considered mulation and burial of organic matter. Under algal deposits referable to the form genus, these conditions much organic matter and carbonate would be preserved by burial, and iron sulfide Girvanella. Numerous students of the western would form abundantly in the putrefying ooze— Cambrian formations have commented upon that is, chiefly below its upper surface." these algal limestones. They form a rather He cites evidence from the studies of Recent common facies in the formations of Utah and sediments by Murray and Irvine (1891; 1895) southeastern Idaho and occur in the section that such depositional conditions are common above the coarse clastic facies interbedded with in modern seas. The writer tentatively accepts the fissile green shale and with strata of the this interpretation as an explanation of the other limestone facies. Normally the intervals origin of the Middle Cambrian black, calcareous of Girvanella limestone are relatively thin, but shale and shaly limestone facies. Further de- some of them are more than 100 feet thick. tailed sedimentological and stratigraphic study They seem to represent an environment de- of the facies is needed. veloped somewhat far from shore, one that MOTTLED AND BANDED, APHANITIC, THIN- probably was seaward from that in which the BEDDED LIMESTONE: Much of the limestone rusty-brown dolomite and brown-weathering assigned to the Lower and Middle Cambrian calcareous sandstone facies was deposited. The formations in Utah and southeastern Idaho Girvanella limestone is especially common in consists of dark-gray, silty, aphanitic, thin- the Langston and Ute Formations, but is bedded limestone and dolomitic limestone scarce in the Blacksmith and Bloomington which weathers to low, light- to medium-gray Formations.

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INTRAFORMATIONAL CONGLOMERATE: This fa- crystalline limestones characterize much of the cies is composed of thin, flat pebbles oriented Middle Cambrian section. Wide variance in in one or more directions, composed of locally color, bedding habit, texture, and weathered derived limestone embedded in a limy matrix. surfaces was noted but few distinctive features It has been referred to as "edgewise conglomer- were observed. However, more detailed investi- ate" (Nason, 1901, p. 360; Grabau, 1924, p. gation might reveal such features. Conditions 785). Units of the conglomerate are relatively for deposition of these limestones were probably thin, and most of them are interbedded with somewhat similar to those described for some other types of limestone or with dolomite. It of the other limestone facies except that, in occurs chiefly in beds a few inches to a few feet general, these undifferentiated limestones were thick in the Langston and Bloomington For- probably formed in deeper waters and farther mations, but is rare in the other limestone from shore than the other facies. formations. UNDIFFERENTIATED DOLOMITES: As in the McKee (1945, p. 65-70) suggests various case of the undifferentiated limestones men- modes of origin for these conglomerates. He tioned above, considerable thicknesses of dolo- shows that the intraformational conglomerates mites are also present in the Middle Cambrian of different beds in the Grand Canyon area have section. Sufficient time for further study of generally similar features, are commonly found these dolomites was not available and the in deposits formed at times of regression, and problem of the origin of the dolomites is beyond are located exclusively along shoreward margins the scope of this paper. Although a detailed of other limestone facies. This means that they study was not made, several kinds of dolomite were deposited, for the most part, more than were observed. Three types are similar to 100 miles seaward from the shore line and were dolomites described by McKee (1945, p. 77- probably deposited when the rate of sinking of 79): (1) a very light-colored (usually white or the depositional basin slowed down so that light-gray), crystalline, thick-bedded dolomite; parts of it were above the profile of equilibrium (2) a light-gray to steel-gray, finely crystalline, and caused regression of the sea (McKee, 1945, laminated dolomite which weathers to cream- p. 68-69). colored surfaces; and (3) a medium- to light- Since all observable data on the origin of the gray, usually thinly bedded, platy-weathering conglomerates in Utah seem to bear out dolomite which often forms light- and dark-gray McKee's interpretation, it is tentatively ac- streaked and mottled outcrops. cepted as valid in this area. McKee (1945, p. 77-79) suggested a mode of OOLITIC LIMESTONE: Dark-gray to black, origin for the "undifferentiated dolomites" in fine- to medium-crystalline, medium- to the Grand Canyon region. His conclusions are thick-bedded limestone containing oolites }£- that the dolomites 1 mm in diameter is commonly interbedded ". . . were all formed in waters of a regressive with other limestone facies in the Middle sea. The dolomite probably was developed on the Cambrian formations of Utah. Most of the sea floor either through direct pecipitation or units of oolitic limestone are thinner than the from penecontemporaneous replacement, as is units of other limestone facies with which they indicated by its uniform distribution over wide areas, and its representation as clastic grains within are interbedded. They are commonly inter- various beds. Nowhere, so far as is known, does bedded with the Ginanella limestone and the it show evidence of being the result of secondary intraformational conglomerate, and less gen- action. The suggestion is made, therefore, that erally with the silty, aphanitic limestone. these deposits are the result of shoaling waters with sea bottom near the base level of deposition, According to Eardley (1938, p. 1359-1387) which, as is pointed out by Twenhofel (1939, p. who described the formation of oolites in Great 358), favor higher concentration and dolomite de- Salt Lake, Utah, calcareous oolites normally velopment." form as the result of limestone deposition The results of the writer's study concur, in around nuclei in open shallow, strongly agi- general, with McKee's. Only in a few local tated waters. Probably the Cambrian oolitic instances was evidence observed of secondary beds were deposited in a somewhat similar en- dolomitization in the vicinity of faults and vironment for they are closely associated with other structural features. This dolomitization other beds that were also deposited in shallow seems to border fault zones and joints and is seas. similar to that described by Hewett (1931, p. UNDIFFERENTIATED CRYSTALLINE LIMESTONES: 57-60) in the Goodsprings area, Nevada. A Considerable thicknesses of finely to coarsely detailed study of the widely distributed and

apparently syngenetic or penecontemporaneous Creek Range (Nolan, 1935, p. 7-8) seems to Cambrian dolomites and their relationships interfinger with the Langston Formation in with the limestones and other facies might well the House Range (Wheeler, 1948, p. 28-29) and yield interesting and valuable data concerning in the Sheeprock Range. This suggests that the mode of origin of dolomite. some elastics, at least in late Early Cambrian time, were derived from the west. Detailed Interpretation and Paleogeograpky studies, similar to those made by McKee (1945, p. 38-51) of the Tapeats Sandstone in the The evidence presented indicates that the Grand Canyon region, are needed before further sediments of Early and Medial Cambrian age conclusions about source areas can be made. in Utah and southwestern Idaho were de- That the strand line of the eastward-trans- posited in an oscillating shallow sea which gressing sea constantly oscillated, especially in transgressed eastward from beyond the western late Early Cambrian time, is indicated by the border of Utah. The surface over which this interbedded strata of orthoquartzite and are- sea advanced was probably mature with con- naceous greenish-brown shale composing the siderable relief because the lowermost Cambrian upper transitional beds of the Prospect Moun- formation (the Prospect Mountain Quartzite) tain and the Pioche Formations. Probably these ranges considerably in thickness and has at its oscillations resulted from periodic rapid sub- base in some localities a coarse subangular sidence followed by decreased subsidence or conglomerate. These conditions suggest ad- still-stand, when the sea would temporarily jacent highlands. For example, between the regress as the basin was gradually filled to northern part (Wellsville Mountain) and the above the profile of equilibrium. central part of the Wasatch Range the ortho- By Medial Cambrian time, Utah and south- quartzite thins southward from more than 3000 eastern Idaho were inundated, and the Pre- feet to about 900 feet, and near Ogden, Salt cambrian highlands were sites of deposition. Lake City, and Provo, Utah, where the base of The strand line was far to the east, and the the orthoquartzite is exposed, the conglomer- seas were probably somewhat deeper in most ates commonly constitute the basal member of places than they had been in the Early Cam- the formation. This is the locale of the Pre- brian. Thus, in Utah this epoch was primarily cambrian Northern Utah Highland (Eardley, a period of carbonate and mud deposition in an 1939, p. 1277-1310) which probably persisted environment closely approximating the epi- as a highland during earliest Cambrian time. neritic and shallower parts of the infraneritic Very early in Cambrian time, perhaps even in zones of modern seas. Oscillations of the strand late Precambrian (Wheeler, 1948, p. 19-20, line continued throughout the epoch and are Fig. 5), the eastward-transgressing sea had attested to by the alternate interbedding and inundated the lands to the west in Nevada and interfingering of layers of regressive shallow- southern California and was advancing across western Utah. The biostratigraphic relation- water facies such as the green fissile shale, the ships of the Lower and Middle Cambrian for- oolitic limestone, and the intraformational con- mations of Utah, Idaho, and Wyoming indicate glomerates with strata of the deeper-water that the strand line reached the eastern bound- facies. No evidence of unequal subsidence and ary of Utah near the close of the Early Cam- the resulting formation of separate basins was brian epoch. observed. Highland areas, except far to the east, The descriptions of the various facies and were probably inundated. The area of the old faunas indicate that the Early Cambrian was Northern Utah Highland was re-elevated and primarily an epoch of clastic deposition through deeply eroded in post-Medial Cambrian time, Utah. The source of the clastic sediments has and all of the Upper Cambrian and most of the been suggested by Deiss (1941, p. 1090) as ". . . Middle Cambrian formations are missing. How- the isolated granitic areas to the east and ever, the formations that are exposed exhibit north." The writer did not observe conclusive no thinning, and some formations thicken from evidence that this interpretation is wholly the north across this area. Therefore, the High- valid. Much of the material must have been land was inundated throughout Medial Cam- derived from the east because the sea was brian time. No physical evidence of discon- transgressing in that direction and adjacent formity or biologic evidence of discontinuity areas in Nevada were covered by it. On the was found between the Middle and Upper Cam- other hand, the Busby Quartzite of the Deep brian rocks, and it is believed that sedimenta-

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tion continued without a break into the Late brian formations of North America: Geol. Cambrian. Soc. America Bull., v. 55, p. 993-1003, chart no. 1. Howell, E. E., 1875, The geology of portions of SELECTED REFERENCES Utah, Nevada, Arizona, and New Mexico: Geol. Geog. Explor. Surveys West of the Baker, A. A., 1947, Stratigraphy of the Wasatch One Hundredth Meridian, v. 3, p. 231-306 Mountains in the vicinity of Provo, Utah: Humphrey, F. L., 1945, Geology of the Groom U. S. Geol. Survey, Oil and Gas Inv., Prelim. district, Lincoln County, Nevada: Univ. Chart 30 Nev. Bull., v. 39, no. 5, Geol. and Min. Ser., Blackwelder, Eliot, 1909, New light on the geology no. 42, 53 p., 17 figs. of the Wasatch Mountains, Utah: Geol. Soc. King, Clarence, 1878, Systematic geology: U. S. America Bull., v. 21, p. 517-542 Geol. Explor. 40th Parallel, v. 1, p. 127-227 Burling, L. D., 1914, Early Cambrian stratigraphy Lochman, Christina, 1952, in Cooper, G. A. et in the North American Cordillera, with dis- al., Cambrian stratigraphy and paleontolog) cussion of the Albertella and related faunas: near Caborca, Northwestern Sonora, Mexico: Geol. Survey Canada Mus. Bull., no. 2, p. Smithson. Misc. Coll. v. 119, no. 1, 184 p., 93-129 13 pis. Butler, B. S., and others, 1920, The ore deposits 1953, Corrections to trilobites in "Cambrian of Utah: U. S. Geol Survey Prof. Paper 111 Stratigraphy and Paleontology near Caborca, '672 p. Northwestern Sonora, Mexico": Jour. Paleon- Calkins, F. C., and Butler, B. S., 1943, Geology tology, v. 27, p. 486-488 and ore deposits of the Cottonwood: American Ludlum, John C., 1943, Structure and stratigraphy Fork area, Utah: U. S. Geol. Survey Prof. of part of the Bannock Range, Idaho: Geol. Paper 201, 152 p. Soc. America Bull., v. 54, p. 973-986 Deiss, C. F., 1938, Cambrian formations and sec- Mansfield, G. R., 1927, Geography, geology and tions in part of the Cordilleran Trough: mineral resources of part of southeastern Geol. Soc. America Bull., v. 49, p. 1067-1168 Idaho: U. S. Geol. Survey Prof. Paper 152, 1939, Cambrian formations of southwestern p. 48-58 Alberta and southeastern British Columbia: McKee, E. D., 1945, Cambrian history of the Geol. Soc. America Bull., v. 50, p. 951-1026 Grand Canyon Region, Part I, Stratigraphy 1941, Cambrian geography and sedimentation and ecology of the Grand Canyon Cambrian: in the central Cordilleran region: Geol. Soc. Carnegie Inst. Wash. Publ. 563, 168 p., 12 America Bull., v. 52, p. 1085-1116, 10 figs. figs., 15 pis. Denson, Norman, 1942, Late Middle Cambrian Mertie, J. B., 1922, Graphic and mechanical com- trilobite faunas and stratigraphy of Alberta, putation of thickness of strata and distance Montana, Wyoming, and Utah: unpublished to a stratum: U. S. Geol. Survey Prof. Paper doctoral thesis, 76 p. Princeton University. 129, p. 39-52 Eardley, A. J., 1933, Stratigraphy of the southern Murray, John, and Renard, A. F., 1891, Deep-sea Wasatch Mountains, Utah: Mich. Acad. deposits: CHALLENGER Rept., p. 229-233 Sci. Papers, v. 18, p. 307-344 Murray, John, and Irvine, Robert, 1895, On the 1938, Sediments of Great Salt Lake, Utah: chemical changes which take place in the com- Am. Assoc. Petroleum Geologists Bull., v. position of the sea-water associated with 22, p. 1359-1387 blue muds on the floor of the ocean: Royal 1939, Structure of the Wasatch-Great Basin Soc. Edinburgh Trans., v. 37, p. 481-507 region: Geol. Soc. America Bull., v. 50, p. Nason, F. L., 1901, The geological relations and 1277-1310 the age of the St. Joseph and Potosi lime- Eardley, A. J., and Hatch, R. A., 1940, Proterozoic stones of St. Francois County, Missouri: (?) rocks in Utah: Geol. Soc. America Bull., Am. Jour. Sci., ser. 4, v. 12, p. 360 v. 51, p. 795-844 Nolan, T. B. 1929, Notes on the stratigraphy and Goldman, M. L, and Merwin, H. E., 1928, Color structure of the northwest portion of Spring chart of the Committee on Sedimentation Mountain, Nevada: Am. Jour. Sci., 5th Ser., of the National Research Council: Am. Assoc. vol. 17, no. 101, p. 461-472, 4 figs. Petroleum Geologists Bull., v. 9, p. 1018- 1935, The Gold Hill mining district, Utah: 1019 U. S. Geol. Survey Prof. Paper 177, 172 p. Grabau, A. W., 1924, Principles of stratigraphy: Peale, A. C., 1879, Report of the geology of the 2nd ed. New York, A. G. Seiler, p. 785 Green River district, Wyo.: U. S. Geol. Hague, Arnold, 1883, Abstract of report on the Geog. Survey Terr. (Hayden), Ann. Rept. geology of the Eureka district, Nevada: U. S. 11, 720 p. Geol. Survey 3rd Ann. Rept., p. 237-290 Pettijohn, F. J., 1949, Sedimentary rocks: New Hague, Arnold, and Emmons, S. F., 1877, Descrip- York, Harper and Bros., 526 p. Rasetti, Franco, 1951, Middle Cambrian stratig- tive geology: U. S. Geol. Explor. 40th Par. raphy and faunas of the Canadian Rocky (King), v. 2, 890 p. Mountains: Smithson. Misc. Coll., v. 116. Hewett, D. F., 1931, Geology and ore deposits no. 5, 277 p. of the Goodsprings quadrangle, Nevada: U. S. Resser, C. E., 1939a, The Spence shale and its Geol. Survey Prof. Paper 162, p. 57-60 fauna: Smithson. Misc. Coll., v. 97, no. 2, p. Hintze, F. F., 1913, A contribution to the geology 1-29 of the Wasatch Mountains, Utah: New 1939b, The Ptarmigania strata of the north- York Acad. Sci. Annals 23, p. 85-149 ern Wasatch Mountains: Smithson. Misc. Howell, B. F., et al., 1944, Correlation of the Cam- Coll., v. 98, p. 1-72 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/69/6/647/3431780/i0016-7606-69-6-647.pdf by guest on 02 October 2021 SELECTED REFERENCES 687

Richardson, C. B., 1913, The Paleozoic section in 1916, Cambrian trilobites: Smithson, Misc. northern Utah: Am. Jour. Sci., 4th ser., v. Coll., v. 64, no. 5, 454 p. 36, p. 406-416 Westgate, L. G., and Knopf, Adolf, 1927, Geology 1941, Geology and mineral resources of the and ore deposits of the Pioche district, Ne- Randolph quadrangle, Utah-Idaho: U. S. vada, pt. 1, General geology: U. S. Geol. Sur- Geol. Survey Bull. 923, 54 p. vey Prof. Paper 171, p. 1-44 Ridgway, R., 1912, Color standards and nomen- Wheeler, H. E., 1943, Lower and Middle Cambrian clature: Baltimore, A. Hoen and Co., 43 p., stratigraphy of the Great Basin area: Geol. 53 pis. Soc. America Bull., v. 54, p. 1781-1982, 2 Rubey, W. W., 1930, Lithologic studies of fine- pis., 5 figs. grained Upper Cretaceous sedimentary rocks 1947, Base of the Cambrian System: Jour. of the Black Hills region: U. S. Geol. Survey Geology, v. 55, p. 153-159, 1 fig. Prof. Paper 165-A, p. 1-54 1948, Late Pre-Cambrian-Cambrian strati- Twenhofel, W. H., 1939, Principles of sedimenta- graphic cross-section through southern Ne- tion: New York, McGraw-Hill Book Co., vada: Univ. Nev. Bull., Geol. and Min. Ser., Inc., p. 358 no. 47, 58 p. 1950, Principles of sedimentation: New Wheeler, H. E., and Lemmon, D. M., 1939, Cam- York, McGraw-Hill Book Co., Inc., 673 p. brian formations of the Eureka and Pioche Walcott, C. D., 1886, Second contribution to the districts, Nevada: Univ. Nev. Bull. 4, v. studies on the Cambrian faunas of North 33, no. 3, Geol. and Min. Ser., no. 31, 60 p. America: U. S. Geol. Survey Bull. 30, 369 p. Williams, J. Stewart, 1943, Carboniferous forma- 1890, The faunas of the Lower Cambrian or tions of the Uinta and northern Wasatch Olenellus zone: U. S. Geol. Survey 10th Ann. Mountains, Utah: Geol. Soc. America Bull., Rept., pt. I, p. 511-568 v. 54, p. 591-624 1891, Cambrian correlation papers: U. S. Williams, J. Stewart, 1948, Geology of the Paleo- Geol. Survey Bull. 81, 447 p. zoic rocks, Logan quadrangle, Utah: Geol. 1908a, Nomenclature of some Cambrian Soc. America Bull., v. 59, p. 1121-1164 Cordilleran formation: Smithson. Misc. Coll., Williams, J. Stewart, and Maxey, G. B., 1941, v. 53, no. 1, p. 1-12 The Cambrian section in the Logan quad- 1908b, Cambrian sections of the Cordilleran rangle, Utah and vicinity: Am. Jour. Sci., area: Smithson. Misc. Coll., v. 53, no. 5 vol. 239, p. 276-285 p. 167-230 1908c, Cambrian trilobites: Smithson. Misc. ILLINOIS STATE GEOLOGICAL SURVEY, URBANA Coll., v. 53, no. 2, p. 13-52 ILL. 1912, Cambrian Brachiopoda: U. S. Geol. MANUSCRIPT RECEIVED BY THE SECRETARY OF Survey Mon. 51, pt. 1, 872 p. THE SOCIETY, JULY 3, 1952

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