Stratigraphy of the Mascot-Jefferson City Zinc District, Tennessee
GEOLOGICAL SURVEY PROFESSIONAL PAPER 277
Prepared with the cooperation of the Tennessee Department of Conservation^ Division of Geology Stratigraphy of the Mascot-Jefferson City Zinc District, Tennessee
By JOSIAH BRIDGE With an introduction by JOHN RODGERS
GEOLOGICAL SURVEY PROFESSIONAL PAPER 277
Prepared with the cooperation of the Tennessee Department of Conservation^ Division of Geology
UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1956 UNITED STATES DEPARTMENT OF THE INTERIOR Douglas McKay, Secretary
GEOLOGICAL SURVEY W. E. Wrather, Director
For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. CONTENTS
Page Page Abstract-...______1 Stratigraphy—Continued Introduction, by John Rodgers-______—______1 Knox group—Continued Scope and purpose of the present report______1 Chepultepec dolomite—Continued Work before 1929______3 Bedrock lithology__—______38 Recent work in the Knox group of East Tennessee __ 3 Residual products______40 The geologic map and mapping procedures.______5 Facies relationships______41 Acknowledgments______5 Paleontology and correlation_ ——— ______41 Geography______6 Relation to the Longview dolomite______45 Stratigraphy ____—_____ —— ______7 Longview dolomite.-______46 Pre-Knox formations______7 Name______46 Summary description______7 Limits______47 Names and distribution______7 Thickness______— __ 47 Rome formation______8 Bedrock lithology______47 Rutledge limestone______8 Residual products______48 Rogersville shale______8 Paleontology and correlation______48 Maryville limestone______10 Kingsport limestone______49 Nolichucky shale______10 Name______49 Maynardville limestone member of Nolichucky Limits______50 shale______11 Thickness______53 General features. ______17 Bedrock lithology______53 Facies relationships.______17 Correlation______-__---____---___- 54 Topographic expression______18 Mascot dolomite______---___-_-_-_-__ 54 Paleontology and correlation ______19 Name______54 Knox group______21 Limits and thickness—______54 General remarks______21 Bedrock lithology———______55 Definition______21 Correlation______55 History______21 Topographic expression..______55 Present usage.______23 Post-Knox formations.______—______56 Ozarkian and Canadian systems of Ulrich__ 24 The name Chickamauga limestone.______56 Copper Ridge dolomite.______25 Unconformity at base of Lenoir limestone____ 57 Name.______25 Lenoir limestone.— — — ______59 Distribution ______26 Mosheim member______59 Limits and thickness______26 Lenoir limestone exclusive of Mosheim Bedrock lithology______30 member______60 Residual products______31 Structure______61 Subdivisions. _____'______33 Appalachian Valley______-_--_-____- 61 Mascot belt______61 Facies relationships______33 Jefferson City belt______62 Paleontology and correlation.______34 Shields Ridge belt______66 Chepultepec dolomite.______37 Mechanics of rock structure______68 Name.______-_--______--___-_--_--__ 37 Economic generalizations______-_____-__-_--___- 69 Limits_____--______---_--_---_-__ 37 Literature cited______72 Thickness______38 Index______75 m IV CONTENTS ILLUSTRATIONS
[All plates are in pocket] PLATE 1. Geologic map and sections of the Mas cot-Jefferson City zinc mining district, Tennessee, 2. Map showing the relation of the Mascot-Jefferson City area to the main structural features of the Appalachian Valley. 3. Geologic maps of type areas of formations in the Mascot-Jefferson City zinc district, Tennessee. Page FIGURE 1. Index map of part of East Tennessee, showing location of Mascot-Jefferson City district-____-_--___-_---_-_-- 2 2. Generalized columnar section for the Mascot-Jeff erson City district ______7 CHART 1. History of the stratigraphic terminology applied to the Knox group and associated Cambrian and 0"dovician formations in the southern Appalachians._-______-.______-----__----_-__-_------_---_--_ In pocket
TABLES
Page TABLE 1. Distribution of species from the Chepultepec dolomite._-_-_-_-_--______43 2. Distribution of species from the Longview dolomite and equivalent formations. 49 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE
By JOSIAH BKIDGE
ABSTRACT report are incomplete, notably the descriptions of some The Mascot-Jefferson City zinc district is underlain by Cam of the Ordovician formations. Incomplete as it is, brian and Ordovician sedimentary rocks. Sulfide zinc deposits, however, the report summarizes the stratigraphy of the the only ores now being exploited in the district, occur in lime zinc-bearing rocks and of the Knox .group in East Ten stone and dolomite layers of the Knox group. This group in nessee generally as no one but Bridge could have sum East Tennessee has been divided, on the basis of work begun in this district but carried also into other areas, into five forma marized it. tions—in ascending order, the Copper Ridge dolomite, the Chepultepec dolomite, the Longview dolomite, the Kingsport SCOPE AND PURPOSE OF THE PRESENT REPORT limestone, and the Mascot dolomite. These units are distin The present report is the result of a project of long guished and mapped by key beds of sandstone and limestone, by minor differences in type of dolomite, and especially by dif standing, begun in 1929 as a pioneer attempt to sub ferences in the residuum overlying them. In the Mascot-Jef divide stratigraphically the Knox dolomite of East ferson City district, the rocks have been deformed by large folds Tennessee. For this attempt, the Mascot-Jefferson City and thrust faults; the pattern of folding and faulting generally zinc district was chosen for several reasons: the area in conforms to but is less regular than that in East Tennessee as cludes a belt continuous with the type section of the a whole. The zinc deposits are found in the lower part of the Kingsport limestone (and locally in the top of the Longview Knox at Knoxville, information was desired on the dolomite) where the beds show brecciation or recrystallization unknown relation of the zinc deposits in the district or most commonly both, especially near the ends of minor thrust to the surrounding geology, and a large-scale map of faults in the vicinity of anticlinal changes in strike. the vicinity of the Holston River within the are?, had recently been issued by the U. S. Army Engineers. INTRODUCTION Three general aims were set for the project: to test how By John Rodgers far the Knox dolomite could be subdivided, to deter mine the stratigraphic and structural control, if any, The Mascot-Jefferson City zinc district, one of the of the zinc deposits, and to provide data for a possible principal metal mining districts in the southeastern revision of the State geologic map. United States, is located in Knox and Jefferson Coun It was hoped from the beginning that this project ties, Tenn., eastward from and within 25 miles of the would be only the first in a series of projects directed city of Knoxville. Its location is shown in figure 1. toward these aims; its success in achieving them in The present report, which includes a geologic map this area was indeed a major stimulus to the great (first published in 1945) of the zinc district and im amount of geologic work that has been canned out mediately surrounding area, emphasizes the stratig in East Tennessee in the last two decades. The original raphy of the district in relation to the stratigraphy of aims have now been almost completely achieved: the the whole southern Appalachian region; it is only sec Knox dolomite is now a group divided into named ondarily concerned with the economic geology of the formations in every part of East Tennessee and ad zinc deposits, which are described by Brokaw (1955). jacent areas where detailed work has been done, the The manuscript for the present report was left un stratigraphic and structural control of the zinc deposits finished at the death of its author in April 1953 and has been prepared for publication by John Rodgers, who is fairly well understood (Brokaw, 1955), and a new has written the abstract and most of the introduction. geologic map of East Tennessee has been compiled and Except for these, no sections were added to the report as published (Rodgers, 1953). All these developments Bridge left it, though several were expanded from other are outgrowths of Bridge's pioneering project. material that he left or in accordance with his instruc Bridge was of course in close touch with all thes^ new tions on the manuscript. As a result, some parts of the projects—which he aided enormously by his enthu- to
VIRGINIA
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IUTLEDGE AYNARDVILLE f POWDER SPMNGS S, ^ 36 BRICEVILLE ' 27 MORRISTOWN -^J MORRISTOWN H A M B L E N / ts f? BOTT^ ^ \\ JEFFERSON CITY. \ •o-NEW MARKET / WHJTE PI MASCOT ^ JJE FFERSON O STRAWBERRY MILLAN'
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FIGURE 1.—Index map of part of East Tennessee, showing location of Mascot-Jefferson City district and other areas covered by detailed geologic maps. INTRODUCTION siastic encouragement and assistance—and, as they de classed as Cambrian and Silurian 2 or Cambrian and veloped, his project also changed in scope. At his Ordovician in age. Moreover, they repeatedly rtated death, then, the aims of his report were to set forth the that the base of the formation contained Cambrian evidence on which his geologic map of the zinc district fossils whereas the top contained Silurian (CaHfer- was based, to discuss the regional aspects of the geologic ous) fossils and that it was impossible to drav^ any control of the zinc deposits, and, abovfc all, to provide a boundary between parts of the formation. definitive description of the subdivisions of the Knox The most significant of these folios, for the present to serve as a standard of comparison for other areas in report, are the Knoxville folio (no. 16), the Morris- the southern Appalachians. town folio (no. 27), the Maynardville folio (no< 75), the Greeneville folio (no. 118), and the Roan Mountain WORK BEFORE 1929 1 folio (no. 151), all the work of Keith (fig. 1). The In his pioneer work in Tennessee, Safford (1869, p. first of these folios covers the region immediately to the 204) named the Knox group and divided it into three southwest of the area under discussion and contains units which he termed the Knox sandstone, the Knox Safford's original section. The second and third in shale, and the Knox dolomite, respectively (chart 1). clude the Mascot-Jefferson City area. In the other He placed these, together with the underlying Chil- two, which embrace the area to the east and were pub howee sandstone and Ocoee series, in a large group lished at a later date, there is a much more extended which he termed the Potsdam, and he referred the Chil- discussion of the Knox dolomite, but still no attempt howee sandstone to the Potsdam proper (that is, the to subdivide it. Potsdam of New York). The limestones overlying the The first subdivision of the Knox was made by Ul- Knox dolomite, which was the youngest member of rich (1911, p. 633-640), who divided the Knox in the Safford's Potsdam group, were termed the Lebanon, Knoxville area into three units: a lower unnamed lime Trenton, or Maclurea limestones. The name Knox was stone, the Copper Ridge chert, and an unnamed "Up taken from Knoxville and Knox County (Safford, 1869, per Division of the Knox." Ulrich stated thr.t the p. 204), and Safford's original section was measured sequence of units within the Knox is not the same in along Second Creek in the city of Knoxville. This different parts of the Appalachian Valley. He also section lies just west of the area studied for the present discussed many sections, proposed several new forma report, partly in direct prolongation of the Mascot belt tions (including the Copper Ridge chert), and pointed (p. 7 and pi. 2). Safford extended the term Knox out many of the unsolved problems of correlation. dolomite to cover all the dolomitic limestones in this For many years after this, Butts worked on prob portion of the section in East Tennessee, and this clas lems of Appalachian stratigraphy. With the cooper sification was used with slight local modifications by ation of Ulrich, he subdivided the Knox in Alrbama various writers until about 1890. Smith (1876 and and Virginia (also later Georgia) into several units, later publications) used the term to include supposedly and his results appeared on the geologic maps of those equivalent strata in northeastern Alabama. States. Before 1929, however, no attempt was made to Between 1890 and 1905, the U. S. Geological Survey map the areal distribution of these units in Tenr^see. mapped the greater portion of the southern Appala Purdue (1912) and Secrist (1924) described th^ zinc chian Valley in considerable detail and published a deposits of the district, but neither of them attempted series of geologic folios covering most of eastern Ten a subdivision of the Knox, although Secrist published a nessee and adjoining States. These folios were the correlation table for East Tennessee compiled by work of several men, chiefly C. Willard Hayes, Marius Nelson from data supplied by Ulrich. R. Campbell, and Arthur Keith. In the folios, the RECENT WORK IN THE KNOX GROUP OF Knox sandstone and shale were subdivided into a num EAST TENNESSEE ber of formations and Safford's terms were discarded. The name Knox dolomite was retained as a formation In 1929, Captain Walter F. Pond, the State Geolo name with practically the same limits which Safford gist of Tennessee, employed Bridge, who was then gave it, but the overlying Trenton, or Lebanon, lime teaching at the Missouri School of Mines and had re stone of Safford was called the Chickamauga limestone. cently completed mapping two 15-minute quadrrngles These men realized the composite nature of the Knox in the Ozarks in formations equivalent to the Knox dolomite; in all their reports the Knox dolomite is group, to undertake the project of subdividing the Knox in East Tennessee. In April, Bridge and Pond, 1 This section is taken with little change from one entitled "Previous work" In the preliminary report prepared by Bridge after his 1929 * The Ordovician period had not been recognized by the U. S. Geological field season. Survey at the time the earlier folios were published. STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE representing the Tennessee Division of Geology, took the Tennessee Valley Authority was organized, and part in a field conference with Ulrich and Butts, of since then it has carried on a great deal of geologic the U. S. Geological Survey, making a reconnais work in East Tennessee. In the first yearr of the Divi sance trip from Bristol to Knoxville by way of Bluff sion, a reconnaissance survey of the Norris Reservoir City, Johnson City, Greeneville, and Morristown. area was made by James S. Cullison am? others, who During this trip Ulrich and Butts gave Bridge the used some of the subdivisions of the Knox group already benefit of their knowledge of the sequence of units then established by Bridge. The report on this survey has recognized in the Knox group of the southern Appa not been published. Several short papers on other lachians, pointed out the criteria used for separating projects have appeared, and a more general report on these units, and especially introduced him to the two the work of the Division has been published by the principal standard sections of the Knox in East Tennes Authority (Moneymaker, Leonard, and others, 1949). see—the section along Jockey Creek near Limestone in In 1937, the Tennessee Valley Authority began the Washington and Greene Counties and the section along publication of large-scale planimetric maps of East Forked Deer Creek near Thorn Hill in Grainger Tennessee. As a joint project of the Tennessee Division County. Following this field conference, Bridge spent of Geology and the U. S. Geological Survey, Bridge the summer mapping the Mascot-Jefferson City zinc spent several months in 1937,1938, and 1939 remapping district on the maps available: the Holston River Sur the area on the new base and began a revision of the vey of the U. S. Army Engineers, a map of the area 1930 report. At this time, Oder and Bridge agreed between New Market and Jefferson City, compiled and upon a terminology for the subdivisions of the Knox kindly loaned by the Universal Exploration Co. (now group for their two reports; this terminology has part of the Tennessee Coal & Iron Division of the U. S. been accepted and used in all more recent work in East Steel Corp.), and planetable traverses made especially Tennessee. Bridge's revision was interrupted, how for the project by W. B. Brewer and T. G. Andrews, ever, for strategic minerals defense projects in 1941, of the U. S. Geological Survey. During the school and neither he nor Oder was able to prepare a definitive year 1929-30, Bridge prepared a report of about 85 publication of the new terminology. typescript pages which he transmitted to the Tennessee In 1942, the U. S. Geological Survey, as a part of its Division of Geology in 1930. strategic minerals program, continued its investigations In 1930, Bridge became a member of the U. S. Geo of the zinc deposits of East Tennessee, leading to the logical Survey, and Pond employed C. R. L. Oder to publication beginning in 1943 of several preliminary carry forward the Tennessee Division of Geology pro maps and reports, depending for their stratigraphy on ject on the subdivision of the Knox group. From 1930 Bridge's unpublished report and inakirg use of its until 1934, when he became geologist with the American terminology. The final report on this project is in prep Zinc Co. of Tennessee, Oder worked on this project, aration by Brokaw. As a phase of this project, Bridge's mapping subdivisions of the Knox in several parts of data were transferred to the new topographic maps East Tennessee, notably in the Morristown-Kussellville published jointly by the Tennessee Valhy Authority area northeast of the Mascot-Jefferson City district. and the U. S. Geological Survey, and the map was In 1934, he published a preliminary paper on the results published without text in 1945 by the Tennessee Divi of this work (Oder, 1934). More recently he has car sion of Geology. ried forward his detailed mapping in the Morristown- Since 1945, much geologic work has been done in East Russellville area, but his report on this area has not Tennessee, and most of it through 1950 was incorpo appeared. rated into a new geologic map of East Tennessee com In 1932 and 1933, the late Professor George M. Hall piled by Rodgers and published by the Tennessee and Professor H. C. Amick, of the University of Ten Division of Geology in 1952. Again the terminology of nessee, made a detailed bed-by-bed measurement of the the Knox group was taken from the unpublished re Thorn Hill section. This very useful document was ports by Bridge and Oder; a fairly detailed though published in 1934. not definitive discussion of this terminology was in In 1934, the U. S. Geological Survey began a project cluded in the text accompanying the imp (Rodgers, to investigate the zinc deposits of southwest Virginia 1953). and East Tennessee, under the direction of D. F. Hewett In 1947 and again in 1950, Bridge and Rodgers re and L. W. Currier. Considerable material was assem viewed the Mascot-Jefferson City repor4: in order to bled and some short articles were published, but no final begin a final revision, and from 1950 until his death in report on the Tennessee phase of the project was com April 1953, Bridge carried forward his work on the pleted. Shortly thereafter the Geologic Division of report along with work on other commitments. At the INTRODUCTION time of his death, he had completed in semifinal form several thinner limestone beds but excludes at the top the descriptions of the rock formations through the a thick and fairly distinctive bed that can be found Chepultepec dolomite and the sections entitled "Struc wherever exposures are sufficient), and the band between ture" and "Economic generalizations" and had pre it and the contact in the sandstone bancj. is mapped as pared less final and less complete material for all other the Chepultepec dolomite. The band stratigraphically parts of the report except the introduction. This ma above the Longview is further divided into the Kings- terial constitutes the present report. port limestone below and the Mascot dolomite above by finding residual float or outcrops of a characteristic THE GEOLOGIC MAP AND MAPPING PROCEDURES sandstone with a chert matrix, which forms a valuable Bridge intended to prepare a section for the introduc key bed in this part of East Tennessee. tion entitled "Accuracy of the map," in which he wished But residual materials, such as chert or sardstone particularly to emphasize how the contacts between the blocks, are very apt to creep downhill or to settle verti formations of the Knox group were drawn and how cally far below the level at which they were originally uncertain they may be locally. Although the pre-Knox released from the bedrock, and either process could and post-Knox formations crop out fairly extensively introduce serious systematic errors into the mapping. in most areas where they occur, the rocks of the Knox Bridge was well aware of this difficulty, and, as far as group are mostly covered with a thick mantle of cherty possible, he checked the residuum against all available residual clay. Scattered outcrops occur, and the map outcrops and against the projected dip and strike of indicates nearly all by dip and strike symbols. Except any known contacts. Moreover, it should be mentioned where the outcrops form nearly continuous sections, that at no time during the mapping did Bridge have however, they are of little direct help, for the various access to any underground information, except for a kinds of dolomite are repeated through most of the few scattered drill records. Despite these difficulties, group and isolated outcrops are rarely critical. In most Bridge's mapping has proved in fact to be remark of the area, therefore, the contacts are based on evidence ably accurate, when checked by later drilling and under from residuum: on fossils in the chert if they can be ground development, and he often took considerable found, on differences in the kinds of chert, or on other pride in these verifications, as, for example, his predic residual materials like sandstone. In a broad way, a tion of not only the surface trace but the subsurface first division of the Knox group in this area is made position of the Rocky Valley fault under Koppick Knob by finding the band of sandstone residuum from the south of Jefferson City. zone of sandstone layers that straddles the boundary between the Copper Ridge and Chepultepec dolomites. ACKNOWLEDGMENTS On the stratigraphically lower side of this band, the In a letter dated 1947, Bridge states that "acknowl sandstone blocks are commonly mixed with blocks of edgments will of necessity be many," but unfortunately coarsely oolitic chert; there are also other differences he was unable to prepare the list. The one below, there in the chert on the two sides. This band, or more ex fore, reconstructed by Rodgers after Bridge's death, actly the stratigraphically higher edge of the part with runs the risk of injustices, both of omission and of mis oolitic chert blocks, is assumed to indicate the-Cambrian- placed emphasis. Ordovician boundary. The part of the Knox group Acknowledgments for assistance during the life of below this boundary, the Copper Ridge dolomite, is not the project and in the preparation of the manuscript further divided, except locally by special criteria, but are due to Walter F. Pond, who originally proposed the base of the group may also be mapped on the basis the project; H. A. Buehler, who suggested I Edge's of residuum, for it is marked by the abrupt lower limit assignment to it on the basis of his successful vork in of abundant chert. Missouri; E. O. Ulrich, Charles Butts, August F. The Ordovician part of the Knox group can generally Foerste, and the others who helped train him in the be further divided into three parts by a band in which paleontology and stratigraphy of the Knox group and the residuum is exceptionally cherty—the chert being its equivalents; the geologists in charge of the various normally in large massive light-colored blocks and con field parties in the southern Appalachians witli whom taining molds of the gastropod Lecanospiror-r&n<{ over he collaborated—D. F. Hewett, L. W. Currier, E. C. which the hills are generally somewhat higher than on Eckel, and C. H. Behre, Jr.; the zinc companies in the either side. On the stratigraphically higher side of this area—the American Zinc Co. of Tennessee, and the band, limestone (or recrystallized dolomite, see p. 47,54) Universal Exploration Co., now part of the Tennessee is commonly found if outcrops are present. This band Coal & Iron Division of the U. S. Steel Corp.—and is mapped as the Longview dolomite (which includes their officials and geologists—Hiram Mills, Mark H. 339223—55———2 6 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE Newman, Charles K. L. Oder, H. A. Coy, Floyd Weed, North of Jefferson City, the Holston is ponded by and Johnson Crawford; and many other geologists, in Cherokee Dam to form Cherokee Reservoir, which cluding George M. Hall, H. C. Amick, and R. E. Lee covers several square miles in the northeast corner of Collins; Robert A. Laurence, Benjamin Gildersleeve, the area and extends many miles farther eastward. Berlen C. Moneymaker, C. B. MacGavock, James S. Most of the mapped area drains into the Holston, but Cullison, John C. Dunlap, and C. H. Prouty, Jr.; Mrs. south of Shields Ridge the streams flow generally south Christina Lochman Balk, A. R. Palmer, and Arnold ward to Dumplin Creek, a tributary of the French L. Brokaw, for their help at various stages in the Broad. Important tributaries of the Houston within project. the area are, on the north side, Buffalo, Richland, Big GEOGRAPHY Flat, and Roseberry Creeks, and, on the south side, Mossy, Lost, and Beaver Creeks. One of the striking The Mascot-Jefferson City area lies in the Valley of hydrographic features of the region is the prominence East Tennessee, a part of the Appalachian Valley and of underground drainage; thus Lost Creek goes under Ridge province. The Valley extends entirely across ground about a mile from the Holston River and per Tennessee from Bristol to Chattanooga between the haps 40 feet above it, and its waters apparently reap Unaka and Great Smoky Mountains along the North pear in a large spring on the east bank of the river Carolina State line on the southeast and the Cumber opposite McBee Island. Many smaller streams likewise land Plateau on the northwest. The Mascot-Jefferson disappear into sinks, and an area of several square miles City area lies about halfway from Bristol to Chatta east of Jefferson City, extending nearly to Morristown, nooga, almost in the center of the Valley, here about 50 14 miles north-northeastward, is entirely without or miles wide. dinary surface drainage but is pocked with innumer This part of the Valley of East Tennessee is chiefly able sinks, large and small. rolling country, marked by several broad ridges trend A very large proportion of the area is cleared, much ing northeast. The ridges crossing the area mapped of it for cultivation of tobacco, corn, and rmall grains, are less regularly distributed than in most parts of the much of it for pasture. Woodland is sparse on low Valley. The most prominent is Shields Ridge (called ground, commoner in hilly areas, and widest spread Bays Mountain on the 1945 map, Bridge, 1945 3), which on the steeper slopes of the more prominent ridges, reaches an altitude of about 1,750 feet above sea level. such as Shields Ridge. The principal towr^ in the area Narrower, sharper ridges with the same northeast are Jefferson City (1950 population, 3,633), New Mar trend extend along the northwest and southeast edges ket (600), Strawberry Plains (400), and Mascot of the mapped area. Just to the north and northeast (1,800); the city of Knoxville (124,769) lies at the are House and Clinch Mountains, the southwestern- southwest corner of the area. Mascot—a company- most of the prominent linear mountains that character owned town—Jefferson City, and New Market are ize the northwest part of the Valley and Ridge prov the main seats of the zinc mining industry, though Jef ince in northeast Tennessee and Virginia. The total ferson City has also several mills or shop^ and is the relief in the mapped area is about 900 feet, but House seat of Carson-Newman College (1950 enrollment, 895). and Clinch Mountains add another 500 feet. The local A main line of the Southern Railway (here double- relief rarely exceeds 600 feet. (See pi. 1.) tracked) crosses the center of the area from east to The Holston River winds westward across the cen west, connecting Washington, D. C., and Bristol, Va.- ter of the area, and just south of the southwest corner Tenn., with Chattanooga, Tenn., Memphir Tenn., and it joins the French Broad River to form the Tennessee. Birmingham, Ala.; and Charleston, S. C., and Ashe- 8 The name Bays Mountain, or Bays Mountains, is indiscriminately ville, N. C., with Cincinnati, Ohio, and Lcnisville, Ky. applied to a series of disconnected ridges between Kingsport and Mary- The railway maintains a large freight classification ville, Tenn. The principal ridge and the one most universally known as Bays Mountain is the synclinal mountain group starting just south yard at John Sevier, near the west end of the area. west of Kingsport and extending southwestward past Bulla Gap to the U. S. Highway 11-E roughly parallels the railway Nolichucky River about 7 miles southeast of Morristown. The name is also applied to a series of three or four subparallel monoclinal ridges across the area, U. S. Highway 11-W crosses the north starting in the vicinity of Whitesburg, extending southwestward along west part of the area, and U. S. Highways 25-W and the valley of Dumplin Creek, crossing the French Broad River, and finally dying out in the vicinity of Rockford north of Maryville. These 70 (here following the same route) skirt the southern ridges are not a continuation of the first one mentioned but are about edge; the highways and the railroad converge at Knox 3 mile northwest of and in echelon to it. Still a third ridge, sometimes known as Bays Mountain, is the short, steep ridge forming the south ville at the southwest corner of the area. State High wall of Rocky Valley within the New Market and Jefferson City quad rangles. This ridge lies 2 or 3 miles northwest of the second group way 92 passes north and south through Jefferson City, described above and is entirely distinct from them. It is also known connecting it with U. S. Highway 11-W at Rutledge locally as Shields Ridge. That name appears on the new Jefferson City . quadrangle map and will be used1 in this report. and U. S. Highway 70 at Dandridge, both a little be- STRATIGRAPHY yond the limits of the map. U. S. Highway 25-E passes north and south through Morristown, about 10 miles to the east of the area. A network of county roads, some paved, the others Ottosee and Tellico formations, undifferentiated, Oto, with b«ds mostly macadamized, gives ready access to all parts of of red and gray marble, Otm the area. The Holston River forms the most significant barrier to movement, and it is bridged at three points: Holston marble, Oh just north of Jefferson City (State Highway 92), be tween Strawberry Plains and Mascot, and south of Lenoir limestone, 01, with Mosheim member, Om, at base John Sevier (U. S. Highways 11-E, 25-W and TO). 0-50' 0-100 STRATIGRAPHY 500- -Oma- 600' Mascot dolomite The rocks of the Appalachian Valley are almost en tirely of sedimentary origin and consist of conglomer ates, sandstones, shales, limestones, and dolomites. 400' 400' They range in age from Early Cambrian to Carbonifer ^OK Kingsport limestone ous. In the Mascot-Jefferson City district limestones and dolomites are by far the most abundant lithologic 250- types, and no consolidated rocks younger than Middle 500' Longview dolomite Ordovician are present.
The stratigraphic column for the district is shown 011 as>feaa/
PBE-KNOX FORMATIONS 450- 650' 520' Maryville limestone SUMMARY DESCRIPTION \~\ 500' NAMES AND DISTRIBUTION 150'" The pre-Knox formations range from Early to Late 20Oi Rogersville shale, €rg, with Craig 250 limestone member, Crgc, near top Cambrian in age and consist of five easily differentiated formations. These, in ascending order, are the Rome -€rf- 200- I~T 500' 350'+ Rutledge limestone formation (Lower Cambrian), the Rutledge limestone, I..-, i . i Rogersville shale, and Maryville limestone (Middle Cambrian), and the Nolichucky shale (Upper Cam brian) . The Rogersville shale is further divided into Rome formation; includes Purrrckin a lower and upper shale member separated by the Craig 1000'd Valley shale of early Middle Cam brian age at top *On the geologic map issued in 1945 (Bridge, 1945), the Saltville fault was called the Bichland fault, but the name Saltville is older and has been widely used for this fault. Likewise, the Rocky Valley fault was called the Bays Mountain fault, but that name had previously been used by Gordon (1918, p. 54) for an entirely different fault south of Knoxville, and it is therefore abandoned in this report. For a discussion FIGURE 2.—Generalized columnar section for the Mascot-Jefferson City of the various Bays Mountains of East Tennessee, see Safford (1869, district. p. 43) and the footnote on page 6 of this report. 8 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE limestone member; the Nolichucky shale is divided into underlying part of the Rome formation as well. Good a lower shale member and an upper limestone and shale exposures may be found in the gap north cf Bethlehem member, the Maynardville limestone member. All five Church (John Sevier quadrangle) and along State formations were named and described in the early Ap Highway 92 in the gap southeast of Flat Gr.p (Jefferson palachian Valley folios, and their distribution was well City quadrangle). shown on the accompanying maps. More recently, their faunas have been figured and described (Resser, 1938). RUTLEDGE LIMESTONE All five formations crop out within the mapped area; The remaining four formations were named by Keith but, inasmuch as they have been well described in other for exposures in the Maynardville, Morris town, Knox- reports, do not carry any of the zinc deposits in the ville, and Greeneville quadrangles, respectively (Keith, area, and, with the exception of the Maynardville lime 1901, 1896, 1895, 1905), but the first description of all stone member of the Nolichucky shale, are not connected four was given by Campbell (1894, p. 2). The descrip with the problem of subdividing the Knox group—the tions of the formations in their type areas followed at original aim of this report (see p. 1)—only a general intervals over a period of several years. ized description will be given. They have been mapped The Rutledge limestone was named for exposures throughout the Mascot-Jefferson City area partly for "in the valley of Rutledge, Grainger County," Tenn. the sake of completeness but mostly because of their (Keith, 1901, p. 2). No type section has ever been importance in interpreting structure. designated, but there are good exposures of the forma tion in the valley of the unnamed tributary of Rich- ROME FORMATION land Creek about 1 mile, west of Rutledge (Dutch Val The Eome formation, named by Hayes (1891, p. 143- ley quadrangle), and with further study a type sec 146) from exposures in the city of Eome, Ga., forms tion might be established here. Good exposures have the base of the section in the Mascot-Jefferson City also been made nearby along the new location of U. S. district. Along the eastern edge of the Appalachian Highway 11-W west of Rutledge. Most of the forma Valley, where complete sections of the formation are tion is massive dark-blue to black limestone exhibiting exposed, the Rome formation rests upon the Shady banding, especially on weathered surfaces, and close dolomite, also of Early Cambrian age. Throughout the ly resembling much of the limestone in the overlying central and western portions of the Valley, however, it Cambrian formations, but according to Keith the lower is the oldest formation exposed in any section and either part of the formation includes shale bed^1 and grades occupies the center of an anticline or is cut off below imperceptibly into the underlying shales of the Rome by a thrust fault. In the Mascot-Jefferson City district formation. Resser (1938, p. 11), on the basis of Middle the Rome formation averages about 1,000 feet in thick Cambrian fossils in these shales, considered them to ness and consists largely of thick rusty sandstones be be part of the Rutledge. Actually they were originally low and of arenaceous varicolored shales above. Yel included in the Rome formation, and they are now low, orange, and maroon tones are prominent in the placed in the Pumpkin Valley shale of Rodgers and shale, but the highest beds are mostly greenish; these Kent (1948). greenish beds appear to correspond to the Pumpkin Within the Mascot-Jefferson City area the Rutledge Valley shale as described by Rodgers and Kent (1948, limestone is exposed near the northwest edge of the p. 7-9) at Lee Valley, Hawkins County, Tenn. Thin Mascot belt in the John Sevier quadrangle and in Rocky beds and lenses of limestone and dolomite, some of Valley in the Shields Ridge belt in the Nev Market and which are fossiliferous, occur locally in the Home Jefferson City quadrangles. The limestores are highly formation. soluble, and good exposures are rare; the best are in Within the district the Home formation crops out in Rocky Valley about 3 miles south of New Market. three areas: in Legg, Rogers, and McAnnally Ridges The Rutledge limestone is about 500 feet thick in along the northwestern edge of the Mascot belt in the the type area near Rutledge, but the limestone beds are John Sevier quadrangle; in the center of the Rocky replaced by shales toward the southwest. In the sec Valley anticline in the New Market quadrangle; and tion along Loves Creek near the westerr edge of the in the high unnamed ridge between Piedmont in the Mascot belt (John Sevier quadrangle) the formation New Market quadrangle and Oakland in the Jefferson is difficult to recognize, for it is composed largely of City quadrangle along the southeastern border of the shale. area. The material in the crest of the Rocky Valley ROGERSVILLE SHALE anticline would now be classed as Pumpkin Valley The Rogersville shale was named from exposures shale; the other areas contain strata belonging to the near Rogersville, Tenn. (Keith, 1896, p, 2), but the STRATIGRAPHY 9 exact type locality was never specified. It is a gray Rogersville shale—Continued argillaceous shale that weathers to a fairly distinctive Craig limestone member—Continued Feet inches 3. Limestone, similar to bed 12————— 13 0 light-greenish color (5 GY 6/1, light greenish gray, 2. Limestone, similar to bed 12————— 5 0 to 10 Y 6/2, pale olive, according to color measurement 1. Limestone, similar to bed 12; top of by Robert A. Laurence, personal communication, 1953). this bed is the floor of the lower half It is remarkably persistent in this part of the Appala of the quarry———————————— 1 0 chian Valley in East Tennessee and, because of its color and persistence, is an excellent key bed. In the Total Craig member. 0 Mascot-Jefferson City district and in much of the sur Lower shale member: Poorly exposed below quarry but rounding region the shale is divided into upper and contact well shown in road cuts 100 yd west. About 30 lower members by a thick bed of limestone, here termed ft exposed to creek. the Craig limestone member (name first used by Rodgers The limestone of the Craig member was quarried for and Kent, 1948, p. 10). The name is taken from the dimension stone and interior trim. It takes a hig'h. pol Craig quarry (pi. 3(7) in the southern edge of the ish and is said to furnish a superior grade of black village of Rutledge, where the entire member is well marble, though somewhat mottled. In the section exposed. above, the units are purely arbitrary and were selected Type section of the Craig limestone member of the Roger%- with reference to the prominent bedding planes at this viUe shale, measured in the quarry 0.14 mile south of the locality. Except for the nonpersistent bed of do^mite junction of U. 8.11-W and Tennessee 92 at Rutledge, Tenn.t (unit 11), the limestones are remarkably unifonr from in oluff south of Richland Creek and just east of sharp turn top to bottom; such differences 'as appear to exist are in Highway 92 (pi. SC) merely due to differences in the amount of weathering [Measured by Josiah Bridge, 1940] of the particular surface studied. Maryville limestone: Base, exposed in field about 100 ft south The Craig limestone member is indistinguishable of the quarry. lithologically from the Rutledge limestone beneath and Eogersville shale: Feet inches the Maryville limestone and some of the limestone in Upper shale member: Exposed on flat at top the Maynardville limestone member above, but, occur of bluff. Shale, light-green, well-bedded, soft, calcareous, weathering to small, splint ring as it does between two bands of light-green shale, ery chips. Strike N. 70° E., dip 20° S. it is an extremely valuable key bed. Calculated thickness______—_—————— 17 0 The Rogersville shale crops out in the Mascot belt Craig limestone member: across the John Sevier, Mascot, and Luttrell qurdran- 13. Limestone, rather poorly exposed on flat south of the quarry, similar to gles; it is well exposed in the center of the Rodrr Val the main mass described below. ley anticline in the New Market and Jeffersor City Calculated thickness ———————— 8 0 quadrangles. Formerly there were poor exposures of 12. Limestone, dark-blue, finely crystalline the shale in the center of the Cherokee anticline oast of to aphanitic; massively bedded with Cherokee Dam in the Talbott quadrangle, but these irregular, wavy partings of black glistening carbonaceous material, were submerged by the filling of Cherokee Lake. also with irregular mottlings of gray The Rogersville shale (including the Craig limestone finely crystalline dolomitic material, member) reaches a maximum thickness of 250 feet in which weather into low relief and this area, but northeastward and southeastward it thins resemble fucoidal markings, espe cially when seen on bedding planes— 2 0 and finally is completely replaced by limestone. To the 11. Dolomite, gray, crystalline; weathers southwest it becomes indistinguishable because of the to a sugary surface————————— 3 0 replacement of the overlying and underlying limestones 10. Limestone, similar to bed 12_—_— 4 6 by shale, and it has not been recognized as a mappable 9. Limestone, similar to bed 12_——— 2 0 8. Limestone, similar to bed 12; dolo unit much west of the longitude of Maryville, Plount mitic portions weathered into high County (see p. 18). The Craig limestone member is 86 relief and closely resembling feet thick in the type section and thins to the south and fucoids ———————————————— 5 0 7. Limestone, similar to bed 12_____ 11 6 southwest, but it is present in all exposures of the Rog 6. Limestone, similar to bed 12__—— 7 0 ersville in the Mascot-Jefferson City district. It is 5. Limestone, similar to bed 12__——__ 7 0 about 50 feet thick in Rocky Valley where it commonly 4. Limestone, similar to bed 12, forms has a thin band of shale near the top. It coir prises the floor of the upper half of the quarry. Strike N. 70° E., dip 25° units 63 to 70, inclusive, of the Thorn Hill section (Hall SE ______17 0 and Amick, 1934) where it has a thickness of 36 feet, 10 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE 11 inches,5 and it forms unit 52 (47 feet thick) of the ville limestone in East Tennessee in the Upper Cam Lee Valley section (Rodgers and Kent, 1948, p. 11). brian, but these fossils are now known to have come The shales of the Rogersville are quite fossiliferous, from the Maynardville limestone member of the Noli and the fauna from them has been described and figured chucky shale (Resser 1938, p. 12,15; 1942, p. 3). About byKesser (1938). 1935 or 1936, fossils were found in a thin shale layer, unit 103 of the Thorn Hill section. The fauna from MAKYVILLE LIMESTONE this layer was described and figured by Fesser (1938, The Maryville limestone was named for exposures p. 27, 74, 94, 48) and consists of the following: Delto- near Maryville, Term. (Keith, 1895, p. 3). The exact phthalmus hdlli Resser, Proagnostu.8 waryviUensis location of the type area was not stated, but it is pre Resser, Perioura masoni Resser, and Obolit* sp. Resser sumably in the belt of Cambrian rocks cropping out (1938, p. 13) also mentions the occurrence of oboloid northwest of the town. This belt extends northeast brachiopods in a thin shale on U. S. Highway 25-E ward and occupies the valley of Dumplin Creek south "a little more than 6 miles north of Morristown." of Jefferson City and just south of the area mapped. Later, Resser (1942) listed a number of faunas from The Maryville limestone is composed of massive dark- the'"Maryville formation" at various localities in Ten blue or bluish-black limestones, similar to the Rutledge nessee, Alabama, and Georgia. He was us;ng the term limestone and the Craig limestone member of the Rog- "formation" in a faunal rather than a lithologic sense, ersville shale below and also to some phases of the May- and in most of the localities listed the formation has nardville limestone member of the Nolichucky shale either lost or nearly lost its distinctive litl ologic char above. The formation is between 300 and 400 feet thick acter and has been replaced by shale. All the faunas in the type area and apparently reaches a maximum listed by him have been found either in shale or in of between 600 and 700 feet on the Richland Knobs limestone nodules in shale commonly mapped as escarpment south of Rutledge. Like the Rutledge, its Conasauga. limestones thin out rapidly to the southwest, and in the In 1943, P. E. Cloud, Jr., found a single trilobite in section along Loves Creek at the western end of the area limestone at the base of unit 124, in the Thorn Hill it is largely replaced by shale. It has not been mapped section, and this was identified by N. M. Denson as as a distinct unit more than a short distance southwest Alokistocare cf. A. georgense Resser, a typical Middle of Madisonville, Monroe County. Cambrian form (personal communication to Cloud, The Maryville limestone crops out near the northern 1943). The specimen came from a bed 23 feet below edge of the Mascot belt, in the John Sevier quadrangle, the Nolichucky contact and was the first known occur and also in Rocky Valley in the New Market and Jeffer rence of fossils in limestone in the formation in Ten son City quadrangles. As with the Rogersville, there nessee ; the present statement is probably the first pub were once exposures of this formation in the center of lished notice of the find. According to Denson, this the Cherokee anticline as shown on the Joppa and Tal- fossil indicates a horizon very near the top of the Mid bott quadrangles, but these are now almost entirely sub dle Cambrian in the Cordilleran trough, rnd its pres merged except at low stages of Cherokee Lake. There ence in the Appalachian Valley lends strong support to are good exposures in the abandoned quarry on the old route of U. S. Highway 11-W where it crosses Big Flat the current practice of drawing the top of the Middle Creek at Brice Bridge (Mascot quadrangle), on State Cambrian at the top of the Maryville limestone in East Highway 92 south of Rutledge, and on the road on the Tennessee. Early in 1953, the writer and /. R. Palmer north face of Shields Ridge 3 miles south of Jefferson found additional fossils in the Maryville limestone that City. confirm this age assignment. For many years the Maryville limestone had been NOLICHUCKY SHALE considered to be unfossiliferous, and its stratigraphic age was inferred from its position between the fossilif The Nolichucky shale was named by Jreith (1905, erous Rogersville and Nolichucky shales. Walcott p. 5) from exposures along the Nolichucky River in the (1916, p. 391-392, 396-401, 404) described species of Greeneville region, but the name was first used by Asaphiscus,Blountia,Haryvillia, and Lisania(l) from Campbell (1894, p. 2) for strata in the Estillville quad limestones classed as Maryville limestone at several rangle, which he correlated with those afterward de localities, and on the basis of these placed the Mary- scribed by Keith. No type section was designated, but the type area is certainly the long, narrow anticline 6 A few errors in addition in the section of Hall and Amick have been crossed and recrossed by the Nolichucky River a few corrected in the thicknesses from the Thorn Hill section given in this report. See Rodgers and Kent, 1948, p. 3. miles southeast of Greeneville. This is in the area cov- STRATIGRAPHY 11 ered by the Greeneville folio, not by the Morristown carefully excluded all strata carrying identifiable folio as stated by Wilmarth (1938, p. 1505). Nolichucky fossils from his "Basal division." Despite The bulk of the Nolichucky consists of soft well- the evidence cited above, he believed the contact between bedded yellowish to olive-green calcareous shale. The this basal division of the Knox and the Nolichiicky to slightly darker and browner color of the weathered be unconformable and placed the "Six Mile series" of shale (5 Y 5/2, light olive green, to 10 YR 5/4, moder Alabama in this hiatus (see p. 26). ate yellowish brown, according to color measurements In 1933, in fieldwork around Norris Dam for the by Robert A. Laurence, personal communication, 1953) Tennessee Valley Authority, Arthur Keith recognized and the much greater thickness of the unit serve to dis two mappable units—the limestone and the chert-free tinguish it from the Eogersville shale. Locally, some dolomite—between the shale of the Nolichucky r.nd the of the shales near the base are maroon and in this re cherty dolomites of the Knox group, but the results spect resemble the thick shales of the Rome formation. of this work have not been published. Thin beds of limestone from a fraction of an inch to a The name Maynardville was proposed by Oder (1934, few inches thick commonly occur at irregular intervals p. 475-476) for essentially the same limestones that throughout the formation—another distinction from were included in Ulrich's "Basal division of the Knox." the Kogersville shale. Some of these limestones are fine Like Ulrich, he regarded it as a distinct formation and grained, others coarser. Beds of edgewise conglomerate considered it the basal unit of the Knox group, although as much as 18 inches thick occur at various levels, but he realized that the rocks contained in it had at times the number of these beds varies from place to place and been considered wholly or in part a portion of th<^ Noli- some sections reveal none. Toward the top of the for chucky. Oder's type section (unpublished) war meas mation the limestone beds become much thicker and ured along old Tennessee State Highway 33, at the much more abundant; therefore in this report this lime mouth of Fall Creek on the northwest slope of Chest stone unit is separated from the lower shale unit as the nut Ridge, &y2 miles north of Maynardville and just Maynardville limestone member. Because these beds southwest of Ousley Bridge (Oder, 1934, p. 475; Keith, have been included in the Knox group by some authors, 1901, map). Inasmuch as this section is now covered the Maynardville member is more fully discussed in by Norris Lake and is no longer accessible ever at ex this report than the formations underlying it. treme low lake stages, a new section has been selected on the present State Highway 33, at a point 7 miles MAYNABDVILLE LIMESTONE MEMBER OF NOLICHUCKY SHALE northeast of Maynardville between the bridge cross ing Cox Branch and the south end of the Clinch River Keith and other early workers noted the thick lime bridge crossing Norris Lake (pi. 35). This is in the stone beds in the upper part of the Nolichucky shale. vicinity of Needham Ford on the MaynardvilJe folio Where these beds were separated from the overlying Knox by a distinct bed of shale they were considered map. The old and new sections are only abcnt 3*4 to be a portion of the Nolichucky, but, where the shale miles apart and are located on the same belt of ontcrop, bed was missing, the uppermost limestones, especially so that the transferring of the type section to tl is new the fine-grained magnesian varieties, were included in locality does not raise any serious question of mis- the Knox. correlation. Ulrich recognized these beds as a stratigraphic unit Oder's original locality is well shown on the new and, in his first subdivision of the Knox dolomite, called 7%' Maynardville quadrangle and the new locality is it the "Basal division of the Knox dolomite (s. st.)" shown on the adjoining Powder Springs quadrangle. and described it as "grayish dolomite and limestone, Oder, like Ulrich, excluded all beds carrying Noli- practically free of chert" (Ulrich, 1911, p. 635). He chucky trilobites from the Maynardville and limited noted that it "varies considerably in thickness, possibly his formation to the aphanitic to fine-grained lami being absent altogether locally," and stated that it had nated slightly magnesian unfossiliferous limestones been recognized at Knoxville and therefore was a part that occur in the top of the member in the sections of the original Knox dolomite of Safford. He did not north of Clinch Mountain. This in part accounts for discuss the contact with the Nolichucky, although else where in the same paper he states that "gradual transi some of the astonishing variations in the thickness of tion is suggested either by increasing development of the Maynardville as given by Oder, for in some sec limestone upward in the Nolichucky or by interbedding tions thin beds of coarsely crystalline limestone carry of thin layers of shale with relatively pure and more ing trilobites occur high in the section above tl ^ finer highly magnesian limestone in the basal part of the grained unfossiliferous limestones which he thought Knox" (Ulrich, 1911, p. 627). At the same time he characteristic of the member. 12 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE The Maynardville, as interpreted by the writer, is the abrupt appearance of abundant residral chert in different from Ulrich's and Oder's concepts; he con the soil. The member thins in a short distance to the siders it the upper member of the Nolichucky shale southwest, along the strike, and is barely present in and includes in it the bulk of the limestones and mag- the area between Millertown and Loves Creek (John nesian limestones occurring between the shale of the Sevier quadrangle). lower Nolichucky and the cherty dolomite of the Knox In the southeastern part of the area, along Shields group. Ridge in the New Market and Jefferson City quadran The Maynardville is a highly variable unit and ex gles, the Maynardville member consists of two units hibits regional f acies changes that throw much light on composed mainly of medium to coarsely crystalline the sedimentary history of the Appalachian Valley and dark-blue somewhat fossiliferous limestone, separated are in harmony with f acies relationships observed in by a thick unit of shale—similar in all respects to that older and younger strata. In the sections northwest of of the underlying mass of the Nolichuck^^—and also Clinch Mountain along Chestnut and Copper Ridges, separated from the overlying Copper Ridge dolomite the lower portion commonly consists of thin- to thick- by a similar but thinner shale unit. bedded fine to coarsely crystalline dark-blue limestone. The limestones in this section are more heterogene Some layers contain beds of edgewise conglomerate, ous in color and texture than in the sect'ons farther some are oolitic, and many are highly fossiliferous. north. It is especially noteworthy that magnesian lime Bedding surfaces are commonly rough and uneven, and stones are almost wanting, and that beds of coarse the limestone units are separated -by various amounts grained fossiliferous limestones overlie beds of light- of shale of the Nolichucky type. One conspicuous bed colored fine-grained to lithographic limertones. The of black oolitic chert in the Maynardville limestone percentage of shale in these sections is also much greater member is represented by unit 167 of the Thorn Hill than in those farther north. It seems that from north section (Hall and Amick, 1934, p. 167) and by unit 76 to south there is a gradual increase in the amount of of the Lee Valley section (Rodgers and Kent, 1948, pure limestone, as contrasted with magnesian limestone; p. 13). What appears to be this same bed has also been an increase in the proportionate amount of coarsely recognized at many other localities, and it is the lowest crystalline limestone present in the section and a de conspicuous bed of oolitic chert observed in the strati- crease in the amount of fine-grained apranitic lime graphic column in this part of the Valley. The indi stone; and an increase in the proportion of shale vidual ooids are large, ranging from 1 to 2 millimeters present. in diameter. Very little chert is produced by the weatl °-ring of the In the upper part of the member, the limestones are Maynardville member or by any of the pre-Knox form fine grained to aphanitic, subcrystalline, light colored, ations, but chert is abundant in the residua] soil over all laminated, and somewhat magnesian. Shale partings the formations of the Knox group. At some places, are fewer and much thinner and more highly calcareous the upper part of the Maynardville, consisting of very than those lower in the section. In places a thin shale pure chert-free fine-grained to aphanitic dolomitic parting marks the contact with the overlying Copper limestone, leaches to a banded chert-free clay, the band Ridge, but more commonly the contact is drawn at the ing being interpreted as traces of the original bedding. base of the massive, more coarsely crystalline dark dolo Such clay has been observed at many places within the mites. The dolomite beds in the Maynardville weather Mascot district. At one time it was well erposed along light gray, almost white, and the fine laminations stand State Highway 92 about 2% miles north of Jefferson out in low relief on most weathered surfaces. These City, at the point where the highway crossed the divide beds are magnesian limestones rather than true dolo on the west side of Mossy Creek; these exposures are mites and are almost totally devoid of chert. They are now covered by Cherokee Dam and Lake. It was also included in units 159 to 202 of the Thorn Hill section. noted in creekbank exposures along Legg and Strong In the Mascot belt in the vicinity of Rutledge, the Creeks in the John Sevier quadrangle and at many other crystalline fossiliferous limestones in the lower part of places. Normally, where the clay is found, the upper the member are overlain by a great thickness of massive, beds of the Maynardville member fail to crop out, but compact sublithographic light-gray unfossiliferous the basal beds of the Copper Ridge are Apell exposed. limestone, which is well exposed in the quarry at the In other areas, notably along Richland Knobs and top of the hill on State Highway 92, about 2 miles south Shields Ridge, the fine-grained limestones of the May of Rutledge (Dutch Valley quadrangle, see section, nardville resist solution more than the ccarse-grained p. 15). The contact with the Copper Ridge is concealed, dolomites of the Copper Ridge, and commonly they crop but its approximate position is readily ascertained by out, forming the crest of the ridge, whereas the Copper STRATIGRAPHY 13 Ridge is represented on the south slope of the ridge by systems, and he believed that a great unconformity an orange-red cherty soil in which there are few out existed at this contact. crops. The following detailed sections show the character The contact of the Maynardville limestone member of the Maynardville member in the Mascot-Jeflforson with the main body of the Nolichucky shale is grada- City district and adjoining territory. tional, and it is drawn at that level in the section above which limestone predominates over shale. It is a f acies New type section of the Maynardville limestone member of the NolicfmcTcy shale, exposed on the south side of State Highway and not a time boundary. 33, between the bridge across Cox Branch and the Clinch River The contact between the Maynardville and the over bridge across Norris Lake (pi. SB) lying Copper Ridge dolomite is marked by a change in types of rock. Below the contact there is blue crys [Measured by Josiah Bridge, probably about 1938] talline commonly fossiliferous limestone of the type Copper Ridge dolomite: common in the Maynardville (and found locally, Covered interval, concealing possibly 50 ft of beds. Hill side above road is strewn with chert float of Copper Ridge though rarely fossiliferous, in the Maryville and Rut- type, and there are scattered outcrops of coarse-grained ledge limestones) or fine-grained thin-bedded well- dolomite. No outcrops in road ditch. stratified light-colored noncherty unfossiliferous some Nolichucky shale: what calcitic dolomite. Above the contact there is Maynardville limestone member: Feet inches more coarsely crystalline rather heavy-bedded poorly 47. Limestone, blue, fine-grained, heavily bedded with gray, coarser grained stratified virtually unfossiliferous dark dolomite typi mottlings. This limestone is similar cal of the Copper Ridge. The contact is not abrupt. to rocks in unit 32, and the gray The rock types alternate through a zone of several feet; mottlings are evidently a weathered there is no evidence of a disconformity. Oder states phase of the buff and tan mottlings that in sections along the west side of the Valley of in the lower beds——————————— 3 0 46. Dolomite, dark-bluish-gray, finely crys East Tennessee the contact is "usually marked by 2 feet talline ; weathering moderately light, of dark-gray, shaly dolomite, with an undulating upper thick bedded, laminated, the lami contact" (Oder, 1934, p. 475). Such undulating con nae standing in low relief on weath tacts are common throughout the lower Paleozoic se ered surfaces. A few layers of ir regular soft porous siliceous nodules quence in the Appalachian Valley, and no especial im along the bedding planes in the portance is to be attached to most of them. For con upper portion of the unit______28 0 venience in mapping, the writer has consistently drawn 45. Shale, olive-green, hard, well-bedded, the base of the Copper Ridge dolomite at the base of with thin dolomite layers near top. Hand specimens would be indis the lowest bed of dark coarsely crystalline dolomite; tinguishable from the bulk of the this practice has been followed by most field parties in Nolichucky shale__-______2 4 recent years. The advantages of this boundary are 44. Dolomite, similar to unit 46 but with out the siliceous nodules_—___ 2 6 1. The first appearance of the dark coarse dolomite reflects 43. Limestone, light-blue, fine-grained, be a change in the conditions of sedimentation; it is readily picked coming dolomitic toward the top— 3 4 in well-exposed sections. 42. Dolomite, similar to unit 46 but with 2. The dark coarse dolomite produces much chert on weath out siliceous nodules; shaly at top ering; therefore the boundary can be readily determined in and base______2 0 areas covered by residual materials by mapping the edge of the 41. Limestone, dove - colored, sublitho- residual chert. graphic, massive _-___—___ 1 10 3. The boundary lies between the upper limit of the Aphelas- 40. Shale, olive-green, hard, well-bedded, pis fauna, which is the highest of the Dresbach faunas and is with thin platy fine-grained lime here confined to the Maynardville, and the lower limit of Fran- stone layers averaging less than 1 conia faunas, representatives of which are found sparingly in in. thick______1 8 the Copper Ridge. Thus it corresponds to an important faunal change that has been recognized and used as a datum plane 39. Dolomite, like unit 46______9 over a large part of North America. 38. Shale, olive-green, hard, with thin platy layers of dolomitic limestone_ 1 0 As thus drawn, the boundary is one of the more easily 37. Dolomite, dark bluish-gray; weather recognized and mapped contacts in the area. In the ing light colored, finely crystalline, Thorn Hill section it is placed at the base of unit 203 of heavy bedded, finely laminated__ 6 6 36. Limestone, dark-blue, finely crystalline 2 0 the Hall and Amick section (1934). This is essentially 35. Dolomite, like unit 37______4- 6 the contact pointed out to the writer in 1929 by Ulrich 34. Limestone, like unit 36___————_— 2 10 as the boundary between the Cambrian and "Ozarkian" 33. Dolomite, similar to unit 37__—___ 2 4 14 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE Nolichucky shale—Continued Nolichucky shale—Continued Maynardville limestone member—Continued Feet inches Maynardville limestone member—Continued Feet inches 32. Limestone, dark-blue, weathering to 11. Limestone, dark-blue, finely orystTl- bluish gray, finely crystalline to line, massive—————————————— 12 0 sublithographic, with broad irregular 10. Shale, olive-green, hard————————— 4 6 tan and buff stripes and mottlings 9. Limestone, similar to unit 11; expos ed arranged roughly parallel to the opposite south end of bridge———— 5 0 bedding surfaces _-_——__-_ 11 0 8. Shale, olive-green, hard, well-beddec' —13 31. Dolomite, similar to unit 37————— 1 4 7. Limestone, like unit 11, with bed of 30. Limestone, light-blue to dove-colored, edgewise conglomerate at base-— 2 0 fine-grained to sublithographic, mot 6. Shale, like unit 8, typical Nolichucky— 6 tled and striped______— 3 10 5. Limestone, similar to unit 19————— 1 0 29. Limestone, dark-blue, crystalline, 4. Shale, typical Nolichucky, with tl in oolitic and conglomeratic; pebbles platy beds of fine-grained limestone, of limestone, seemingly from the averaging less than 1 in. thick.— 8 0 underlying beds, flat, as much as 3. Limestone ______————————— 1 6 6 to 8 in. long; most abundant in 2. Covered interval ______- 10 0 lower 10 in. of unit______1 10 1. An alternating series of limestor^s 28. Shale, greenish-gray, hard; well-strati- and shales like units just above, the fled with thin layers of dark-blue individual units of shale and line- fine crystalline laminated dolo stone varying from 2 to 8 ft in mite______2 6 thickness, but the relative amounts 27. Dolomite, finely crystalline, laminated, of shale and limestone about eqral. dark-blue-gray, weathering light; Top of unit, a 4-ft bed of b'ne locally crossbedded; one layer of coarsely crystalline fossiliferous stylolites______3 0 limestone; the base, a 3^-ft bed of 26. Limestone, dark-bluish-gray, with tan light-blue to dove-colored apha- stripes and mottlings similar to unit nitic to finely crystalline limestone, 32; upper part badly shattered—_ 28 6 with narrow yellow irregularly 25. Limestone, light-dove-gray, fine-grained clayey partings, exposed at maxi to sublithographic; in some places mum lake level, 1,020 ft______64 0 showing mottlings as above, other places with no traces of bedding__ 6 0 Total Maynardville limestone 24. Limestone, blue, crystalline, somewhat member ______315 banded, massively bedded_____ 3 6 At low stages of Norris Lake a part of the underlying 23. Limestone, dark-blue, somewhat banded with irregular buff and section is exposed; it consists of alternate beds of tan stripings and mottlings similar shale and limestone much as in unit 1, but the thick to unit 32; rather poorly exposed__ 7 0 nesses of the individual units are greater, and shale 22. Limestone, dark-blue, coarsely crys predominates. This is considered the vpper part of talline, magnesian, with few but the shale member of the Nolichucky shaK broad bandings and mottlings___ 15 0 This section can be divided into three- major parts. 21. Limestone, dark-blue, finely crystalline to sublithographic, with buff and At the base is a division about 124 feet thick (units 1- tan stripings and mottlings as in 16) composed of alternating beds of limestone and unit 32______12 0 shale in about equal amounts. This is overlain by a 20. Shale, olive-green, hard, well-strati division 103 feet thick (units 17-26) consisting almost fied______6 entirely of limestone with small amounts of shale. 19. Limestone, finely crystalline to apha- nitic, massively bedded, with irregu Finally an upper division about 88 feet thick (units lar tan stripes and mottlings similar 27-47) is composed of alternating beds of shale, lime to those in preceding units, a 2-ft stone, and noncherty dolomite. This gradation from bed at top—______13 0 shale and limestone, to limestone, to limestone and dol 18. Covered interval______10 0 17. Limestone, blue, nodular______8 0 omite is characteristic of sections in the northwestern 16. Shale, olive-green, hard, well-strati part of the Valley. fied ______3 0 Although the upper contact is not exp osed, it seems 15. Limestone, similar to unit 19_____ 2 0 certain that the base of the dark coarse-grained cherty 14. Covered interval ______4 0 Copper Ridge is not far above the last limestone crop 13. Limestone, similar to unit 19, largely covered ______3 0 ping out along the highway. Scattered outcrops show 12. Shale, olive-green, hard, well-strati- that a large part of the covered interval above the meas fied—______2 0 ured section is occupied by coarse-grain^-d dark dolo- STRATIGRAPHY 15 mite, a type of rock characteristic of the Copper Ridge. Feet inches 6. Covered ______————— 1 0 The hillside is also covered with abundant chert float, 5. Limestone, fine-grained to aphanitic, dove-col which is not derived from the Maynardville or any ored, with semiconchoidal fracture; beds as older unit. much as 4 in. thick, but averaging 1 in. Mas The lower contact is taken at about the point below sive on fresh surfaces; bedding developed which shale is the predominant lithologic type; it could by weathering. Bedding irregular, gently wavy _———__——_—————————————— 1 0 have been drawn at the base of some other limestone 4. Shale, thin-bedded, fissile, olive-green, weather unit either higher or lower in the section. In the Thorn ing to small, thin, rusty, and yellowish flakes, Hill section (pi. 3J.) the writer refers units 136 to 202 interbedded with thin layers of platy apha to this member (Hall and Amick, 1934, p. 166-168). nitic to finely crystalline limestone, the indi The total thickness is 168 feet 9 inches. In the Lee vidual layers less than 1 in. thick______3 6 3. Limestone, a single bed of edgewise conglom Valley section, units 69 to 85 with a total thickness of erates; matrix of aphanitic to finely crystal 181 feet are assigned to this member (Rodgers and line light-bluish limestone, pebbles of the same Kent, 1948, p. 13-14). The gradations from limestone material as much as 1 in. thick and 6 in. long. and shale, through limestone, to limestone and mag- Thickness of bed variable, average______1 0 nesian limestone with subordinate amounts of shale 2. Shale, similar to unit 4, but without the limestone partings______l 10 are much the same as in the type section, although the 1. Limestone, fine-grained to aphanitic, light-gray entire unit is much thinner. to dove-colored. Bedding slightly irregular, The Maynardville limestone member is fairly thick wavy. Some layers weather to smooth along the northern edge of the Mascot-Jefferson City surfaces, others to a rough matte surface. area and forms the crest of the north-facing escarp Strike N. 40° E., dip 10° SE______4 2 ment known as the Richland Knobs that extends north Below unit 1 the limestone units are fewer and thin eastward just south of U. S. Highway 11-W from the ner and finally give way to a mass of shale that makes vicinity of Blaine in Grainger County to a point a few up the great bulk of the Nolichucky. The lower contact miles east of Tate Springs, near the Grainger-Hawkins of the Maynardville member in this section is grada- County boundary (see Luttrell, Dutch Valley, and tional and for convenience is drawn at the base of unit Bean Station quadrangles). The lower part of the 7, thus giving a thickness of 70 feet for the part exposed member is well exposed along State Highway 92, about in the quarry. The section extends 140 feet abcve the 2 miles south of Rutledge (Dutch Valley quadrangle), floor of the quarry to the top of the knob to the north where the following section was measured: east and, as the average dip is 11°, this part of tl ^ unit Section of the lower part of the Maynardville limestone mem has a minimum thickness of about 250 feet. Similar ber of the Nolichucky shale, measured in State Highway beds also crop out at intervals along the highway be Department rock quarry on State Hiffhway 9B, and along the highway at top of hill 2 miles south of Rutledpe, Tenn. tween the quarry and a point 0.25 mile north of Hammer Store (Joppa quadrangle). If the dip remains con [Measured by Josiah Bridge, 1940] stant, the computed thickness of the Maynardville mem Top of quarry. Feet inches ber in this section is at least 350 feet. The upper contact 8. Limestone, exposed in back wall of quarry, sub- cannot be located definitely, but the characteristic resid crystalline to lithographic, light bluish to ual cherts of the Copper Bidge dolomite cover tt e hill pearl gray, often mottled with buff and pink tones. Thick bedded, the individual layers sides between the last outcrops seen and Hammer Store, 8 to 10 ft thick. Individual layers often finely and a few yards south of the store there are outcrops and indistinctly laminated, the laminations of typical Copper Ridge dolomite. more conspicuous on weathered surfaces. About 3% miles southwest, along the road through Laminations often wavy, sometimes contorted, apparently caused by thin films of clayey and Owl Hole Gap (northwest corner of Joppa quad- organic matter. In the lower 15 or 20 ft, drangle), the contact is fairly well indicated by the toward the edges of the quarry are large ir abrupt change from outcrops to residual cherty clays. regular gray to buff-colored masses of fine Strata believed to lie near the top of the Maynardville grained dolomitic material, of irregular shape and size, evidently a selective replacement of are exposed in a roadside quarry in Owl Hole Gap. In the limestone. Thickness to floor of quarry_ 60 0 this quarry several small veinlets of sphalerite have 7. Limestone, exposed along road at north end of been found by Robert A. Laurence. The quantity is in quarry, similar to the preceding, with fine ir regular yellow laminations; weathers smooth significant, but the locality is of interest as the only re and to a light bluish gray_——___——_ 10 0 ported occurrence of sphalerite in the Maynardville in 16 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE the Mascot-Jefferson City district. A short distance Nolichucky shale—Continued south of the quarry all outcrops disappear, and road Maynardville limestone member—Continued Feet inches side cuts show only residual clays and cherts of the 17. Limestone, medium to finely crystal Copper Kidge dolomite. This somewhat abrupt change line, heavy-bedded, minor beddir* irregular; contains irregular dolo from outcrops to residuum is characteristic of the May- mitic lenses, rarely more than an nardville-Copper Kidge contact over much of the Mas inch thick, which weather light col cot-Jefferson City area. ored and stand out in low relief. In the southern part of the district, the Maynardville Strike N. 55° E., dip 30° SE. Fonrs member is thinner, and its limestones are commonly summit of pass. Fossiliferous, con more crystalline, resembling more closely those of the tains typical upper Nolichucky tril->- upper Nolicliucky. The following section, measured bites ______13 6 16. Limestone, shaly, fine-grained, thinly in the southern part of the New Market quadrangle, and irregularly bedded becomir^ will serve to illustrate this phase: more massive toward the base___ 4 0 Section of the Maynardville limestone member of the Nolichucky 15. Shale, hard, platy, fissile, blue to oli^e shale, measured along the secondary road between Rocky when fresh, weathering greenirh. Valley and Piedmont, 0.9 mile south of Rocky Valley Church buff. Contains a few thin beds of fine-grained platy sparingly fossil- [Measured by Josiah Bridge and C. R. L. Oder, October 1940] iferous limestone. Unit incorr- Feet incites pletely exposed______17 0 Copper Ridge dolomite: Lower part of formation forms top of Shields Ridge. 14. Limestone like unit 17. Alternatir«r 25. Covered, orange to red residual clays irregular layers of medium-crystal with fragments of black-banded line dark-blue, and finely crystallir«i cherts showing cryptozoan struc dull-blue-gray limestone, the latter tures. weathering shaly and occasionally more nearly pure shale than lime 24. Largely covered but road cuts show stone; lowest bed a massive crystal thin platy black cherts in clay, pre line limestone 2 ft thick. Noli serving a rude orientation, which is chucky trilobites in the more crys interpreted as stratification modified talline layers___—______19 0 by slump. At the base a thin platy brown sugary sandstone, 1 to 2 in. 13. Shale, hard, platy, olive-green_———— 5 0 thick, also not definitely in place. 12. Limestone, like unit 14, a single mas This is taken as the base of the sive layer exposed at bend in road— 8 0 Copper Ridge. Calculated thick 11. Shale, hard, platy, olive-green, upper ness_——__——————____— 30 0 part poorly exposed, fossiliferous— 10 0 Nolichucky shale: 10. Limestone, fine-grained to aphanitic; Maynardville limestone member: the two varieties intricately mottle-1, 23. Largely covered, but with a few small light bluish to pearl gray; massive, outcrops of greenish calcareous the individual beds 8 to 10 ft thick shale of Nolichucky type. The but splitting into thinner slabs where most prominent of these is about 10 weathered; fracture variable, sub- ft above the first limestones. Cal conchoidal to splintery; weathers culated thickness______75 0 dirty grayish white, with yellow mot- 22. Limestone, dark-bluish-gray to lead- tlings which seem to represent tl 3 color, slightly magnesian, weathers more crystalline part of the original dull gray. Fine grained, finely lam rock. Exposures almost continuous. inated, the laminations accentuated This limestone is identical with that by weathering, rather evenly bed exposed in units 7 and 8 in the sec ded, beds from 6 in. to 2 ft thick, a tion south of Rutledge (p. 15)——— 15 0 conspicuous 3-in. shale parting 9 in. 9. Covered, but exposed in woods abo^Q below the top, other thinner part the road. Similar to unit 10.______9 0 ings throughout the mass_____ 10 6 8. Limestone, similar to unit 10, but grad 21. Covered (possibly shale)______8 0 ually becoming more coarsely crystal 20. Limestone, similar to the above, with line in texture and darker in color, a few beds and lenses of light-gray toward the base, the lowermost, fine-grained dolomitic limestone_ 9 0 beds greatly resembling those in units 19. Covered ______4 0 16 and 17 above the big shale break.— 75 0 18. Limestone, similar to unit 20_____ 1 0 7. Shale______——————————— 6 STRATIGRAPHY 17
Nolichucky shale—Continued (Greeneville quadrangle). The last two localities are Maynardville limestone member—Continued Feet inches described by Oder and have not been studied in detail 6, Limestone, dark- to medium-blue, fine ly to medium crystalline similar to by the writer. lowest beds of unit______25 0 The Maynardville member shows considerable vari ation in thickness, which is what would naturally be Total Maynardville limestone expected if the interpretation of the member as a cal member ______308 careous f acies of the Nolichucky shale is correct. Oder Lower shale member: (1934, p. 4T5, 494, 497) gives the thickness as between 5. Shale, hard, thin-bedded, olive-green_ 55 0 60 and 250 feet, allowing 120 feet for the thickness in 4. Limestone, crystalline, like Maynard the Thorn Hill section (units 14T-202 of Hall and ville ______2 0 Amick, 1934), and 250 feet for the section on Jockey 3. Shale ______15 0 2. Limestone ______8 0 Creek in Greene County. He does not give the thick 1. Shale, calcareous, platy with a few thin ness in the type section. As previously stated, the pres limestone partings______35 0 ent interpretation includes a greater thickness of beds Estimated thickness to base of Noli at the base. The measurements in 6 sections here dis chucky shale______250 0 cussed are—new type section on Highway 33, 31f feet; Total lower shale member_____ 365 Thorn Hill section, 172 feet; Lee Valley section, 181 feet; section along State Highway 92, south of Rut- Total Nolichucky shale______673 6 ledge, about 350 feet (calculated thickness); section on The Maynardville member is well exposed at many Loves Creek, north of Caswell, about 300 feet; section other localities outside the Mascot-Jefferson City area. on Shields Ridge southeast of New Market, 337 feet. The type area north of Maynardville and the Thorn Large variations from these figures have been noted Hill section have been discussed. Dolomitized lime elsewhere in the Valley, and they suggest that Oder's stone in the lower part of the Maynardville member is minimum figure is correct. exposed in the workings of the old lead-zinc mine at Ulrich (1911, p. 636) estimated the thickness of his New Prospect (Ausmus quadrangle; Kent, Eodgers, lower Knox in the Thorn Hill section at 345 feet. and others, 1945, erroneously state that the mine is in GENERAL. FEATURES the upper dolomitic part of the Maynardville), and at one time there was an excellent section of the lower FACIES RELATIONSHIPS limestone part of the member (not dolomitized) be The limestone units of the Rutledge, Rogersville, tween the mine and the old bridge across Powell River Maryville, and Nolichucky formations show many (Keith, 1901, geologic map). Most of this section is lithologic similarities, and, in isolated outcrops where now covered by Norris Lake. According to Rodgers the sequence cannot be determined, it is commonly diffi the total thickness of the Maynardville in this area is cult to identify the particular formation to which the 350 feet. Keith (1901) included all the dolomite and outcrop belongs. In general, the limestones of the Rut- nearly all the limestone beds in this area in the Knox ledge are more dolomitic, and those of the Maynardville dolomite. member of the Nolichucky contain a greater variety of Another good section is exposed in the Knox County lithologic types and locally many thin shale layers. Certain types of limestone are common in all thes^ for workhouse quarry on Blackoak Ridge at Tecoy mations however, and the entire sequence was probably (Bearden quadrangle). The limestone is highly fos- deposited in a relatively constant environment in which siliferous at this locality and yields a fauna similar to the proper conditions of deposition were frequently re that found on Shields Ridge. Still another good ex peated. The most abundant type is a dark-blue to posure is in another Knox County quarry (Biagiotti black finely crystalline massively bedded noncherty quarry), on the northwest side of Rogers Ridge, about limestone that appears to be quite uniform in composi 0.7 mile northwest of Bethlehem Church (John Sevier tion and texture when seen in fresh exposures. It is quadrangle). This is within the mapped area, but it is commonly quarried as a source of crushed stor^ for just north of the Saltville fault that bounds the north roadbuilding; some layers yield large blocks thr.t can ern edge of the Mascot belt. Strata of equivalent age be sawed and polished and used as a decorative marble. are exposed around the Straight Creek mine (Clouds Weathered outcrops are light bluish gray in color and quadrangle), along the Kingsport-Gate City highway commonly display a characteristic mottling of lighter 2 miles north of Kingsport (Kingsport quadrangle), and darker colored stripes and patches. Limestone and along Gass Creek 1 mile northeast of Greeneville showing this mottling is made up of an intricate mix- 18 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE ture of two types of rock, the difference between which Southwestward from the district, on the other hand, is almost invisible on freshly broken surfaces but is the limestones thin out and eventually disappear, the brought out conspicuously by weathering. The two formations lose their identity, and the entire section types of rock differ in grain size: one type is composed between the Rome and the base of the Knox group is of very fine calcite crystals visible only under low represented by a thick mass of calcareou^ shale with magnification, averaging 0.04 millimeter in diameter; thin irregular limestone beds and lenses known as the the other type is composed of coarser crystals of dolo Conasauga formation. mite (with a little calcite), quite distinct to the unaided Thus it would appear that the limestones forming the eye, averaging 0.1 millimeter in diameter. The finer Rutledge, Craig, Mary ville, and Maynardville units are grained variety may be slightly silty. The two types westward-trending tongues of a great limestone unit in generally are arranged in rather irregular layers 0.25 the northeastern part of the Appalachian Valley, and to 0.5 inch thick and roughly parallel to the bedding, that they interfinger with shale tongues—the Rogers- but the coarser material lenses in and out through the ville and the Nolichucky—that extend northeastward fine and is much more abundant at some levels than from the Conasauga formation. The sequence is one at others. The coarser material weathers to lighter of the finest and clearest examples of intergrading shades than the fine and on weathered face perpen facies known in the Appalachian region (see diagram dicular to the bedding produces an unusual and highly on chart, Howell and others, 1944, but the limestone characteristic striped and mottled appearance. On tongues should be shown at the southeast side of this strongly weathered faces the coarser grained lenses diagram) and the fact that the Maynardville limestone commonly stand out in high relief. Weathered bed member participates in this intergradaticn. is a third ding planes show an irregular mottling, and in some reason for classing it with the formations of the Cona places branching anastomosing rodlike masses that sauga group, rather than with those of the overlying strongly resemble f ucoids. No limestones in the Knox Knox group. group possess these peculiar textures or weather in this Still farther south in Alabama and Georgia other fashion; and the occurrence of such limestone in the limestone and dolomite tongues invade th°- Conasauga four pre-Knox formations indicates that they are shale (p. 26), but this does not alter the interpretation closely related, which is one of the reasons for excluding presented here. the Maynardville member from the Knox group. The fossils found in the Maynardville arc yet a fourth Another similarity of the limestones of all four reason for grouping it with the Nolichucky shale rather formations is the absence of appreciable quantities of than with the Knox group; this evidence is discussed chert in any of them. A single thin zone of black below under paleontology (p. 19 ff.). oolitic chert and one or two thin layers of rather soft, spongy chert nodules have been noted near the top of TOPOGRAPHIC EXPRESSION the Maynardville at a few localities (p. 12,13), but in The alternate limestone and shale units of the Cam general the limestones and the deep red residual soils brian have a strong influence on the topography of the derived from them are remarkably free from chert. region which they underlie, so much so that on well- On the other hand, practically all the strata of the Knox made topographic maps, especially those ccmpiled from group yield chert under most conditions, indicating an aerial photographs by the multiplex method, it is often entirely different set of environmental factors during possible to identify individual formationr and groups deposition. The absence of chert in the Maynardville of formations and to trace their approximate bound is a second reason for grouping it with the lower chert- aries by the characteristic topographic patterns. free strata and not with those of the Knox group. The topography developed on the Rome is quite dis Northeastward from the Mascot-Jefferson City dis tinctive. The thick sandstones in the lower part of the trict the Eutledge, Craig, and Mary ville limestone units formation are resistant to weathering, and, in areas merge into a single limestone and dolomite unit, the where moderate or steep dips prevail, the formation Honaker, for the Rogersville shale ceases to be recog forms long, narrow, bugged second-order ridges that nizable in Eussell County, Va. Still farther northeast rise from 300 to 500 feet above the valley f oors. These ward, between Marion and Roanoke, Va., the Noli- ridges are notched at intervals by wind and water gaps chucky shale is also replaced by limestone and ceases and are generally heavily forested because the soil to be identifiable as a distinct unit; here the entire lime developed over the Rome is not fertile. The deeply stone and dolomite mass between the Rome and the notched profile and the heavy forest cover are usually base of the Knox group is known as the Elbrook dolo sufficient to distinguish a ridge over the Rome from mite (Butts, 1933, p. 6-7; 1940b, p. 67,74). one over the Copper Ridge dolomite. STRATIGRAPHY 19 The Eutledge limestone commonly forms a valley The Rome formation is classed as chiefly Lower at the foot of the dip slope of the ridge consisting Cambrian,6 the Rutledge, Rogersville, and Maryville of the Rome formation, though in some places, in areas formations as Middle Cambrian, and the Nolicl ucky of steeply dipping rocks, it may stand up as a low dis shale as Upper Cambrian. The regional correlations continuous ridge between valleys cut on the shales of of these formations have been discussed by Kesser the Upper Eome and Eogersville formations. The (1938), and a somewhat revised correlation ha? ap Rogersville shale forms a valley, commonly continuous peared on the Cambrian correlation chart, prepared with the one developed on the Rutledge. Where the by the Committee on Stratigraphy of the National Re beds are steeply dipping, the Craig limestone member search Council (Howell and others, 19M). may locally be identified by a row of low knolls scarcely The relations of Nolichucky and Maynardville to more than 20 feet high. Where the dip is gentle, the each other and to the Copper Ridge are the only ones Craig commonly forms a low but well-defined and per pertinent to the present report. sistent escarpment, the flat surface at its summit being Th'e Nolichucky shale, including the Maynardville developed on the upper shale member of the Rogers- limestone member, is highly fossiliferous and if cor ville and the basal beds of the Maryville. An excellent related with the Dresbach formation 7 of the Upper example of this scarp may be seen in the valleys of Ray Mississippi Valley and its equivalents elsewhere in and Richland Creeks, at the foot of the Richland Knobs North America. The Cedaria, Crepicephakte, and escarpment, on the Joppa, Dutch Valley, and Avondale Aphelasph faunal zones, which characterize the Dres quadrangles. In areas where the rocks dip steeply bach formation as here defined, are present in the Noli (over 60°), the Maryville limestone, especially its upper chucky shale. The Oedaria zone is found in the lower part, forms a low steep-sided, narrow ridge cut by part of the shale member, and the species listed by Hall many water gaps. The Nolichucky shale forms a dis and Amick (1934, p. 166) from several levels in their tinct valley behind the ridge, and the Maynardville unit 131 all belong to it. The Crepicephalus zor?. oc member beyond forms a second, parallel, lower and less curs higher in the shale member, and elements of it are definite ridge, generally merely a row of spurs. Good sometimes found in the lower part of the Maynardville examples of these features occur on the John Sevier limestone member. The number, kind, and relative quadrangle in the area north of Mascot and south of abundance of species differ from shale to limestor°i. U. S. Highway 11-W, also on the Luttrell quadrangle The Aphelaspis fauna, as far as now known, if con south and east of Blaine. Where the dip of the strata fined to the Maynardville limestone member, but it has is gentle, the Maryville forms a steep but strongly not been found in all sections. Inasmuch as there is dissected scarp along one side of the valley, the basal little or no evidence for unconformity at the top of the part of the Nolichucky forms a much dissected bench Maynardville, the failure to find this fauna at some at the top of the Maryville, and the remainder of the localities is most probably due to a shift in facier that formation rises in a steep escarpment capped and up permitted the deposition of fine-grained unfossiliferous held by the Maynardville limestone member and the lime muds, now preserved as magnesian limestones. Copper Ridge dolomite. This sequence is well shown The fossils differ markedly in abundance from lith^logy in the Richland Knobs escarpment on the Luttrell, to lithology; they are most abundant in coarse-grained Joppa, and Dutch Valley quadrangles beyond the limits limestones, extremely rare in the aphanitic, sublitho- of the map, and on the north face of Shields Ridge graphic varieties, and virtually unknown in the mag on the New Market and Jefferson City quadrangles. nesian limestones. Even in the coarsely crystalline The topographic profile is highly characteristic and easily identified and has been recognized on many of strata, the fossils commonly occur in richly fos the new TVA quadrangles between Knoxville and siliferous beds or lenses separated by barren areas of Bristol. otherwise similar rock. Inasmuch as most of the fos PALEONTOLOGY AND CORRELATION sils are dissociated fragments of trilobite tests, these accumulations are interpreted as the result of current Many of the fossils found in these five formations have been listed and figured by Resser (1938). Butts 6 Middle Cambrian fossils occur in the shale here classed as- upper (1926, p. 67, 72-78, pis. 5, 8, 9; 1940b, pt. 2, pis. 65-67) Rome. This shale corresponds to the Pumpkin Valley shale of Todgers and Kent (1948, p. 7-9), but the fossils were erroneously listed) by has figured many of the species and has discussed their Resser (1938, p. 27) as Rntledge. distribution in equivalent strata in Alabama and Vir 7 The name Dresbach formation as used here conforms to thii usage of Trowbridge and Atwater (1934), and includes the Mt. Simcn, Ban ginia; Resser and Howell (1938) have figured and de Claire, and Galesville members. This is not the classification of the scribed the Lower Cambrian faunas of the Appalachian U. S. Geological Survey (Wilmarth, 1938, p. 631-632), but it ccnforms with generally accepted usage of Cambrian stratigraphers throughout Valley. North America (Howell and others, 1944). 20 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE action. The scarcity of fossils in the fine-grained lime Aphelaspis zone stones is probably environmental, for it is well known Aphelaspis camiro (Walcott) that today areas of fine-grained lime muds are almost hamblenensis Resser devoid of benthos. laxa Resser Lochman and Duncan (1944, p. 31), discussing the quadrata Resser simulans Resser ecology of these faunal assemblages, wrote: tumifrons Resser Although a lack of knowledge of the physiologic processes of walcotti Resser (Va.) trilobites precludes a positive statement of water tempera CheilocepJialus breviloba (Walcott) tures, the large diversified faunal assemblages of the Cedaria Raaschella appalachia (Resser) (listed by Resser as and Crepicephalus zones would by analogy indicate warm tem Stenochilina) perate conditions, while the assemblage of the Aphelaspis zone, bristolensis (Resser) (Va.) (listed by Resser as rigidly restricted to five trilobite genera throughout the entire Terranovella) country, and represented by large numbers of individuals, may Species listed by Resser that are probably referable to the indicate the introduction of cooler waters. Aphelaspis zone: Blountia assimilis Resser Further, Lochman writes (personal communica crassa Resser tion) : Crepiceplialus zone The CrepiceJialus fauna contained a large number of species ; therefore some of the diagnostic forms are almost certain to Blountia alexas (Walcott) be present, no matter what the lithology of the formation may anser (Walcott) be. It also appears that certain genera characteristic of the mimula (Walcott) fauna, notably Crepicephalus, Uncaspis, and Llanoaspis, were rogersvillensis Jtesser=Blountiella lata Resser able to live in environments containing quite a bit of clastic BlountieUa buttsi Resser (Va.) material; therefore species belonging to these genera are fairly Coosia rofaista (Walcott) well represented in shales and sandstones, as well as in lime Crepicephalus etepansiis Resser stones, and thus serve as a means of correlation between dif reotiformis Resser ferent f acies. Kingstonia rotunda Resser Llanoaspis blandensis (Resser) (Va.) In his discussion of the Upper Cambrian faunas of ~buttsi (Resser) (Va.) the Appalachian Valley, Resser (1938, p. 28-30) listed campbelli (Resser) (Va.) species occurring in the Cedaria, and Orepicephalus clinchensis (Resser) zones, in eastern Tennessee, mentioned the presence of peculiai"isi (Resser) ulrichi (Resser) the Aphelaspis zone without listing its fauna, and stated virginica (Resser) (Va.)=L. roffersv'Hensis (Resser) that a fourth zone, his so-called Blountia zone, was pres walcotti (Resser) ent above the Aphelaspis zone. His list of species from Maryvillia arion (Walcott) this zone is lengthy and includes at least 8 forms known keithi Resser sp.=Coosia alethes (Walcott) to be characteristic of the Aphelaspis zone, 23 known Pemphigaspis appalachia Resser from the Orepicephalus zone, and a few species that are TricrepicepJialus magnispinus (Walcott) unknown in this part of the Cambrian and are thought thoosa (Walcott)* to have been misidentified. Most Cambrian stratig- ivalcotti Lochman raphers and paleontologists now believe that the so- Uncaspis micans Resser called Blountia zone does not exist as a distinct unit, Species listed by Resser that probably belong in the Crepi but that the fauna attributed to it is made up primarily cephalus zone (ranges of those marked with an asterisk (*) may of species from the Aphelaspis and Orepicephalus zones, extend into the Cedaria zone) : particularly those forms characteristic of coarse Blountia arcuosa Resser grained limestones. This would account for the ex *Coosella amage (Walcott) traordinary development of the so-called Blountia zone andreas (Walcott) in sections where such limestones are abundant and its tennesseensis Resser *Devracephalus buttsi Resser scarcity or absence in sections where fine-grained lime Genevievella marionensis Resser (Va.) stones or dolomites make up the bulk of this member. *Kmgstonia walcotti Resser The lists of species characteristic of the Orepicephalus Terranovella typicalis Resser and Aphelaspis zones given below were prepared by Trierepicephalus comus (Walcott) Mrs. Christina Lochman Balk and have been checked To the above lists should be added the species as for changes in generic assignments by her and A. R. signed by Resser (1938, p. 29) to the Orepicephalus Palmer. zone. In compiling these lists a few obvious mistakes All species listed are from the Appalachian Valley; have been corrected, but no attempt has been made to those indicated (Va.) are known only from Virginia. eliminate possible homonyms and syronyms as this STRATIGRAPHY 21 would involve a detailed paleontological study that is Safford (1869, p. 203-226) proposed the term "Knox beyond the scope of this report. ville or Knox Group" 8 to include all the strata cropping Eesser (1938, p. 28) also mentioned the presence of out in the Valley of East Tennessee below the "Trenton graptolites in some of the faunas from the Nolichucky and Nashville Series," now the Lenoir limestone and shale. These are mostly dendroid forms and are com higher formations. (The older Lower Cambrian quartz- monly found associated with the Aphelaspis fauna in ites and shales, which he assigned to the Chilhowoe and the Maynardville limestone member. One of the best Ocoee groups, do not crop out except in the mountains localities is at the Knox County quarry at Tecoy along the southeast margin of the valley.) In the (p. 17), but they have also been found at several other group, he recognized three divisions: from below up localities. Decker has studied this f aunule but has not ward—the Knox sandstone, the Knox shale, and the published a list of species. Knox dolomite. This classification was used by others, notably the geologists of the early State Surveys of KNOX GROUP Alabama and Georgia (Smith, 1876, and many other GENERAL, REMARKS publications). DEFINITION The section that Safford considered "typical of the The Knox group as used in this report comprises all Knox Group" begins at the fault on "Webb's (or Rose- strata above the Maynardville limestone member of the bury's) Ridge, nearly three miles northwest from Knox Nolichucky shale and below the Lenoir limestone or ville, and extends to the Holston River. It is about its Mosheim member. It is essentially the Knox dolo three miles in length, and was taken along Second mite of the Knoxville, Maynardville, and Morristown Creek." (Safford, 1869, p. 204 and fig.). Y^ebb's folios (Keith, 1895, 1901, 1896). The establishment Ridge is now known as Sharp Ridge. The section of a satisfactory subdivision of the Knox dolomite was crosses two belts of Knox dolomite, the northwestern of the major task undertaken when the author began the which is the southwest extension of the Mascot belt. geologic work that led to this report. Such subdivision Safford (1869, p. 205) gave a generalized section of the is important economically because mineral deposits in limestones and dolomites in this northwestern ridge and the Knox group are commonly confined to definite, stated that their total thickness was 3,504 feet. This rather thin, stratigraphic zones and at the same time section is now entirely within the built-up part of the are related to relatively minor structural features; city of Knoxville—the valley of Second Creek is oc therefore the more stratigraphic and structural detail cupied by the tracks and yards of the Southern Rail that can be shown on a geologic map, the more valuable way—and at present little can be seen of the or'ginal it will be to the mining geologist and mine operator and section. The section on Loves Creek, about 6 miles to any others who may have occasion to use it. northeast of Second Creek and in the western part of the area mapped for the present project, crosses the HISTORY same belt of outcrop, and from it one can obtain a rea The history of the terminology of the Knox group sonably accurate picture of the Knox group of Ssifford and of the underlying and overlying formations is in its type area. Even this is threatened by the growth shown in chart 1. The columns of this chart list the of the city. A much better exposed section, and the one now commonly considered to be the most representa names applied to Cambrian and Ordovician rocks in tive both of the Knox group of Safford and of the Knox the publications cited, but the order is not necessarily group of present usage, is that at Thorn Hill, Grainger that of the author cited; instead the names have been County (p. 25; pi. 3A). rearranged to show how the rocks included in the In the 1890's the U. S. Geological Survey began to author's units are now classified. Thus, where a name, publish folios covering 30-minute quadrangles in the such as Sevier shale, was applied to two units now southern Appalachian region. In these, the Knox separately classified, the name appears in two places group of Safford was abandoned and new names were in the appropriate column. Similarly, Ulrich (1911, proposed for the two lower divisions. The upper third p. 637-638, pi. 27) places his Jonesboro limestone of the original Knox group retained the name of Knox on the eastern side of the Appalachian Valley entirely dolomite. No attempt was made to map subdivisions above his "Upper Knox" on the western side; it within the Knox dolomite, although it was recognized is now known that the Jonesboro as originally de s "The city of Knoxville is located on a ridge made up of its limestones fined includes the facies equivalent of the entire Knox and dolomites; and this circumstance, together with the fact tJ at the sequence in the western belts, and it is so indicated on threefold typical character of the series is well developed in Knox County, has induced me to. name it the Knoxville, or the Knox Proup," the chart. (Safford, 1869, p. 204.) 22 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE from the start that the formation contained both Cam were interested in these problems. The impress of his brian and Silurian fossils. (At that time the term Or- work upon studies of Appalachian stratigraphy will dovician period was not recognized by the U. S. Geolog remain for a long time to come, and it is greatly to be ical Survey.) The boundaries of the Knox dolomite regretted that he did not find time and opportunity to were drawn on purely lithologic grounds, the presence publish more of his ideas. The writer was closely asso of dolomite being the chief criterion. Thus it hap ciated with Ulrich during the years that this study pened that, in Alabama, Georgia, and southeastern Ten was in progress and is fully conscious and most appre nessee, beds of pure limestone that are laterally equiv ciative of the help that this association r.fforded. In alent to the upper third of the Knox dolomite farther spite of this, many of the interpretations presented north and northeast were excluded from the Knox and herein are directly contrary to some of Ulrich's most mapped with the overlying Chickamauga limestone. firmly held convictions. This is regrettable but un According to Butts (Butts and Gildersleeve, 1948, p. avoidable as long as so many of the facts are unknown 18-19), the Chickamauga at its type locality contains or at best imperfectly understood; at the same time the Newala limestone, which is equivalent to the Kings- it is fully realized that the results of this rtudy are not port and Mascot formations of the present report. Sim final and that they will undoubtedly be modified and ilarly at the lower limit, beds of dolomite in central improved by subsequent workers. Alabama, now known to be equivalent to the Noli- In general, Ulrich believed that the sequence of chucky and Maryville and perhaps also the Eogersville formations and faunas in the Knox group is different formations, and therefore older than the Knox dolomite in different areas; that facies changes are quite unim of Safford and Keith, were mapped as, and considered portant; that certain formations and their associated a part of, the Knox dolomite. At the same time, equiv faunas are locally absent either because of nondeposi- alents of the Knox dolomite in States farther north re tion or because of subsequent uplift and erosion; and ceived other names, such as Shenandoah, Natural finally that formations are normally separated from Bridge, Kittatinny, and Conococheague limestones, and, each other by disconf ormities. Butts, who was closely owing to scarcity of fossils and the failure to utilize the associated with Ulrich for many years, aclHred to these few that were found, little progress was made for many views during much of his earlier work in the Appa years in correlating the rocks in the several areas. lachian Valley, but he recognized several important The first attempt at correlation and subdivision of facies changes (for example, between the Lowville and the Knox dolomite was made by Ulrich (1911, p. Moccasin limestones and between the Conococheague 633-640), who demonstrated that it could be zoned and limestone and the Copper Eidge dolomite). divided. During the next two decades, a considerable As the present investigation progressec1 , and as the amount of subdivision was accomplished in Alabama writer became familiar with the problems of the Knox and Virginia through the detailed mapping of Butts group, the conviction grew on him that there are few, (1926; 1933; 1940b; Butts and Gildersleeve, 1948) and if any, unconformities of great magnitude within the others (Woodward, 1932) aided by the paleontological Knox group; that the sequence of fauna* within the work of Ulrich. The correlation of certain paleonto group is the same throughout the Appalachian Valley, logical zones throughout the length and breadth of the at least in Tennessee; that any one of these faunas may Appalachian Valley was fully established, but little be better developed or preserved and thus seemingly detailed mapping was done in Tennessee until the pres more abundant at one locality than at mother; and ent investigation was started. that this in turn may be due to the lithology of the After the publication of the Eevision of the Pale rocks containing the fossils or to various environmen ozoic Systems (Ulrich, 1911), Ulrich did not publish tal factors at the time of deposition. much concerning the subdivision of the Knox, but the It is now known that the Knox group contains the subject was constantly in his mind. Some of the results same series of faunas on both sides of the Valley, but of his studies are available in the form of correlation that it is in a predominantly dolomitic facies on the charts inspired by him and published by others (Bassler, northwestern side and a predominantly calcareous 1915, pis. 1, 2; Gordon, 1924, p. 34; Secrist, 1924, p. 16; facies on the southeastern side. The intervening belts, Ulrich and Cooper, 1938, pi. 58). For many years he among them the three belts included in the Mascot- was absorbed in regional stratigraphic studies of lower Jefferson City district, show various gradations be Paleozoic rocks in the Appalachian Valley and else tween these two extremes. In general, an increase in where in the eastern and central United States and was the amount of dolomite in a given formation is accom consulted on many occasions by geologists of the Fed panied by a decrease in the number of foss'ls preserved. eral and State Surveys as well as by many others who Failure to recognize these facies relationships largely STRATIGRAPHY 23 vitiated Ulrich's classification and correlation of the over, no two workers define them with the same limits. rocks of the Knox group, for, if fossils characteristic It is true that the Kingsport limestone corresponds to of a given unit were not recognized, the unit was pre some part of the Jefferson City formation of the Ozark sumed to be absent by unconformity. For example, region, and the Mascot dolomite corresponds to some Ulrich (1911, p. 671-674) considered the "Jonesboro" portion of the Cotter, but there is no evidence to indi limestone on the east side of the Valley, which carries cate that the Jefferson City-Cotter boundary is the Canadian fossils in its upper part, to be much younger same as the Kingsport-Mascot boundary; in fa rt.t, re than the generally unf ossilif erous dolomite on the west cent studies indicate that they are not exactly the same side, but when fossils were finally found in this dolomite (Cullison, 1944). There is at present no evidence to they showed that the two sequences are to be correlated. indicate that any beds in the Appalachian Valley of Similar reasoning underlies Oder's remark that the Tennessee are equivalent to the Powell formation of Stonehenge limestone "intervenes between the Chepul- the Ozark region; on the contrary, fossils from the top tepec formation and the Nittany [Longview] dolomite of the Mascot dolomite in several localities correlate in the northeastern part of the valley, not being known it with the upper part of the Cotter. elsewhere in the area" (Oder, 1934, p. 481), yet the The five formations into which the Knox group has fossils show that the Stonehenge and Chepultepec are been divided are generally recognizable within the facies equivalents within a single formation (Grabau, Mascot-Jefferson City district and over much of the 1937, p. 66-67; Butts, 1940b, p. 101). Failure to take surrounding territory, but their recognition and deline regional facies relationships into consideration was ation depend to some extent on the scale of the map on the cause of the unusual variations in thickness that which they are to be shown. Moreover, they are not Ulrich reported for certain formations, and also of the always easy to map because of similarities in litl ology very great total thicknesses he assigned to the lower from unit to unit, both in the bedrock and in the re Paleozoic systems. sidual cherts, and because of lack of outcrops, coHuvial PRESENT USAGE movement of residuum, and absence of fossils anc1 other In this report the Knox group is divided into five diagnostic criteria. Hence the boundaries on the geo formations, which are, in ascending order, the Copper logic map are indefinite in many places. Eidge dolomite of Late Cambrian age, and the Chepul For example, in the Mascot belt, the Chepultepec tepec, Longview, Kingsport, and Mascot formations of and Longview dolomites are both strongly dolomitic Early Ordovician age. (As previously noted, the May- and can only be separated from one another with great nardville limestone of Oder is here considered to be a difficulty, but in the area around Jefferson City the member of the Nolichucky shale and is excluded from Chepultepec contains a great deal of limestone which the Knox group.) These formations are lithologic makes it easier to differentiate. Similarly, the Kings- units; the confusion of formations with faunal units, port and Mascot formations are reasonably distinct in that is, the definition of formations solely by their the Mascot-Jefferson City district, the former being faunal content, has led to much of the confusion now largely limestone, the latter dolomite. To the south existing in the correlation of the formations of the Knox and southwest of the Mascot-Jefferson City district, the group and of the overlying formations in the Appa percentage of limestone increases; in southern Tennes lachian Valley. see, Georgia, and Alabama the two formations los^ their The names Kingsport and Mascot were chosen jointly identity in a great mass of limestone—the Newalr, lime by Bridge and Charles E. L. Oder for use in this re stone. To the north and northwest, on the other hand, port and a similar report being prepared by Oder on the limestone beds diminish in number and thickness the area to the northeast. They were proposed by and, except for a few layers near the base of the Kings- Oder and Miller (1945) and have been used in several port, totally disappear, so that the separation of the abstracts and maps in the last few years. They re two formations in the western belts of outcrop is also place the terms "Jefferson City formation" and "Cot extremely difficult. ter- Powell beds" used by Oder (1934) and also Forked There is little evidence of an unconformity at the Deer and Thorn Hill used by Hall and Amick (1934). base of the Knox group. Although generally speaking Jefferson City, Cotter, and Powell are the names of it is fairly easy to separate the Maynardville frm the formations exposed in Missouri and Arkansas, and Copper Eidge, in practice it is often difficult to draw there is no possibility that they can ever be traced into the precise boundary, especially toward the western the Appalachian Valley. Even today, the limits of side of the Valley (see p. 13). these three formations in their type areas and their There is now ample evidence of an unconforirity of relations to one another are not well known. More some magnitude at the top of the Knox group in East 24 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE Tennessee, though even here it is sometimes difficult valid reason for separating the so-callei Canadian to separate the uppermost limestones of the Mascot rocks from the rest of the Ordovician, unless it be the dolomite from the overlying Mosheim member of the unconformity at the top of the Canadian or Lower Lenoir limestone. Fossils collected in the upper 50 feet Ordovician. These results are not at all astonishing of the Mascot at a few widely separated localities in for, whereas the Canadian was simply split off from the dicate that faunas of latest Beekmantown age, such early part of the Ordovician in order to lessen the as have been found in the Warm Springs Valley and amount of time allotted to that period and make it more at other localities in western Virginia, are not present nearly commensurate with other periods, notably the in Tennessee. The Lenoir limestone, including the Silurian and Devonian, the Ozarkian was believed to Mosheim member, carries a Chazyan fauna, and there be a new and hitherto unrecognized system wedged in does not seem to be a sufficient thickness of strata be between the Cambrian and the Canadian. It can now tween the Mosheim above and the highest fossiliferous be stated that, with the possible exception of the Madi beds in the Mascot below to carry the upper Beekman son sandstone in Wisconsin, there is not a single for town (Cassin) faunas. Furthermore, a conglomerate mation among those assigned to the Ozarkian by occurs locally at the base of whatever unit overlies the Ulrich that cannot be and has not been properly cor Mascot dolomite; the pebbles of this conglomerate are related with formations that Ulrich hims3lf placed in chiefly chert fragments derived from the weathering of either the Cambrian or the Canadian. This seeming the upper formations of the Knox group and are clear paradox came about because most of the formations ly identifiable as such. This unconformity and the de assigned to the Ozarkian are predominantly dolomitic posits upon it are discussed more fully below (p. 57-59). in character, whereas their equivalents elsewhere are The most probable break within the group itself is limestones, shales, and sandstones. The dolomites, as that between the Copper Ridge and Chepultepec dolo always, are sparingly fossiliferous and many of the mites, which corresponds to the break between the fossils found are those of forms adapted to this peculiar Cambrian and Ordovician periods, but even this break environment and hence at first sight seemingly differ does not appear to involve a long interval of time as ent from those found in the other rock tyj es. 110 faunas are known to intervene elsewhere. In defining the Ozarkian, Ulrich (1911, p. 627) included OZARKIAN AND CANADIAN SYSTEMS OF TJLRICH all the formations in the Appalachian Valley that can be shown Many of the papers cited in this report make frequent to be younger than (1) the top of the Upper Cambrian Noli- references to the proposed Ozarkian and Canadian sys chucky shale in northeastern Tennessee and (2) the top of tems of Ulrich. These systems, proposed by Ulrich in the Conasauga shale in southeastern Tennessee, northwestern 1911, were never formally adopted by the U. S. Geologi Georgia, and northeastern Alabama and which are older than the base of the Stonehenge limestone of the Canadian system cal Survey. They were used, however, by a consider in southern and central Pennsylvania. able number of geologists for three decades and were Thus the Copper Ridge dolomite of Ee.st Tennessee adopted either formally or informally by a number and its equivalents elsewhere were considered to be of of State organizations. As a result, the names Ozark Ozarkian age. In more recent years, however, ele ian and Canadian have appeared in publications and ments of a number of faunas of Late Cambrian age maps issued by several State surveys and on certain maps and publications of the Geological Survey, at have been found in the Copper Ridge (p. 34 ff.), and it can now be shown that the formation is probably the least as quoted from Ulrich. Since the death of Ulrich in 1944 and of Butts in 1946, these systems have re equivalent of both the Franconia and the Trempealeau formations of Wisconsin and of their equivalents ceived little support. But many questions concerning them are still unanswered, and, as the Mascot-Jefferson elsewhere. City district and East Tennessee lie in an area where The distinguishing feature of the Ozarkian faunas, these systemic terms were applied, some discussion is according to Ulrich, was an association of trilobites of here devoted to them. Upper Cambrian affinities with gastropods and cephalo- It may be stated at the outset that no evidence favor pods of Ordovician or Canadian affinities. Not all his able to the recognition of the Ozarkian has been found trilobites, however, are distinctly Cambrian in charac in the course of this investigation. For the Canadian ter; in fact, those assigned to the upper Ozarkian are the results are more noncommital. A case for a some all types unknown in the Cambrian and all have definite what enlarged Canadian system can be made if the es relationships to the forms occurring higher in the Ordo tablishment of a new system for the Lower Ordovician vician. The gastropods are about equally well repre seems desirable; on the other hand there seems to be no sented on both sides of the period boundary. Their STRATIGRAPHY 25 association with the Cambrian trilobites in the lower of the Knox group but for a number of older and Ozarkian is largely a matter of facies—the gastropods younger formations as well. It differs in some details lived in a lime-mud environment, and, when this was from the sections in the Mascot-Jefferson City district, invaded by trilobites, the characteristic Ozarkian as and these differences are pointed out below in the de semblage was formed. Most formations recognized by scriptions of the various units. The section begins at Ulrich as being of Late Cambrian age are composed of a thrust fault about TOO feet north of the north end crystalline limestones, shales, and sandstone. Trilobites of the bridge across Indian Creek at the northwest base are abundant in these rocks, but gastropods are com of Copper Ridge, where the Lower Cambrian Rome paratively rare. Even the trilobites vary in abundance, formation is thrust over the Moccasin limestone of however, according to the type of sediment in which Middle Ordovician age, and extends southward crossing they are found. The well-known Upper Cambrian Clinch Mountain to Poor Valley Ridge, where the Rome genus DikelocephaluS) once believed to be the index formation in the base of the next fault block to the fossil for the Upper Cambrian, is actually restricted to south is thrust over the lower Mississippian Grainger a shale environment. formation. The exposures in the older part of this section are COPPER RIDGE DOLOMITE practically continuous, and Hall and Amick (1934) NAME measured a detailed section from the beds low in the Ulrich (1911, p. 635-637) proposed the term "Copper Rutledge limestone exposed close to Indian Crsek to Ridge chert" for his second division of the Knox dolo the lowest red beds of the Moccasin limestone opposite mite of eastern Tennessee and southwestern Virginia. Thorn Hill P. O. This was a bed-by-bed measurement The name was taken from Copper Ridge, the long, nar using planetable, alidade, and steel tape and contains row, monoclinal ridge at the northwest base of Clinch notes on the lithology and paleontology, but, although Mountain, recognizable as a distinct topographic fea the Knox was divided into four formations and new ture from Russell County, Va., to a point some miles names were applied to two of them, no discusnon of west of Knoxville.9 The type locality 10 is along "the formations or correlations was given. At the sugges road from Bean Station u to Evans Ferry, on Clinch tion of the writer, Hall and Amick painted the numbers River" (Ulrich, 1911, p. 636), now U. S. Highway 25-E. assigned to many of their units on the exposures. Many It is shown on the Morristown folio (Keith, 1896) and of these are still visible (1950) and make it easy for on the Avondale T^-minute quadrangle sheet of the anyone having their paper to orient himself in the sec TVA series (pi. 3A). No detailed section was in tion. Rodgers and Kent (1948) reinterpreted the sec cluded, but the approximate thickness of the various tion in the light of the further development of ic^-as by the writer and others, and correlated it with a similar formations and some description of the lithology, one exposed along State Highway 66 at Lee Valley 16 paleontology, and correlation of each were given. miles northeast. In making these comparisons, they This remarkable section, commonly known as the pointed out a few significant key beds missed by Hall Thorn Hill section from Thorn Hill P. O. at its south and Amick and corrected a few errors in addition. ern end, exposes almost every foot of the beds included Oder (1934, p. 489-494) also measured and described in the Knox group as well as a great thickness of the this section, divided it into five formations, and cor overlying and underlying strata. It is one of the best related it with other sections in East Tennessee. These exposed most continuous sections of lower Paleozoic are the only detailed descriptions of the Copper Ridge rocks in East Tennessee and is now considered the stand dolomite in its type area that have been published. ard of reference for this region, not only for the strata Hall and Amick's formations are not exactly tlie same as Oder's, and both differ in certain particulars from •East of the gap at Speers Ferry, Va., where Troublesome Creek cuts through the ridge to join Clinch River, this ridge is known as those used in this report. Moccasin Ridge, and the name Copper Ridge is transferred to the next As originally defined, the Copper Ridge included all structural belt to the northwest (see Estillville 30' quadrangle and the new Clinchport and Duffleld 7%' quadrangles). the strata above Ulrich's "lower limestone" (roughly 10 Wilmarth (1938, p. 519) states that the formation was "named for equivalent to the Maynardville limestone member of Copper Eidge, NB. of Knoxville, Tenn.,1* and Resser (1938, p. 17) says that "The type locality for the Copper Ridge formation is on Copper this report) and the base of the "Upper Knox" (Kings- Ridge, Knox County, Tenn. (Ulrich, 1911)." Cooper (1944, p. 23) makes a similar statement. The only section of the formation on Copper Ridge port limestone and Mascot dolomite). It included, mentioned by Ulrich in his original description is the one in Grainger therefore, the Chepultepec dolomite and the Longview County, discussed here, and Ulrich stated to the writer on several occasions that this is the section to which he was referring in the "Re dolomite of this report. This was not Ulrich's inten vision" and that he regarded it as the type section. tion but was due to failure to find the fossils charac 11 This locality is now submerged by Cherokee Lake, and Bean Station is in a new location, more than a mile to the west. teristic of the Chepultepec and Longview in the Thorn 26 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE Hill section; the absence of the fossils was considered DISTRIBUTION evidence that the formations were missing because of In the Mascot-Jefferson City district the Copper a disconformity (see p. 22). Later the Copper Ridge Ridge covers a greater area than any othe~ formation. dolomite was studied in greater detail in Alabama and It is found in all three belts of outcrop (p. 7) but is Virginia by Butts (1926, p. 84-87; 1940b, p. 90-95) and most extensively developed in the northwestern or Ulrich (mostly unpublished, but see charts in Bassler, Mascot belt, particularly in the region between Jeffer 1915, pis. 1, 2; Gordon, 1924, p. 34; Secrist, 1924, p. 16; son City and Rutledge, where, because cf its nearly Ulricli and Cooper, 1938, pi. 58), and its position be horizontal position, its outcrop belt cover? an area of neath the Chepultepec was clearly established. Sub many square miles. sequent work on the Thorn Hill section by Ulrich, Butts, The best outcrops and most complete sections of the Oder, the writer, and others has brought to light both Copper Ridge within this area—and for that matter the Chepultepec and Longview faunas in the upper part of the other subdivisions of the Knox group—are in of the original Copper Ridge, and the formation in the the western part of the Mascot belt between Knoxville type section is now restricted to the beds above the May- and Richland (Ada on the Maynardville 30-minute nardville limestone member of the Nolichucky shale and quadrangle). Here the steeply dipping beds of the below the Chepultepec dolomite, more specifically to group form a belt 2,000 to 3,000 feet in wid*to, and there units 203 to 304 of Hall and Amick's section. are good sections along almost every creek crossing the In Tennessee, Virginia, and northern Alabama the strike. The best sections are along Lover (p. 27-30), Copper Ridge is the oldest formation that has been as Woods, Strong, and Roseberry Creeks (all on the John signed to the Knox group, but in central Alabama, par Sevier quadrangle), and along Big Flat Creek on the ticularly in the Cahaba Valley, other units, namely the Mascot quadrangle. Northeast of Richland the outcrop Bibb, Ketona, and Brierfield dolomites, are believed by belt of the formation widens abruptly because of a sudden flattening of the dip, reaching a maximum some (Ulrich, 1911, p. 633-634; Bassler, 1915, pi. 2; width of about 8 miles in the region just north of Jeffer Butts, 1926, p. 81-84; 1940a, p. 6) to lie above the Noli son City and gradually narrowing nortl ^ast of this chucky shale or its equivalent but below the Copper point to a termination about 10 miles north of Morris- Ridge dolomite. Other geologists, including the writer, town. Northeast of Mascot the exposures are small, believe that these formations, collectively known as the discontinuous, and less common, and most of the map "Sixmile series" (Resser, 1938, p. 17), represent a dolo- ping has had to be done on the basis of small outcrops mitic f acies of the upper part of the Conasauga shale, and residual materials. An excellent section of the being the stratigraphic equivalents of the Nolichucky, Copper Ridge dolomite in the Jefferson City belt was Maryville, and Rogersville formations of Tennessee, formerly exposed on Pearce Branch in the Talbott for the few fossils found in the immediately underlying quadrangle, but the greater part of this section is now Conasauga shale in the Sixmile area are Middle Cam submerged beneath Cherokee Lake. brian forms similar to those found in the Rutledge lime stone of Tennessee (Butts, 1926, p. 73, pis. 5, 8; 1940a, LIMITS AND THICKNESS p. 5). If the Bibb, Ketona, and Brierfield were indeed The contact of the Copper Ridge with tiN Maynard younger than the Nolichucky shale and older than the ville limestone member of the Nolichucky sHale has been Copper Ridge dolomite, then a notable disconformity discussed (p. 13) ; it is commonly taken at the base of would exist between these two formations in East Ten the lowest bed of coarsely crystalline H-avy-bedded nessee; this was always Ulrich's belief. The writer knotty dark dolomite, for example, unit 203 of the however finds no evidence for such a disconformity in Thorn Hill section (Hall and Amick, 1934, p. 168) and East Tennessee (p. 13). Cooper (1944, p. 27) likewise unit 86 of the Lee Valley section (Rodgers and Kent, found no physical evidence for an unconformity in the 1948, p. 14). Burkes Garden area of Virginia, though he realized that The top of the formation lies somewhere within a one was to be expected if the Brierfield dolomite really thick zone characterized by beds of calcareous sand overlies equivalents of the Nolichucky shale in Alabama. stone, thin-bedded fine-grained light-colored dolomite, If, however, the Brierfield rests on equivalents of the and, in the lower part, oolitic chert, which taken alto Rutledge limestone, it and the Ketona and Bibb are rep gether forms one of the most distinctive lit Tiologic units resented in East Tennessee by the Rogersville, Mary within the Knox group. This zone comprises the beds ville, and Nolichucky formations and not by the Copper from unit 295 to the lower part of unit 379 of the Thorn Ridge dolomite or an unconformity beneath it. Hill section and is about 540 feet thick. STRATIGRAPHY 27 Cullison 12 placed the top of the Copper Ridge dolo Copper Ridge chert included all strata between these mite at the base of the lowest sandstone bed in this limits except for 345 feet of "lower limestone," so that zone (unit 295) and, mostly for convenience, used this his total was 1,690 feet. Hall and Amick's figure for boundary consistently in all his mapping in the Norris the beds in question is 1,961 feet; Oder's is 1,975T feet. Reservoir area. Oder (1934, p. 492, and personal com An unpublished section, measured by the writer in munication in the field about 1938) placed the boundary 1929 and originally intended for this report, agrees al about 30 feet below the top of Hall and Amick's unit most exactly with Oder's figure. Ulrich's section was 379, about 444 feet above Cullison's contact. He also measured in 1905, when the exposures along the high reported the finding of StenocMlina spinifera Ulrich, a way were not as continuous as at present, and some Late Cambrian trilobite, in loose chert somewhere in of his thicknesses appear to have been estimatec1 ; the the upper part of this sandy zone. Later (personal other three thicknesses are in close agreement. communication) he was inclined to place the upper con The thickness of the formation as now delimited is tact of the formation at about the top of unit 348, the 907 feet in the Thorn Hill section. Rodgers and Kent same point selected by Hall and Amick (1934, p. 201) (1948, p. 14^19), measuring the same strata at Lee for their Copper Ridge-Nittany 13 boundary. Valley, obtained a figure of 925 feet. Within the. Mas The contact agreed upon at informal field confer cot-Jefferson City area, the most satisfactory section ences in the forties and used consistently by most field is that on Loves Creek at the west edge of the area; here parties working in East Tennessee during the past 10 the calculated thickness is 943 feet. The formation years is at the base of a prominent sandstone, unit 305 probably retains approximately this thickness through of the Thorn Hill section. Admittedly it is an arbi trary boundary difficult to place accurately in many lo out the mapped area. The Loves Creek section is given calities, but its approximate position can almost always below. be determined with enough accuracy for the purposes of Section of the Copper Ridge dolomite and NoUchucJoy shale a map, such as the one in this report, by drawing it exposed along the tracks of the Southern Railway in the just above the appearance of the highest white siliceous valley of Loves Creek, at the western edge of plate 1 of this oolite, which commonly crops out where exposures are report good and occurs as large float blocks in the soil where [Measured by Josiah Bridge, November 1937] mapping must be done on residual materials. (See also Section begins opposite iron post with sign "Station J mile" p. 38.) and continues in a north-northwesterly direction on either side Ulrich (1911, p. 636) stated that the Copper Ridge of the track to the grade crossing where the old Millertown dolomite is 1,345 feet thick in the Thorn Hill section; Pike crosses the tracks, 900 ft south of the present overpass. Hall and Amick (1934) assigned it a thickness of 1,217 Traverse distances were measured along the rail with a tape- line, and thicknesses of most units were computed frorr these feet 3 inches (after correction); Oder (1934, p. 492) horizontal measurements and the average dips. Thicl'nesses gave it 1,379 feet; and according to the limits assigned of some small units were measured directly across the outcrops. in the immediately preceding paragraphs it is only All thicknesses are computed to the nearest foot. 907 feet. The discrepancies between these figures are Unit Total tfcicfc- thick largely apparent, for no two measurements include ness ness exactly the same set of strata. Moreover, the published (feet) (feet) Ordovician system: sections are difficult to compare because of the monot Chepultepec dolomite (Section measured in cut onous repetition of varieties of dolomite through most on east side of railroad track) : of the sequence. Two points can be almost certainly 15. Traverse distance 0-122 ft, unit dis identified in all sections, however, and when the meas tance 122 ft. Strike 65°, average urements between these points are compared, the agree dip 45°, bearing 155°; thickness calculated______85 85 ment is remarkably close. These points are the rather Dolomite, with many arenaceous == abrupt transition from dominant shale to dominant layers and some distinctive chert limestone about the middle of the Maynardville lime beds. The dolomite is very poor stone member of the Nolichucky shale, and the first ap ly exposed, the interval being largely covered with residual pearance of aphanitic structureless limestone near the materials—chiefly blocks of brown base of the Kingsport limestone. Ulrich's original sandstone, derived from the weathering of arenaceous dolo u Cullison, J. S., 1937, Geology of Norris Reservoir basin: Ms. in mite beds, and of chert. Certain files of Tenn. Valley Authority. layers of sandstone and chert are 18 Hall and Amick did not recognize the presence of the Chepultepec in this section and, following the usage of the time, used "Nittany" for still approximately in place -and what is now called Longview. show the general structure. A 28 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE Unit Totth Unit Total thick- thick thick- thick ness ness ness ness (feet) (feet) (feet) (feet) Ordovician system—Continued Cambrian system—Continued Chepultepec dolomite—Continued Copper Ridge dolomite—Continued conspicuous bed of white siliceous Dolomite, light-steel-gray with a oolite about 1 ft thick crops out few scattered layers that are dark about 32 ft stratigraphically (45 ft gray to chocolate brown. Bed horizontally) below the top of the ding distinct, zones with beds 1 to section; above it are some layers 3 in. thick alternating with zones of white compact platy chert con in which the individual layers are taining long, narrow, oblong slots from 5 to 8 in. thick. Texture arranged parallel to the bedding; compact and very fine grained, these are believed to be the molds more fine grained than in unit 12. of flat limestone pebbles that have Weathered surfaces light grr.y, been dissolved. A thin bed of lighter than those in unit 12, sandstone crops out about 1 ft be often streaked with shades of tin low the oolite bed; 23 ft strati and buff. Several horizons of graphically (33 ft horizontally) chert in beds as much as 4 in. beneath this is a second bed of soft thick. Chert is commonly hon^y rusty brown sandstone about 2 ft colored, compact, with a waxy thick. The base of the unit con texture and splintery fracture. sists of about 8 ft of medium- Joints normal to bedding, w?ll grained sandstone, soft, friable, developed and closely spaced. and porous at the top, becoming 12. Traverse distance, 693 to 770 ft, harder and more quartzitic to unit distance 77 ft. Strike 65°, ward the base. This sandstone is dip 60°, bearing 155°; thickness commonly stained rusty brown calculated ______66 539 but freshly broken surfaces are Dolomite, medium-gray to brown white. ish-gray ; darker than in unit 13, Cambrian system: much lighter than in unit 11; be<*s Copper Ridge dolomite: commonly 10 in. or more thick, 14. Traverse distance 122 ft to 245 ft, bedding planes indistinct, some unit distance 123 ft. Strike 65°, what wavy and minutely irregu average dip 53°, bearing 155°; lar. Fracture sharp and clean, thickness calculated______98 98 but not conchoidal. Weathered Dolomite, with arenaceous layers, surfaces smooth to granular weathering to sandstones, the ex (sandpaper texture), dark gray posure in the railroad cut being with tan and buff stains. Bc4s made up largely of ledges of dolo mite exposed in the creek bed to cut by widely spaced vertical the west. Stratigraphically 44 ft joints belonging to two systems. below the top of the unit is a zone Between traverse distances 715 of oolitic chert about 2 ft thick, ft and 747 ft is a zone about 28 ft and 52 ft stratigraphically below thick composed largely of resM- this are 2 thin beds of oolitic ual chert with a few scattered chert from 1 to 4 in. thick. These outcrops of dolomite. The chert beds are 180 ft and 243 ft, respec is platy and occurs in layers as tively, north of the initial point much as 3 in. thick. It is bteek (horizontal measurement) and are and semitranslucent when fresh believed to correspond to the oo but weathers to light-gray or lites in units 304 and 282, respec cream-colored somewhat tripolitic tively, of the Thorn Hill section chert. Surfaces are commonly (Hall and Amick, 1934, p. 198- 199). Both oolite beds are ex stained by oxides of iron and posed in the bed of Loves Creek manganese, and the fracture is a few tens of feet west of the rail hackly or splintery. Associated road. Beneath the lower oolite with the chert are beds of silici- is about 2 ft of soft porous brown fied cryptozoa irregular in outline sandstone. because of crowding; the indi 13. Traverse distance 245 to 693 ft, unit vidual heads, which are as nnreh distance 448 ft. Strike 65°, aver as 6 in. across, are grouped into age dip 57°, bearing 155°; thick confluent masses 2 ft or more ness calculated______375 473 across. STRATIGRAPHY 29
Unit Total Unit Total thick thick thick- thick ness ness ness ness (feet) (feet) (feef,) (feet) Cambrian system—Continued Cambrian system — Continued Copper Ridge dolomite—Continued Noliehucky shale— Continued 11. Traverse distance 770 ft to 895 ft, Maynardville limestone member — Con. unit distance 125 ft. Strike and line. Thin bedded, commonly with dip as in unit 12; thickness cal many alternations of limestone culated______106 645 and dolomite layers. Mostly light Dolomite, dark-gray, brown, and steel gray with a few thin shale chocolate-brown, finely to medium partings. The lower 15 ft more crystalline; individual layers 10 thickly bedded and more strongly in. to 2 ft thick, little or no sign dolomitic. of laminations, major bedding 8. Traverse distance 1,295 to 1,489 ft, planes indistinct, somewhat wavy, unit distance 194 ft. Strike and minutely irregular. Fracture dip presumably as above ; thick sharp and clean. Weathered sur ness calculated ______173 235 faces dark gray but lighter than Covered interval, a few scattered freshly broken surfaces, often outcrops of limestone. (Road to stained with buff and tan shades, church crosses railroad 1,439 ft smooth to minutely granular. north of initial point.) Beds cut by at least two systems 7. Traverse distance 1,489 to 1,565 ft, of widely spaced vertical joints. unit distance 76 ft. Strike 65°, Chert is present at various dip 63°, bearing 155° ; thickness levels as irregularly laminated calculated ______C8 303 roughly tabular masses parallel Limestone, fine-grained to apha- to the bedding planes. Most of it nitic, blue to bluish-gray, with thin was originally dark gray to black, nodules and seams of dolomitic but some of the masses are white. and clayey material parallel to the All of it weathers to a dead chalky bedding planes. These magnesian white, the surfaces usually stained layers weather dark and stand out by oxides of iron and manganese. in relief, giving the outcrops a It breaks into small rectangular characteristic mottled and rib blocks and splinters with sharp boned appearance. Beds 1 to 3 ft edges. (The railroad cut ends 840 thick in fresh exposures but break ing down into thin plates 1 to 5 in. ft north of the initial point in the thick on further weathering. This middle of this unit, and, from here sequence is well exposed in the north, the section is compiled from fields west of the road opposite outcrops in the creekbed and in Spring Place Church and in the the fields and road cuts on either creekbed between the road and side of the track.) the railroad. 10. Traverse distance 895 to 1,225 ft, Lower shale member : unit distance 330 ft. Strike and 6. Traverse distance 1,565 to 1,875 ft, dip as in units 11 and 12; thick unit distance 310 ft. Strike 65 G , ness calculated______298 943 dip assumed to be 65°, bearing Dolomite, mostly light gray with —— 155° ; thickness calculated ____ some dark beds as in unit 11. Shale, soft, thin-bedded, olive- Beds commonly 1 to 3 ft thick; green ; the interval mostly cov lower beds poorly exposed. The ered, best exposures toward the base of this unit and the base of base. (At traverse distance, 1,875 the Copper Ridge dolomite are ft the section appears to be broken about 140 ft south of the point by a small strike fault (not shown where the road to Spring Park on the map), which is probably Church crosses the railroad. a sliver of the main Saltville Noliehucky shale: thrust, and which repeats the up Maynardville limestone member: per part of the lower shale mem 9. Traverse distance 1,225 to 1,295 ft, ber of the Noliehucky shale and unit distance 70 ft. Strike 65°, the Maynardville limestone mem dip 63°, bearing 155°; thickness ber. This fault was not recog calculated ______62 62 nized when the section was meas Limestone, somewhat dolomitic, ured and has not been traced aphanitic to very finely Crystal- laterally along the strike.) 839223—55——3 30 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE
Unit Total thick thick would indicate a thickness of about 360 feet. The Rog- ness ness (feet) (feet) ersville shale is well exposed in the cuts at the over Cambrian system—Continued pass, where the present Millertown road crosses the Nolichucky shale—Continued railroad. Just north of this is a zone of limestone about Maynardville limestone member: 280 feet wide, representing a stratigraphic interval of 5. Traverse distance 1,875 to 2,075 ft, unit distance 200 ft. Strike 70°, about 255 feet. This zone seems to be the thinned rem dip averaging 70°, bearing 160°; nant of the Rutledge limestone. thickness calculated______188 North of the base of this limestone unit, the shales Limestone, fine-grained to apha- of the upper part of the Rome formation (Pumpkin nitic, blue, with patches and thin Valley shale of Rodgers and Kent, 1948) are rather layers of coarser grained lighter colored dolomitic material; simi complexly folded, dipping both southeast and north lar to and probably a repetition west, and are cut by one or more small strihe faults so by faulting of the beds in units 7 that it is difficult to obtain an accurate estimate of their and 8. thickness. The shales here are now being quarried Lower shale member: and expanded into lightweight aggregate. 4. Traverse distance 2,075 to 2,295 ft, unit distance 220 ft. Strike and BEDROCK LITHOLOGY dip as in unit 5; thickness cal culated ______207 207 The most distinctive rock type of the Copper Ridge Largely covered, but with a few dolomite is a dark, medium to coarsely crystalline thick- outcrops of soft olive-green shale, bedded dolomite. Freshly broken surfaces of this rock similar to unit 6. 3. Traverse distance 2,295 to 2,345 ft, give off a strong fetid odor, which is one of the most unit distance 50 ft. Strike and characteristic aids in the recognition of the formation. dip as in unit 5; calculated thick A similar odor can be detected in f racturec1 rock from ness _—______-______47 254 few beds in other formations in the section, and even in Partly covered, but with several these the odor is rarely as strong as that from charac small outcrops of soft olive-green shale, similar to unit 4. teristic dark dolomite of the Copper Ridge. 2. Traverse distance, 2,345 to 2,720 ft, The fracture is rough and hackly, and freshly bro unit distance 375 ft. Strike and ken surfaces are dark purplish gray to reddish or brown dip as in unit 5; thickness cal ish gray. This dark color is also a distinctive charac culated______352 606 teristic. The texture appears sugary, and tl °> rock com Shale, olive-green to greenish- gray, soft, well-bedded; well ex monly shows many small veinlets and kncts of white posed in low railroad cut. dolomite or quartz. Beds are commonly from 12 to 24 1. Traverse distance 2,720 to 3,095 ft, inches thick. The principal bedding planes are essen unit distance 375 ft. Strike and tially parallel, but their surfaces are irregularly knobbed dip as above; thickness cal and pitted, these minor features having a relief of an culated______352 958 Shale, similar to unit 2, not con inch or less. Minor bedding planes are faint or invisi tinuously exposed but with many ble. Jointing is well developed, but the individual joint exposures in low cuts on the east planes are commonly rather widely spaced. Weather side of the Loves Creek road. ing accentuates the joint and major bedding planes and Base not exposed but somewhere causes the outcrops to break into large blocks with near the grade crossing of the old Millertown road and the railway. rounded edges, more rarely into a mass of pinnacles. Total lower shale unit, units 1 to 4______958 Weathered surfaces are commonly dull lead gray, Total Maynardville limestone member, units 7 which however is of a lighter shade than the color of to 9______303 the fresh surfaces. This dark odoriferous crystalline knotty dolomite is Total Nolichucky shale______1, 261 the most distinctive lithologic type found in the Copper There are many but discontinuous exposures of the Ridge dolomite, but normally it is interb°-dded with older Cambrian formations along the railroad track fine-grained light-steel-gray dolomite of a t^pe common and in cuts along the roads parallel to it from this point throughout the Knox group. The dark dolomite is con north to the trace of the Saltville fault that crosses the fined to the lower two-thirds or three-fourths of the railway about 6,000 feet north of the initial point. The formation and is one of the best means of identifying Mary ville limestone is represented by a band of red soil the formation in fresh exposures. This criterion must about 400 feet wide, which, assuming a dip of 65°, be used with a certain amount of caution, however, for STRATIGRAPHY 31 this lithologic type, together with its characteristic odor, The silicified layers found not only in outcrops but also reappears as single beds, or in short sections composed in drill holes and mine workings in all probability rep of several beds, at several levels through the Ordovician resent replacement of layers along which the movement part of the Knox group. The most conspicuous recur of ground water was especially active. rence of this type is found in a zone about 20 feet thick The bulk of the residual chert from the Copper Kidge near the top of the Mascot dolomite. dolomite is dull and opaque, grayish white, with the The lithology of the upper part of the Copper Ridge surfaces commonly stained various shades of yellow, dolomite is quite different from that of the lower part. red, and black by the oxides of iron and manganese. The strata are mainly medium- to thin-bedded com It is mostly compact and even textured, finely grarular monly laminated fine-grained to aphanitic light-gray to aphanitic, and free from large cavities. On further to bluish-gray dolomite, similar in many respects to the weathering, it breaks down into smaller and smaller dolomite in the tipper part of the Maynardville lime rectangular blocks and splinters. stone member and also to much of the dolomite found in In wooded areas where the soil has been undisturbed the Ordovician formations of the Knox group. The for years and where the ground cover of vegetation is distinctive lithologic features of this part of the forma sparse, the surface of areas underlain by the Copper tion are not found in these widely distributed rather Ridge dolomite is commonly covered by a pavement of nondescript rocks, but rather in the layers of chert, sili small angular light-colored chert fragments, with very ceous oolite, and calcareous sandstones that are interbed- few large blocks of chert. Chert-covered slopes of this ded with them. Many of these special lithologic types type are a rather reliable index to the underlying for also persist into the overlying formations, and, as a gen mation. Areas that have been cultivated seldom rhow eral rule, it is the combination of several factors, rather this pavement, but on the other hand they show a much than any single one, that is relied upon in making final larger proportion of large chert blocks. identifications. Another variety common in the lower part of the for RESIDUAL PRODUCTS mation and rather characteristic of it is black s ^mi- The principal residual products of the Copper Bidge translucent chert in irregular masses, commonly stained dolomite are clay, chert, and sandstone. a dull red on weathered faces but breaking with a The clays are heavy, brittle when dry, sticky and conchoidal fracture and lacking the regular jointir g of tenacious when wet, and commonly orange to brick red the other varieties. These black cherts are particularly where little or no soil is present. 'Soils developed on abundant in the zone of the dark dolomites. these clays are much lighter in color, gray and grayish- Oolitic cherts are found throughout the formations of brown tints predominating. the Knox group, but they are especially numerous and Chert of various types, the greater part of it derived distinctive in the residual chert of the Copper Ridge from the selective silicification of the dolomite during dolomite. Several varieties are distinguishable, and weathering, is extraordinarily abundant in the clay and because they can be recognized in drill cuttings and mine soils of most areas underlain by the Copper Ridge workings (Oder and Miller, 1945, p. 9; Alien, 1P48), dolomite. On the contrary, beds and layers of chert they are extremely useful for correlation. About 33 are not common in fresh exposures; many of those that feet above the base of the formation is a bed of oolitic are found seem to be replacements of structures that dolomite, commonly silicified, which is a rather con were originally deposited as limestone, that is, siliceous spicuous marker (Oder, 1934, p. 477; Hall and Amick oolites and silicified algal lime secretions (cryptozoa). 1934, p. 195, unit 214). The ooids in this bed average Layers of flat ovoid compact chert nodules arranged iy2 millimeters in diameter and commonly are strik along bedding planes, such as a^e common in the ingly color banded. Except for the oolite in the May Chepultepec and younger formations of the Knox group nardville limestone member (p. 12,18), this is the lowest and could be regarded as syngenetic, are not conspicu bed of siliceous oolite known in the area. Other beds of ously developed in the Copper Kidge. The dolomites siliceous oolite are found throughout the Copper Ridge of the formation contain much interstitial colloidal dolomite, but they are most concentrated in the upper silica, invisible in hard samples but appearing as a zone of light-colored dolomite. Some of the more con characteristic insoluble residue when fragments of the spicuous of these oolite beds in this zone are mentioned dolomite are dissolved in hydrochloric acid. The writer by Hall and Amick (1934, p. 197-199, units 271, 282, believes that during the process of weathering this 302), but the most persistent and widely recognized one colloidal silica goes into solution and is redistributed is the oolite bed in unit 304 of this section which they and concentrated as chert on exposed surfaces, and that list as "an 18-inch chert bed." This bed is 27 feet below this process accounts for most of the surficial chert. the top of the Copper Ridge dolomite as here delim ited 32 STRATIGRAPHY OP THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE and, together with the bed 39 feet below it in unit 302, not universal, distribution at such levels and appear to has been recognized in so many parts of East Tennessee be reefs or bioherms. They are commonly grouped that the two beds are commonly used as a guide to the under the generic designation Cryptozoon and a num top of the Copper Kidge dolomite. Beds of siliceous ber of "genera" and "species" have be*m described. oolite believed to be equivalent to the beds at Thorn Hill Their habits of growth are variable, however, and com have been recognized in the Lee Valley section (Rodg- monly one type passes into another by almost im ers and Kent, 1948, p. 17-19, units 132, 148, 157, 161), perceptible gradations. The distance between the in where the intervals between the two upper beds and be dividual pillars of a colony, the diameter of these tween the uppermost bed and the top of the formation columns, and their relative spacing do not seem to be are 43 and 29 feet, respectively. This close agreement specific characters, although attempts hr-ve been made between the two sections some 16 miles apart emphasizes to use them as such. In this report about all that can be the persistence of small distinctive lithologic units and done is to class cryptozoans as solitary or colonial. the importance of their recognition and use in correla Several varieties of each of these tv^o classes are tion, a fact long recognized and used by Ulrich and re known at various levels in the Knox gro'ip, but two of peatedly stressed by him. them are abundant and practically restricted to the Within the Mascot-Jefferson City area two beds of si Copper Ridge dolomite. One type, belonging to the liceous oolite—believed to be the same as those just men solitary class, consists of circular or cup-shaped masses tioned—have been found in many places. In the Loves of chert ranging from 4 or 5 inches to more than a foot Creek section the two beds are 44 feet apart, a figure in diameter, the mass consisting of thin parallel plates that is very close to the distance between the two beds in concentrically arranged around a common center of the Thorn Hill and Lee Valley sections. In the Loves attachment on the basal side. They resemble thick- Creek section, however, the uppermost bed is 48 feet walled shallow saucers and commonly oc",ur as isolated below the heavy sandstone taken as the base of the individuals distributed along certain bidding planes Chepultepec dolomite. The greater thickness in this but locally as loose colonies. locality may be due to a local thickening of the Copper A second and more common type is the colonial Ridge dolomite, or it may be due to a miscorrelation variety that consists of a series of cores or pillars spaced between the sandstones in the Copper Ridge belt and from 1 to 2 inches to a foot or more apar1:. Each pillar the ones in the Loves Creek section. It could also be is formed by a series of thin laminae convex upward. due to local erosion of the upper beds of the Copper Where the pillars are widely spaced the cryptozoans Ridge dolomite on Copper Ridge. have a superficial resemblance to cabbage heads in lon All these siliceous oolites are conspicuously color gitudinal section; where they are tightly crowded they banded, and this, together with the comparatively large give the impression of closely contorted laminae in size of the individual ooids, distinguishes them from the cross section and the surfaces of the laminae them smaller uniformly colored oolites of the younger forma selves exhibit a distinctive "waffle-iron." pattern of tions of the Knox group. knobs and furrows. Entire layers 2 feet or more thick Another common and distinctive variety of chert is in the lower part of the Copper Ridge dolomite may made up of silicified masses of supposed lime-secreting be made up of this form and locally several such lay algae, commonly and collectively known as cryptozoa. ers may be grouped together in a ratl <*T thick zone At some localities, notably in certain beds in the Thorn (Hall and Amick, 1934, units 226-232, p. 195-196). Hill section and also in the small abandoned quarry at This small waffle-iron form is very common in the the north end of the bridge across Holston River on lower part of the Copper Ridge dolomite and was for State Highway 92 just west of Cherokee Dam, these many years believed to be restricted to that horizon. structures are preserved in dolomite beds, thus indicat Recently, howeverf Cattermole (personal communica ing that the silicification so common in other layers and tion, 1949) has found quite similar cryptozoans in the in residual materials is secondary. Thin sections, both Mascot dolomite. The colonies appear to be much of the dolomitic and siliceous varieties, have not shown smaller, seldom more than a foot in diameter, and are any traces of plant structure, and because of this some not so numerous or so widely distributed as in the Cop have argued that the so-called cryptozoa are not fossils per Ridge dolomite, so that abundant cryptozoans of but merely inorganic structures. Opposed to this purely this type are an almost certain indication of the Copper negative evidence are the facts that they occur at definite Ridge dolomite. One variety of this small colonial stratigraphic levels in certain formations, that certain form has been described as Cryptozo'tn undulatum broadly generalized types are restricted to certain Bassler. It is well exposed in the small quarry at the stratigraphic levels, and that they have wide, though north end of the bridge across Holston River near STRATIGRAPHY 33
Cherokee Dam. Chert derived from beds of these cryp- member up to and including some of the arenaceous tozoans is abundant on the hills just south of U. S. layers. Thus his Morristown member seems to corre Highway 11-W about 0.75 mile north of Three Points spond approximately to the entire Copper Ridge dolo on the John Sevier quadrangle and at many other lo mite as here delimited. The Bloomingdale limertone calities both within and beyond the Mascot-Jefferson member was said to range from 170 to 650 feet in thick City district. A variety of this form in which the col ness in various parts of the Valley of East Tennessee, umns are more widely spaced is exposed in the bed of though no explanation of these variations in thichness Buffalo Creek about 0.2 mile north of the road fork was given. It is now thought that most of the strata at BM 1057 on the Joppa quadrangle. placed in the Bloomingdale member by Oder belong The large solitary saucer-shaped type is less com in the lower part of the Chepultepec dolomite as now mon but it is also widely distributed. It has been seen recognized. in place in the Thorn Hill section, and at one time FACIES RELATIONSHIPS there was an excellent exposure weathered out along The Copper Ridge is a dolomite in the type area, and the county road just east of Mascot on the Mascot this dolomitic phase extends along the western side of quadrangle, about 0.25 mile south of the crossing of the Appalachian Valley in East Tennessee and south Roseberry Creek at BM 903. eastward into and across the Mascot-Jefferson City dis All these forms are highly characteristic of the Cop trict. To the southeast of this area, however, beds of per Ridge dolomite, and their abundance in residual limestone wedge into the section, and on the eastern materials is of great value in mapping. side of the Valley, particularly in the belts southeast Many dolomitic layers in the upper part of the Cop of the Bays Mountain syncline (pi. 2), the entire forma per Ridge dolomite are highly arenaceous and when tion is dominaiitly a slightly magnesian limeetone. weathered appear both on the outcrop and in residual This limestone extends northeastward along the east accumulations as soft, porous brown sandstone. Lo ern side of the Valley into Virginia, and in the central cally, these sandstones are recemented by silica and and northern parts of that State it extends progres thus become hard, impervious, and quartzitic. Beds sively into the western belts as well, until in northern of this material also occur in the base of the overly Virginia, Maryland, and southern Pennsylvania the ing Chepultepec dolomite and with the beds in the limestone phase extends almost entirely across the Val upper Copper Ridge mark one of the most distinctive ley, though not into the western ridges of the Ap zones in the Knox group. Other thin beds of arena palachians. ceous dolomite occur at higher levels and some of these This limestone facies is commonly known as the are important key beds, but nowhere in the Knox group Conococheague limestone, from Conococheague Oeek, is the concentration of sandy layers as great as near Franklin County, Pa. (Stose, 1908, p. 701-703), and the Copper Ridge-Chepultepec boundary. the name has been extended into Virginia (Wood SUBDIVISIONS ward, 1932, p. 37; Butts, 1933, p. 8-9) and Tenr«*5see (Oder, 1934). Ulrich recognized the presence of the The Copper Ridge dolomite could be logically di Conococheague limestone in these areas but contended vided into two members: a thick lower member com that it was older than the Copper Ridge dolomite, and posed mainly of dark thick-bedded cherty dolomite, that it thinned westward and was overlapped uncon- and an upper member consisting of light-colored thin f ormably by the Copper Ridge. For a while Butt? also ner bedded dolomite, also chert-bearing and contain maintained this view, but later as a result of detailed ing many arenaceous beds. If such a subdivision were mapping he realized that the two formations were inter- made, the break would come within unit 282 in the grading facies equivalents (Woodward, 1932, p, 37; Thorn Hill section and at the base of unit 148 in the Butts, 1940b, p. 90). This has been demonstrated Lee Valley section (Rodgers and Kent, 1948, p. 14). at several places, and the correlation is strongly sup This upper member is about 228 to 235 feet thick along ported by paleontologic evidence. Copper Ridge, and, although it has not been named, Still farther north in central Pennsylvania, the Cono it has been separately mapped there (Rodgers, 1943). cocheague limestone seems to grade northwestward into Oder (1934, p. 476-479) also divided the Copper a sandy magnesian limestone facies, the Gatesbur^ for Ridge dolomite into two members, calling them the mation (Butts and Moore, 1936, p. 15-17; Butts, 1939, Morristown dolomite and the Bloomingdale limestone p. 10-12; 1945, p. 2-3). The Gatesburg formation to members. He assigned a thickness of 800 to 1,000 feet gether with the overlying Mines dolomite (same refer to the Morristown dolomite member and included in it ence) occupy about the same stratigraphic internal as all strata from the top of the Maynardville limestone the Conococheague limestone a few miles to the south- 34 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE east. Resser (1938, p. 20) correlated the Mines and zone, then a considerable hiatus is suggested in the Missouri Gatesburg with the Conococheague, without, however, section between the Eminence and Potosi formations. clearly stating his reasons. Still later (Howell and It is now known that the Syntropfiia campbelli fauna others, 1944), Resser made the Mines dolomite an upper does not occur in the Copper Ridge dolomite but is member of the Gatesburg formation, assigned two well- confined to the upper part of the Chepultepec and the known Upper Cambrian faunal subzones to it, and lower part of the Longview dolomites and to similar again correlated his enlarged Gatesburg formation with parts of equivalent formations elsewhere (see p. 43,49). the Conococheague, without giving definite reasons. The gastropod-cephalopod fauna mentioned by Ul More recently Wilson (1949), in discussing this same rich does occur in the Eminence dolomite of Missouri, general area, writes that "A general facies change west but the forms that Ulrich had in mind at the time he to east from arenaceous dolomite (Gatesburg forma made that statement are now known to have come from tion) to silt-laminated limestone (Conococheague for the lower beds of the Van Buren member of the Gas mation) is indicated in the geosyncline." This state conade dolomite (Bridge, 1930, p. 106-10P). The state ment, based as it is on detailed field studies, strongly ment that "several of the Van Buren species, and sev- , supports the idea of facies equivalence here advocated. eral others which are closely allied hare been found Wilson says nothing about the relation of the Mines in the Copper Ridge dolomite in Alabama" (Bridge, dolomite to this problem, but such evidence as is avail 1930, p. 108) is an error resulting from this miscor- able indicates that Eesser's assumption is logical and relation (see p. 36). probably correct. This point is discussed in more detail Oder (1934, p. 478, 493) discovered the trilobite below. Stenochilina spinifera Ulrich in float cheH in the sand PALEONTOLOGY AND CORRELATION stone zone at the top of the Copper Ridge dolomite in No fossils, aside from cryptozoa, have been found the Thorn Hill section (p. 27). The exa ct layer is not in the Copper Ridge dolomite within the limits of the known, and a careful search has yielded no additional Mascot-Jefferson City district, and, although a few specimens. From Oder's description it is entirely pos fossils have been found at widely separated localities sible that the specimen came from beds that are included throughout the Appalachian Valley, the formation is in the Chepultepec dolomite in this report. He also nowhere abundantly fossiliferous. This scarcity of collected Oalmnella cf. C. ozarkensis (Walcott) and C. well-preserved and identifiable fossils has been one minor Ulrich near the top of the formation at an un of the most serious drawbacks in regional correlation, specified locality in Greene County. These are all high for many of the supposedly equivalent formations in Upper Cambrian forms, characteristic of the upper part other parts of the United States carry well-preserved of the Eminence dolomite of Missouri and of the Jordan and abundant fossils at many horizons. From, the evi and Madison sandstones of Wisconsin. dence now available the writer believes that the Copper In 1911 Ulrich and Kirk made an extensive collection Ridge and Conococheague formations of East Ten of trilobites in thin-bedded platy black conglomeratic nessee may be correlated almost exactly with the Madi chert associated with a very fine grained black lime son, Trempealeau, and Franconia formations of the stone and thin sandstone beds along the old Knoxville Upper Cambrian section in the upper Mississippi Valley Pike (now approximately U. S. Highway 11-E) about and their equivalents elsewhere. Some of these corre 1 mile west of the railroad station at Gre^neville, Tenn. lations are based on the presence of identifiable fossils, The trilobites, which are rather poorly preserved, all seem to belong to a single species, Pleihopeltis sara- whereas others are merely inferred from similarity of togensis (Walcott), a species originally described from stratigraphic position. the Hoyt limestone of the Saratoga region in New York. In his original description of the formation, Ulrich The genus is also found in the Eminent dolomite of (1911,p. 636), says: Missouri and in the Madison sandstone of Wisconsin. So far as the collections go, they indicate at least two Its age is late Late Cambrian, and the level occupied fossiliferous horizons, both apparently near the middle of the by these fossils is approximately the same as the one Copper Ridge formation. Aside from this, their stratigraphic carrying StenocMlina at Thorn Hill. relations are unknown. One contains Syntrophia campbelli and fragments of so-called Cambrian trilobites, the other gastropods Ulrich provisionally referred the beds carrying this and cephalopods found in the Eminence formation of Missouri. fauna to a new formation, the Greeneyille limestone, The same or a close ally of the Syntrophia, also trilobites of and, according to his notes, the collection came from very similar character to those associated with it in Tennessee, a horizon between 1,450 and 1,463 feet above the top are found in Shannon County, Missouri, in the same formation (Eminence) above the gastropods. If these faunal occurrences of the Nblichucky shale. By this he meant the top of are trustworthy indications of one and the same stratigraphic the lower shale unit as herein described. Thus the STRATIGRAPHY 35 Greeneville limestone of Ulrich included not only the fauna has been found at many localities in the Norris entire Copper Ridge dolomite or Conococheague lime Reservoir area,14 commonly in residual cherts but lo stone but also the Maynardville limestone member of cally from chert beds in place. At a locality in the the Nolichucky shale (chart 1). LaFollette quadrangle, now submerged by the Norris Ulrich never published any description of his Greene Reservoir, it is associated with specimens of Pletho- ville limestone or of this fauna. In 1924, however, Nel metopus. son published two correlation tables (Gordon, 1924, The Scaevogyra fauna has not been found in the p. 34; Secrist, 1924, p. 16) representing his interpreta Thorn Hill or Lee Valley sections nor within the Mas tion of Ulrich's views. In these the Greenville [sic] cot- Jefferson City district, but it has been found at other dolomite was placed beneath the Copper Ridge dolomite localities in the Valley of East Tennessee to the south and was credited with a thickness of 400 feet. Thus and southwest of the district. Presumably it occurs the Greenville dolomite of Nelson seems to be almost within the district, and more careful study and col the exact correlative of the Maynardville limestone lecting should reveal its presence. It was originally member of this report. found in the southern Appalachian Valley by Butts James L. Wilson (written communication, March 3, (1926, p. 87, pi. 14; 1927, p. 4; 1940a, p. 7) at three 1950) reports finding a specimen of Plethometopus(f] widely separated localities, all east and southeast of sp. somewhere in the upper 550 feet of the Conoco Birmingham, and it is the gastropod-cephalopoi fauna cheague limestone on the northwest side of the Mosheim mentioned in Ulrich's original description of the- forma dome just north of Big Spring Church, Mosheim quad tion. The list of species, in which the names hs.ve been rangle. This is about 7 miles west-northwest of the revised to conform with current usage, is given below: localities at Greeneville. These 4 localities are the only Scaevogyra sweezyi Whitfield ones known to the writer from which trilobites have elevata Whitfield been collected in the upper part of the Conococheague Sinuopea htimilis Butts or Copper Ridge formations of East Tennessee. In typicalis Butts Euconia(l) sp. Virginia the trilobite Tellerina wardi (Walcott) has. ''Scen
Arenaceous limestone or dolomite beds are common two groups of formations, they have many species in in the lower hundred feet and thin sandy beds rarely common (see discussion below under "Paleontology and more than 2 or 3 inches in thickness occur sparingly correlation"), and it now seems certain that the Tribes throughout the formation. These weather to soft Hill and Stonehenge limestones are facies equivalents brown porous sandstone, fragments of which are present of the Chepultepec. in the residual soils. These fragments are especially This interpretation brings the physical and paleon- abundant near the base of the formation and in general tologic evidence into general agreement and disposes of they are indistinguishable from those in the Copper the necessity of postulating a great unconformity be Ridge residual materials. tween the Chepultepec and Longview dolomites, an un conformity for which there seems to be no physical or FACIES RELATIONSHIPS paleontologic evidence. The two formations appear to The Chepultepec dolomite is a dolomitic or at best be conformable at nearly every locality thus far studied magnesian limestone unit, and until quite recently all (p. 37), and in addition there is a rather close relation regional correlations were made knowingly or unknow between the faunas of the Chepultepec and the Long- ingly on this basis. Accordingly, the Chepultepec was view dolomites, which suggests that 110 great time in considered to be equivalent to the Larke dolomite of terval could have elapsed between them. the Pennsylvania section and to other dolomitic forma PALEONTOLOGY AND CORRELATION tions in the central United States (see p. 45). On the other hand, the Stonehenge limestone of Pennsylvania, The Chepultepec dolomite is moderately fossilifer- which occupies the same stratigraphic interval and con ous. Fossils are very rare in the dolomites and lime tains many of the same fossils, was correlated with the stones themselves and where present are commonly un Tribes Hill limestone of the Mohawk Valley on the basis identifiable unless silicified. The best and most abun of lithologic and faimal similarity; these two forma dant fossils are preserved in the cherts, commonly as tions were believed to be younger and to occupy the external and internal molds. More rarely the. fossil supposed time interval between the Chepultepec and itself is silicified and stands out in relief on a limestone Longview dolomites. This distinction and assumed surface. The fauna is doniiiiaiitly molluscar, with difference in age was repeatedly stressed by Ulrich, gastropods and cephalopods most abundant. Tie lat-' Butts, Oder, and other workers in the Appalachian ter group, although not completely unknown in older Valley. formations, makes its first appearance in large numbers Butts (1939) mapped the Larke and Stonehenge and with great diversity of form in this formation; in formations in different belts in the Tyrone, Pa., quad fact, the finding of cephalopod fragments of any appre rangle, and commented on the absence of the latter for ciable size is almost proof positive that the beds in ques mation in the Holidaysburg-Himtiiigton quadrangle tion are of Chepultepec age or younger. Bracl iopods and trilobites are next in importance among the immediately to the south (Butts, 1945, p. 3). He also Chepultepec faunas and members of these four classes extended the Stonehenge limestone into Virginia (Butts, alone make up between 90 and 95 percent of the known 1933, p. 11) but mapped it with the Chepultepec, and fauna. Minor elements are phyllocarid crustaceans, later (1940b, p. 101) suggested that it might be, in part forms doubtfully classed as pteropods and chitons, and at least, a facies equivalent of that formation, a sugges a few graptolites. The last were probably more abun tion that had already been made by Grabau (1937, p. dant than their occurrence in the fossil faunas would 29,66-67). indicate; their absence is most probably due to unfavor At a field conference in 1934, attended by Ulrich, able conditions of preservation. Butts, Oder, Pond, and the writer, Ulrich recognized The complete fauna of the Chepultepec clolorrite has the Stonehenge limestone in northeastern Tennessee, never been described as a unit. Lists of species from it particularly in the belt passing through Church Hill in have appeared in various publications, among them Hawkins County, and Oder (1934, p. 481-482) pub Ulrich m Butts (1910, p. 4), Ulrich (1911, p. 639), lished this interpretation. Ulrich m Butts (1927, p. 4; 1940a, p. 7), Butts (1940b, In the meantime, detailed studies on the brachiopods p. 101), and Oder (1934, p. 480-481). A few of the (Ulrich and Cooper, 1938) and on the cephalopocls (Ul more characteristic and distinctive fossils from the rich, Foerste, Miller, and others, 1942, 1943, 1944) and formation have been figured by Butts (1926, pi. 15; unpublished work on the gastropods and trilobites by 1940b, pt. 2, pis. 68, 69). Some of these lists have been the writer and others have shown clearly that, although republished by others without comment or correction there are some differences between the faunas of the (Grabau, 1937, p. 27). 42 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE The lists mentioned above are unreliable, especially (1896), Cleland (1900, 1903), Ulrich and Bridge, Ul those that are unaccompanied by illustrations, for there rich and Foerste, and Ulrich in Bridge (1930), Dake are no descriptions and many of the generic and specific and Bridge (1932), Bridge, in Sellards (1932, pis. II names were nomina nuda at the time of publication, and III), Bridge and Cloud (1947), Cloud (1948), and, although some of the forms have since been de Cloud and Barnes (1948), and Ross (1951). The fol scribed under the names given, or under new names, lowing table, which is reasonably complete, as far as many are still undescribed and the actual identity of published forms go, has been compiled from recent some is not determinable. Furthermore, in the Ala sources and the nomenclature has been revised to con bama report (Butts, 1926), some of the specimens form to present usage. Only species which have been figured did not come from the Chepultepec dolomite in found in the Appalachian Valley either in the the Appalachian Valley but rather from equivalent Chepultepec dolomite or in one of its recognized equiva strata in the central United States, statements in the lents are listed; their distribution elsewhers is indicated report to the contrary notwithstanding. A single example will suffice to show the unreliability by appropriate symbols. The Chepultepec fauna is one of the mosrt widely dis of most of these lists. The list presumably prepared by'Ulrich and given by Butts (1927) and repeated tributed faunas of early Paleozoic age in the United without comment or correction by Grabau (1937) and States and forms an excellent datum for regional cor Butts (1940a) contains 30 species referred to 19 genera. relation. In the Appalachian Valley the Chepultepec Of these 19 genera, 9 were nomina nuda at the time of is to be correlated directly with the Larke dolomite of publication and 2 still are, and even of the 10 that are Pennsylvania and possibly with all or at least the valid 3 had not been formally described at that time greater part of the underlying Mines dolomite. It also and are valid only because one or more of the species seems to be equivalent to the Stonehenge limestone of assigned to them had been previously described and Pennsylvania and of the Tribes Hill limestone of New assigned to some other genus. York (see section above on facies relationships). Seven of the 30 species in the above list were desig Many species found in the Chepultepec-Tribes Hill nated as "sp." Of the 23 named forms, 14 were nomina faunas occur in the Oneota dolomite of th°. upper Mis nuda at the time of description and of these, 7 have sissippi Valley region; in the Van Buren and Gascon since been validated, some of them under other generic ade dolomites of Missouri; 17 in the Kindblade forma names. This leaves only 9 species valid at the time of tion of the Arbuckle uplift; and in the Tanyard publication, and 2 of these were based entirely upon fig formation of central Texas. Still farther west, ele ures published without description in the preceding ments of this fauna have been found in the so-called year. Bliss sandstone near Van Horn, Tex. (King, 1940, Thus, out of the 19 genera and 30 species listed, only p. 154-155; Cloud and Barnes, 1948, p. 360-361) but 10 genera and 9 species were actually valid at the time not in the type area of the Bliss sandstone at El Paso. of publication and some of these were misidentified. Elements of this same fauna also occur in the Manitou The list given by Oder (1934, p. 480-481) is much limestone of Colorado, in the lower part of the Pogo- better. It contains 23 genera, all valid, although the nip limestone of the Great Basin area, anc1 in the Mons presence of some of them in the Chepultepec dolomite is formation of Alberta in the Canadian area. Finally doubtful. The list contains about 54 species of which some of the species characteristic of this fauna have 7 are definitely identified with described forms, at been found in the Cass Fiord formation of northern least 14 others are designated as "cf." or "aff." described Greenland (Poulsen, 1937). forms, and the remainder are designated as "sp." The Chepultepec dolomite has been var;ously classed Such a list gives the reader a much better idea of the as Upper Cambrian, Cambrian or Ordovician, and actual makeup of the fauna than the one used by Butts. most recently Lower Ordovician. It seems to be sepa Detailed studies of the brachiopods (Ulrich and rated from the older formations by a minor but wide Cooper, 1938) and of the cephalopods (Ulrich, Foerste, spread disconformity, the physical evider°« for which Miller, and others, 1942, 1943, 1944) have been pub is clear at some places (Bridge, 1930, p. 142-145; Dake, lished ; in these all the forms known from the Chepul 1930, p. 128-129) ,18 less clear at others. As would natu rally be expected, the physical evidence is strongest tepec dolomite and its equivalents elsewhere in North America are described and figured. 17 The Van Buren and Gasconade formations as described by Bridge (1930) are now considered by him to be a single formation, the Lists of species, together with descriptions and illus Gasconade. trations of fossils from correlative formations in other 18 Recent work by geologists of the Missouri Geolotfcal Survey may indicate that the evidence for the disconformity is no* as definite as it parts of the country, have been published by Sardeson was thought to be by Pake and Bridge. STRATIGRAPHY 43
TABLE 1.—Distribution of species from the Chepultepec dolomite [T = States from which species was originally described: X = States from which species has been identified; ?=States from which species has been tentatively identified; *=Deepkill shale of New York]
Chepultepec dolomite Penn Mary Mary syl New land land vania York Wis (Stone- (Stone- New (Tribes Michi Min con Mis Okla Tex henge (Grove Jersey Hill gan nesota Iowa souri homa as Ala Geor Ten Vir lime lime henge lime sin bama gia nessee ginia stone) lime stone) stone) stone)
Graptolites: X * Brachiopods: T Finkelnburgia beUatula Ulrich and X X T y X Cooper. T T T Olyptotrophia marylandica Ulrich and T Cooper. T T T Schizambon pennsylvanicum Ulrich and T Cooper. T X X T Tetralobula delicatula Ulrich and Cooper- T Gastropods: ? T T X X T X X T ? T Euomphalopsis involuta Ulrich and Bridge X X T X T X X X X T X X X X X X X T X X X T X X X X T T T T X X X X X X X X X X T X X X T X X ? X T X ———— ^ T aft. O. supraplana Ulrich and X Bridge. T Ozarkina complanata Ulrich and Bridge. X X T X X T X Ozarkispira subelevata Ulrich and T Bridge. T T X T X T X X X T X T X X obesa (Whitfield).. ———— ——— —— T X X T X . X X T Cephalopods: Bassleroceras clelandi Ulrich, Foerste, T Bathmocerasl tennesseense Ulrich, T Burenoceras peramplum Ulrich, Foerste, T X cf. B. ungulatum Ulrich, Foerste, X T ? Caseoceras conicum Ulrich, Foerste, T Clarkoceras buttsi Ulrich, Foerste, and Miller T Clarkoceras'! delandi Ulrich, Foerste, T Clarkoceras curvatum Ulrich, Foerste, T iasperense Ulrich, Foerste, and Miller T ? T X X ? parrisiphonatum Ulrich, Foerste, T mohaiekense Ulrich, Foerste, and Miller——.———.———.. T X Conocerinal bassleri Ulrich, Foerste, and Miller.— . —— ___ — — __ .. T 44 STRATIGRAPHY OP THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE
TABLE 1.—Distribution of species from the Chepultepec dolomite—Continued [T = States from which species was originally described; X = States from which species has been identified; ?=States from which species has been tentatively identified; *=Deepkill shale of New York]
Chepultepec dolomite Penn Mary Mary syl New land land vania York Wis (Stone- (Stone- New (Tribes Michi Min con Iowa Mis- Okla Tex henge (Grove Jersey Hill gan nesota sorri homa as Ala Geor Ten Vir lime lime henge lime sin bama gia nessee ginia stone) lime stone) stone) stone)
Cephalopods— Continued Conocerina cf. C. beani Ulrich, Foerste, ? T X X X obligua Ulrich, Foerste, and Miller - T Ectenoceras arcuosutum Ulrich, Foerste, and Miller—— — — _ —— — __ — — _ — _ T chepultepecense Ulrich, Foerste, and Miller___- — __-_ — _--__—— T T millsi Ulrich, Foerste, and Miller __ T perobliquum Ulrich, Foerste, and Miller——— ——— ——— — —— T EUesmereoceras hotchkissi Ulrich, Foerste, T cf. E.hotchkissi-. ------. —— _ X X Endocydoceras leoorense Ulrich, Foerste, T Eremocerasl marylandicum Ulrich, T cf. E. teres Ulrich, Foerste, and Miller—— — — — — — —— ——— , X T X Levisoceras arcttdorsatumUlricli, Foerste, T cf. L. complanatum Ulrich, Foerste, V V T ellipticum Ulrich, Foerste, and Miller———— — ———— —— ———— T X instabile Ulrich, Foerste, and Miller. X X T cf. L. raaschi Ulrich, Foerste, and Miller— — — ———— —— ———— X T transitum Ulrich, Foerste, and Miller—— ------T v X X T X percurvatum Ulrich, Foerste, and Miller T X X SP X Pachendoceras confertum Ulrich, Foerste, ~j v T Walcottoceras obliquum Ulrich, Foerste, X X X X T >' X Trilobites: (List never completed by Bridge).
around old positive areas, such as the Adirondack up group and older formations of the Appalachian Valley lift, the pre-Cambrian shield in Wisconsin and Minne and their equivalents throughout the United States were sota, the Ozark dome, and the Llano uplift in Texas. studied and described. Conversely the evidence is less strong in geosynclinal Only a single genus, Shelfoyoceras, represented by areas such as the Appalachian Valley, the Arbuckle three species, has been found in the Copper Ridge uplift, and the Cordilleran area. dolomite and its equivalents,19 but beginning with the The principal evidence for drawing a systemic Chepultepec the nautiloid group is represented by 26 boundary between the Copper Ridge and Chepultepec genera and 199 species in which two of the three major dolomites and their equivalents is found in the abrupt divisions of this group, straight and curved types, are faunal changes which occur at this boundary. These represented. The original source of this cephalopod are of two types: the sudden development and expan fauna and the reasons for its sudden appearance are sion in the Chepultepec dolomite of classes of fossils unknown, but the latter certainly suggests a rather sud that are absent, or at best only faintly represented, in den and drastic change in ecologic conditions. the older formations, and the almost complete extinc The trilobite, gastropod, and brachiopod faunas all tion of genera and families belonging to certain classes show changes of the second type. Among the trilobites that were abundant in the older formations and their there is an almost wholesale extinction of genera and replacement in the younger formations by new groups. families of the so-called Cambrian types at the close of The first type of change is represented by the nau- Copper Ridge time and their replacement ir the Chepul- tiloid cephalopods. The early members of this group have recently been made the subject of an intensive 19 R. H. Flower, in a letter in 1951, states that additional specimens study by Ulrich, Foerste, Miller, and others (1943,1944), belonging to other groups have been found in some of the high Upper Cambrian strata of central Texas, but even so the number of forms in the course of which all forms known from the Knox found in the Cambrian is still very small. STRATIGRAPHY 45 tepee dolomite by new groups. Studies on this group and the Nittany dolomites, whereas in others the Larke are admittedly incomplete, but at present no genera are dolomite lies between the same two units. The Mines known to cross this boundary. Furthermore, the tri- dolomite is correlated with the upper part of the Copper lobitas cease to be the dominant element in the faunas, Eidge or the lower part of the Chepultepec dolomite,20 and from here 011 are always subordinate both in kinds and the basal part of the Nittany dolomite is admittedly and in numbers of individuals. the equivalent of the Longview. Among the gastropods, Simwpea, 8cfiizopea, and Nowhere so far as known do all four formations— Pelagietta, are common to both groups of formations, Mines, Larke, Stonehenge, and Nittany—occur in the though represented for the most part by different same section; the sequence is either (1) Mines, Larke, species; most of the abundant Cambrian genera disap Nittany or (2) Mines, Stonehenge, Nittany. From this, pear at this boundary, however, and are replaced in the the assumption of disconformity arose. Except for Ghepultepec by a host of new forms whose affinities New York State where the Tribes Hill limestone, the are largely with forms found in younger formations. equivalent of the Stonehenge, was believed to occupy a Furthermore, the gastropods, which have nearly al similar position, there are no formations in other parts ways been a minor element in the Cambrian faunas, of the country that are known to lie between the equiva suddenly become the dominant element in the Chepul- lents of the Chepultepec and Longview dolomites, tepec faunas, not only in numbers of individuals but though the existence of such beds has been suggested also in numbers of genera and species. If the studies by Ulrich, Oder, and the writer in Oklahoma, Tennes on this group had been completed in the same detail as see, and Texas, respectively. These, however, were the those on the cephalopods, the list on page 43 would be result of miscorrelation, and the only remaining strong nearly twice as long. holds of the so-called disconformity lie in central Like the cephalopods, the brachiopocls on both sides Pennsylvania and in the Mohawk Valley. Butts and of the Cambrian-Ordovician boundary have recently Moore (1936, p. 20) gave typical evidence for the dis been studied by Ulrich and Cooper (1938). A few long- conformity: '"as the Larke dolomite is not generally ranging genera, Fitikeliiburgia. and Westonia, cross the recognizable and is believed to be generally absent in boundary, but 5 genera die out at the top of the Cam the Bellefonte quadrangle, there is a hiatus between the brian, and 2, possibly 3, die out in Chepultepec time. Mines and the Stonehenge due to its absence." This On the other hand, 11 genera appear for the first time in statement, of course, is not necessarily true. the Chepultepec; many of these continue into higher In the northwestern part of the Tyrone quadrangle beds of Early Ordovician age and some extend into (Butts, 1939) the Stonehenge limestone is mapped as Middle Ordovician strata. Three of these 11 genera resting directly on the Mines dolomite, and the, belts are doubtfully reported from the Upper Cambrian, but in which this relationship is shown continue on to the their occurrence may be based on misidentification of Bellefonte quadrangle to the northeast (Butts and the formations involved. Moore, 1936). Data on other groups are less complete but seem to In the southwestern part of the Tyrone quadrangle be in line with those of the four dominant groups just the sequence is dijferent, for in this area the Larke dol mentioned. omite overlies the Mines, and in turn is overlain by the Nittany dolomite, the Stonehenge limestone being RELATION TO THE LONGVIEW DOLOMITE / absent. The belts in which this sequence occurr con Although there appears to be no disconformity be tinue to the southwest on to the Huntington and Hol- tween the Chepultepec and the Longview dolomites, it lidaysburg quadrangles (Butts, 1945), no Stonehenge has been repeatedly stated that such a break exists. being mapped in either of these two quadrangles. The The idea was first advocated by Ulrich (in Bassler, geographic distribution of the two formations, £fone- 1915, pis. 1, 2) and was subsequently reaffirmed by henge and Larke, strongly suggests that here is an other Butts, Oder, and many others, including the writer. example of an intergrading limestone-dolomite facies, The main basis of this idea is found not in physical limestone to the northwest and dolomite to the south- evidence of a disconformity that can be seen in any given section, but rather in the assumption that certain and Howell (in How ell and others, 1944) placed the Mines dolomite in the Upper Cambrian and made it the upper member of the formations carrying specific faunas intervene between Gatesburg formation, but Butts (Butts and Moore, 1936, p. 18 ; Butts, the Chepultepec and Longview dolomites or their recog 1939, p. 13; 1945, p. 3) lists three species of Sinuopea from the base of the Mines. In the first two reports Butts also classes the formation nized equivalents. The best evidence for this assump as Cambrian but in the final one he places it at the base of the Ordovi tion is found in central Pennsylvania, where in some cian. If these gastropods are correctly identified, they indicate that the Mines is post-Copper Ridge and equivalent to the lower part of the areas the Stonehenge limestone lies between the Mines Chepultepec dolomite. 46 STRATIGRAPHY OP THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE east. This supposition is strengthened by various com At Bellefonte, in Centre County, the Mines dolomite is suc ments in the texts of the publications just cited which ceeded above by the Stonehenge limestone, which is 662 feet thick. Throughout most, if not all, of these quadrangles [the indicate that the distinctions between the Larke and Hollidaysburg and Huntington quadrangles], however, the the Stonehenge are not nearly so clean cut as the map Stonehenge limestone is absent and the Larke dolomite is over ping would suggest and that occasionally there has lain unconformably by the Nittany dolomite. been some doubt in the mind of the author as to which Recognition of this f acies relationship appears to have formation was actually present. For example, in the been delayed by Ulrich's view that the faunas of the two Hollidaysburg-Huntington folio (Butts, 1945, p. 3), it groups of formations are different and that the fossils of is stated that the Tribes Hill and Stonehenge limestones are younger in these quadrangles the Stonehenge, which underlies the Nit- than those of the Chepultepec and its equivalents. tany farther east, is not certainly known, but it may be repre sented by a few feet of dark, compact limestone at the base of While differences do exist, the two groups of forma Nittany exposed about four-fifths of a mile southeast of Ore tions have many species in common, and had the f acies Hill. About 10 feet of thin-bedded dolomite is exposed beneath relationship been recognized at the time when certain this limestone at that point. fossils were being described, more identical species On the other hand it is stated (Butts and Moore, 1936, would probably have been recognized in the two groups. p. 19) that The writer's present view is that there is no convinc the Larke is not generally recognizable or mappable in the ing evidence, either physical or faunal, to prove the ex Bellefonte quadrangle, but [that] limestone believed to represent istence of a hiatus between the Chepultepec and the the Larke is exposed in an old ore pit 1% miles N. 75° W. of Longview dolomites and their equivalents elsewhere, Scotia. . . . Here about 200 feet of vertical rock has been ex and they are here regarded as a part of a conformable posed. It is mainly dolomite but includes thick layers of fos- sequence. siliferous limestone near the middle. In this bed of limestone LONGVIEW DOLOMITE occurs a large gastropod provisionally referred by Ulrich to Helicotmna loinonensis (Sardeson) ; a large Ophileta shown in NAME cross section and not positively identifiable specifically, but comparable to O. grandis; and numbers of specimens of a spe The name, Longview dolomite, was firs* published by cies of Hemitheca [Hemithecella]. ... As the Larke also be- Nelson, in a correlation chart based on Ulrich's ideas belongs to this general zone, the fossiliferous beds at the old (Gordon, 1924, p. 34; Secrist, 1924, p. 16). The forma ore pit are identified with the Larke. However, as the Larke tion was first described by Butts (1926, p. 92-95) as the is elsewhere unknown in the region and its known area in the old pit is very small, it is mapped with the Stonehenge in what Longview limestone. The name was tr.ken from ex seems to be a small fault block as shown on the geologic map. posures near Longview, Shelby County, Ala., and the formation was subsequently mapped in the Bessemer- Both of these quotations suggest the presence of an Vandiver and Montevallo-Columbiana folios (Butts, intergrading limestone-dolomite f acies, and it is rather 1927, 1940a), the latter folio containing the town for surprising that Butts, who was usually keenly aware which the formation was named and whr.t may be con of such gradations and their stratigraphic significance, sidered its type area. No type section was ever de failed to recognize it. He had his doubts on the sub scribed, and Butts states that the formation boundaries ject, however, for in 1935 in the course of a field trip are not well exposed in the vicinity of Longview. He into the Tyrone area he remarked to the writer that it also lists (Butts, 1926, p. 92) three sections in Cahaba was very strange that the belt between the Mines and Valley and on Little Cahaba River which may well serve Nittaiiy dolomites was always wide enough for one as typical sections. formation, either the Larke or the Stonehenge, but The name was reintroduced into Tennersee during the never wide enough for both, and at that time he seemed to be trying to convince himself of their equivalence. course of this investigation as a substitute for the Penn Later on (Butts, 1940b, p. 101), he stated that sylvania name Nittany dolomite (Hall and Amick, 1934; Oder, 1934). This was done at the suggestion of Ulrich, the occurrence of several common species in the Chepultepec, Stonehenge, and Tribes Hill of New York has led some geolo who claimed that the Nittany formation in its type area gists to the tentative conclusion that those formations are all in central Pennsylvania contained more time and faunal the same. units than its so-called equivalent in Tenr°.ssee and sug And at that time he had practically accepted this view gested that until more detailed information about the in spite of seemingly later statements to the contrary Nittany in its type area became available it would be such as the following (Butts, 1945, p. 3) : a ton (Butts, 1945) reports had all been written many years before their publication and that Butts' report on the geology of the Appalachian a lt should be remembered that the texts of the Bellefonte (Butts Valley in Virginia, though dated 1940, actually presented his last pub and Moore, 1936), Tyrone (Butts, 1939), and Hollidaysburg-Hunting- lished views on this subject. STRATIGRAPHY 47 advisable to discontinue use of the name in Tennessee. throughout the Mascot-Jefferson City district, though The name Longview has been used as a formation name exact measurements between its contacts have been in Tennessee in several recent publications, notably difficult to obtain. The calculated thickness of th?, sec Oder and Miller (1945) and Rodgers and Kent (1948). tion on Loves Creek is between 458 and 554 feet, but Though these publications do not entirely agree on the here, as noted above, there is uncertainty as to the posi limits of the formation, both, as well as most other re tion of the contact between the Chepultepec and Long- cent papers, have considered the Longview to be a for view dolomite, which may have been placed too low mation. Alien (1947) on the other hand has regarded in the section. it as the lower member of an enlarged and expanded In the chart published by Nelson, the Longview is Kingsport formation. given a thickness of 1,000 feet, but this thickness doubt less included beds now assigned to underlying and over LIMITS lying formations. Butts (1926, p. 93, and elsewhere) The Longview dolomite in East Tennessee comprises gives a thickness of from 400 to 500 feet for sections in units 406 to 458 of the Thorn Hill section (Hall and Alabama, and Oder (1934, p. 482) states that the thick Amick, 1934, p. 203-205) and units 203 to 239 of the ness varies from 25 to 250 feet. These abnormally large Lee Valley section (Eodgers and Kent, 1948, p. 22-25). and small thicknesses appear to depend on the assump Throughout the Valley of East Tennessee it is invari tion that unconformities exist at the top and bot ably underlain by the Chepultepec dolomite and over tom of the formation and upon miscorrelations. The lain by the Kingsport limestone; these relations ex failure to find the distinctive faunal zones of the Long- tend northward into Virginia and southward into Ala view has many times resulted in its strata being placed bama and Georgia. The gradational contact with the either in the Chepultepec dolomite or in the overlying Chepultepec dolomite has been described (p. 37). The formation. upper contact is likewise conformable with the over As pointed out by Rodgers and Kent (1948, p. 25-26), lying Kingsport, but, because of sharp lithologic dif the contact between the Longview and Kingsport used ferences, the topography resulting from them, differ herein lies about 100 feet above the contact as d^awn ences in the residual cherts, and differences in fossil by Oder and Miller (1945) and appears to correeioond content, it is generally much easier to place. In the exactly to the "zero bed" or "footwall sand" of the Thorn Hill and Lee Valley sections and throughout Mascot mine section described by them, though rot to the Mascot-Jefferson City district, this contact is com the "zero beds" of the New Market or Jefferson City monly drawn at the base of a unit of aphanitic light- sections. bluish to brownish semilithographic and normally BEDROCK LITHOLOGY moderately fossiliferous limestone from 25 to 50 feet The bulk of the formation is composed of thin- to thick. The individual beds of this limestone unit are thick-bedded well-bedded fine-grained light-colored in general a foot or more thick and are characterized by dolomite that closely resembles the dolomite in tin un thin crinkly shale partings at intervals of about an inch. derlying Chepultepec. The upper half or third cf the Locally, as on Copper Kidge and elsewhere, the upper formation may include beds of fine-grained to aphan part of the Longview also contains beds of fine-grained itic light-bluish-gray limestone, which locally may to aphanitic limestone that superficially resembles the make up half of the upper part of the formation. Both limestone assigned to the overlying Kingsport in color the limestone and the fine-grained dolomite are locally and general texture. These layers are commonly much replaced by a coarser grained "recrystalline" dolomite thinner and more discontinuous, however, and typically they lack the irregular crinkly shale partings that char that is clearly younger than either of the primary types acterize the basal limestone of the Kingsport. Oder, of rock. The transition from original carbonate, into Alien, and others have suggested that these thinner recrystalline dolomite is commonly sharp, and hand limestones also be included in the Kingsport, but the specimens showing both at once are easy to obtain. The presence of Lecanospira in these beds in the Thorn Hill recrystalline material is common in areas of structural section and elsewhere indicates that they belong with complexity, along fault and shatter zones, and in areas the Longview dolomite. of brecciation; it is invariably present where there is zinc mineralization though not all recrystalline areas THICKNESS contain zinc. As a general rule, the limestone is much The Longview dolomite is 230 feet 8 inches thick more commonly replaced than the fine-grained dolo in the Thorn Hill section and 264 feet thick in the Lee mite, yet examples of both types of replacement c^ti be Valley section. It maintains a comparable thickness found. 48 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE
RESIDUAL PRODUCTS PALEONTOLOGY AND CORRELATION The rocks of the Longview dolomite commonly Fossils are not abundant in the Longview dolomite, weather to a light-ash-gray soil that is in rather sharp and most of those found occur as intern?,! or external contrast with the more highly colored soils developed molds in residual cherts derived from th^ weathering on the Chepultepec and Kingsport formations. Weath of the formation. It is almost useless to search for ered surfaces of the Longview rocks are commonly fossils in fresh or even well-weathered exposures of the lighter than the fresh rock; light-gray, bluish-gray, dolomite and limestone; the best collecting is commonly and tan tones predominate. In the fine-grained dolo on the chert-covered hillsides where there are few or mites, solution appears to be most active along closely no outcrops. For this reason it is generally difficult or spaced microscopic fracture planes. These are prac impossible to attribute collections to def nite parts of tically invisible in the unweathered rock but appear on the section, and only in a few places is th°re the fortu weathered surfaces as narrow subparallel sets of gashes nate combination of circumstances that makes this that intersect each other at various angles and give the possible. dolomite a curious slashed appearance that is particu The fauna thus far recovered from the Longview larly noticeable on exposed bedding surfaces. This dolomite and its equivalents in the Appalachian Valley type of weathering is not confined to the dolomites of is given in the following table. the Longview but is associated with fine-grained dolo The brachiopods occasionally provide an exception mite throughout the Knox group; it is one of the most to the foregoing statements concerning the rarity of useful criteria for distinguishing between limestone fossils in limestone, for locally they do occur as silici- and dolomite. fied shells in a limestone or dolomite matrix, from Ordinarily the Longview yields abundant chert 011 which they can be freed by etching witl acid. They weathering, but locally there may be almost none. are, however, not abundant in the Appalachian Val Most of the chert belongs to a type that is highly char ley, only six species having been recorded and only two of these from Tennessee. They ar«- much more acteristic of the formation, and a study of the residual abundant in equivalent formations in'Oklahoma and materials affords the best means of separating the Long- Texas and there they form a most important element view from the associated formations. The bulk of it in the faunas. consists of massive porcellaneous dead-white to light The most important and characteristic fossils of the pink, brown, and gray chert in large blocks as much Longview dolomite, both from the standpoint of as 2 feet or more in diameter. This chert is brittle and abundance and ease of recognition, are tH gastropods, compact, very rarely cavernous, and never mealy or particularly the genera Leccmospira and Rhombella, porous. Like the dolomite from which it is derived, it both of which seem to be confined to this formation and is cut by many closely spaced microscopic joints, and its equivalents. Of these, Lecmwspira is by far the upon weathering it breaks down into small rectangular more abundant, the more widely distributed, and the blocks and splinters that are normally white or light more easily identified. Specimens belonging to various yellow though fairly commonly stained with iron and species of the genus have been found throughout the manganese oxide. Round or oval chert nodules occur length of the Valley from Alabama to Quebec, and also ring in specific layers, such as are characteristic of the in Newfoundland and in the Durness limestone at the Chepultepec and Kingsport formations, are not com northern tip of Scotland. The genus ie abundant in the Roubidoux formation of Missouri (Bridge, 1930, mon in the Longview. Oolitic chert is sparingly pres p. 124) and in the German formation of central Texas ent, and dolomoldic chert and the porous, ropy, and (Dake and Bridge, 1932, p. 737; Clone1 and Barnes, anastomosing chert that is such a conspicuous feature 1948, p. 40). It also occurs in the Cool Creek forma of certain parts of the Chepultepec dolomite are rare. tion of the Arbuckle and Wichita Mountains and pos Sandstone beds are thin and inconspicuous, though sibly at a level equivalent to the Gormar formation in rounded sand grains occur in certain dolomite and the El Paso limestone of West Texas (Cloud and limestone layers. Barnes, 1948, p. 359). It has not yet been reported The chert of the Longview is well displayed in the from the Rocky Mountains or from arear farther west. ridge north of the John Sevier railway yards, on the Rhombella (formerly called Roubidouwia) is nearly low hill just west of Roseberry Creek at Mascot, in the as widely distributed, and about as characteristic, but ridge north of Friends Station, and in the high part of it is much less abundant than Lecanospira. It is found Crockett Ridge about 3 miles northwest of Morris- mostly as molds in residual cherts, but specimens in town. limestone have been found at a few localities, parti cu- STRATIGRAPHY 49
TABLE 2—Distribution of species from the Longview dolomite and equivalent formations [T = Species described from State or Province indicated; X=Species reported from State or Province indicated; cf=Similar species reported from State or Province indicated]
Longview dolomite Mary Okla Pennsyl New Quebec Missouri Texas Ala Ten Vir land vania York homa bama nessee ginia
Brachiopods: Diaphelasma pennsylvanicum Ulrich and Cooper X X T cf Finkelnburgia virginica Ulrich and Cooper _ T Syntrophina campbelli (Walcott) T X X Syntrophinella typica Ulrich and Cooper T X cf fradiata (Whitfield) rp Gastropods: Lecanospira compacta (Salter) X X X X X X T X X X conferta Ulrich T X X X salteri Ulrich and Bridge _ T X X X biconcava Ulrich and Bridge X X X T sigmoidea Ulrich and Bridge T X X X Rhombella umbilicata (Dake and Bridge) __ X X T X Sinuopea spp w Cephalopods: Allopiloceras breve Ulrich, Foerste, and Miller T Cumberlandoceras buttsi Ulrich, Foerste, and Miller T T Endocycloceras perannulatum Ulrich, Foerste, Miller, and Unklesbav T Bassleroceras bridgei Ulrich, Foerste, Miller, and Unklesbav T Leptocyrtoceras virginianum Ulrich, Foestre, Miller, and Unklesbay__ _ T Monogonoceras alabamense Ulrich, Foerste, Miller, and Unklesbay_ _ __ _ , T magnisiphonatum Ulrich, Foerste, Miller, and Unklesbay X T Pachendoceras newportense Ulrich, Foerste, Miller, and Unklesbav - T Parendoceras jeffersonetise Ulrich, Foerste, T clinchburgense Ulrich, Foerste, Miller, T Trilobites: Hystricurus spp ___ _ X X X X larly in Oklahoma and Texas and to a lesser extent in has had a long and varied history in the Ozark region, the northern Appalachians, in Pennsylvania and New and its present status there is not very well defined. York, and in certain areas in Quebec. The Jefferson City formation of the Ozark region, as originally proposed by Winslow (1894, p. 331), included KINGSPOBT LIMESTONE all strata between the Roubidoux sandstone beneath and NAME the Saccharoidal (St. Peter) sandstone above. Ulrich The Kingsport limestone is named from exposures (1911, p. 632-633, pi. 27) restricted the Jefferson City along U. S. Highway 23, beginning about 0.5 mile limestone to the lower third of the rocks in this interval; north of the junction of this road with U. S. Highway subsequently Purdue and Miser (1916, p. 4-5) intro 11-W just north of Kingsport, Sullivan County, Term. duced the names Cotter dolomite and Powell limestone The name was originally suggested by Oder (personal for the remaining two-thirds of the original Jefferson communication about 1937 for use in the present re City of Winslow. Still later, Dake (1921, p. 12) raised port. It replaces the names Jefferson City formation the Jefferson City to the rank of a group composed of (Oder, 1934) and Forked Deer formation (Hall and three formations, the Jefferson City formation (re Amick, 1934). stricted) at the base followed by the Cotter and Powell The name Jefferson City was discarded as a forma dolomites. The boundaries of the three formations tion name in Tennessee to avoid confusion with its were never clearly defined. In brief, in the typ?, area long-standing use in Missouri and Arkansas. The name of the Jefferson City dolomite in and around Jefferson 50 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE City, Mo., 110 Cotter is present, whereas at Cotter, Ark., LIMITS the type locality for the Cotter dolomite, which is about As here defined, the Kingsport limertone includes 140 miles to the south on the opposite flank of the Ozark units 459 to 519 (lower 3 feet, 3 inches) of the Thorn dome, the contact between Jefferson City and Cotter is Hill section (Hall and Amick, 1934, p. 205-208) and below river level. As a result, the assumed contact units 240 to 256 of the Lee Valley section (Rodgers and between the two formations was a fairly arbitrary Kent, 1948, p. 25-27). The contacts in the Thorn Hill boundary. section are those originally selected by Oder and the On the basis of detailed stratigraphic and paleon- writer about 1937 and subsequently used by the writer tologic studies, Cullison (1944) redefined the Jefferson in revising the map of the Mascot-Jefferson City dis City formation of Missouri, raised it to a group, and trict. The base of the formation is drawn at the bottom divided it into two formations—the Theodosia forma of a thick unit of aphanitic sublithogr^phie "dove"- tion above and the Eich Fountain formation below. colored limestone with thin crinkly shale partings; the He discussed the relationship of the Jefferson City top is drawn at the base of a thin but persistent sand group to the overlying Cotter dolomite and described stone whose grains are cemented with white chert—the and figured many of the fossils characteristic of each chart-matrix sandstone of Oder, who discovered this of these formations, adding materially to our knowl valuable key bed. There are actually two or three chert- edge of these units in their type region. His conclu cemented sandstone layers in most sections examined; sions, however, have not been adopted by either the the one here used, however, occurs at the top of a fine Missouri or the U. S. Geological Surveys. grained dolomite bed forming the lower part of unit Although the Kingsport limestone is f aunally equiva 519 at Thorn Hill and unit 257 at Lee Valley. What is believed to be this same sandstone is well exposed in lent to a part of the Jefferson City, there is still un unit 68 in the type section of the Kingsport limestone certainty and much difference of opinion as to exactly on U. S. Highway 23 (p. 51) and at many localities in what is contained within the limits of the Jefferson City the Mascot-Jefferson City district and elsewhere. in Missouri. The boundaries of the Kingsport limestone as here The other older name, Forked Deer formation, was drawn are not exactly the same as those of the Jefferson taken from Forked Deer Creek at the Thorn Hill sec City formation of Oder or of the Forked Deer forma tion and was used only as a heading for a group of tion of Hall and Amick. Furthermore, the lower limit descriptions of individual strata in that section (Hall does not agree with the lower limit of the Kingsport and Amick, 1934, p. 205). No attempt was made to limestone as now drawn by Oder and his associates define it as a formation or to give any account of its (Oder and Miller, 1945; Alien, 1947,194?). In naming geographic or regional correlation. It was never for the Kingsport limestone, Oder and Miller (1945, p. 1) mally adopted by the Tennessee Division of Geology stated that the names Kingsport and Mascot had been and has never been used outside the original publication. selected by Oder and Bridge for use in their forthcom In the meantime Oder's name Kingsport limestone was ing reports on the Knox dolomite of East Tennessee. adopted informally by the various mining companies In their paper, the stratigraphic sections as developed in the mines at Mascot, New Market, and Jefferson City and formally by the State Division of Geology and the are described in considerable detail, and the characters U. S. Geological Survey, and it is now well established and importance of a number of marker beds useful in in geologic literature. subsurface correlation are thoroughly discussed; no The name Kingsport limestone was first published attempt is made, however, to correlate this information without description on several strategic mineral maps with surface data, although residual materials from issued during and after the Second World War many of the marker beds have been found to be ex (Eodgers, 1943; Dunlap and Rodgers, 1945; Kent, tremely useful in surface mapping. The top of the Eodgers, and others, 1945; Dunlap, 1947). The first de formation is placed at the base of the chert-matrix sand scription of the formation was by Oder and Miller stone (Oder and Miller, 1945, p. 5), but no mention is (1945), but this applied only to mine sections in the made of the contact with the Longviev7 dolomite be Mascot-Jefferson City district. Subsequently the for neath ; in fact, one gets the impression on reading the mation was briefly described by Miller and Fuller paper that all the sections end below within the Kings- (1947) for southwestern Virginia and by Rodgers and port. This is still Oder's opinion, but other workers Kent (1948, p. 25-26) for the Thorn Hill and Lee Valley including the writer now place the base of the formation sections, but the present report contains the first de at the "zero bed" in Oder and Miller's Mascot section, scription of the type section. at the — 66 bed in their New Market section, and some- STRATIGRAPHY 51 where in the 10-3 (T) bed in their Jefferson City sec Mascot dolomite—Continued Feet inches tion, for these beds are believed to correspond almost 79. Chert, brittle; china white on fresh sur faces, rusty on weathered surfaces, band exactly to the base of the Kingsport limestone in the ed and brecciated_————————————— 3 0 Thorn Hill and Lee Valley sections (Rodgers and Kent, 78. Dolomite, fine-grained, well-bedded; light 1948, p. 25-26; Brokaw, oral communication, 1950) and bluish gray on freshly broken surfaces, to the base of the formation as exposed in the type sec dull gray on weathered surfaces. Many tion on U. S. Highway 23. layers of small ovoid chert nodules, most of them 1 in. or less across, but with some The type section of the Kingsport limestone is on the as much as 2 in. Chert is light gray on east side of U. S. Highway 23 just northwest of Kings- freshly broken surfaces but rusty orange port (pi. 3E). The top of the formation is 0.55 mile on the outside rind where weathered. north of the traffic light at the intersection of U. S. Some layers of small siliceous geodes Highways 23 and 11-W; the base is 0.23 mile farther similar to those in unit 82. A powerline pole is opposite this exposure______7 0 north. The section of the Kingsport proper was meas 77. Chert, brittle, white, porcellaneous; bluish ured by Oder and the writer in 1940; the other details white and semitranslucent where fresh, have been added by the writer on subsequent visits. dead white with yellow stains where The area is shown on plate 3#. weathered __—_____——_—_— 2 6 76. Dolomite, similar to unit 78, with many Section of the Kin-gsport limestone and associated formations scattered ovoid chert nodules (mostly on U. S. Highway 23 north of the junction with U. 8. High less than 1 in. across) and with one or way 11-W, Kmgsport quadrangle, Tennessee (pi. 3E) two layers of larger flat chert nodules__ 4 0 [Units 68-85 measured by Josiah Bridge, 1951] 75. Chert, like unit 77______3 0 74. Dolomite, similar to units 76 and 78, well- The contact of the Mosheim member of the Lenoir limestone bedded ; individual beds from. 8 in. to 3 and the Mascot dolomite crosses the highway about 0.15 mile ft thick, a few thin bands of chert north of the intersection and passes northeastward to the north nodules ______19 6 of the school. It is not well exposed but is marked by a sudden 73. Dolomite, similar to unit 74, a single thick break in topography and by a line of shallow sinks. bed with widely spaced layers of small Between this point and the entrance to the Kingsport ceme chert nodules (less than 1 in. across) ar tery 0.45 mile north of the intersection, the section is largely ranged along incipient irregular poorly covered, but scattered outcrops of Mascot dolomite appear in developed bedding planes______4 6 the fields along the east side of the highway. Specimens of 72. Dolomite, fine-grained, well-bedded, light- Ceratopea, keithi Ulrich and Orospira sp., both characteristic bluish-gray, similar to unit 78, a single Mascot fossils, were found in the dolomites about 80 ft strati- bed. Contains a few scattered chert graphically above the base of the formation. Section begins at the top of the continuous outcrops near the nodules _——______—______10 powerline pole north of the cemetery entrance. 71. Dolomite, like unit 72______10 70. Dolomite, fine-grained, light-bluish-gray; Mascot dolomite: Feet Inches weathering yellowish gray to dull gray. 85. Dolomite, fine-grained; light gray on fresh Contains from 6 to 8 bands of small ovoid ly broken surfaces, darker on weathered chert nodules, most of them less than 1 surfaces —————_—_—______4 0 in. across———_—————————————— 1 9 84. Dolomite, similar to unit 85 but with thin 69. Dolomite, like unit 70 with conspicuous layers of chert, chert nodules, and small band of chert nodules from 1 to 2 in. siliceous geodes.:______7 0 across, 9 in. above the base. Several 83. Dolomite, similar to unit 84. Two beds, each about 9 in. thick______1 6 thin bands of chert nodules less than 1 in. 82. Dolomite, similar to unit 83, with many across in the upper 9 in—————————— 2 0 thin (half-inch to two-inch) chert lay 68. Dolomite, gray, fine-grained, almost pure ers, and with layers of small chert at the top but becoming arenaceous nodules and geodes near the top of the below. The sand grains are well unit. The chert nodules are smooth, rounded, frosted, increasing in abund rounded, light gray to white on fresh sur ance toward the base of the unit; the faces, rusty tan on weathered surfaces. lower 3 to 4 in. are almost pure sand The geodes resemble small cauliflower cemented by chert, forming a chert- heads averaging less than 1 in. across, matrix sandstone. This sandstone is rusty red on the outside, and filled with hard and white in fresh exposures, be small clear quartz crystals______7 0 coming rusty and crumbly in weathered 81. Dolomite, like unit 82, but no chert; a pieces _—————————————————— 9 single layer______———_____— 1 6 80. Dolomite, like unit 82, but no chert; a Thickness, measured part of Mascot single layer———_____————_—————— 2 6 dolomite ———————————————— 73 52 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE
The total thickness of the Mascot dolomite in this section is Kingsport limestone—Continued Feet inches calculated as either 545 or 670 ft, assuming uniform dips of 47 Limestone, mostly fine-grained to' apha- 20 and 25 degrees, respectively. The larger figure is prob nitic, light-blue; some beds near top ably more nearly correct. coarsely "recrystalline"; fine-grained material fossiliferous-—— ———————— 9 4 [Units 1-67 measured by C. R. L. Oder and Josiah Bridge, 1940] 46. Dolomite, with thin bands of flat ovoid white chert nodules as much as 8 in. Kiiigsport limestone: Feet inches long. Upper 2 ft coarsely "recrystal 67. Dolomite, fine-grained, light-gray, well- line"______—__—————— 7 8 bedded with very little chert; unit partly 45. Limestone, thin-bedded, with some si ale covered __-______-__ 6 9 partings_____.._.._————————————— 1 10 66. Chert layers, almost continuous, white, 44. Limestone, fine-grained to aphanitic, at out stained with yellow and orange, thick 1 in. of black chert at base—______4 6 and nodular______4 6 43. Limestone, blue, aphanitic to subcrystal- 65. Dolomite, fine-grained, light-gray, with line, with wavy very thin clay partings, scattered layers of flat ovoid chert nob- subconcholdal fracture. The limestone ules as much as 2 in. across and a few weathers light blue; the clay partings thin layers of white chert along bed weather to a chalky white and stand out ding planes. A conspicuous layer at the in low relief. The "brown rock" of the top ______2 8 Mascot district. Strike N. 60° E., dip 64. Chert, dark-gray, with a sugary testure_ 6 20° SE ______5 3 63. Dolomite, fine-grained, light-gray, without 42. Chert, ropy, porous, white, weathering to chert ______1 4 yellow ______———————————— 4 62. Dolomite, fine-grained, light-gray, with 41. Shale, black, platy______1 thin chert layers in the base and sili 40. Dolomite, fine-grained, light-gray, two ceous rosettes or geodes in the upper beds ______.._-.-____- ._____ 2 6 part______4 6 39. Limestone, like unit 43, thick-bedied, 61. Dolomite, like unit 62, with thin slabby aphanitic to subcrystalline, fossilifer chert nodules, 1 in. thick and 8 to 10 in. ous ______14 0 long; also thin black shale partings___ 1 8 38. Clay, with flattened banded nodules* of 60. Largely covered, probably dolomite with dead-white chert with black translucent heavy white chert bands______3 0 streaks that weather yellow like chert 59. Dolomite, in part fine-grained, in part of the Chepultepec dolomite______10 37. Limestone, like units 43 and 39, tl'ck- "recrystalline" ______15 2 bedded, aphanitic, fossiliferous—————— 8 8 58. Covered interval ______1 10 36. Covered interval, much platy chert in the 57. Chert, compact, white, ropy, in part con residual materials______2 0 glomeratic and containing false oolite, 35. Dolomite, light-gray, fine-grained-__-_ 1 0 fossiliferous ______1 10 34. Limestone, like unit 43. A single bed 45 in. 56. Largely covered; about 1 ft of "recrystal thick overlain by a 10-in. bed-_—_ 4 7 line" dolomite at top______30 0 33. Shale parting______6 55. Limestone, blue, the lower inch coarsely 32. Limestone like unit 34, largely covered_ 14 0 "recrystalline," the remainder aphanitic_ 7 4 31. Covered interval, probably limestone (not 54. Limestone, blue, aphanitic, no clay part recorded) ______——______~ ings, with layer of black chert nodules 30. Limestone like unit 34. Three marsive at base______9 beds exposed in small quarry______8 8 53. Dolomite, light-gray, fine-grained, with 29. Covered interval, probably limestone—_ 2 0 Ceratopea capuliformis Oder______4 28. Dolomite, coarsely "recrystalline," n^edi- 52. Dolomite, with an irregular band of sili um-gray, with pink vugs. A cast-iron ceous oolite (the C oolite of the Mascot pipe crosses this outcrop_—————___ 1 6 geologists, 130 ft below the top of the 27. Limestone, blue, aphanitic to subcrystal formation at Mascot) ______6 line, with thin crinkly shale partings_ 8 4 51. Dolomite, fine-grained, light-gray______8 6 26. Covered interval, probably limestone—_ 2 0 50. Limestone, very fine grained to aphanitic, 25. Chert, brittle, white, platy, with algal im light-blue; Ceratopea capuliformis Oder pressions on bedding planes, weathers seen on upper surface______5 0 yellowish on surface, oolitic and con 49. Dolomite and limestone, most of the dolo glomeratic ______——__——————— 4 mite coarsely "recrystalline" ______4 6 24. Covered interval, mostly limestone—_ 5 0 48. Chert, white, brittle, enclosed in gray very 23. Limestone, like unit 27, blue, aphanitic to fine grained dolomite. Top and bottom subcrystalline ——————————————— 10 surfaces brecciated; top fairly smooth, 22. Covered interval, with limestone like unit bottom with waffle-iron pattern. _____ 4 23 at base______——_——————— 7 0 STRATIGRAPHY 53
Kingsport limestone—Continued Feet inches are fair exposures of the Copper Ridge dolomite. On 21. Dolomite, fine-grained, light-gray, with the north face of the hill about 1.33 miles north of the scattered vugs of pink dolomite, weath base of the Kingsport, the contact between the Copper ers buff to tan__——_—______20. Chert, brittle, white, platy, and laminated Ridge dolomite and the Maynardville limestone member 19. Chert, rusty, porous, with many rectangu of the Nolichucky shale is well exposed, and from here lar slots which may represent leached to the base of the hill the exposures are all Nolichucky limestone pebbles. Fossiliferous, Hor- shale. motoma on upper surface______- 6 Oder (unpublished mimeographed notes, distributed 18. Dolomite, like unit 21______10 17. Limestone, blue, aphanitic to subcrystal- during Kentucky Geological Society field trip in Nay line, with wavy clay partings, subcon- 1947) gives thicknesses of 346, l73i/2, and 605 feet for choidal fracture. Weathers very light the Kingsport, Longview, and Chepultepec formations, blue, the clay partings weather to chalky respectively, in this section. Apparently he drew the white and stand out in low relief, grades base of the Kingsport 63 feet below the base as here upward into unit 18____—______1 16. Dolomite, fine-grained, blue-gray______o described. These 63 feet should be added to the Long- 15. Limestone, similar to unit 17______13 view dolomite, making its thickness in this section 14. Dolomite, very coarsely "recrystalline"_ 1 2361/0 feet. 13. Covered interval, some outcrops of blue THICKNESS limestone like unit 15______12. Dolomite, in part fine-grained, in part The Kingsport is about 280 feet thick in its type coarsely "recrystalline." Some layers section along U. S. Highway 23 at Kingsport. It thins of chert nodules at the base and a few to the west, being but 218 feet thick in the Lee Valley thin seams of chert______section and 232 feet in the Thorn Hill section, both 11. Dolomite, medium-gray, sandy and "re- of which are in the Copper Ridge belt on the northwest crystalline" ; chert layers at the base. Grades laterally down the dip into a fine side of Clinch Mountain. The formation becomes grained sandy limestone______thicker to the south; in the Mascot-Jefferson City dis 10. Limestone, like unit 15, with a drusy net trict, Oder and Miller (1945) give thicknesses of 266, work of dolomite crystals and wavy 306, and 320 feet, respectively, for those beds in the green clay partings______mine sections at Mascot, New Market, and Jeffevson 9. Dolomite, light-gray, fine-grained, sandy- textured, with several layers of ovoid City that are included in the Kingsport limestone by chert no.dules______the present writer. 8. Shale, with ovoid chert nodules______At Eve Mills in Monroe County southwest of Knox- 7. Dolomite, like unit 9______ville, approximately on strike southwest of the Mascot- 6. Shale, greenish-gray______Jefferson City district, the formation averages 300 feet 5. Limestone, like unit 15______4. Shale, parting, with platy chert______thick (Dunlap, 1947), but, to the southeast of Pays 3. Limestone, blue, like unit 15______Mountain on the Mosheim anticline, it appears to have 2. Dolomite, light-gray, coarsely "recrystal thinned to about 200 feet (Dunlap and Rodgers, 1£45). line" ; grades locally into blue aphanitic According to Kent, Rodgers, and others (1945), the limestone like unit 3______Kingsport limestone is about 250 feet thick in the 1. Dolomite, sandy-textured, fine-grained, light-bluish-gray. Weathers buff gray Powell River area. and locally to a rusty coarse sandstone. Two or three beds. Strike N. 55° E., dip BEDROCK 1ITH010GY 20° SE______10 The Kingsport limestone is composed of dolomite and limestone with subordinate amounts of shale, chert, Total Kingsport limestone______283 0 Longvievv dolomite: siliceous oolite, and sand. The most abundant rock Top 10 ft massive, fine-grained, light-steel-gray, fine-grained type is dolomite, but the most striking is the pure lime dolomite. Some layers partly "recrystalline." Weathers stone, thick beds of which make up the bulk of the lower cream colored. Overlies a massive chert bed. third to half of the formation; the limestone forms a Lower part of section not measured. conspicuous new element in the monotonous sequence of The Chepultepec and Longview dolomites are ex dolomitic strata that make up the formations of the posed to the north in a rather thickly settled area, and Knox group. the contact between them could not be determined with The limestone is thick bedded (6 inches to 2 foet), certainty. About 0.7 mile north of the base of the compact, aphanitic, sublithographic, bluish gray to Kingsport limestone are thick sandstones believed to pinkish brown on freshly broken surfaces, bluish white mark the base of the Chepultepec; still farther north to gray on clean weathered surfaces, breaking with a 54 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE splintery to subconchoidal fracture. Some weathered still hardly abundant. They include the oldest species surfaces show a thin white chalky rind. The limestone of the genus Ceratopea, G. capuliformis Oder, and also beds show rather closely spaced very thin irregular, of several characteristic gastropods, notably Orospira. wavy clay partings that are dark gray to black on fresh The Kingsport limestone is shown by its fossils to be surfaces and weather tan to white and stand in low re equivalent to the lower portion of the Newala limestone lief on weathered surfaces. The great bulk of the insol (Butts, 1926, p. 95-99) in southeastern Tennessee, uble residues obtained from these limestones consists northwestern Georgia, and northeastern Alabama and of thin flakes, representing fragments of these films. to a portion of the Jonesboro limestone in the north The limestones are the "brown rock" of the miners at eastern part of the Valley in East Tennessee where it is Mascot, and the "dove limestones" of the miners at not possible to divide the Ordovician part of the Knox Jefferson City. group into separate formations. It is also roughly The dolomites are of two types: first, the very fine equivalent to the Jefferson City of Missouri, but the grained and light-colored variety that is common exact correlation is not yet certain. throughout the middle and upper parts of the Knox MASCOT DOI/OMITE group, and second, a more coarsely crystalline granular gray and blue-gray variety. The latter, commonly NAME called "recrystalline" in this district, is evidently a re The Mascot dolomite is named for the town of Mas placement of both the limestones and the fine-grained cot, Knox County, Tenn. The history of the name dolomites; the transition between the country rock and closely parallels that of the name Kingsport, and the this coarse-grained phase may be seen at many places, reasons for preferring it to the older names Cotter- both in surface exposures and in mine workings. No Powell beds (Oder, 1934) and Thorn Hill formation direct evidence bearing on the origin of the fine-grained (Hall and Amick, 1934) are identical. The name first dolomites can be cited; it is thought that they are also appeared on the geologic map of the Cc r>per Ridge dis of secondary origin, but that they were formed at a trict (Eodgers, 1943) without description; it was sub much earlier time than the coarse-grained varieties. sequently published by Oder and Miller (1945) and Certain beds contain an abundance of small cavities, there credited to Oder and the writer. No description normally less than an inch in diameter, which have been of the formation is contained in that pp.per, but several filled or partly filled with calcite, dolomite, or milky preliminary reports published as a result of the wartime quartz. The quartz fillings stand out in relief on investigations of the zinc deposits of East Tennessee weathered surfaces and are commonly found as small contain brief descriptions of the formation and show cauliflowerlike masses in the residual clays. its areal distribution in small areas. Chert occurs in several forms. Flattened nodules of light-gray compact chert occur in rows parallel to the LIMITS AND THICKNESS bedding in certain layers and are so distinctive of par The Mascot dolomite overlies the Kingsport lime ticular layers that those layers can be recognized from stone wherever the two have been reco^ized. In turn one mine to another throughout the district. In addi it is overlain by limestone belonging to various Middle tion, compact to finely porous white rusty-weathering Ordovician formations; in the Mascot-Jefferson City chert occurs sparingly as layers in weathered exposures district, the overlying unit is either the Mosheim mem and abundantly as small blocks and chips in the red or ber of the Lenoir limestone or more rirely the Lenoir orange residual clay derived from the dolomite and in limestone itself. The Mascot dolomite includes all beds the overlying soil. from the upper 2 feet of unit 519 to tin top of unit 687 A few thin layers consist of sandstone or of dolomite in the Thorn Hill section (Hall and Amick, 1934, p. containing scattered rounded frosted sand grains; like 208-214) and unite 257 to 315 in the Lee Valley section the layers containing chert nodules, these sandy layers (Rodgers and Kent, 1948, p. 27-32). No complete sec can be traced for miles even where the sand is confined tion is exposed in the vicinity of Mascot, but several to a layer an inch or two thick. partial sections are exposed nearby. The thickness at Detailed sections of the Kingsport limestone in the Thorn Hill is 520 feet 10 inches, and at Lee Valley 510 zinc mines of the district are given by Oder and Miller feet. In the Mascot-Jefferson City district, the forma (1945, table 2). tion may be as much as 600 feet thick. It is certain that CORRELATION the thickness varies considerably because of later ero Fossils are more common in the Kingsport limestone sion, which produced a pronounced disconf ormity at the than in the older formations of the Knox group, though top of the formation. STRATIGRAPHY 55 BEDROCK LITHOLOGY Belts underlain by these formations where they have The Mascot consists chiefly of dolomite, similar to moderate to steep dips commonly rise above th°, sur that in the Kingsport limestone, with chert layers, lay rounding country as ridges of the second order, reach ers of chert nodules, and scattered bods of sandy dolo ing approximately to the level of the so-called "^alley mite that weather to rusty poorly cemented sandstones. Floor or Harrisburg peneplain. They are about as Near the top in some sections, particularly in the high as the ridges developed on the Rome formation Mascot-Jefferson City district, layers of aphanitic blue but are normally separated from those by a valley de limestone are interbedded with the dolomites; these veloped on the nonresistant Middle and lower Upper resemble the limestones of the Kingsport but lack, in Cambrian rocks. The topographies of the two types the main, the thin clay partings. They also resemble of second-order ridges are entirely different: the the limestones of the overlying Mosheim member but in ridges developed on the Rome formation are nr.rrow, general lack the small clear calcite crystals that are so steep, intricately dissected, and commonly cut by common in the Mosheim. closely spaced water and wind gaps; the Knox ridges The chert of the Mascot is much like that of the are broader, with gentle slopes and few conspicuous Kingsport but is rather more abundant in the residuum gaps. Because of the nature of the underlying rocks over the lower part of the formation. The sandstone and the sterility of the soils developed from them, layers, especially close to the base of the formation, Rome ridges are commonly forested, whereas Knox produce thin slabs and small blocks, which may also be ridges are normally partly cleared and localh7 are found in the residuum over that part of the formation. farmed to their summits. Where associated with mountain ridges of the first order, such as Clinch CORRELATION Mountain (Avondale and Luttrell quadrangles), the Fossils, chiefly gastropods and cephalopods, serve to second-order Knox ridges are separated from the first- establish the general equivalence of the Mascot with order ridge by a broad shallow high-level valley de the upper Newala limestone of Alabama, the uppermost veloped on the less resistant Middle Ordovician lime Jonesboro limestone of northeast Tennessee, the Cot stones and shales. ter dolomite (but not the Powell dolomite) of Mis The same open rolling topography is found in areas souri and Arkansas, and the Shakopee dolomite of the where the strata of the Knox group are essentially hori Upper Mississippi Valley region. Ceratopea is com zontal, as, for example, over most of the Joppa quad rangle. The principal difference between the topogra mon, and the formation includes the zones of G. keithi phy developed on the Knox group in this area ani that Ulrich and G. tennesseemis Oder in its lower part, and in the belts of steep dips, for example, the central part locally the zone of G. arikylosa Cullison close to the top of the John Sevier quadrangle, is the dendritic drain (seep. 59). age pattern and the absence of any conspicuous aline- TOPOGRAPHIC EXPRESSION ment of topographic features. Areas underlain by the formations of the Knox Where the formations of the Knox group dip at mod group develop a characteristic topography that com erate to steep angles, it is often possible to recognize monly is in sharp contrast to that developed on the un the approximate limit of the several formations from derlying and overlying rocks. The details of this to the topography alone. For example, on the Jol^n Se pography are beautifully shown on many of the new vier quadrangle, between the west edge of the map and 7%-minute quadrangles of the TVA series, and ele Ellistown, the Copper Ridge dolomite forms a high ments of it can even be recognized on some of the old continuous ridge along the northwestern side of the 30-minute quadrangles made a generation or more ago. belt, the Longview dolomite forms a somewhat 1 igher In general, this topography is characterized by mod and even more prominent ridge to the southeast, and erate to gentle broad smoothly rounded slopes, without the Chepultepec dolomite occupies a series of straight cliffs or abrupt changes of slope except along major valleys and low saddles between. streams. These characteristics are due, of course, to The Kingsport and Mascot formations have less ob the homogeneous nature of the underlying rock. Al vious topographic expression. The limestone in the though the area is well drained, the main drainage lines lower part of the Kingsport may be recognized by a flat are widely spaced and commonly have gentle gradi terrace or a series of saddles, commonly accompanied by ents, whereas the minor tributary valleys are shallow sinks, developed on the southeast slope of the Long- and also rather widely spaced. This again is due to the view ridge, whereas the somewhat more resistant lower homogeneously resistant underlying rocks. part of the Mascot dolomite is indicated by the row of 56 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE low inconspicuous knobs parallel to the Longview ridge American Zinc Co. has for years marketed the finely and at a still greater distance from it. ground fresh tailings from its mills as agricultural lime This same sequence of topographic belts is even bet stone, and some of the best farms in the area have been ter shown on Copper Ridge in the western part of the consistently treated with this material. Dutch Valley quadrangle, where the three ridges formed by the Copper Ridge, Longview, and lower POST-KNOX FORMATIONS Mascot dolomites and the strike valleys and sags de THE NAME CHICKAMAUGA LIMESTONE veloped on the Chepultepec and Kingsport formations The Chickamauga limestone was named by Hayes are remarkably clear. Still farther northeast on Cop (1891, p. 142-144). The name replaced tiH term "blue per Ridge in the Avondale quadrangle, the ridges limestone group" of Safford, the change, being made formed by the Copper Ridge and Longview dolomites in conformity with the practice of using geographic unite to form a single high ridge on which the Chepul rather than lithologic names for formations. No type tepec dolomite is represented by a break in slope which section was ever designated or described, but the name gives the effect of a broad terrace. was taken from the area around South Chickamauga These are the normal aspects of the topography de Creek in southeastern Tennessee and northwestern veloped on the formations of the Knox group. There Georgia. As originally denned the formation included are also some surprising abnormalities. One of the all limestone above the Knox dolomite and beneath the most interesting of these is the band of sinkholes on Sevier shale (which at that time was extended to in the Talbott quadrangle southeast of TJ. S. Highway clude the Martinsburg and Reedsville shales), and in 11-E, between Rocktown Church and Alpha. This this sense it was used in all the folios of the southern area of about 7 square miles is literally honeycombed Appalachian region, beginning with Hayes (1894) and with sinks of various sizes and depths, so much so that ending with Butts (1910). in the whole area there is virtually no surface drainage. The Chickamauga limestone, as mapped in the folios, At least three-fourths of the area is underlain by included the equivalents of the Kingsport and Mascot the Kingsport and Mascot formations. The explana formations of this report in those areas IE southeastern tion of this abnormal topography is that the area is a Tennessee, northwestern Georgia, and northeastern part of a belt of complex structure (p. 64-65) in which Alabama where they are represented by the Newala the Mascot dolomite has been crushed and broken by limestone (Butts and Gildersleeve, 1948, p. 19). With large and small faults and joints. This shattering the close of the folio mapping in the Appalachian together with the gentle sloping surface has favored the region the name Chickamauga fell into disuse, but it work of solution over that of normal surface erosion and has recently been revived as a convenient general term produced the highly abnormal pitted plain shown on the by Roclgers (1953). In reviving the name, he has re map. moved from it all beds known to be equivalent to strata This general area is described by Safford (1869, p. of the Knox group, so that as now define! the unit in 219) as follows: cludes limestone strata of Middle and Late Ordovician There is an interesting plateau of this formation [the Knox age. The unit is thinnest along the southeastern edge dolomite] in Jefferson County, between the Holston and the of the Valley where it represents a very short span of so-called Bay's Mountain, and extending from the vicinity of time; it is thickest in the sections near the Cumberland New Market to Russellville; these towns, and Morristown, be Plateau front where it represents practically all of ing upon it. This area is from 300 to 400 feet above the Holston, Middle and Late Ordovician time. and presents some excellent and extensive farming regions. A portion is called the New Market Valley, and is noted for its About 1900 Ulrich began dividing the Chickamauga fertility. The rocks of this plateau, are at many points, but limestone into a number of formations. Some of these little .inclined. They are, in reality, at the northern disap were described in the Revision of the Paleozoic Systems pearing end of a synclinal trough. (Ulrich, 1911, pi. 27); others appeared only as names Originally, the ridges of the Knox group were cov in correlation charts; and others were simply names ered with a thick stand of hardwood timber, chiefly used in notebooks and unpublished manuscripts.^ Only oak and hickory, and these were in sharp contrast a few were ever adequately described, and still fewer to the pine-covered slopes of the ridges of the Rome. have been mapped in detail over any considerable area. Much of this hardwood has been cut, and today the In making these subdivisions Ulrich v^as influenced ridges are largely cultivated or used for pasture. by several ideas. He believed that sedimentation dur Their soils, though stony, are among the best upland ing this period took place in a number of parallel soils in the Valley, though like most soils derived from troughs, an idea he took from Safford (18C9, p, 229-239) limestone they are commonly deficient in lime. The and greatly elaborated and expanded. He believed that STRATIGRAPHY 57 these troughs were at times connected and at other and the units commonly intergrade laterally. The times separate basins of sedimentation, and that some Mosheim is best regarded as a member of the Lenoir were dry or receiving terrestrial sediments while others limestone; it is considered separately below. Th«, name were submerged. His units were based on specific Holston has been indiscriminately applied to the first faunas and lithology, for he had no concept of the lat marble (that is, coarsely crystalline pink or gray lime eral gradation of formations. These views seemed es stone that will take a polish) beds above the Lenoir in pecially plausible because of the peculiar structural pat all parts of the Appalachian Valley, but it is by no tern of the region, for the formations in any structural means certain that all the beds so mapped represent a belt may be quite different from those in adjoining continuous unit, or that the top of the Lenoir t;°jieatli belts, as a result of shortening by the thrusting of one is everywhere the same. In fact, the preponderance of belt over another. evidence would indicate otherwise. Ulrich's general concept of the stratigraphy of the . The areas underlain by the Lenoir and Holston are Chickamauga limestone is given in his Revision (Ulrich, normally characterized by gently rolling topography. 1911); later it was more fully elaborated by Butts Sinkholes are locally abundant, and in such places sur (1928) and by Ulrich himself (1930). In general face drainage lines are poorly developed. Cedar glades Ulrich believed that the strata included in the Chicka are practically limited to the outcrop of these limestones. mauga group consisted of a few widely distributed formations at the base, correlating with formations of UNCONFORMITY AT BASE OF LENOIR LIMESTONE Ghazy age elsewhere; other widely distributed forma The contact between the Knox group and th?- over tions at the top, correlating with formations of Black lying Middle Ordovician units in East Tennessee is River or later age elsewhere; and a great thickness of marked by a surface of unconformity or, better, dis- strata in between not equivalent to any formations else conformity, which is inconspicuous at many localities where, the so-called Blount group, wedged in the middle but which actually extends far beyond the boundaries between the Chazy and Black River beds (Butts, 1928, of the State and marks one of the most widespread fig. 2). No complete section of the Blount group has interruptions in deposition during Paleozoic time in ever been found, and at present the idea that such a unit eastern and central North America. exists, intermediate in age between the Chazy and Black In general, throughout East Tennessee the uppermost River and represented only in, the southern Appa formation of the Knox group is the Mascot dc^omite, lachians, has been completely discarded. and the writer knows of no place within the State where The present theory is that there is a thick limestone this formation has been completely removed lNy pre- sequence, the Chickamauga limestone, developed in the Middle Ordovician erosion, though such places may central and western parts of the Valley of East exist. Such erosion has occurred locally, however, in Tennessee and adjacent States, and that this grades Alabama, Georgia, and Virginia, and in those States laterally southeastward into a complementary shale and Middle Ordovician rocks are known to rest on various sandstone sequence, the Sevier shale and higher forma older formations down to the Chepultepec dolomite— tions, developed along the southeastern side of the and possibly in Alabama even the Copper Ridge dolo Valley. The two sequences intertongue in a central belt, mite (Butts, 1926, p. 115, 117; Cooper, 1944, p. 33-34; and by the close of Middle Ordovician time shale de Butts and Gildersleeve, 1948, p. 20). In other parts of position had lapped westward almost completely across Virginia, the reverse may be true, for fossils collected the Valley. No complete statement of the details of in Warm Springs Valley, near Healing Springs, sug Chickamauga stratigraphy can be given here, as they gest the presence of a Lower Ordovician formation of are in the course of being worked out by G. A. Cooper, post-Mascot age. Similarly the Odenville limestone of B. N. Cooper, R. B. Neuman, and many others. Alabama (Butts, 1926, p. 99) appears to be Early Ordo In the Mascot-Jefferson City district, the Chicka vician but post-Mascot. mauga limestone—the Middle Ordovician limestone se Within the Mascot-Jefferson City district, the Mascot quence—is made up of three units originally classed as dolomite is overlain by the Mosheim member of the separate formations. These are, in ascending order, Lenoir limestone or, where this is locally wanting, by the Mosheim limestone, the Lenoir limestone, and the the typical Lenoir limestone itself. The contact is Holston marble. These were all considered as distinct rarely well exposed, but it can commonly be located formations by Ulrich, Butts, and many others, includ within a distance of a few feet. At most places, even ing the writer, and are so shown on the map of the dis where clearly exposed, it could easily be taken for a trict published in 1945 (Bridge, 1945). The boundaries conformable contact. It is normally marked by an between them are rarely sharp and distinct, however, abrupt transition from dolomite beneath to limestone 58 STRATIGRAPHY OP THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE above, but the upper part of the Mascot dolomite may | 11-E 22 about 0.6 mile southwest of its intersection with contain individual limestone beds as much as 6 feet the road leading south from Friends Station. The thick, and at a few places these beds coalesce to make exposure is in the ditch on the south side of the highway, up the greater portion of the upper part of that forma 0.15 mile south of BM TGS 112 (1,033 fe^t), and con tion. These limestones are lithologically similar to sists of a deep-red hematitic clay containing small peb those in the overlying Mosheim member, and, where the bles and fragments of chert. The actual contact is two are in contact, the boundary may be difficult to not exposed, but Mascot dolomite dipping gently south locate. Often it can be located because abundant mi east is exposed in the fields north of the Hghway, and nute clear bits of calcite are present in the Mosheim conglomeratic red and gray limestone in the Mosheim but absent in the limestone in the Mascot. In other member is exposed at the base of the hill just south parts of East Tennessee the contact is further obscured of the highway. The sequence is normal and there is no by earthy clolomitic beds at the base of the Middle Ordo- doubt of the position of the conglomerate. vician, but these have not been found in the Mascot- These are the most conspicuous examples that were Jefferson City district. found during the detailed mapping of the district; A fair section across the contact is exposed on the doubtless there are others that were overlooked. south side of the 1,240-foot knob 0.8 mile southeast of The most striking physical evidence of this uncon Hodges Station in the New Market quadrangle. Here formity in East Tennessee has been found at Douglas the upper beds of the Mascot dolomite are dominantly Lake, about 10 miles south of the Mas cot-Jefferson limestone and seemingly grade upward into the litho City district. During the construction of the dam, logically similar beds assigned to the Mosheim member an Ordovician sinkhole, 60 by 90 feet in plan and 150 of the Lenoir limestone. The chief distinction here is feet deep, was encountered. This sink was filled with the presence or absence of the small clear calcite crystals volcanic ash and shaly dolomite unlike any other rock believed to characterize the Mosheim. in the region (Laurence, 1944; Caster, 1944). The con A few localities show definite evidence of uncon tact of the Mascot dolomite and the Lenoir limestone formity. At the mouth of Legg Creek in the John is well exposed along the north shore of the reservoir Sevier quadrangle, just west of McMillan Station be at low stages of the lake (Bridge, 1955). In an area tween the Southern Railway and the Holston River, about a mile long, the relief on the surf aco of the Mas small outcrops of the basal limestone of the Mosheim cot dolomite measures at least 140 feet. There are also member containing angular fragments of chert as much two sinks, each about 50 feet deep, filled in part by as 2 inches in diameter, clearly derived from the weath debris from the Mascot dolomite. This old surface is ering of the Mascot dolomite, are exposed in the bed generally covered by impure dark-gray to black dolo of the creek. The top of the Mascot dolomite is also mite, locally as much as 50 feet thick, thr.t grades up exposed a few feet farther upstream, though the actual ward into typical, nodular Lenoir limestone. In places contact was not observed. the dolomite is absent, but, where present, it fills chan The contact is cleanly exposed in a cut on the Mascot nels, sinks, and solution cavities along jcmt and bed ding planes in the Mascot dolomite, some of which road, at the crest of the slope about 0.65 mile west of extend to depths of 50 to 60 feet below the old surface. the underpass beneath the Southern Railway about The lower beds are conglomeratic, containing angular 1 mile west of Strawberry Plains, in the Mascot quad and rounded bits of chert and dolomite and weathered rangle. Slight irregularities in the contact can be de chert nodules, all derived from the weatl ?-ring of the tected, and the lower beds of the Mosheim member Mascot dolomite, in a matrix of fine-grained dolomite. contain a conglomerate composed chiefly of small peb The conglomerate is thickest and coarsest in the large bles and fragments of dolomite, most of them less than depressions on the upper surface of the Mascot dolo 0.5 inch in diameter. mite; it becomes fine grained and thins to extinction Chert conglomerate in the base of the Mosheim mem on the intervening high areas. Where the dolomite is ber, just like that found at McMillan Station, is exposed absent and the basal beds of the characteristic nodular in the bed of a small tributary of Lewis Branch where Lenoir limestone overlap onto the Mascot dolomite, it crosses the county road 1.5 miles north of the intersec they are also finely conglomeratic; elsewhere within tion of this road with old U. S. Highway 11-E just west this area no conglomerate was seen above the dolomite. of Friends Station, in the northwestern part of the New Market quadrangle. 82 In 1950, U. S. Highway 11-E was completely relocated, beginning A fourth locality for basal conglomerate was un 0.5 mile west of the junction of the old highway with U. S. Highway 70 on the Mascot quadrangle and extending eastward across the remainder covered during construction of the new U. S. Highway of the mapped area. STRATIGRAPHY 59 Filled channels on the eroded surface of the Mascot In the Mascot-Jefferson City district, the lower part dolomite have been mapped and discussed by Rodgers of the Lenoir limestone has been separately mapped as (1943) and Rodgers and Kent (1948, p. 32) on the the Mosheim member. south side of Copper Ridge, Grainger and Hancock Counties. One of these, near Shiloh School (Press- MOSHEIM MEMBER mens Home quadrangle), indicates a relief of nearly The Mosheim, considered in this report to be a brsal 200 feet on the surface of the Mascot dolomite. What member of the Lenoir limestone, was named from Mos are believed to be similar occurrences have been men heim, a small village on the Southern Railway about 7 tioned by Keith (1901, p. 2; 1905, p. 8) in East Tennes miles west of Greeiieville, Greene County, Tenn. (Ul- see, by Campbell (1894, p. 2) and by Cooper (1944, rich, 1911). No type section was ever published, bu* in p. 33) in southwest Virginia, and by Munyan (1951, 1933 Ulrich took the writer to a cut on the Southern p. 54-59) in Georgia, but they have not been investi Railway about 1 mile southwest of Mosheim and stated gated by the writer. These widely scattered occur that the exposures in this cut were the type section. rences show that the disconf ormity extends throughout This area has been mapped by J. C. Dunlap (Dunlap the region. and Rodgers, 1945), and the sketch map, plate 3Z>, Within the Mascot-Jefferson City district there is has been compiled from his map with additions and also indirect evidence of unconformity, based entirely details by the writer. At this locality, the beds strike on the presence or absence of certain f aunal zones. In N. 65°-70° E. and dip about 55° SE. The strike of the the western part of the Mascot belt, C'eratopea ankyl- railway cut is almost parallel to that of the beds, so osa Cullison has been found at two localities, one near that the belt of outcrop crosses the cut very gradually John Sevier Station, the other on the Mascot farm of and the same units are exposed for long distances along the American Zinc Co. At the present writing (1953), its walls. The Middle Ordovician limestones are very it has been found only at two other localities in East thin at this point, measuring only about 180 feet across the outcrop from the base of the Athens shale to the Tennessee, one just north of Lickskillet in the May- top of the Mascot dolomite and having a calculated nardville quadrangle, the other on the north shore of thickness of slightly less than 150 feet. Forming the Douglas Lake in the western part of the area described basal member of the Athens shale is 30 to 35 feet of above. At all four localities it occurs within a few feet moderately crystalline compact dark-blue limestone, of the top of the Mascot dolomite. At Douglas Lake which crops out in conspicuous ledges on the hills the beds carrying this fossil are cut off by the uncon south of the railway cut and especially toward the formity, and this truncation can be clearly demon western edge of the cut. This limestone is underlain strated. by 5 to 10 feet of thin irregularly bedded shaly noiu- Because of the intensive study that the Mascot-Jef lar blue limestone, which grades laterally into and is ferson City district has been given not only by the underlain in turn by 100 to 110 feet of thick-bedded writer but by some of his associates on the Geological very fine grained to aphanitic light-blue limestone, v^ell Survey and by geologists employed by the various zinc exposed along the south wall of the railway cut. 'T'he companies, the failure to find this fossil elsewhere base of this unit is concealed, but it evidently rests upon within the area suggests very strongly that the beds a series of alternating fine-grained gray dolomites and carrying it were removed by erosion from most of the fine-grained somewhat nodular blue limestones, which are exposed in the north wall of the cut. The compact region before the deposition of the Middle Ordoviciaii crystalline limestones represent the Whitesburg lime rocks. stone of Ulrich (1930, p. 2, footnote), the 5 to 10 feet LENOIR LIMESTONE of shaly nodular limestone appears to be typical Leroir The Lenoir limestone was named by Safford and limestone, and the massive aphanitic limestones are the Killebrew (1876) from Lenoir City, Loudon County, Mosheim member, whereas the alternating dolomite Tenn.; the beds so named had previously been called and limestone beds represent the top of the Mascot the Blue or Maclurea limestone by Safford (1869, p. dolomite. Strata near the base of the Athens shale are 232-233). Plate SF is a sketch map of the area exposed in the road crossing the railway at the eastern around Lenoir City, based on a manuscript map pre end of the cut about 50 feet south of the tracks, and the pared by J. C. Dunlap and P. P. Fox for the Geologic compact limestone believed to represent the Whitesburg Division of the Tennessee Valley Authority, and kindly cross the cut about 300 feet west of this road crossing. lent to the writer by Berlen C. Moneymaker, chief of No Mosheim appears on the north wall of the cut, the the Division. space where it should appear being covered. The ex- 60 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE posures in the cut are about 0.25 mile long and the top the true Mosheim of the central part of the Valley, and of the Mascot apparently crosses the tracks about 0.4 it is believed that the true Mosheim does not extend mile west of the road crossing at the eastern end. To northwest of Clinch Mountain, but knowledge of its the west of the cut, the aphanitic limestone of the exact distribution will have to await the results of de Mosheim intertongues with the typical nodular lime tailed studies now in progress. stone of the Lenoir. The Mosheim member is composed cf thick-bedded In the Mascot-Jefferson City district, the Mosheim very pure structureless light-pearl-gray or bluish-gray member occurs in all three belts and commonly inter limestone, a typical lime-mudstone or calcilutite. It venes between the Mascot dolomite and the typical somewhat resembles the limestone of the Kingsport and Lenoir limestone. Locally, however, it is absent—for Mascot formations, especially on weathered surfaces, example, in much of the area south of Friends Station but it lacks the crinkly shale partings that characterize and on the south side of the small knob of Mascot dolo the Kingsport limestone. In addition, the Mosheim is mite between the highway bridge and Mascot. In these much bluer, locally almost black, although this dark areas it seems to have been overlapped by the typical phase is rare in the Mascot region. An additional pecu Lenoir on an uneven surface of Mascot dolomite. Lo liarity of the formation, and one which is a ready means cally, as for example on the north side of this same of identification, is the abundance of very small crystals knob, it is replaced by a crystalline limestome which of clear calcite scattered through the aphanitic ground- at places is red and resembles the Holston marble. mass. The rock weathers to a deep-red clay and de At two other localities, both of them on the west side velops no chert. Weathered surfaces are either rounded of the Strawberry Plains basin, coarsely crystalline red or subpyramidal and are commonly radially fluted. fossiliforous limestone, closely resembling the coarser This fluted weathering has also been seer on outcrops of and darker phases of the Holston marble, crops out the limestones in the Mascot and Kingsport formations, where the Mosheim member should occur. The larger and it seems to be characteristic of the weathering of of these two areas begins in the woods just west of the these aphanitic limestones. American Limestone Co.'s quarry on Holston River just north of the Southern Railway bridge and extends LENOIR LIMESTONE EXCLUSIVE OF MOSH7IM MEMBER in a southwesterly direction to within about 100 yards The typical limestone of the Lenoir is composed of of the county road on the north side of the Holston thick- to thin-bedded irregularly bedded to nodular fine River. The other outcrop is about a mile to the north grained dark-blue to bluish-black limestone. Weath west, just west of the north-south road that connects ered surfaces are lighter bluish in color, and in weath the county road just mentioned with U. S. Highway ering the rock commonly breaks up into small irregu 11-W. In both localities these beds rest on the Mascot larly rounded nodules. The residual soils developed on dolomite and are overlain by typical nodular Lenoir the Lenoir limestone, including its Mosheim member, limestone. Although the evidence is by no means con are a deep maroon red, similar to those on the overlying clusive, there is apparently a lateral gradation from Holston marble. typical aphanitic limestone of the Mosheim to red crys In the Mascot-Jefferson City district, the Lenoir talline limestone in the woods west of the limestone limestone exclusive of the Mosheim member is rarely quarry on Holston River. more than 250 feet thick. At other localities coarsely crystalline limestone re The index fossil of the Lenoir limestone is the large placing the Mosheim is gray and resembles the basal gastropod Maclurites magnus Lesueur. In the Mascot- beds in the type section of the Lenoir limestone at Lenoir Jefferson City district it is abundant r-t many locali City. ties, one of the best being the outcrops r,bout 31/2 miles The distribution of the Mosheim member through the due south of New Market. Average specimens are 3 Appalachian Valley is at present uncertain. Ulrich to 4 inches in diameter, but individuals as much as 8 (1911, p. 544) and Butts believed it to be widespread inches across have been found. A number of smaller and they identified it in all belts from southeast to north and less conspicuous gastropods are associated with west and from Alabama far into Virginia. Actually Maclurites, and certain other beds are crowded with they were applying the name Mosheim to the lowest poorly preserved sponges. fine grained lithographic limestone in the Middle Ordo- [Bridge left no material describing the hig-her stratigraphic yician section. It is now known that the beds called units of the Mascot-Jefferson City district—the Holston marble, Mosheim in the western belts are much younger than the Tellico sandstone, and the Ottosee shale.] STRUCTURE 61
STRUCTURE MASCOT BELT APPALACHIAN VALLEY The Mascot belt is the northwesterly of the three belts. It is a portion of a major thrust slice that can The major structural features of the Appalachian be traced as a narrow continuous zone across the State. Valley have been described in many reports and only a Beginning at the Tennessee-Georgia line this slice brief discussion need be given here. The Valley in passes northward through Cleveland and swings north East Tennessee is a portion of a belt of faulted and easterly through Loudon, the northwestern portion of folded Paleozoic rocks which extends from northern Knoxville, and Mascot. Throughout this entire dis Alabama and Georgia through East Tennessee into tance of about 110 miles it averages about 2.5 miles in Virginia and on to the northeast.. The rocks exposed in width; the rocks are homoclinal, and dip to the south the Valley range from Early Cambrian to early Penn- east. A short distance east of Mascot the belt logins sylvanian in age, and the proportion of rocks belonging to widen, reaching a maximum width of about 8 miles to each period varies greatly in different parts of the in the area northwest of Jefferson City, changing from Valley. Cambrian and Ordovician rocks predominate a homocline to a shallow syncline, pitching southwest. in the Valley in East Tennessee. Northeast of Mooresburg (pi. 2) the belt again becomes In East Tennessee the Valley is from 40 to 60 miles narrow but continues northeastward as a distinct struc wide; it is bounded on the east by the major low-angle tural unit at least to the Virginia-Tennessee linQ.. In thrust faults of the Unaka and Great Smoky Moun this section the principal structure is again homoclinal tains and on the west by the great east-facing escarp with the prevailing dip to the southeast; there are, how ment of the Cumberland Plateau, beyond which the ever, many minor structural irregularities. strata lie virtually flat. Its boundaries are thus deter Only that small portion of the Mascot belt extending mined by major structural features. Within the Valley from the northeastern city limits of Knoxville to the itself, the outstanding structural features are a series vicinity of Mill Spring is shown on the geologic map of subparallel southeast-dipping thrust faults, which accompanying this report. may be traced for long distances, and which divide the The northwestern edge of the Mascot belt is bounded Valley into narrow, linear belts, each of which repeats, by the trace of a major overthrust, which extends with in general, the stratigraphic succession in the adjacent out interruption across the State. This is the Saltville belts. The structure in most of these belts is homo- fault, named for Saltville, Va., where it was earJy rec clinal, and the prevailing dip is to the southeast. Anti ognized by Lesley (1862, p. 33) and named by Stevenson clines and synclines are locally developed and may be (1887, p. 265). In the present study, this fault ha-* been the dominant structure in a given belt or portion of a mapped only on the John Sevier quadrangle in the ex belt, but in East Tennessee such structures are not as treme western part of the area, between Loves Creek abundant as homoclines. Where developed, the axes and Strong Creek, but its general course is shown on of the anticlines and synclines are, in most places, plate 2 and on the geologic map of the Maynardville roughly parallel to the thrust faults. This repetition folio (Keith, 1901). The average dip of the fault plane of formational sequences of different degrees of resist in the area mapped is about 40° southeast. ance to erosion by folding and faulting is responsible Immediately northwest of the trace of the Saltville for the peculiar and distinctive valley and ridge topog fault in this same general area are two small fault slices raphy and the attendant trellis drainage that charac or slivers, which are clearly related to it. Only the terize the Appalachian Valley. southeastern one is shown on the accompanying- map, As noted above (p. 7, pi. 2), the Mascot-Jefferson but both are shown on the geologic map in the May- City area includes three of these narrow, linear belts, nardville folio (Keith, 1901). They are bounded along here termed the Mascot, Jefferson City, and Shields their northwest edges by small thrust faults th^t are Ridge belts. These belts strike northeast, and each ex presumably offshoots of the Saltville fault. tends beyond the limits of the area mapped. Each is The southeastern fault diverges from the mair fault a portion of a fault block that has been thrust out upon just west of Woods Creek and rejoins it between Strong the block lying to the northwest of it. The faults form and Roseberry Creeks. The sliver included between ing the boundaries of these belts are here called (in this and the main thrust is a block of Nolichucky shale order from northwest to southeast) the Saltville,23 and the overlying Maynardville limestone member and Mill Spring, Rocky Valley,23 and Dumplin Valley not Knox dolomite as shown by Keith.24 faults. » On the 1945 map the dotted line connecting the northern end of 88 On the geologic map and sections published in 1945 (Bridge, 1945), this fault with the main fault along the 05' parallel Is a printer's line the Saltville fault Is called the Rlchland fault, and the Rocky Valley used to delimit the color pattern and should have been removed before fault Is called the Bays Mountain fault. See footnote, p. 6. the edition was printed. 339223—55———5 62 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZINC DISTRICT, TENNESSEE The northwestern fault diverges from the Saltville here called the Strawberry Plains basin. Beyond this fault about 2 miles west of Loves Creek and encircles swing, the formations between the Ottosee and the the southeastern one. It encloses a block composed al Chepultepec strike about S. 65° E. and dip 10° to most entirely of Copper Ridge dolomite. It was not 25° SW., until they pass beneath the Mill Spring fault mapped during this study, but its trace is believed, to that forms the northern edge of the Jefferson City belt. lie in the valley of Murphy Creek, and, according to Between these diverging strike belts, the intervening Keith, it also rejoins or passes beneath the main Salt formations flatten out into a broad and slipllow syncline ville thrust in the area between Strong and Roseberry in which few dips exceed 10° and most are less than 5°. Creeks. This syncline contains some minor folds and small The structure of the Mascot belt within the mapped faults. It plunges gently southwest toward the Straw area is comparatively simple. From Loves Creek at berry Plains basin of which it is the northeastern con the western edge of the mapped area to Mascot, the tinuation. To the northeast it extends for some miles belt is narrow and the strata strike N. 60°-65° E. and beyond the limits of the map. For the most part it dip southeast, the average dip ranging from 50° at includes nearly horizontal strata belonging to the Loves Creek to 25° along Flat Creek at Mascot. The Copper Ridge dolomite, though some of th?, higher hills, creeks that cross the belt between these limits expose especially along the southeastern limb, are capped by the best and most complete sections of the Knox group remnants of the Chepultepec and Longvi°.w dolomites. within the mapped area. Two tear faults displace the Maryville limestone JEPFEBS01T CITY BELT along this belt near the west edge of the mapped area, The Jefferson City belt is part of a thrust slice that and, though they have not been traced above the base can be traced from Strawberry Plains r ortheastward of the Nolichucky shale, it is possible that the dolomite beyond the area mapped. To the southwest it seems to in the Knox group has been shattered in these areas merge with the Mascot belt in the vicinity of Mascot, by the same forces that produced the tear faults. It is because of the dying out of the Mill Spring fault, which noteworthy that both strike directly towards gaps in in this area forms the boundary between these two belts. the topographic ridge underlain by the Copper Ridge The displacement along this fault diminishes in a south dolomite. They also strike toward notches or gaps in westerly direction; the fault itself has not been traced the ridge to the northwest formed by the Rome forma beyond the general vicinity of Mascot. tion; in fact, the one in the vicinity of Bethlehem The Mill Spring fault is named for Mill Spring, a Church may actually go through the gap. Both tear small settlement in the southeastern part of the Joppa faults strike northwest obliquely to the strike of the quadrangle, about 3 miles northwest of Jefferson City. rocks, and the southwest side of each has moved rela It is a minor thrust fault which emerges from the east tively northwest; in these respects they resemble many ern side of the Strawberry Plains basin about 1.25 miles other tear faults in East Tennessee, for example, those north of East Hodges Station and has be^n traced in a in the Copper Ridge zinc district (Rodgers, 1943). northeasterly direction through Mill Spring to the Near Mascot, the strike of the formations swings northern edge of the map. It has not been traced be from N. 60° E. to N. 35° E. In the pre-Knox forma yond this point; it is believed to die out in the long, tions the swing is gradual, but in the formations of shallow syncline that forms the northeast extension of the Knox group, especially those near the top, the swing the Strawberry Plains basin. The trace of this fault is fairly abrupt and forms a blunt anticlinal nose can be readily observed along both side? of the road plunging southeast about a mile east of Mascot, close leading north from U. S. Highway 11-E to Nances to the eastern end of the mine workings. Grove Church. The fault has not been napped to the Northeast of Mascot the.strike remains N. 35° E. southwest across the central part of th°> Strawberry and the dip is 20° to 30° SE. as far as Richland (Ada Plains basin, because this structure is filled with a mass 011 the Maynardville 30-minute quadrangle); no irregu of structurally complex Ottosee shale, th^ mapping of larities are known. Near Richland, however, the struc which was not a part of the project. In g.ll probability ture changes considerably. The formation from the it does cross this unmapped area and connects with one Nolichucky shale down continue northeastward along of the faults shown emerging from the southwest side Richland Valley with little change in strike or dip, but of the basin. the formations above the Chepultepec swing abruptly The surface evidence for the faults on the southwest east and southeast through 90° around a synclinal mass side of the basin is well shown along both sides of the of Ottosee shale centering in the unmapped area north county road, about 1.5 miles east of Mascot, that con east of Strawberry Plains. This synclinal structure is nects the Mascot-Strawberry Plains road with U. S. STRUCTURE 63 Highway 11-W, along Holston Kiver on the west side about 0.5 mile north of this point. Still farther north of Big Bend, and along the road in Big Bend. The east, in the vicinity of Mill Spring, the evidence for general trend of the faults was established by these ob the fault becomes much more definite, and displace servations, and the projection to the southwest through ment of strata caused by it can be seen in the low bluff the Mascot mine of at least the northern fault coincides, on the southwest side of Holston Eiver about 1 mile according to Harley M. Coy (personal communication, northwest (downstream) of Cherokee Dam, and also 1940), with zones of extensive shattering in the mine in the riverbed when the water is low. At this point which have permitted extensive leakage in the past from the fault plane dips steeply southeast and the displace both Big Flat and Eoseberry Creeks. This fault may ment is small. Both of these features suggest that it continue to the southwest beyond the mine and eventu is dying out to the northeast. Hence in this direction ally die out in the thick mass of Lenoir limestone be also the Jefferson City belt merges with the Mascot tween Mascot and John Sevier. belt. None of these faults was recognized by Keith (1901) The structure of the Jefferson City belt is dominated in his mapping of the Maynardville quadrangle, but by the large anticline lying just southeast of the Chero the course of the Mill Spring thrust across the Straw kee Dam, here called the Cherokee anticline. Tte axis berry Plains basin is indicated on his map by sharp of this fold strikes N. 40° E. near the dam and extends zigzags in the formation boundaries on both sides of in this direction for 10 miles or more to the northeast. the basin. The northeastern part of this fold lies beyord the The relatively straight traces of the faults in the boundaries of the map and was not studied in the prep area to the southwest of the Strawberry Plains basin aration of this report. It is fairly well shown, however, would seem to indicate that the fault planes dip at by the mapping of the Cambrian formations on tH geo comparatively steep angles. The small amount of off logic map of the Morristown folio (Keith, 1896). The set of formation boundaries suggests that the amount axial part of this fold, including most of the exposures of displacement is relatively slight (pi. 1, sections of the Nolichucky shale and all those of the formations E-E',F-F' and #-#'). beneath it, is now submerged beneath Cherokee Lake. On the eastern side of the Strawberry Plains basin To the southwest of Cherokee Dam the axis of tt^ fold the fault plane dips at a much lower angle, as is shown turns more nearly south, and the anticline plunges on the map by the sinuous trace of the fault in the vi southward, passes between the towns of Jefferson City cinity of the Nances Grove Church road. Further con and New Market, and heads into the large reentrant in firmation of the low dip of the fault plane in this area the trace of the Eocky Valley fault between T'omas is to be found in the logs of certain drill holes put down and Koppick Knobs. Near the dam the dips on the many years ago by the American Zinc Co. According flanks of the fold range from 15° to 30°, but farther to M. H. Newman (personal communication, 1929), south the dip is much more gentle, rarely exceeding 10° these holes were drilled in the fields adjacent to the as each formation of the Knox group swings around the road south from Nances Grove Church, about 0.25 plunging nose of the anticline. mile south of the outcrop of the fault. They started West of the south-plunging portion of the Cherokee in the Mascot dolomite and passed through the fault anticline is a broad, shallow syncline, plunging south plane into Lenoir limestone within a few hundred feet past New Market beneath a large projecting mass of of the surface. the Eocky Valley thrust block, and broken by minor For 3 to 4 miles northeast of a point about a mile faults parallel to the axis. On the west limb of this east of the Nances Grove Church road, the trace of the syncline the higher formations of the Knox group strike Mill Spring fault is only approximately located. This S. 70° W. and dip gently south for 2 miles; then the is partly because of lack of outcrops and also partly be strike swings northwest and north around an ant: ?linal cause much of the area through which this portion of the nose until the rocks are cut off by the Mill Spring fault. fault passes has been under cultivation for many years, This nose appears to represent the anticline out of so that large quantities of the residual chert boulders which the Mill Spring fault developed. have been removed from the fields by successive genera Farther southwest, extending to and beyond JT^raw- tions of farmers. Further evidence for the approximate berry Plains, is an area of complex structure lying be position of the fault is found in the large blocks of tween the Strawberry Plains basin and the Eocky sandstone, from high in the Copper Eidge dolomite, Valley fault. This area has not been completely in cuts along the road 2.25 to 2.5 miles east of Nances mapped because it involves chiefly beds younger than Grove Church, and in the abundance of Copper Eidge the Knox group and therefore was not relevant to the residuum on the northwest slope of a wooded hill project. The structure of the narrow central p
Cloud, P. E., Jr., 1948, Brachiopods from the Lower Ordovician Laurence, B. A., 1944, An early Ordovician sinkhole deport of of Texas: Harvard Coll. Mus. Comp. Zoology Bull., v. 100, volcanic ash and fossilferous sediments in East Tennessee: p. 451-472. Jour. Geology, v. 52, p. 235-249. Cloud, P. E., Jr., and Barnes, V. E., 1948, The Ellenburger group Lesley, J. P., 1862, On the coal formation of southern Virginia: of central Texas: Tex. Univ. Bur. Econ. Geology Pub. 4621, Am. Philos. Soc. Proc., v. 9, p. 30-38. 473 p. Lochman, Christina, and Duncan, D. C., 1944, Early Upper Cooper, B. N., 1944, Geology and mineral resources of the Burkes Cambrian faunas of central Montana: Geol. Soc. America Garden quadrangle, Virginia: Va. Geol. Survey Bull. 60, Special Paper 54, 181 p. 299 p. McQueen, H. S., 1931, Insoluble residues as a guide in strati- Cullison, J. S., 1944, The stratigraphy of some Lower Ordovician graphic studies: Mo. Bur. Geology and Mines Bienn. Bept. formations of the Ozark uplift: Mo. Univ. School Mines and State Geologist [1929-30], p. 102-131 [preprint, 1930]. Metallurgy Bull., Tech. Ser., v. 15, no. 2,112 p. Miller, B. L., and Fuller, J. O., 1947, Geologic and structure con Currier, L. W., 1935, Structural relations of southern Appa tour map of the Bose Hill oil field, Lee County, Va.: U. S. lachian zinc deposits: Econ. Geology, v. 30, p. 260-286. Geol. Survey Oil and Gas Inv. Prelim. Map 76. Dake, C. L., 1921, The problem of the St. Peter sandstone: Mo. Moneymaker, B. C., Leonard, G. K., and others, 1949, Geology Univ. School of Mines and Metallurgy Bull., Tech. Ser., and foundation treatment, Tennessee Valley Autlority v. 6, no. 1, 225 p. projects: Tenn. Valley Authority Tech. Bept. 22. ———— 1930, The geology of the Potosi and Edgehill quadrangles: Munyan, A. C., 1951, Geology and mineral resources of the Dal- Mo. Bur. Geology and Mines 2d ser., v. 23, 233 p. [1931]. ton quadrangle, Georgia-Tennessee: Ga. Geol. Survey Bull. Dake, C. L., and Bridge, Josiah, 1932, Faunal correlation of the 57, 128 p. Ellenburger limestone of Texas: Geol. Soc. America Bull., Oder, C. B. L., 1934, Preliminary subdivision of the Knox dolo v. 43, p. 725-741. mite in East Tennessee: Jour. Geology, v. 42, p. 469-4f 7. Dunlap, J. C., 1947, The Eve Mills zinc area, Monroe County, Oder, C. B. L., and Hook, J. W., 1950, Zinc deposits o* the Tenn.: U. S. Geol. Survey Strategic Minerals Inv. Prelim. Southeastern States, in Snyder, F. E., ed., Symposium on Bept. 3-215. mineral resources of the Southeastern United States, 1949 Dunlap, J. C., and Rodgers, John, 1945, Geologic map of the Proc., p. 72-87: Knoxville, Univ. Tenn. Press. Mosheim anticline, Greene County, Tenn.: U. S. Geol. Survey Oder, C. B. L., and Miller, H. W., 1945, Stratigraphy of the Strategic Minerals Inv. Prelim. Map. Mascot-Jefferson City zinc district [Tenn.]: Am. Inst. Min. Gordon, C. H., 1918, Barite deposits of the Sweetwater district, Met. Eng. Tech. Pub. 1818; ibid., Trans., v. 178, p. 22?-231, East Tennessee: Tenn. Geol. Survey, Bes. Tenn., v. 8, 1948. p. 48-82. Poulsen, Christian, 1937, On the Lower Ordivician faunas of Gordon, C. H., and others, 1924, Marble deposits of East Ten East Greenland; Meddelelser om Gronland, band 110, Nr. nessee: Tenn., Dept. Education, Div. Geology, Bull. 28, 3; reprinted in Copenhagen Univ. Mus. mine'ralogie et g6ol- 264 p. ogie Commun. pal^ont. 57. Grabau, A. W., 1937, Paleozoic formations in the light of the Purdue, A. H., 1912, The zinc deposits of northeastern Ten pulsation theory, v. 3, pt. 2: Peking Univ. Press. nessee : Tenn. Geol. Survey Bull. 14,69 p. Hall, G. M., and Amick, H. C., 1934, The section on the west Purdue, A. H., and Miser, H. D., 1916, Description of the Eureka side of Clinch Mountain, Tenn.: Tenn. Acad. Sci. Jour., Springs and Harrison quadrangles [Ark.-Mo.]: U. S. Geol. v. 9, p. 157-168, 195-220. Survey Geol. folio 202. Hayes, C. W., 1891, The overthrust faults of the southern Appa Resser, C. E., 1938, Cambrian system (restricted) of the s-outh lachians : Geol. Soc. America Bull., v. 2, p. 141-152. em Appalachians: Geol. Soc. America Special Paper 15, ———— 1894, Binggold atlas sheet [Ga.-Tenn.]: U. S. Geol. Survey Geol. Atlas, folio 2. 140 p. Howell, B. F., and others, 1944, Correlation of the Cambrian ———— 1942, Faunal content of the Maryville formation [Ala., formations of North America [Chart no. 1]: Geol. Soc. Ga., Tenn.] : Smithsonian Misc. Coll., v. 101, no. 10, Pub. America Bull., v. 55, p. 993-1003. 3676. Keith, Arthur, 1895, Description of the Knoxville sheet [Tenn.- Besser, C. E., and Howell, B. F., 1938, Lower Cambriar OZe- N. C.]: U. S. Geol. Survey Geol. Atlas, folio 16. nellus zone of the Appalachians: Geol. Soc. America Bull., ———— 1896, Description of the Morristown sheet [Tenn.]: U. S. v. 49, p. 195-248. Geol. Survey Geol. Atlas, folio 27. Rodgers, John, 1943, Geologic map of Copper Bidge district, —— 1901, Description of the Maynardville quadrangle [Tenn.]: Hawkins, Hancock, and Grainger Counties, Tenn.: U. S. U. S. Geol. Atlas, folio 75. Geol. Survey Strategic Minerals Inv. Prelim. Map. ———— 1905, Description of the Greeneville quadrangle [Tenn.- ———— 1948, Geology and mineral deposits of Bumpass Cove, N. C.] : U. S. Geol. Survey Geol. Atlas, folio 118. Unicoi and Washington Counties, Tenn.: Tenn. Dept, Con- Kent, D. F., Bodgers, John, and others, 1945, Areal and economic serv., Div. Geology Bull. 54, 82 p. geology of the Powell Biver area, Claiborne and Union ——— 1953, Geologic map of East Tennessee with explaratory Counties, Tenn.: U. S. Geol. Survey Strategic Mineral Inv. text: Tenn. Dept. Conserv., Div. Geology Bull. 58, pt. 2,168 p. Prelim. Map. Bodgers, John, and Kent, D. F., 1948, Stratigraphic section at King, P. B., 1940, West Texas-New Mexico symposium, Part 1, Lee Valley, Hawkins County, Tenn.: Tenn. Dept. Corserv., Older rocks of Van Horn region, Texas: Am. Assoc. Petro Div. Geology Bull. 55, 47 p. leum Geologists Bull., v. 24, p. 143-156. Boss, B. J., Jr., 1951, Stratigraphy of the Garden City formation Knight, J. B., 1947, Some new Cambrian bellerophont gastro in northeastern Utah, and its trilobite faunas: Yale Univ. pods : Smithsonian Misc. Coll., v. 106, no. 17,11 p. Peabody Mus. Nat. Hist. Bull. 6,161 p. 74 STRATIGRAPHY OF THE MASCOT-JEFFERSON CITY ZDSTC DISTRICT, TENNESSEE Safford, J. M., 1869, Geology of Tennessee: 550 p., Nashville. — 1930, Ordovician trilobites of the family Telephidae and Saff ord, J. M., and Killebrew, J. B., 1876, The elementary geology concerned stratigraphic relations: U. S. Natl. Mus. Proc., of Tennessee: 255 p., Nashville. v. 76, art. 21, 101 p. Sardeson, F. W., 1896, The fauna of the Magnesian series: Minn. 1931, Origin and stratigraphic horizon of the zinc ores Acad. Nat. Sci. Bull., v. 4, p. 92-105. of the Mascot district of East Tennessee [abst.] : Washing ton Acad. Sci. Jour., v. 21, p. 30-31. Secrist, M. H., 1924, Zinc deposits of East Tennessee: Tenn. Ulrich, E. O., and Cooper, G. A., 1938, Ozarkisn and Canadian Dept. Education, Div. Geology Bull. 31, 165 p. Brachiopoda: Geol. Soc. America Special Paper 13, 323 p. Sellards, E. H., 1932, The pre-Paleozoic and Paleozoic systems Ulrich, E. O., Foerste, A. F., Miller, A. K., and others, 1942,1943, in Texas, in The geology of Texas, v. 1, Stratigraphy, p. 1944, Ozarkian and Canadian eephalop->ds: Geol. Soc. 15-231: Tex. Univ. Bur. Econ. Geology Bull. 3232 [1933]. America Special Papers 37, 49, 58. Smith, E. A., 1876, Report of progress for 1875: Ala. Geol. Survey, Walcott, C. D., 1916, Cambrian trilobites: SiMthsonian Misc. 220 p. Coll., v. 64, p. 303^56. Stevenson, J. J., 1887, The faults of southwest Virginia: Am. Willis, Bailey, 1893, The mechanics of Appalachian structure: Jour. Sci., 3d ser., v. 33, p. 262-270. U. S. Geol. Survey 13th Ann. Rept, pt. 2, p. 211-281. Stose, G. W., 1908, The Cambro-Ordovician limestones of the Wilmarth, M. G., 1938, Lexicon of geologic nair^s of the United Appalachian Valley in southern Pennsylvania: Jour. Geol States: U. S. Geol. Survey Bull. 896. ogy, v. 16, p. 698-714. Wilson, J. L., 1949, Stratigraphy and faunal relationships of the Upper Cambrian in the central Appalachians [abst]: Geol. Trowbridge, A. C., and Atwater, G. I., 1934, Stratigraphic prob Soc. America Bull. v. 60, p. 1929-1930. lems in the upper Mississippi Valley: Geol. Soc. America Winslow, Arthur, 1894, Lead and zinc deposits: Mo. Geol. Survey, Bull., v. 45, p. 21-79. v. 6, 7, 763 p. Ulrich, E. O., 1911, Revision of the Paleozoic systems: Geol. Soc. Woodward, H. P., 1932, Geology and mineral resources of the America Bull., v. 22, p. 281-680; Index, v. 24, p. 625-668,1913. Roanoke area, Virginia: Va. Geol. Survey Bull. 34,172 p. INDEX
Acknowledgments______-______....—__.__„___-. 5-6 Highways.----- 6-7 American Zinc Co. of Tennessee______._____. 4,5,56,59,63 Holston marble . 57 mines______.______..._.___.__ 69,72 Aphelaspis zone, list of characteristic species. Appalachian Valley, structural features__ JeffersonCitybelt-———-——————————— ————. 7,38,61,62-66,69,72 Joints..______.______71 in chert nodules.--..______.-._____-- 65 Balk, Christina Lochman. See Lochman, Christina. Bays Mountain..______...... _..... 6,56,66 K Bays Mountain fault______.______...... ___ -.. 7,61,68 Kingspori limestone______._ 23,69 Bays Mountains————___—..______.______.__ 6,7 correlation____--______54 Breccias, origin___.__....______._.__ ———...... 70-71,72 description-..___-.-______-.______49-54 Butts, Charles, quoted...____.______.______.______..__ 45,46 fossils______54 occurrence of ore______. ______. __ _ 69-70,71,72 0 section______.______.______.______51,52-53 Canadian system of Ulrlch...______24-25 Kingsport-Longview contact______70 Cedaria zone, fauna.______._ —____--.._.__-...___. 20 Klippen.—____-_...... _....____._-__.___....__..._ 64,66 Chepultepecdolomite--———————__-————————— 23,27-28,33,55,56 Knox dolomite...__.______.______.______21-22 correlation.._————————— —— —————————.-- —— ._ — 42,44,45 Knox group..--.______.______. 21-60,71 description..______.______.___...... __ 37-46 history of terminology______.______.__ 21-23 chart I distribution of species.______.______— -_ 43-44 present usage—.. ——————————————— ————————————.——— 23-24 facies relationships.. — ______....__.._-_____ — ____.—_._ 41 recent work..—.. —— ______———...... ——... — ______3-5 fossils....___.__...... __._——— — ————— — — ——— — — —— 41-45 ridges.--— — — - — ______— —... —... —— — — ___- — ______.. 55-56 quartz cavity-fillings—.„—______.______.____.„.-__.. 40 unconformity at top of.—.—. ——- — -- —— —— ——— — ————— — - 23-24 relation to Longview dolomite______.__...__.....__ 45-46 work before 1929______. ______. ______3 residual chert______. ______. ______. __ 40 Koppick Knob...------..--.-__...___—.——._.__———— 5,66,67 TVA quarry section______.____.__.___...__ 39 Chepultepec-Longview contact._.___.__...______._._____.__ 37,53 Cherokeet-Qticline——.—.—— — — ————.—.— 9,10,63,64,65,67,70,72 Cherokee Dam.______.______.___ 12,33,38,39 Laurence, R. A., color measurements. -----_------..-----_------.- 9,11 Cherokee Lake...__...... __...... __-—...... __- 10,12,25 Lenoirlimestone._.-._--.-—... ——._——-———. ————————.—_ 57,59 Chert residual----————.——— ———— ——— 12,13,15,31-32,40,48,54,55,65 description_——. ——————.——————————————————————— 60 Chickamauga limestone, description______. 56-57 fossils._---_----_----..----__._.--.------.——------—._.-—. 60 Clay, residual...... ———-----——-_ — _-.——- — .-.. — ___.- 31,54,60 unconformitj at base.- ————— -- —— ——— -_. —————— —— —. ——. 57-59 Cooper, B. N., quoted_____.______.______..._____. 38 See also Mosheim member. Copper Ridge dolomite—...... 13,16,23,53,55,56,62,63 Location of area....————— ———————————— -——————————————— 1 correlation...___.-..---.——....—-.—.-...—....-...-.__„.——. 34-36 Lochman, Chiistina, quoted_- —— ——— ——— —— ————— ———— —— - 20 description.______.._____.______...______. 25-37 Longview dolomite. ______—______23,53,55,56,69 facies relationships__.______.______...__.___. 33-34 correlation————————————————————————————————————— 48-49 fossils—-——————————. — — ————————— — .. 34-37 description.. — ——— —— - — — -- ——————— —— ———.- —————— — 46-49 Loves Creek section__.___. ______—..._.____. 27-29 distribution of species.------— —————— —————— —————— - 4* residual chert______.______. 31-32 fossils—————— ————————————————— ———— 48-49 Craig limestone member of Rogersville shale._——..___..._...... __ 7-8 relation to Chepultepec dolomite...— —— —— ———— ——. ——————. 45-46 type section______-____ - _____ — ___._. 9 residual chert.....—.——————————————————————.——————— 48 topographic expression.______. _ _. _____. 19 Cre-picephalus zone, list of characteristic species______. _.__....__. 20 M Cryptozoans____.______.______...______. 32-33,40 Mapping by U. S. Geological Survey.—————————————————————— 3,4 Mapping procedures—.——————————————————————————————— 5 D Maryville limestone....——.———————...—.——-—-———————— 7,9,30 Domes..-_..._—————..—————— ———————.—.————— — . 64,72 description.--————— ——————————— -- —————— ————————— 10 Douglas Lake.—__——---..-.--.______.__.______.._ 58,59 facies relationships—.————— ——————— ————————————————— 17-18 Drainage.______.______.______55 topographic expression—.——.. — —— — ——— ——————————— —— 19 by Holston River______.______._ 6 Mascot belt.— ---_------— -—— —— _ 7,9,10,12,21,26,38,61-62,63,69,71,72 underground__-.--.-...-__-______..._____._ 6,56,65 Mascot dolomite__...__—— ———— — ———__—-—— 23,55, 56,57-58,*72 Dumplin Valley thrust fault--..-_.——————___...... 7,61,67,69 correlation— — ————— —— - ——————————————— ————————— 55 Duncan, D. C., quoted______.______.______20 description...---..- — — — -- ——————— ——————— ————— —— —— 54-55 relief on surface.. - —.____. —— —————— —————— ————————— 58,59 F % section_—— — ———— —. ——— ——. — ———— — ————— —— 51 Faults____._____.____...—.___...._____...... 61-66,68-69,71,72 Maynardville limestone member of Nolichucky shale————. ————— 7,8,53,61,72 Faunallists, Aphelaspis zone...______20 Aphelaspis fauna.-.-- — —... ——————— ———————.. ——————.— 19,21 Cedaria zone..——.—.——...„_._____...___.______20 description.-----.------——-———-—————— ————— 11-21 Chepultepecdolomite..______.______.______43-44 Loves Creek section.—.-_——————————.——————————————-— 29-30 Crepicephcdus zone..______20 sections——— —————————————————_— 13-14,15,16-17 Longview dolomite______..______...______. 49 topographic expression....----- ——— ——— ————————————— -— 19 Folds———__——_————————————————————— 68-69,70,71,72 MiU Spring thrust fault. — ——————————————— 7,61,62,63,64 68,71,72 Mines, Athletic..------——.——— ————-————— 69 Q Davis- —— — ——— — —————————————————— 69,71 Geography-..______...„______—...______._ 6-7 distribution------— -- ——————-—-———————————— 69,70 75 76 INDEX
Mines—Continued Page Grassellior New Market—.- — — - ——— — — ._— — -.__— — — __ 53,69,70,72 Rocky Valley thrust fault....—_————————— 7,61,63-64,65,66-«7,68-69 Jarnagin_--_..———____-_--- — ... — .._._..______69,72 Rogersville shale__.______...—______7,30 Mascot__ ———„—------— — ------.-....-...... „.-. — . 47,53,69,71 description...——..——————————.—————————__.__..._ 8-10 fault..--..-..____ — -- — ------— .------— ....—— 63 facies relationships_—.————————...————.———______17-18 Mossy Creek--...-————__— — — — - — -—.- — - — — — -_-...___ 70,71 topographic expression___—————....——.——.—______19 Rocky Valley fault through. _.. — — _— - ——— -_ — — — -_____ 66,70 See also Craig limestone member. North Friends Station...-—-.___- — — — — — __...... ______72 Rome formation______....______7,30,69,72 Young____._ ———— ___ —._---_-.____-----______72 description...... ______„——__————————______8 Moccasin Ridge_____.—.______...____.______25 ridges .....————————————————...————————————————— 55-56,62 Moore, E. S., quoted-______.__. ____.______45,46 topographic expression_——————————————————_.._. ___ 18 Mosheim anticline__————__.__---——....______63 Rutledge limestone.—.____—————_———.————______7 Mosheim member of Lenoir limestone.——————_____-...——____ 57,58 description.. ______.__—.——___...__——...______8 description...__—————_—_...——..______.______59-60 facies relationships______17-18 topographic expression___—.——____._...... ______1ft N Nolichucky shale______. ______7,8.61,72 S description.-———————————————————__-...-...-———___. 10-11 Safford, J.M., quoted————————————_..._._...... _ 21,40,56 facies relationships————....————————...___.._._.__... 17-18 SaltvUle thrust fault—————————————————_ 7,29,30,61,62,67,68,69 faunal zones..„_-———___...———-...______..______19 Sandstone, residual..——————————.————————__.. 33,41,48,54.55 Loves Creek section.———_____..._...______29-30 Scope of present report...... ——————————————.————.....———.. 1-2 topographic expression ...... ———...______19 Shady dolomite—..—-___——————...... —————..___..___ 8,72 See also Maynardville limestone member. Shields Ridge-————.———.—————...——_——__...... 6 NorrisDam.__———————————————————.....—.—————__. 11 Shields Ridge belt——.__———...——————_...... ____ 7.8,38,61,66-67 .———..—..———..—...... 11,13,14,17 Sinks————————_—.————————————._...... 6,55,57,58,65 Soils————————————__———————__ . __ 31,40-41,48,54,56,60,65 Sphalerite, ore-bearing zone..————-—————————————————— 69-70,71,72 Oder, C. R. L., quoted..——..___...————...__-__._____.__ 13,23 veinlets in quarry in Owl Hole Gap. — .—————————————————— 15 Ore-bearing zone of sphalerite.._____————______——. 69-70,71,72 Stratigraphic columns____————————.————————_.__.. 7; chart 1. Owl Hole Gap, veinlets of sphalerite in quarry——.———....——————— 15 Stratigraphy.—.——————————————————————————..——.—— 7-60 Ozartlan system of Ulrich——....————————___.____——___ 24-25 Strawberry Plains basin______———______62,63-64 Structural belts——————————————————————— — - 7,55-56,61-68 Structural features_—__—————————————————————.———— 61-69 Pre-Knoxformations.. —————————————————————.——————--- 7-21 formation—————_———————————————————————————— 68 names and distribution.—___—.—————______——___ 7-8 Synclines, between Cherokee and Rocky Valley anticlines—-______65 Prospects, distribution... ———————————————————.———————— 70 east of Jefferson City. __—————————————————————————— 64 Pumpkin Valley shale.—.——....„———————..„._....————__. 8,19,30 Strawberry Plains basin..._...————.—————————.—————— 62 Purpose of present report———————— ——————————————-—— 1-2 T Q Quarries, BiagiottL-———————.....————————————-----———....— 17 Tennessee Coal & Iron Division, U. S. Steel, mines——————_...———... 69,71 Craig. 9; pi..3C7 Tennessee Valley Authority, Geologic Division, work in East Tennessee—„ 4 Knox County at Tecoy.——...————————.._..——————__.. 21 Topographic expression, pre-Knox formations————————————————— 18-19 Knox County workhouse...... ————————___..——————__— 17 Topography, Knox group...... ————————————————————————— 55-56 near Cherokee Dam.———___._..————______..——___ 32-33 Towns, principal-..—__——————————————————————————— 6 Owl Hole Gap, veinlets of sphalerite...———_____..————___. 15 Troughs, parallel______————————————————————————— 56-57 State Highway Department-—————————....————————_.... 15 TVA....——..—---.—.-.-..—.——.-—....——....-.—.-...-. 38-39 U Quartz cavity-fillings, Chepultepec dolomite_—._-____...... ___. 40 Ulrich, E. O., quoted..—.————————————————...... 11,24,34,37,40 Unconformity, at base of Lenoir limestone._...——————————————— 57-59 R at top of Canadian or Lower Ordovician....———————————————— 24 "Recrystalline" dolomite,_.______.....______47,54 at top of Knox group..._...——.—...... ————...... —-——. 23-24,68 ore bodies.-____———___--—————____——————_--.- 70 Relief, of the area-——————————————————————————————— 6 on surface of Mascot dolomite..——————————.———.——————... 58,59 Resser, C. E., quoted——.———...——.———.——'...... 25 Veinlets of sphalerite in quarry in Owl Hole Gap.——————————————— 15 Richland fault———————————————————————————— 7,61 Volcanic ash—_——————————————————————————————————— 58 Richland Knobs escarpment______....——____..—————_. 10,15,19 Ridges, description___———....————————_...—————.————— 55-56 W Roads, county____————___——.————___——————————— 7 Wilson, J. L., quoted-_——————————...—————————————————— 34 Rock structure, mechanics_...... —...... ———___—————————— 68-69 Work before 1929-._..__———————————————————— 3 Rocks of the Appalachian Valley. _____———__——.—————....— 7 Rocky Valley anticline——__.___—.—...... __._..__ 9,40,66,67,68-69 - material in crest..————_....———————_..._————————— 8 Zinc————————————————————————————— 69,70,71,72 O