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DESCRIPTION OF THE TAHLEQUAH QUADRANGLE

By Joseph A. Taff.

GEOGRAPHY. character and the topographic details of which are southern slopes and by drainage which has eaten in the adjoining quadrangle is marked by sharp- dependent upon the character and attitudes of the by headwater erosion into its northern border. crested, level-topped ridges. Location and area. The Tahlequah quadrangle rocks. These plateaus succeed one another con­ The crests of the ridges which slope southward is bounded by parallels of latitude 35° 30' and 36° centrically westward from the St. Francis Moun­ from the main divide to the border of the Arkan­ TOPOGRAPHY OF THE QUADRANGLE. and meridians of longtitude 94° 30' and 95°, and tains as a center. They cross the axis of the main sas Valley may be said to define approximately a The Springfield structural plain and the Bos­ contains 969 square miles. It is in the Cherokee uplift and main watershed, giving an effect of structural plain. Viewed from eminences on the ton Mountain plateau have nearly equal areas in Nation, Indian Territory, except a narrow, trian­ deformed plains. The physiography of the Ozark Springfield plateau, the Boston Mountains have the Tahlequah quadrangle, the former occupying gular tract in the northeastern part, which is in Plateau in Missouri has been clearly set forth by the appearance of a bold, even escarpment with a approximately the northern half. Washington County, Ark. Its name is taken from C. F. Marbut (Missouri Geol. Survey, vol. 10, level crest. Instead, however, of presenting an the capital town of the Cherokee Nation, which is 1896). Geologic mapping by the Arkansas Sur­ even northward .front the escarpment sends out SPRINGFIELD STRUCTURAL PLAIN. located in the northwestern part of the quadrangle. vey shows the same features in the southern exten­ finger-like ridges and foothills, descending by In the Tahlequah quadrangle, as elsewhere in sion of these plateaus in Arkansas (Arkansas Geol. steps as successively lower hard rocks come to the western part of the Ozark dome, the Spring­ PHYSIOGRAPHIC RELATIONS. Survey, vol. 4, 1890). the surface. Toward the northern ends many of field plain is developed principally on the Boone The Tahlequah quadrangle is situated in the ex­ The first of these plateaus has been termed by the these foothills are intersected, becoming flat-topped formation. In this part of the region the Boone treme southwestern part of the Ozark region. Its Missouri Survey the Salem platform. It occupies outliers on the Springfield plain. Toward the east formation consists almost entirely of beds of cherty southern end includes a small area of the Arkan­ southeastern Missouri and a large part of northeast­ end of the Boston Mountains, where the capping limestone and flint. On weathering, a surface sas Valley region, which bounds the Ozark region ern Arkansas. The magnesian limestones, cherts, sandstone formations are thicker and lie more mantle of disintegrated porous chert is formed, on the south. Fifteen miles west of the Tahle­ and saccharoidal sandstones of the Cambrian and nearly horizontal, and where White River in its which is exceedingly durable. Waters falling quah quadrangle the Ozark region merges into Ordovician periods occur in this plateau, and are deep valley approaches its northern front, the upon it readily pass downward and reach the the Prairie Plains. A brief consideration of the inclined at low grades away from the St. Francis escarpment attains its greatest height. Here high, valleys gradually beneath the weathered mantle salient topographic features of the Ozark and Mountains. The edges of the lower of these depos­ flat-topped, precipitous ridges 1000 to 1500 feet or issue in springs through subterranean solution Arkansas Valley regions will assist the reader its face the lowlands surrounding the St. Francis high project northward on a level with the moun­ channels. Thus only the valleys of considerable in understanding the topography of the Tahle­ Mountains in distinct escarpments. Higher for­ tain top, making a high and rugged escarpment. size afford streams of sufficient power to corrode quah quadrangle. mations of limestone and chert qutcrop in succes­ In the western part of the Boston Mountains, the fresh rock or even to remove the fragmentary Ozark region. The Ozark region is a broad and sion farther away, making subordinate platforms toward the Arkansas-Indian Territory line, the chert. The general result of these conditions is relatively flat dome-shaped dissected plateau. In and escarpments. The intervening softer saccha­ Winslow formation, especially its sandstone beds, that broad, level tracts are developed on the durable parts, notably the southern and eastern, the greater roidal sandstone beds occur in the lower back thins out or becomes shaly. In proportion as these surface of the Boone formation between the principal elevations attain the prominence of mountains and slopes of benches and in the bases of the escarp­ rocks change in thickness and nature the Boston drainage lines. From these level tracts flat-topped are widely known as the Boston Mountains and ments. The Salem platform is generally deeply plateau decreases in elevation and in distinctness ridges extend out in the level of the plain between the St. Francis Mountains. Elsewhere, there are cut by stream erosion, and the tops of the higher of topographic form. The change in the charac­ the subordinate drainage channels to the narrow, numerous lower elevations, remnants of dissected ridges and hills of the dissected escarpments fall in ter of the rocks and in the topography northward steep-sided valleys of the rivers and larger creeks. subordinate plateaus, to which, names have been the same general level. Thus the Salem platform from the west end of the Boston Mountains is pro­ The valleys of the Springfield plain are of two given and which are locally called mountains, has been developed on the truncated edges of a nounced. Iii the Tahlequah quadrangle the hard kinds and have been developed by two distinct although not generally deserving recognition as number of formations. rocks of the Winslow formation are approximately processes, solution and corrasion. They may be such. In general the region is known as the Surrounding the Salem platform on the north, 1000 feet thick, and the northern edge of the characterized as trough and canyon valleys. In Ozark Mountains, but the name has not been west, and south is an even structural plain which beveled Boston plateau rises but 500 feet above the the trough valley the two processes are combined applied to any mountain or definite group of has been developed on the surface of the Boone Springfield plain. Farther north, on the east side only in parts of the valley's course, and in no mountains in the province. The sketch map formation of chert and limestone. This plain or of Neosho River, .the sandstones of the Winslow instance does corrasion predominate. In the can­ below, fig. 1, shows the main physical features plateau has been named by Marbut the Spring­ formation gradually decrease in thickness until yon valley, while solution plays a large part in of the region and the location of the Tahlequah field structural plain. Its inner border south of they lose their identity in the northeast corner cutting the valley, it is subordinate to corrasion. quadrangle. Osage River is marked by a strong escarpment, the of Indian Territory. Correspondingly, the topo­ The canyon type of valley has been produced by exposed edge of the Boone formation, which over­ graphic forms change from the low, westward- the rivers and their larger tributary perennial looks the Salem platform. The Springfield plain sloping, dissected plateau . to the lowland plain streams. In those parts of the solution valleys inclines at low angles toward the west in Missouri bordering the Springfield plateau in the south­ where the grade is steep and the basins are suffi­ and south and west in northern Arkansas, in the eastern part of Kansas. ciently large to collect a large volume of water, direction of the dip of the formation. In Missouri Arkansas Valley. There is a small area of the the disintegrated chert is removed from the beds of Pennsylvanian shales succeed the Boone formation, Arkansas Valley topography near the southern the streams, but the general trough form remains forming lowland. In northeastern Indian Terri­ border of the quadrangle. As already stated, on unchanged. Where the two types of valley occur tory and Arkansas limestone, shale, and sandstone the north the Arkansas Valley region is bounded in the course of a single stream the change is gradual occur successively above the Boone formation, mak- by the Boston Mountains. On the south it is from one to the/other. ;ing numerous low terraced hills and mountains limited by the Ouachita Mountains. In the .-r> Trough valleys. The upper parts of those valleys j standing as remnants of the Boston Mountains on Arkansas Valley is a great thickness of sand­ which have their beginnings in the plain farthest the Springfield structural plairL Such features of stone and shale of the Pennsylvanian series. removed from the canyons are generally wide and 1 this plain are typically seen in the northern half These beds have been thrown into many imbri­ flat, and the entire slopes are covered by weathered , of the Tahlequah quadrangle. The Springfield cated or lapping folds, which together make a chert. In the lower courses of the valleys, where plain is also deeply dissected by the larger streams deep structural trough, corresponding with the the grade is steep and where large volumes of water which flow through it in narrow, crooked valleys. Arkansas Valley, from eastern Indian Territory accumulate during heavy rains, the disintegrated Between the larger drainage lines are large tracts to the Mississippi embayment opposite Little chert is removed from the stream channel. Lower in of land from which younger formations have been Rock in Arkansas. These folded rocks have the course, where the grade becomes lower, usually FIG. 1. Diagram showing relations of Ozark region to sur­ rounding physiographic provinces; also principal divisions removed, leaving broad, flat surfaces of deeply been beveled off by erosion until their edges near the junction with the larger valleys, the load of the Ozark region. weathered chert. Near the inner border of the form a peneplain 'now standing approximately of chert carried down is so great in many instances Physiographically the Ozark region is bounded Springfield plain the Boone formation is deeply 800 feet above sea level. A few exceptions to as to choke the channel. In occurrences of this as follows: On the north 'and west the gently dissected on the divides between the streams, this general statement may be noted in some of nature the valley floor is almost a plain. In the sloping upland grades almost imperceptibly into giving the escarpment a very irregular outline. the broader synclinal folds in the south side of middle and lower courses of these valleys the slopes the Prairie Plains. On the east it is sharply out­ Hills and buttes, cut off from the escarpments, the valley. Protected by massive sandstone strata of the sides increase gradually from the flat bottoms lined by the Mississippi lowland along the line of stand out above the Salem platform, their crests and aided by their attitude in the broad, basin-like outward until the maximum grade of rest for talus the St. Louis, Iron Mountain, and Southern Rail­ indicating the former extension of the Springfield folds, the rocks remain as conical mountains with accumulations is reached near the tops of the hills; way. On the south it extends to the southern plain. crests 1000 to 2000 feet above the general level of There is another phase of trough valley of com­ border of the Boston Mountains^ p. j-.In outline ' > ' ' the A third plateau that of the Boston Moun­ the valley. Such are Sansbois, Cavanal, Sugar- mon occurrence in the Springfield plain. Valleys Ozark region has rudely the form of a quadrilat­ tains rises back of and above the Springfield loaf, and Magazine mountains, and their crests of this nature have been formed in the sides of the eral whose sides are nearly 225 miles in length. plain. The rocks capping the Boston Moun­ give some idea of the former high level of the larger trough and canyon valleys. They are short On the north, east, and south sides the Ozark tains and extending down the southern slope whole region. Since the formation of the Arkan­ and their grades are steep. A deep covering of region is limited approximately by Missouri, Mis­ are made up of thick deposits of sandstone and sas Valley peneplain- erosion has cut more rap­ angular chert forms the sides arid heads of the sissippi, and Arkansas rivers, respectively. On the shale of the Winslow formation. The sand­ idly into the shaly beds, and the sandstones have valleys and descends in steep slopes down to their west it is followed closely by Neosho (or Grand) stones, being more resistant to erosion, govern been left as low, narrow, and sharp-crested but bases. No streams of water are in view and no River in Indian Territory and in part by Spring the physical features of the mountains. Structur­ generally level ridges. In many of the smaller fresh exposures of rock can be found. The disin-? and Osage rivers in Missouri. White, Black, St. ally the mountains make a deformed monocline synclinal folds remnants of sandstone beds cap low tegrated chert descends from the, head. and sides Francis, Meramee, and Gasconade rivers have their in which the southward dip of the rocks is buttes and hills in the general level of the pene­ of such valleys down to their bases by .the aid of sources in the plateau near the main watershed and slightly greater than the general southward slope plain. The small plain in the vicinity of Akins, gravity with the assistance of percolating- waters; flow out through narrow, sinuous valleys. of the surface. The Boston Mountain plateau, near the southern border of the Tahlequah quad­ frost, and changes of temperature. These-accumu­ Considered in a broad sense the Ozark region is like the other plateaus of the Ozark region, is rangle, is developed on soft Pennsylvanian shales lations continue to move in this manner until a made up of three dissected plateaus, the general deeply dissected by streams which flow down its in the Sallisaw syncline, and its southern border larger valley is entered or a point is reached where 1 watei\accumulates during heavy rains in sufficient Arkansas of certain deposits which were laid tion. For 75 to 80 feet above the base the for­ stones at the top of the formation on Illinois River. volume to transport the talus. Valleys of this type down during other parts of the Silurian and Devo­ mation consists of greenish and relatively soft, Some fossils collected from thin, sandy beds in this are produced entirely by solution of lime from the nian periods afford some idea of the geologic history fissile clay shale with a few beds of brown and locality are listed below. beds of chert. of these times. These ideas are expressed under the yellow, fine-grained sandstone. These interbedded Psiloconcha inornata Ulrich. Canyon valleys. Both the Barren Fork and heading " History of sedimentation," on page 5. sandstones are usually less than 3 feet in thickness. Psiloconcha sinuata Ulrich. Illinois River have narrow, steep-sided, canyon- At the top of the shale there is generally a bed Psiloconcha cf. subovalis Ulrich. Ordovician System. like valleys. These valleys are of even, low grade, Rhytimya sp. undet. consisting of sandstone in the lower part with Whiteavesia sp. undet. essentially parallel to the surface of the Springfield BURGEN SANDSTONE. calcareous sandstone or siliceous cherty limestone plain. Their bottoms are flat, the bed-rock floor The Burgen sandstone is a massive, moderately above. This bed is lithologically variable along These fossils appear to be of Lorraine age, and being covered with chert which has been brought fine-grained, light-brown rock. The beds are thick its outcrop, a sandstone occurring in places above therefore are considerably higher in the Ordovician in by tributary streams. The rivers meander from and planes of stratification are usually indistinct. the cherty layer. It varies in thickness also below than the fauna from the limestone. side to side, touching the valley walls, but rarely The rock consists of a nearly pure siliceous sand an extreme of 8 feet 10 inches, and is believed The variability in the thickness and the absence reaching bed rock in their floors. The steep valley of rounded grains, with a matrix scarcely sufficient to be absent in places. A bluish limestone suc­ of the upper beds of the formation in places are walls are nearly 250 feet in height and are covered to cement them together. ceeds the cherty layers and continues to the base of due to erosion preceding the deposition of the with weathered chert except in an occasional cliff In natural exposures the rock breaks readily the Devonian black shale, its thickness ranging overlying Chattanooga shales. where the rivers in the recent cutting have exposed under the stroke of the hammer, crumbling into from a thin layer to massive beds aggregating 20 The Tyner formation occurs in but three places the fresh rock. In the larger creeks, such as Caney loose sand. The formation varies in thickness feet. These descriptions apply to the district of the in the Tahlequah quadrangle, and these are near and Sallisaw, there is a gradation from the trough from a thin stratum to beds aggregating more Illinois Valley northeast of Tahlequah. In this the northern border, in the Illinois and Barren Fork to the canyon phase through their middle and lower than 100 feet. It is exposed in the Tahlequah district fossils have been found in the cherty lime­ valleys and in Baumgartner Hollow. This is the courses. quadrangle in but a single area, on Illinois River stone and associated calcareous sandstone. Some first description of the formation, and its name is northeast of Tahlequah, where it rises in bluffs to fossils of common occurrence in these beds are listed that of a small creek along which it is exposed BOSTON MOUNTAIN PLATEAU. a height of nearly 100 feet, and the base is not below. The determinations of fossils and the dis- near the northern border of the quadrangle. The Boston Mountains, which form the southern Silurian System. and most elevated plateau of the Ozark region, Correlation table of formations in the Tahlequali quadrangle and northwestern Arkansas. become gradually lower toward the west and ST. CLAIR MARBLE. FORMATIONS MAPPED IN TAHLE­ FORMATIONS MAPPED BY G. I. TJME SCALK. ADAMS AND E. F. BURCHARD IN FORMATIONS IN NORTH ARKANSAS AS PUBLISHED IN REPORTS finally end in low hills and ridges near the mouth QUAH QUADRANGLE, INDIAN FAYETTEVILLE QUADRANGLE, OP THK ARKANSAS GEOLOGICAL SURVEY. This rock is a pinkish white and, in most parts, of Neosho River. This declining western part of TERRITORY. ARKANSAS. coarsely crystalline marble. Only the upper part the mountains forms practically the southern half is exposed and the beds are thick and massive. (Akins shale member.) 'A of the Tahlequah quadrangle. The crest of the s< The marble is even textured, but in parts it con­ H Boston Mountain plateau slopes westward from Winslow formation. Winslow formation. Pn Millstone grit. tains small, irregular cavities about which the rock an elevation of 2000 feet near the St. Louis and is more coarsely crystalline. This characteristic (Kessler limestone lentil.) Kessler limestone. San Francisco Railroad in Arkansas to 1600 feet PENNSYLVANIAN renders the rock locally weak and, in such parts, near the Arkansas-Indian Territory line and 900 unfit for the finer uses to which marbles are adapted. Morrow formation. Morrow formation. Coal-bearing shale. feet in the southwest corner of the Tahlequah The St. Clair marble is found in the bottoms and quadrangle. In this quadrangle the plateau is lower slopes of several small valleys in the south- (Brentwood limestone lentil.) Bostongroup Pentremital limestone. marked by the tops of the ridges and hills of the central part of the quadrangle. The streams in mountainous district, which slopes southward at an (Hale sandstone lentil.) Washington sandstone. these valleys have worn down through the over­ average grade of 100 feet to the mile. Throughout CARBONIFEROUS lying strata into the marble, but have not cut the Boston plateau in Arkansas the north-facing Pitkin limestone. Pitkin limestone. Archimedes limestone. through it. As it occurs in the bottoms of the escarpment is dissected by streams which flow MISSISSIPPIAN valleys, subject to the direct wear of the streams, northward. In the Tahlequah quadrangle the Marshall shale. fresh exposures are common. At four of the entire plateau district is dissected by streams localities the marble is cut off by faults and the which flow southward across it from the Spring­ (Wedington sandstone member.) (Wedington sandstone member.) Batesville sandstone. 1 part on the southeast side is thrown down to a field plain. These streams are Little Lee, Sallisaw, MISSISSIPPIAN depth of more than 100 feet below the surface. and Vian creeks, and their sources are among the Fayetteville formation. Fayetteville formation. Fayetteville shale. The exposures showing the thickest beds of the detached hills near the northern edge of the Boston marble are in the large area opposite the station Batesville sandstone. Wyman sandstone. Mountain plateau. They have eroded their val­ of Marble on the Kansas City Southern Railroad. leys to a depth of 300 to 800 feet in the plateau. Boone formation. Boone chert and limestone. Here a small tributary of Sallisaw Creek has cut a Between them the country is intricately dissected, Boone formation. deep gorge, exposing about 100 feet of the marble, and the tributary streams which flow only during (St. Joe limestone member.) Eureka shale (typical). and prospect drills have penetrated nearly an addi­ abundant rainfall descend in steep, sharp valleys. tional 100 feet without reaching the base of the It has been stated that the Boston Mountains Chattanooga formation. Chattanooga formation. Eureka shale (in part) formation. The .outcrop extends from this gorge are made up of the Winslow formation, which DEVONIAN northeastward a distance of 3 miles along the fault consists of many beds of sandstone and shale (Sylamore sandstone member.) (Sylamore sandstone member.) Sylamore sandstone. bordering Sallisaw Creek Valley. A small area is alternately stratified. In the upper third of the exposed in Illinois River a few feet above low water St. Clair limestone (restricted sense). formation there are some thick, hard sandstone SILURIAN St. Glair marble. SILURIAN opposite Cookson. Here the rock is light gray or' beds which now cap the higher ridges of the nearly white and the beds are thinner than elsewhere. plateau. Where these beds have come to the Cason shale. The St. Clair marble has yielded a considerable surface there are small tracts of table-land or number of fossils from the upper part of the for­ Polk Bayou limestone. flat benches such as may be found in the top Tyner formation. mation. The fossils indicate that the formation and southern spurs of Brushy Mountain and in Izard limestone. is of Niagara age and that its upper part at least some of the high, flat-topped ridges east of Little is equivalent to the St. Clair limestone of northern ORDOVICIAN , Lee Creek. Similar phases of topography occur Burgen sandstone. Saccharoidal sandstone. Arkansas, with which the marble is correlated. It where certain hard sandstone beds at the base of is correlated also by Dr. E. O. Ulrich, who has the Winslow formation cap the northern foothills Yellville formation. Magnesian limestone. studied the formation and determined its fossils, of the Boston plateau and detached mesas in the with the Lockport limestone of New York and the central and western parts of the quadrangle. Sandstones and cherts. Osgood limestone of Indiana. The Morrow, Pitkin, and Fayetteville forma­ The following list of fossils occurring in the tions, composed of resistant beds of limestone and 'In the vicinity of Fayetteville, Ark., the Wedington sandstone member of the Fayetteville formation was erroneously correlated with the Batesville sandstone. upper part of the marble indicates the Niagara- sandstone alternating with soft shale, are exposed exposed. The full thickness, therefore, is certainly cussions of age, classification, and correlations of age of the rocks: on the lower northern slopes of the Boston plateau not less than 100 feet. the formations based upon them are by Dr. E. O. Caryocrinites sp. nov. and on the outlying hills on the Springfield plain. The formation takes its name from a small valley Ulrich. Callicrinus corrugatus Weller. They produce distinct bench and terrace forms of opening into Illinois River northeast of Tahlequah. Pisocrinus gemmiformis Miller. Camarocladia rugosa Ulrich. Stephanocrinus osgoodensis Miller. topography. The crests of the hills and ridges are No fossils have been found in the Burgen sand­ Orthis tricenaria Conrad. Dalinanella elegantula (Dalman). usually flat, being protected by the harder beds of stone. Its age can be inferred only from its strati- Liospira americana Billings. Plectambonites cf. transversalis (Wahlenberg). Strophonella striata Hall. graphic position. The sandstone underlies and is Lophospira sp. of the type of perangulata. rock. Hormotoma gracih's var. Atrypa nodostriata Hall. seemingly stratigraphically conformable with the Leperditia, near L. fabulites Conrad. Cypricardinia arata Hall. GEOLOGY. Tyner formation, which is high in the Ordovi­ Leperditia n. sp. (about 5 rain, in length). Orthoceras cf. inedullare Hall. Ceraurus pleurexanthemus Greene. Gyroceras ? elrodi White. cian section. A formation of magnesian limestone STRATIGRAPHY. and dolomite, known as the Yellville limestone, This association of species indicates lower Tren­ Devonian System. The rocks of the Tahlequah quadrangle are all occurs in the northwestern part of the Fayette­ ton or Black Biver age. Devonian rocks in the Tahlequah quadrangle stratified deposits and were formed in Ordovician, ville quadrangle, which joins the Tahlequah on In Baumgartner Hollow and along the banks of are represented by a single formation of black Silurian, Devonian, and Carboniferous times. The the northeast. It contains an Ordovician fauna the Barren Fork Valley only the upper part of shale with rather pure siliceous sandstone or local sequence of the formations is represented on the considerably older than that of the Tyner, and the formation is exposed and its thickness does bituminous phosphatic conglomerate at the base. columnar section sheet, and their correlations with in the region of Yellville in Arkansas is suc­ not exceed 20 feet. In these exposures the upper These deposits in the Tahlequah quadrangle are the formations in other parts of the Ozark region ceeded by a sandstone in all respects the same part of the formation consists of interbedded brown the extreme southwestern occurrence of like are shown in the correlation table. Almost noth­ as the Burgen. sandstone, calcareous sandstone, and bluish or deposits that are exposed at intervals eastward ing is known of the geologic history of the quad­ greenish shale. The thin sandstone and shale from Indian Territory to the Mississippi ernbay- rangle during parts of the Ordovician, Silurian, TYNER FORMATION. exposed on Barren Fork and Tyner Creek and ment in northeastern Arkansas. In northern and Devonian periods. The stratigraphic relations Greenish or bluish shale, brown sandstone, cal­ probably in Baumgartner Hollow are believed, Arkansas the two parts of the formation have between the formations present, however, and the careous, cherty sandstone, and limestone, abundant both from the character of the rocks and from been recognized by geologists of the Arkansas, occurrence in the contiguous region in northern in the order named, constitute the Tyner forma- the fossils, to be stratigraphically above the lime­ Geological Survey and described as separate for- mations. In the eastern part of the Mississippi dark ferruginous quartz sand with many pebble- Schizoblastus sayi Shumard. the quadrangle. The limestone in tie lower part Platycrinus and fragments of other crinoids. Valley, in the southern Appalachian region, the like lumps of hard, ferruginous, and probably phos­ Spirifer grimesi Hall. has a great influence on the variation of thick­ Devonian black shale occurs widely in the same phatic rock, which give the mass a conglomeratic Syringothyris sp. ness of the member, as it likewise becomes thin­ stratigraphic position as that in Arkansas and appearance. Occasional bluish shaly fragments Productus cf. semireticulatus. ner toward the west. As the shale thins, its upper Indian Territory and carries locally a phosphatic similar to certain shaly beds in the underlying The middle member constitutes almost the whole part gradually becomes darker until in the west­ sandstone at its base. In Tennessee River Val­ Tyner formation are also included. This deposit of the Boone formation as exposed in this quadran­ ern portion of the quadrangle all of it is dark ley in East Tennessee and elsewhere in the south­ is thin and was seen only in a small area near the gle, and is made up essentially of calcareous chert blue or black. ern Appalachians the same formation has been head of a small gulch. At the other localities near or flint with variable bands or beds of limestone. Aside from the small goniatites and other cephal- described as the Chattanooga shale. Marble the Sylamore sandstone is 20 to 30 feet Fresh exposures occur in but few places and opods found in the few limy concretions that occur Fossils in this black shale are few and for the thick and massive, has a generally even texture, these are in steep bluffs and cliffs where the larger in the black shale, the fauna of the lower member most part without very definite diagnostic charac­ and is whitish to light brown in color. The phos­ streams meander against the sides of their valleys, is confined to the limestone near its base. teristics. No fossils were found in the black shale phatic pebbles are small and few in number. or more rarely in the beds of the smaller streams The principal fossils of this limestone are the in Indian Territory, and only fragments of large Fragments of fish bone were occasionally observed in their middle or lower courses where the grades following: fish bones were noted in the sand at the base. in the sand. The sand is calcareous near the base, are sufficiently steep and the volume of water great 1. A large undescribed crinoid, related to Eupachycrinus, The occurrence of the bones, however, together and in places seems to blend with the top of the St. enough to induce active erosion. The chert ele­ but with uniserial arms. The plates of the calyx, being with the stratigraphic identity and striking litho- Clair marble, though no inclusions of marble were ment predominates so greatly over the limestone in thick and bulbous, are striking fossils. 3. Archimedes cf. communis Ulrich. logic similarity between these deposits and those in seen. The sand terminates abruptly at the top in abundance, and is so resistant to the effects of ero­ 3. Orthotetes kaskaskiensis McChesney. northern Arkansas and east of Mississippi River, Walkingstick Hollow, where the contact is clearly sion, that almost the entire surface rock consists 4. Chonetes n. sp., of the type of C. geinitzanus Waagen would place them without reasonable doubt in the (rare). exposed. At one locality noted in this valley, where of angular chert bowlders and fragments. 5. Productus cf. cora and tenuicostus. Devonian and permit the use of Chattanooga as the erosion of the stream had just reached the top The cherts in the upper part of the formation are 6. Productus cestriensis Worthen. the formation name. of the sand, the surface is uneven, the black shales locally very fossiliferous. The following list includes 7 Productus of the :type of P. splendens. 8. Productus sp. undet. filling irregular depressions a foot and less in depth the species most commonly found, and their associa­ 9. Seminula subquadrata Hall. CHATTANOOGA FORMATION. and 2 to 3 feet in width. The contact between the tion is decidedly indicative of Keokuk age: 10. Cleiothyris sublamellosa Hall. This formation consists of a black bituminous shale and the sand is clean, no sand being included 11. Spirifer increbescens Hall. Amplexus fragilis White and St. John. 12. Spirifer of the type of S. pinguis; cf. S. scobina Meek. shale of uniform lithologic character, with a local in the shale, even in the basin-like depressions. Glyptopora keyserlingi Prout. 13. Spiriferina transversa McChesney. or lenticular deposit of conglomerate or sand­ The only fossils from this member of the Chat­ Fenestella multispinosa Ulrich. 14. Camarotoeehia sp. undet. Polypora maccoyana Ulrich. 15. Dielasma cf. forrnosum Hall. stone, known as the Sylamore sandstone mem­ tanooga formation seen are more or less macerated Hemitrypa proutaria Ulrich. ber, at its base. In fresh cuts the black shale fragments of large fish bones, apparently of the Pinnatopora striata Ulrich. Of the above list Nos. 1, 7, and 14 are very is massive at the surface, but in slightly weathered genus Dinichthys. This "terrible fish" swarmed Spirifer logani Hall. Reticularia pseudolineata Hall. abundant and characteristic. exposures it breaks usually into flat blocks of in the late Devonian seas, and its bones are per­ Productus setigerus Hall. Wedington sandstone member. The Wedington rudely rectangular form, due to cross jointing. haps the most characteristic fossil of the upper Orthotetes keokuk Hall. sandstone member in the Tahlequah quadrangle Capulus equilaterus Hall. These surface blocks of shale, on more complete Devonian Ohio black shale in Ohio and other consists of thin-bedded and shaly brown sandstone weathering, disintegrate into thin, paper-like sheets. States east of the Mississippi. The limestone overlying the chert was believed which grades downward gradually into the lighter For some time after the separation of the shale into to be a part of the Boone formation at the time the blue shales at the top of the lower shale member Carboniferous System. fissile laminae its original hardness is generally Tahlequah quadrangle was surveyed and is included of the Fayetteville formation. It has the form of maintained, and in roads and other places where MISS1SSIPPIAN SERIES. with it in the mapping. Later studies of this lime­ a lens or wedge, its thickness near the northeast the soil has been removed it forms a compact stone made in connection with the survey of the corner of the quadrangle, in Alberty and West BOONE FORMATION. surface. Muscogee and Winslow quadrangles., west and east mountains, being about 4.0 feet. It thins toward The black shale of the Chattanooga formation is The rocks of the Boone formation consist of of the Tahlequah, have shown that locally, at least, the south and west, the shaly sandstone in the variable in thickness and occurs unconformably on interstratified chert and cherty limestone. At the a thin bed of black shale occurs between this lime­ lower part increasing in the relative amounts of the Tyner formation and the St. Clair marble in base there are in places thin limestones free from stone and the Boone chert. An abundant fauna, clay, and the sandstone becoming thinner and different parts of the quadrangle. Northeast of chert, while at other localities the chert rests on also, which has been collected from it, shows that more shaly. In the lithologic change the lower Tahlequah, in Illinois and Barren Fork valleys the Chattanooga shale without intervening lime­ it is higher geologically than the Boone and should part becomes indistinguishable from the upper and in Baumgartner Hollow, it is approximately stone beds. The limestone beds at the bottom, be classed with the Fayetteville formation. part of the lower shale member. To the south, 40 feet thick and lies on the Tyner formation. In being , distinct in lithologic character from the The thickness of the Boone formation is variable. in the north slopes of Muskrat Mountain, and Illinois Valley opposite Cookson it is 40 feet thick body of the formation and variable in thickness, It ranges from a minimum of 100 feet to a maxi­ to the west, in Walkingstick Mountain, the litho­ and occurs on the Sallisaw marble. In the vicin­ are properly characterized as a member of the mum approximating 300 feet. Except in a few logic character of the Wedington sandstone mem­ ity of Marble, west of the fault, the black shale is formation. localities the top and base are separated in outcrop ber is lost to view. Toward the northeast the approximately 20 feet thick. Here the Sylamore The base of the Boone formation is exposed in by several miles, and the rocks are so concealed by Wedington sandstone inoreases rapidly in thick­ sandstone member, 20 to 30 feet thick, occurs twelve localities, and in four of these limestone was surface chert debris that the determinations of thick­ ness, reaching a maximum more than 150 feet in between the black shale and the St. Clair marble. found beneath the chert. Of the known occur­ ness are at best only approximate. Wedington Mountain, 2 to 6 miles northeast of In Walkingstick Hollow, near the southwest corner rences of limestone beneath' the chert two were The Boone formation outcrops over nearly one- the Tahlequah quadrangle. of sec. 36, T. 14 N., R. 23 E., there are excellent found bordering the small areas of the Chatta­ half v»of the quadrangle and extends eastward into Upper shale member. The upper shale member exposures of the shale and underlying sandstone nooga shale in Barren Fork Valley south of northwestern Arkansas, where, in Boone County, of the Fayetteville formation is composed of bluish member. The surface of the sandstone here is Westville. In $ie smaller area in the west side of it was described and named by the State geolo­ clay shales with ferruginous limy clay segregations* uneven, appearing as if worn in shallow, oval, sec. 34, T. 17 N., R. 26 E., the limestone is about gist of Arkansas. It also occupies a large area and local thin layers of fossiliferous limestone. pothole-like depressions and irregular elevations, 5 feet thick. At the other locality, 3 miles down in southwest Missouri, including the zinc belt of In the northeastern part of the quadrangle this in and over which black shale has been deposited. the stream, it is 10 to 15 feet thick. At these the Joplin region. member is so obscured by the debris from the A peculiar feature of the contact phenomena here places it consists of fine-textured and dense, white Hale sandstone lentil of the overlying Morrow is that no detrital sandstone material related to the to pinkish, even-bedded limestone. Light-colored FAYBTTBVIJLLE FORMATION. formation that its character is not easily deter­ underlying beds is found in the base of the black crinoidal limestone beds 10 to 15 feet thick occur This formation consists of shales, black to blue mined. The interval between the Wedington shale. The Chattanooga shale crops out at two at the base of the Boone formation in the south in color, thin limestone, and shaly sandstone. sandstone and the succeeding Pitkin limestone, localities in Barren Fork Valley near the north­ bank of Barren Fork at the road crossing in the The larger part of the formation consists of shale, however, indicates that the shale does not exceed east corner of the quadrangle, in a small stream 1 NW. -L sec. 13, T. 17 N., R. 23 E. No fossils and the limestone beds are inclosed in it as thin 30 feet in thickness. As this shale is thin and mile south of Elm Springs Mission, and at places were collected from this limestone at the three lentils or local beds near the base and top, while occurs in bluffs or steep slopes, it is included on near the sources of Caney and Terrapin creeks. localities named, but its position in the formation the sandstone is found above the middle of the for­ the map within the area of the Wedington mem­ At all of these localities the streams have cut into and its lithologic character strongly indicate that it mation inclosed in shale. The sandstone being ber. West and south of the occurrence of the the black shale without penetrating it. At two should be correlated with the basal St. Joe member locally thick enough in the northeastern part of Wedington sandstone the upper shale member is localities, 1J miles north and 4 miles northwest of of the Boone formation exposed in the northern the Tahlequah and in the adjoining Fayetteville not distinguishable from the blue shales in the Bunch, erosion has penetrated to the Sallisaw mar­ part of the Fayetteville quadrangle and farther quadrangle to be regarded as a member, separates upper part of the lower shale member. The ble, and has shown that both the shale and the Syla­ east in northern Arkansas. the shale locally into two parts. The sandstone upper shale member, together with the whole more sandstone members are in these places absent. A fourth locality of the basal limestone member attains its greatest thickness in Wedington Moun­ formation, thins westward, until in the western Sylamore sandstone member. The Sylamore of the Boone formation is in a small valley leading tain, in the southwestern part of the Fayetteville part of the quadrangle the whole is found to be a member of the Chattanooga formation consists into Illinois River in sec. 36, T. 18 N., R. 22 quadrangle, and is known as the Wedington sand­ black fissile shale except the limestone bed that of rather coarse, rounded, limpid quartz sand E., very near the north border of the quadrangle. stone member of the Fayetteville formation. Thus occurs near the base and locally near the top. in which pebbles and grains of dark-brown or Here the beds consist of dull blue and earthy fossil- the formation consists of three parts or members- The fauna of the upper shale member is dis­ black, hard phosphatic rock are scattered at ran­ iferous limestone in the lower part, followed above an upper and lower of shale, and a middle member, tinguished from the other fossiliferous horizons dom. More rarely small fish teeth, fragments of by thicker and harder limestone beds, the thickness the Wedington, of sandstone. of the formation by the much greater abundance large fish bones, and particles or fragments of rock of the whole being 6 feet. These beds belong strat- Lower shale member. The lower shale member and variety of its Bryozoa; also by the presence similar to the subjacent contact beds are found. igraphically below the lighter-colored crinoidal of the Fayetteville formation consists of black to of a pentremite. These, in conjunction with the The sand grains are almost identical in composi­ limestones, both being locally developed. They blue laminated clay shale, with beds of dark-blue absence of the fossils that are most abundant and tion, size, and form with the particles making the contain the following fossils, together with a num­ to black fossiliferous limestone near the base. It characteristic of the other two horizons, impart a Burgen sandstone, of Ordovician age, occurring ber of undetermined and mostly undescribed spe­ grades upward into the Wedington sandstone mem­ very different aspect to its fauna. The species beneath, but nowhere in this district found in cies, all indicating Kinderhook age: ber through sandy shales. The shale in the lower most commonly found are the following: contact with, the Chattanooga formation. Leptsena rhomboidalis Wilckens. part of this member is invariably blacker, harder, The Sylamore sandstone has been found in four Productella concentrica Hall. and more distinctly fissile than in the upper part, Pentremites sp. undet. (a large form between P. Spirifer cf: peculiaris Shumard. godoni and P. conoidens.) localities in the Tahlequah quadrangle, one on the which has shades of dark to light blue on fresh Septopora cestriensis Prout. east side of Illinois River near the northern The lighter-colored, often pink, and generally exposure. The upper part contains numerous thin Fenestella sp. nov. (a common Chester form). Archimedes compactus Ulrich. boundary of the quadrangle, and the other three crystalline crinoidal limestone, together with the and small clay-ironstone concretions. Archimedes communis Ulrich. ,. close together in the west side of Sallisaw Creek lower part of the cherty limestone overlying it, The thickness of the shale is variable, decreasing Archimedes intermedius Ulrich. contains a Burlington fauna. The common fossils from approximately 110 feet in the northeastern Archimedes swallovanus Hall. . Valley northwest and north of Marble. Polypora corticQsa Ulrich. The rock at the locality first named consists .of in this division include the following species: to about 20 feet in the southwestern portion of Productus cestriensis Worthen. Tahlequah. Productus sp. of the type of P. cora. upward, and are properly classed as members. to the Hale sandstone. So far as studied the fos­ underlying limestone. The fauna consists princi­ Productus sp. of the type of P. punctatus. The limits of these members have been traced sils from this member contain nothing that casts pally of brachiopods and bryozoans. Mollusks Seminula subquadrata Hall. Reticularia setigera Hall. from Neosho River in eastern Cherokee Nation doubt on the view that the whole of the Morrow are notably few or absent. The mollusks, how­ Spiriferina spinosa N. & P. eastward through a considerable part of north­ group is younger than Mississippian. ever, especially gasteropods, occur in some of the The Fayetteville formation occurs in bases western Arkansas north of the Boston Mountains. Limestone of the Morrow formation. The middle thin sandstones and shales above the limestone. of escarpments or hills bordering the plain devel­ These members vary in both composition and portion of the Morrow formation consists of rela­ The shale between the main limestone and the oped by the erosion upon the Boone formation, or thickness from northeast to southwest. Toward tively hard, blue, fine-textured limestone with a thinner beds of limestone near the top of the for­ in benches between the more elevated hilly country the southwest the quantity of lime increases to deposit of blue clay shale, usually in the middle mation contains a thin bed of coal at one locality made by the Morrow formation and overlying such an extent that at the west side of the Tah- part. Locally there are thin sandstone and lime­ in the Muscogee quadrangle and at a number of sandstones above and the hard limestones and lequah quadrangle and in the Muskogee quad­ stone beds interstratified with this shale. Shale places in northwestern Arkansas, some of which chert of the Boone below. In most instances the rangle the formation consists of limestone with also occurs near the top of the member interbedded are in the Fayetteville quadrangle. Associated bed of shale outcrops on the watersheds and scarcely any deposits of sand and clay. In the with the limestone in places. In such instances with the coal in the Fayetteville quadrangle are drainage divides at the sources of the streams. opposite direction the amount of limestone grows there is a gradation from limestone to shale from black shales containing fossil plants. Collections This is invariably its position where the Fayette­ less, until in parts of the Fayetteville and adjoin­ the middle to the upper member. Again, there is of these fossil plants were determined by David ville shale bounds isolated areas of higher rocks. ing quadrangles the formation consists locally an abrupt change from limestone to shale where White and correlated with certain plant remains The outcrops of the shale are usually soil covered almost entirely of shale and sandstone. Still the two members are quite distinct. There is a from the Sewell formation of the Pottsville stage or concealed by debris from the overlying rocks. farther east, in the vicinity of St. Joe, it is gradual change in the lithologic character of the in the southern Appalachian region. This corre­ The Fayetteville formation is widespread. It reported by Dr. Ulrich that the limestone is middle member of the Morrow formation toward lation, published in 1895 and again in 1900 (Bull. is exposed westward in the Muscogee quadrangle entirely absent from the lower part of the for­ the west by increase of limestone and decrease of Geol. Soc. America, vol. 6,1895, p. 316; Twentieth to the valley of Neosho River. It occurs eastward mation, this absence being accounted for by clay. Near the eastern border of the quadran­ Ann. Rept. U. S. Geol. Surv., pt. 2, 1900, p. 817), throughout a large part of northwestern Arkansas, overlap. gle the limits of this member are not well defined showed that the rocks above the main limestone and is typically developed in the vicinity of Fay­ ' The lowest member or lentil of the formation and it consists in large part of shale interbedded (Pentremital limestones of the Arkansas Survey), etteville, where it was first described and named in is sufficiently distinct lithologically to be mapped with limestone, while near the western border and at least, belong to the Pennsylvanian series. Studies vol. 4 of the report of the Arkansas Geological and has received the name Hale sandstone, because beyond, in the Muscogee quadrangle, it is com­ made recently by Messrs. Ulrich and Girty show Survey for 1888. of its strong development in Hale Mountain, in posed almost entirely of limestone. The thickness that the limestones both above and below the the Winslow quadrangle near the northeast corner also is variable, in an irregular way, ranging from plant-bearing shale contain a united fauna and PITKIN LIMESTONE. of the Tahlequah quadrangle. The middle mem­ 50 to 200 feet. This variation may be due, how­ that the whole Morrow formation should be classed The Pitkin limestone varies from rusty-brown, ber consists of limestone with minor deposits of clay ever, to the erosion of some of the upper beds prior as Pennsylvanian. granular, earthy, and shaly strata at one extreme shale, which usually grades into the upper mem­ to the deposition of the succeeding formation. to fine-textured, massive, bluish beds at the other. ber, consisting of shale with occasional strata of Some layers of this important limestone member WINSLOW FORMATION. The characteristics first named are usually found limestone and thin sandstone interbedded. The are full of small gasteropods and pelecypods, of The Winslow formation consists of bluish and where the formation is thinnest and in the upper middle member grades into the- upper, and the species mainly undescribed. ' Other layers are blackish clay shale, sandy shale, and brown sand­ and lower beds elsewhere. Blue clay shale locally boundary between them is not usually distinguish­ charged with many kinds of Bryozoa. These, stone, with rarely small accumulations of conglom­ occurs interbedded with the limestone. able. For these reasons they are not mapped or also, are * nearly all new to science, but when erate near the base. For convenience of discussion In thickness the Pitkin limestone varies from distinguished by names, but will be separately compared with known species their alliances are the formation may be separated into three mem­ a thin shaly layer to massive beds aggregating described. in nearly every case nearer Pennsylvanian than bers, which are distinguishable by the increase of 70 feet. The changes in thickness are irregular, The formation is named for the village of Mor­ Mississippian types. A subramose Michelinia sandstone near the middle of the formation. Gen­ though there is a general increase toward the south­ row, near which a typical section of the rock is (near eugenew White) is abundant; also another erally speaking the sandstones are thin bedded west. As illustrations of this variability the fol­ exposed, in Washington County, Ark., 4 miles east coral comparing rather closely with Trachypora and variably shaly. This is especially the case in lowing instances are cited. In Walkingstick of the Tahlequah quadrangle. austini Worthen. Both of these corals are of the lower member of the formation, where also Mountain the formation consists of a thin bed of Hale sandstone lentil. The Hale sandstone in service in distinguishing the horizon from the clay shale is more abundant than in the middle brownish earthy limestone, while in the small its typical development consists of thick-bedded, lithologically similar Pitkin limestone. Among member. The change in abundance of sand in mountain 3 miles west the strata are massive and massive, calcareous sandstone in the upper part and the brachiopods, which class is represented by a the sediments from the lower to the upper mem­ make a section 40 feet thick. This limestone in where it is thickest. In such instances the beds number of undetermined species, a Hustedia cf. ber is gradual and the boundary between the two the mountain east of Stilwell is 20 feet, while in are nearly pure quartz sand of even and moder­ mormoni Marcou affords perhaps the most relia­ can not be continuously traced. The stratigraphic the western and southwestern parts of the same ately fine grain. This member varies in com­ ble evidence of the Pennsylvanian rather than relation between the middle and upper members, township it is 40 to 60 feet thick. In T. 15 N.. position locally. In places parts of the member Mississippian age of the Morrow formation. Sev­ however, is different. The change from the middle R. 24 E., the formation varies between 20 and 30 (usually the lower and middle) become so calcare­ eral very fine species of crinoids occur in the lower member, which is chiefly sandstone, to the upper feet. The same is true for the northeastern part ous as to be classed as siliceous limestones. Again limestone, but as they are all new they throw lit­ member, which is composed for the most part of of the adjoining township (T. 15 N., R. 23 E.), it is shaly, consisting of clay,and sandy shale with tle light upon the age of the bed. The generic shale, is more abrupt than the transition from the but in the western and southwestern parts and in strata of sandstone, especially where the member types represented occur in late Mississippian rocks lower to the middle member. The parting between T. 15 N., R. 22 E., the thickness increases to becomes thin. . and, in part at least, in much later Pennsylvanian the two members is sufficiently distinct in the Tah­ more than 60 feet. In the vicinity of Bunch and The Hale sandstone decreases in thickness west­ deposits. However, so few crinoids are known lequah quadrangle to be mapped and to be distin­ elsewhere in T. 14 N., R. 24 E., the formation is ward, but the change is irregular. The thickest from the latter series of rocks that it is as yet guished by name. It is named the Akins shale usually about 20 feet thick, while farther west, section is exposed in the slopes of the valley east impossible to properly estimate the evidence of member, from the village located on it near the toward the border of the quadrangle, there is a of Muskrat Mountain, where the member is 110 the crinoids. Penlremites rusticus Hambach is southern boundary of the quadrangle. Westward, general increase of the section, the thickness rang­ feet thick. The lower 40 feet are calcareous sand­ one of the common fossils. The old name of however, across the Muscogee quadrangle, the sand­ ing from 40 to 60 feet. stone. In the central part are 25 feet of thin- the member Pentremital limestone was derived stones of the middle member become thinner and The Pitkin' limestone outcrops generally at bedded siliceous limestone. The upper 40 feet from it. more shaly and the base of the Akins shale member the bases of hills and in steep slopes, bluffs, consist of massive brown and nearly pure siliceous Shale in the Morrow formation. The uppermost can not be mapped. Otherwise the Akins shale and escarpments, usually beneath sandstones. sand. In the low mountain in T. 16 N., R. 26 part of the Morrow formation consists of blue and deserves to be distinguished as a formation. The talus from these overlying sandstone beds E., the sandstone becomes thinner in an irregular black clay shale with few local beds of limestone In the lower member, from the base upward frequently conceals the edges of the Pitkin for­ manner and varies between 10 and 50 feet. In T. and more rarely thin layers of sandstone and sandy about 450 feet, to approximately the middle of mation, so that a complete section can rarely be 15 N., R. 24 E., it becomes coarser and more shale near the top. The character of the limestone the formation, the two classes of sediments occur found. While the Pitkin limestone varies in massive, especially in sec. 21, where it reaches a is practically the same as that of the beds njaking in many beds alternately deposited. The sand­ thickness and locally becomes thin, it has been thickness of 70 feet. Farther west the sandstone the upper part of the limestone below. The shale stones are generally shaly or thinly stratified. found at every place where its horizon reaches decreases in thickness, becoming at the border of also resembles that interbedded with the limestone Locally near the base the sandstones are massive the surface. Toward the east, beyond the Tahle- the quadrangle too thin to be mapped. In the of the middle member, except that it is usually more and thick, and in such places are often coarse, con­ quah quadrangle, the Pitkin limestone occurs in adjoining Muscogee quadrangle it has not been arenaceous and more distinctly laminated. In the sisting of small quartz pebbles embedded in a brown isolated areas and outcrops along the northern recognized in mappable thickness. In the valley hills 2 miles west of Stilwell this member culmi­ sand matrix. In a few places these pebbles are suf­ foothills of the Boston Mountains in northwest­ of Vian Creek, near the southwest corner of the nates in shaly calcareous sandstone, thin sandstone, ficiently coarse to justify the classification of the ern Arkansas. Typical exposures occur in the quadrangle, the upper beds of this member are and limestone interstratified. In such places the rocks as conglomerates. north slopes of the Boston Mountains on the St. exposed and the sand is so coarse as to be classed top of the Morrow formation can not be clearly Above these sandstones and shales there is a Louis and San Francisco Railroad, near Pitkin, as a grit or fine conglomerate. defined, since the succeeding formation consists of nearly equal thickness of rocks composed princi­ from which place the limestone receives its name. This member was originally described as a for­ sandstone and shale. The limestone layers of this pally of brown sandstone, which constitutes the The Pitkin limestone is considered to be the top mation. In the Arkansas Survey reports treating member are not numerous and occur in various middle member. A part of this member is com­ of the Mississippian series of the Carboniferous. of the geology of Washington County, it was positions in the shale, chiefly in the upper part. posed of thinly stratified or shaly sandstone, and The reasons supporting this determination are named the Washington sandstone, for Washing­ In many places limestone beds can not be found, minor beds of shale occur interstratified with them. given in the discussion of the correlation of for­ ton Mountain, where it is typically exposed. and there is no assurance that they are everywhere As a whole these beds become thicker and more mations, on page 2. Washington being preoccupied as a formation present. massive upward, and they increase in thickness The fossils of this limestone are with few excep­ name, Hale, the name of a mountain near which This member varies in thickness, reaching a max­ eastward. Certain beds in the upper part are tions the same as those found in the limestone near it is well exposed, is adopted instead. imum of about 100 feet. The changes in thick­ also harder than the sandstone in the lower part, the top of the Fayetteville formation. The Hale sandstone contains locally siliceous ness occur in various parts of the quadrangle, but and their effect is strong in controlling the topog­ limestone beds that are fossiliferous. The fauna there is a general decrease toward the west. These raphy of the southeastern part of the quadrangle. PENNSYLVANIAN SERIES. has been only partially worked up. The most changes are undoubtedly due, in part at least, to Above the thick sandstone beds are deposits of MORROW FORMATION. prominent species is a Spirifer apparently not local erosion prior to the deposition of the suc­ blue and black shales with a few beds of sand­ The Morrow formation consists of three distinct distinguishable from the lower Pennsylvanian S, ceeding Winslow sandstone, which occurs uncon- stone, which culminate in sandstone and shaly classes of rocks, which have considerable range boonensis Swallow. Some of these calcareous lay­ formably on the Morrow formation. beds, aggregating about 50 feet. in thickness and occurrence and are variable in ers contain numerous fenestellid Bryozoa and The limestone beds of this member are locally The hard beds of the Winslow formation occur character. These rocks are sandstones, limestones, fewer Brachiopoda. Some at least of these fossils very fossiliferous, but the fauna consists of rather in the southeastern part, making the most rugged and shales; they can be segregated more or less belong to species found abundantly in the over­ few species. All of the forms observed by the topography of the quadrangle. The lower beds distinctly in the order as named from the base lying limestone, but others appear to be confined writer occur also, and in better condition, in the cap many hills and low mountains in the central and western" parts of the quadrangle. ' Except the ! in Indian Territory, contains a well-preserved and succeeded by other forms. At certain stages in wag an' elevation of the sea bottom and at least hard sandstone beds near the middle of the for­ abundant fauna. It has been mapped from Fay­ the sedimentation gaps occur in the life record, a part of the Ozark region became land. Oscilla­ mation and certain more resistant sandstones and etteville westward through the Tahlequah and accompanied by discordance in the character and tions of land and sea, however, occurred until the conglomerates at the base, the rocks of the Wins- Muscogee quadrangles. Special studies by Dr. structure of the rocks, showing oscillations of the entire Mississippian series was deposited, as shown low formation are generally concealed by sandstone Ulrich in the region of Batesville, Ark., show land and sea. The variations in the coarseness, by the locally variable formation of sand, clay, and talus. As a result few even of the sandstone beds that in that locality the Marshall shale (so named composition, and thickness of the formations record limestone. can be traced for any considerable distance. by the Arkansas geologists) is rich in fossil evidence of the depth of the water in which they In mid-Carboniferous time the sea withdrew, leav­ Akins shale member. Only the lower part of the shells and contains a fauna correlative with that were deposited and give some idea of the extent of ing the Ozark region as land beyond the boundary Akins shale occurs in the Tahlequah quadrangle. of the Fayetteville shale. Thus the Batesville the submergence and the nature of the contiguous marked by the exposed top of the Mississippian It consists of blue and black clay shales and shaly sandstone, which, at Batesville, its type locality, lands. The fossil remains not only show the rela­ sediments. The evidence of the broad land at this sandstone with a few thin sandstone beds. A thin occurs beneath the Marshall shale, belongs beneath tive ages of the successive strata, but aid in identi­ time is shown in the erosion of the highest Missis­ bed of coal occurs near the base of this member in instead of above the Fayetteville shale and is to be fying and correlating the formations which came to sippian formation where the Pennsylvanian rocks the northwestern part of the adjoining Sallisaw classed with the Wyman sandstone which is found the surface in separated localities. come in contact with them. In the south and quadrangle. It has been prospected and worked' near Wyman and in the Fayetteville quadrangle. Stratigraphically below the lowest rocks at the southwest sides of the uplift, notably in the Tah­ for local use in the Sallisaw Creek Valley a few The sandstone overlying the Fayetteville shale surface in the Tahlequah quadrangle lie magnesian lequah quadrangle, the unconformity is not great, miles south of the Tahlequah quadrangle. and mapped as the Batesville sandstone by the limestones, conglomerates, sandstones, cherts, etc., but farther up, toward the crest of the dome, higher In this quadrangle coal should outcrop near Sal­ Arkansas Survey (Geology of Washington County, of Cambrian and Ordovician ages, which come up rocks of the Pennsylvanian series come in contact lisaw Creek and in the vicinity of Akins, but it vol. 4,1888) is now known as the Wedington mem­ around the older igneous rocks of the St. Francis with successively lower beds of the Mississippian. has not been found at these places. The lower ber of the Fayetteville formation. The formation Mountains in southeastern Missouri and also in In southwestern Missouri and toward the center of part of the shale, and probably that part includ­ described as the Marshall shale in the Washington northern Arkansas. They reveal a record of sedi­ the uplift the Boone formation shows evidence of ing the horizon of the coal, is concealed by fault­ County report, which is separated but locally by mentation which is not essential to the geologic mid-Carboniferous erosion, and the depressions in ing along the north side of the Akins shale the Wedington sandstone from the shale beneath, history of the Tahlequah quadrangle. It is suf­ its surface yet contain remnants of Coal Measures exposure in the Tahlequah quadrangle. necessitated the combination of the two with the ficient here to say that the older formations which conglomerates and shales. Thus it is seen that The Akins shale outcrops in a narrow, elongated included sandstone into the Fayetteville formation. approach the crystalline rocks of the St. Francis after the elevation of the Ozark region in mid- area that extends from the Tahlequah quadrangle The Pitkin limestone (Archimedes limestone of Mountains overlap against them, thus recording Carboniferous time it was again submerged, but southwestward to the Arkansas River Valley. It the Arkansas Survey) marks the upper limit of the the fact that they were remnants of the land mass to what extent is not known, since so large a occurs here in an elliptical basin which is known as Mississippian series of the Carboniferous in north­ which probably persisted during their deposition. part of the formations of Pennsylvanian age in the Sallisaw syncline. The thickness of the shale western Arkansas and northeastern Indian Terri-* That a large part of the region underwent numer­ the Tahlequah quadrangle and elsewhere in the in this basin is estimated to be 600 to 700 feet, and tory. Field studies and office investigations of the ous oscillations of level above and below the sea is region record a history differing from that of the lower 150 to 200 feet are exposed in the Tahle­ fauna of the Pitkiii and Morrow formations by Dr. recorded by the rapid alternation of saccharoidal previous sediments. The waters in which they quah quadrangle. Girty and Dr. Ulrich have developed conclusive sandstone and magnesian limestone and the occur­ were deposited were shallow, the bottoms of the It has been determined by areal geologic mapping evidence of this classification. Dr. Girty reports rence of conglom erate. seas frequently reached the surface, and the in the Sallisaw quadrangle, which joins the Tahle­ the following: "There is a rather marked faunal One of these saccharoidal sandstones, probably the lands were low, as attested by the alternating quah on the -south, that the Akins shale member change at the stratigraphic plane between the Mor­ uppermost, is represented by the Burgen sandstone. shale, sand, and conglomerate and the irregu­ represents the upper part, approximately the upper row and Pitkin formations or between the 'Archi-- During its deposition the sea bottom was raised larity of their bedding.' The lands were more third, of the McAlester formation, the lower limits medes' and 'Pentremital' limestones of the Arkansas and the beach bordering the lowland advanced and extensive than the confines' of the Ozark uplift. of which are not determinable in the Tahlequah Survey classification. The Pitkin fauna is related receded back and forth across the district, leaving The Pennsylvanian sediments increase greatly in quadrangle or elsewhere north of Arkansas River. to that of the Mississippian epoch. The faunas of a thick deposit of homogeneous clean sand. Such quantity of coarse material and in thickness toward The average thickness of the lower and middle the different limestone beds in the Morrow forma­ deposits are known to be formed only in shallows the south and east, indicating the direction of the members of the Winslow formation is estimated to tion are closely allied to one another. They both near wave-washed shores. After the Burgen depo­ land from which the great abundance of sand espe­ be approximately 900 feet, which, with the exposed exclude many of the Mississippian types found in sition, an erosion period possibly intervening, the cially was derived. Additional evidence of this is part of the upper or Akins shale member, will the Pitkin limestone and include many which are shores retreated, the retreat being accompanied by the fact that the later beds of the Pennsylvanian aggregate 1050 to 1100 feet in the quadrangle. foreign to it, and some which are distinctly Penn­ a subsidence of the sea bottom, so .that fine waste deposits which overlap the rocks of the Ozark dome sylvanian. For example, /Squamularia is substi­ from the land was laid down as mud in thin lam- decrease in thickness northward and contain little Correlation of Formations. tuted for Reticularia, and Hmtedia for Eumetria. inaB corresponding to successive floods on the land coarse sediment. The determinations of the age, the classification, The flora of the 'Coal-bearing' shale which occurs or rhythmical variations of the currents of the sea, After the close of the Carboniferous the whole and the correlation of the rocks occurring in the between the limestones of the Morrow formation is At certain stages of the deposition thin sheets of firie region was raised above the sea, and there is no Tahlequah quadrangle are based on direct strati- that of the Potts ville, a division of the Pennsylva- sand were deposited over the bottom, and finally, record of sedimentation to indicate that it has graphic connection between the formations in this nian series in the Appalachian province." near the close of the Tyner epoch, muddy sediments since been submerged. The features of the Ozark quadrangle and those mapped in Arkansas to the Formations of Pennsylvanian age in the Tahle­ did not reach this area and limestones were formed. region and the occurrence of later rocks on its east­ northeast and Indian Territory to the south and quah quadrangle can not be correlated definitely Above these sandy and shaly sediments was ern border show that the surface has oscillated and on paleontologic determinations by Messrs. G. H. with * rocks of related age on the south side of the deposited the material which now makes the St. that the rocks have been locally deformed, but these Girty and E. O. Ulrich, paleontologists of the Arkansas Valley. In both localities fossiliferous Clair marble. The marble is surrounded and con­ are records of physiographic and structural history, United States Geological Survey, from observa­ limestones occur at the base. In the area lying on cealed in the Tahlequah quadrangle, outside of a and are described elsewhere. tions and collections made in the field seasons of the south side of the valley and extending west­ few exposures, by younger rocks which rest uncon- STEUCTUKE. 1901, 1902, and 1904. The most abundant col­ ward to the Arbuckle Mountains the formation formably on it. Massive white crystalline lime­ GENERAL STATEMENT. lections were obtained from the Carboniferous sec­ is known as the Wapanucka limestone, and is stone 200 feet or more in thickness, such as the tion, where the more important age distinctions described in the Coalgate and Atoka folios. It is St. Clair marble, indicates deposition in clear All stratified rocks are originally deposited in and revisions of former classifications were made. probably the equivalent, in part at least, of the water, which may have been either some distance nearly flat positions. This may be said to be uni­ Especially valuable is the more definite knowl­ Morrow formation. Above the Wapanucka there from land or at considerable depths in the vicinity versally true of the finely divided sediments, such edge gained concerning the boundary between the is a shale and sandstone formation having a of very low land. as fine sand, clay, and limestone, and of practi­ rocks of Mississippian and Pennsylvania!! age. thickness of 6000 to 7000 feet. It thins toward After the deposition of the St. Clair marble there cally all deposits having broad extent. All the The Burgen sandstone is much like the saccha­ the west, decreasing to 3000 feet in the Atoka is a break in the record, corresponding to the clos­ rocks of the Tahlequah quadrangle are included roidal sandstone of northern Arkansas and south­ and Coalgate quadrangles, where it has been named ing portion of Silurian and early Devonian times. in this classification of stratified rocks. ern Missouri, and its stratigraphic position above the Atoka formation. The Atoka formation is the In this long interval the rocks were folded in low In the discussion of the history of sedimentation the Yellville limestone, the uppermost group of stratigraphic equivalent of probably the lower 600 undulations and uplifted into land. Probably while it was pointed out that the rocks of the Ozark the "Magnesian series," strongly favors its corre­ to 800 feet of the Winslow formation in the Tah­ the folding was in progress, and certainly after it region, of which the Tahlequah quadrangle formed lation with the saccharoidal sandstone recognized lequah quadrangle. Neither formation has been had taken place, the land was reduced by erosion to a part, oscillated from sea bottom to land and from by the Arkansas Geological Survey. It is not found to contain sufficient fossils for paleontologic a low and nearly level surface. This land was sub­ land to sea bottom at various times between the known to contain dossils. correlation. The limestones at the base of each merged in late Devonian times. These conditions Cambrian period and late Carboniferous time, and The Tyner formation contains a considerable are probably equivalent, as stated, and it has been prevailed not only in the vicinity of the Tahlequah that these oscillations were accompanied by slight fauna in the limy layers and in some sandy beds determined by areal mapping that the Hartshorne quadrangle, but extended over a large part of the and variable folding of the strata. Since rocks above and near the top, which indicates that the sandstone, which overlies the Atoka formation on Ozark uplift. The record of this submergence is lower than the Carboniferous crop out in but few rocks range from Trenton to Lorraine in age. the south side of the Arkansas Valley, has a strati- found in the Chattanooga shale, which was depos­ and small areas in the Tahlequah quadrangle, but The St. Glair marble, at least the upper exposed graphic equivalent in the upper part of the Wins- ited over a very broad extent of country. This little can be said of their structure apart from that part, contains a Niagara fauna,. Both the fossils low formation in the Tahlequah quadrangle. shale, which is such as would be formed in a broad, involved in the Carboniferous rocks. At some and the rock characteristics show it to be a west­ shallow sea, was deposited on the eroded surface of time after the Carboniferous period the region was HISTOEY OF SEDIMENTATION. ward continuation of the St. Clair marble of north­ several formations, consisting of various kinds of uplifted and the flat strata were bent into a broad ern Arkansas. All the rocks in the Tahlequah quadrangle were sandstones, shales, limestones, and dolomites. In dome. A better understanding may be had of the The correlation of the Devonian black shale and deposited in water and are composed of the waste the small areas exposed in the Tahlequah quadran­ structure of the Tahlequah quadrangle after a brief sandstone of this area with the Chattanooga shale of neighboring lands and of the remains of animals gle the Chattanooga shale occurs on all three of the description of the Ozark uplift and the Arkansas of the southern Appalachian region is based upon and plants which lived in or near the borders of older formations, and though the Tyner shale and Valley, of which it forms parts. stratigraphic relations to older and younger rocks, the seas when the sediments were being laid down. Burgen sandstones are friable rocks, material from identical lithologic character, and the occurrence These rocks, as described above, are limestones, them does not enter appreciably into the compo­ OZAEK UPLIFT. of similar fish remains in the phosphatic sands in shales, sandstones, and conglomerates, and when sition of the shale. After the deposition of the The Ozark uplift comprises southern Missouri, the lower parts of the two beds. they were deposited consisted of limy ooze, mud, Chattanooga shale submergence of the region con­ that part of Arkansas included in and lying north The Boone formation is widespread in occurrence sand, and gravel, respectively. The characters of tinued well into Mississippian time, until the for­ of the Boston Mountains and west of the Missis­ and has been traced by areal mapping from the these rocks, when traced and studied over a wide mation of the Boone limestone and chert was sippi lowlands, northeastern Indian Territory east of Tahlequah quadrangle to localities first described field, tell the story, though not complete, of the completed. The broad extent of this submergence Neosho River, and the southeast corner of Kansas. in northern Arkansas. manner of their formation. As ages passed and is shown by the fact that patches of the Boone Its approximate outline will be seen in fig. 1, which The Fayetteville formation at its type locality formations were successively deposited the genera­ formation occur almost up to the crest of the shows the physiographic divisions of the Ozark about Fayetteville, Ark., as well as at many places tions of animal life changed or migrated and were Ozark dome. In later Mississippian time there province. The boundaries can not be clearly Tahlequah. 6 defined because the uplift merges into the bor­ STRUCTURE SECTIONS AND MAPS. ward displacement, suggesting a close relation minor undulations almost to the southern border dering provinces of the Prairie Plains and the To aid in understanding the structure of the between the faulting and the folding, to be of the quadrangle. Arkansas Valley. On the north and west the quadrangle two illustrations are introduced. One pointed out more fully below. All of these A small dome-like anticline occurs nearly mid­ inclination of the strata continues downward at of these is a sheet showing the geology with two faults pass beyond the boundary of the quadran­ way in the Boston Mountain monocline, trending a gradually increasing grade beneath the Prairie sections drawn across the strike of the rocks, and is gle, but, with the exception of one immediately northwest and southeast. On the map it is located Plains. The limits are more disdnct on the south known as a structure-section sheet. These struc­ south of Tahlequah, which extends to the middle at the head of Salt Creek, opposite the east end of as a result of the more abrupt change from the ture sections show the approximate attitude of the of the adjoining Muscogee quadrangle, die out Brushy Mountain. The fold probably does not monocline of the Boston Mountains to the folded formations beneath the surface, as if the rocks were within a few miles. At Cookson a small fault exceed 3 miles in extent and the rocks in its center rocks of the Arkansas Valley. On the eastern sliced vertically and their cut surfaces exposed to displaces the rocks downward toward the south­ are bulged upward probably a thousand feet a.bove border of the dome the structure is concealed for view. The scale to which these sections are neces­ east, producing the effect of an elevated, narrow their normal position in the monocline. the most part by the northern extension of the sarily drawn is too small to show the minor undu­ faulted block in the north side of the larger, down- Near the south side of the quadrangle occurs Tertiary and Quaternary flat sediments of the Mis­ lations and details of folding; and of course the thrown block. a narrow, steep monocline bearing nearly east sissippi lowlands. The exposed limit, however, is sections show the structure only near the line along In the northeastern part of the quadrangle there and west. It marks approximately the boundary sharply marked here by the western border of these which they have been drawn. are two small faults associated with minor folds. between the structure of the Ozark uplift and the flat-lying sediments, along which the St. Louis, In order to represent more adequately the struc­ The one near Barren station, on the Kansas City, folded trough of the Arkansas Valley in the Iron Mountain and Southern Railroad has been ture of the rocks in the Tahlequah quadrangle a Pittsburg and Gulf Railroad, strikes in a northerly Tahlequah quadrangle. A synclinal fold of the built. The eastern boundary crosses Mississippi model showing the deformed surface of the Boone direction and is nearly coincident with the axis of Arkansas Valley province enters the center of the River near the mouth of the Ohio, curves north­ formation, the one most widely exposed, has been a small structural basin. In this instance the south side of the quadrangle, trending northeast, ward and then westward, and includes a small area constructed. In the model the vertical dimension down-thrown rocks are on the west side. The and the above-mentioned monocline is a promi­ in southern Illinois. is exaggerated three times as compared with the other small fault is east of Stilwell and strikes nent feature of its northeast end. The steeply The Ozark uplift has the form of an elongated horizontal. Fig. 2 shows this model with the in an easterly direction, with downthrow toward dipping rocks on the northwest side of the syn­ dome, the axial part trending approximately S. 70° light falling on it at a low angle from the left. the south, apparently across the axis of a poorly cline continue southwestward beyond the quad­ W., through the St. Francis Mountains in eastern rangle. Toward the northeast there is an abrupt Missouri to the vicinity of Tahlequah in northeast­ change in the steepness of dip and direction of ern Indian Territory. Thus the Tahlequah quad­ strike along the well-defined line of the monocline. rangle lies on the southwest end of this structural From the vicinitv«/ of Akins westward to Sallisaw dome. The axis of this uplift is not marked by a Creek and probably a mile or two beyond, the definite crest, such as is usual in distinct smaller rocks are faulted along the south side of the mon­ upward folds. For long distances across the axial ocline. The rock south of the fault is shale and is part the strata are flat or but slightly undula­ not sufficiently exposed to show structural details. ting and are locally broken by normal faults. As On the opposite side, however, certain sandstone already explained, the formations incline at low beds of the Winslow formation are terminated angles from the northwest side of the broad dome. along the southern -edge of the monocline. Likewise, the strata pitch at a low degree along RELATIONS OF FAULTS TO FOLDS. the axis toward the southwest. Between the axial p.irt of the uplift and the Boston Mountains the It may be noted by reference to the structure map structure is undulating and the rocks are locally and fig. 2 that in the rocks north of the Boston faulted, resulting in a low slope toward the south­ monocline the faults are all associated with and, east. In the southern slopes of the Boston Moun­ except possibly in one instance, already referred to, tains the tilting is increased by a succession of are parallel to and in most instances occur near strong southward-dipping monoclines accompanied the axes of the synclinal folds. In the four by local faulting. instances of faulting from the vicinity of Tahle­ quah southward it may be noted that the folding ARKANSAS VALLEY TROUGH. is confined to the down-thrown sides of the faults The Arkansas Valley structural province lies and that the deepest parts of the folds are coin­ between the Ozark Mountains and the Ouachita cident with the greatest displacement. Such rela­ Mountains and corresponds very closely with the tions between the folds and faults point strongly physiographic province. It is a wide and deep but to the probability that the same forces produced unsymmetrical trough composed of many relatively the two types of structure and that their occur­ short lapping folds. There is a gradual transition rences were closely related in time. from the strong and close folding of the Ouachita uplift northward into the Arkansas Valley. The ECONOMIC GEOLOGY. depth of the folds decreases northward from the Ouachita Mountains to the Boston Mountains. MINERAL RESOURCES. North of Arkansas River the folds are shallow and The Tahlequah quadrangle has not been found relatively broad. From the Mississippi lowland to contain any of the ores of metals or nonmetallic at Little Rock to eastern Indian Territory the products of economic value other than building trough is of even width and bears almost due west. stone, limestone, clay, and soil. To these products Opposite the west end of the Boston Mountains may be added water, which is a resource of con­ the Arkansas Valley structure curves southwest- siderable value. ward and comes to an end between the Ouachita The surface rocks in the northern part of the Mountains and the Arbuckle Mountains in south­ Tahlequah quadrangle are the same as those of the west Choctaw Nation. Near the Arkansas-Indian zinc region in southwestern Missouri and parts of Territory line, where the Arkansas Valley folds northern Arkansas, and the structural conditions change their bearing from west to southwest, they are very similar; that is, the rocks are essentially approach the^Boston Mountain monocline at angles horizontal and are broken by normal faults, but no of 30° to 45°. A fold of this class is the Sallisaw zinc ores are known to occur in appreciable amount. syncline, which enters the south end of the Tah­ lequah quadrangle. FIG. 2. Model of the deformed surface of the Boone formation in the Tahlequah quadrangle. BUILDING STONE. STRUCTURE OF THE QUADRANGLE. The vertical scale is exaggerated to approximately three times the horizontal in order to bring out the smaller undulations. Contour interval is 50 feet. To give the proper impression of the structure the light is made to fall on the surface from the upper left-hand corner. Stone suitable for building construction may be GENERAL STATEMENT. found in the St. Clair marble, in certain beds The Tahlequah quadrangle lies on the southern The contour lines on this figure represent vertical defined syncline. It is the only instance noted in occurring locally at the base and top of the Boone slopes of the Ozark dome, near its southwest end, intervals of 50 feet, and the numbers on them the quadrangle where faulting and folding do not formation, in parts of the Morrow formation, and and extends from near the axis to the edge of the show elevations above sea. The relief of the correspond in direction. in certain beds of the Winslow formation. trough of the Arkansas Valley. In a general view deformed surface in any part of the quadrangle is A long, sinuous fault extends from the southwest The St. Clair marble is a massive, thick bed of of the structure of the quadrangle (see fig. 2) it may shown by the contours. corner to the middle of the quadrangle. In this white to cream-colored and moderately hard crys­ be seen that the form of the north half is almost instance the rocks are thrown down on the south­ talline limestone. It is believed to be too coarse in FOLDS AXD FAULTS. flat. The undulations in an east-west direction east side of the fault. A broad tract between this texture to produce a stone of high grade for orna­ are very slight, with the exception of a small basin The rocks of the Tahlequah quadrangle, besides fault and the next on the northwest has been only mental or decorative purposes. It is sufficiently southwest of Westville. Toward the southwest the being tilted southward in a broad monocline, have slightly deformed by folding and is an elevated strong, however, to be suitable as a building stone inclination is increased, and the beds descend 600 been thrown into moderate basin-like folds bearing block with respect to the rocks on each side. It and its color is pleasing and durable. Four of the feet from the northeast corner to the southwest cor­ northeast and southwest parallel to the general is anticlinal in form, but almost flat in cross sec­ six localities of its exposure are in the Sallisaw ner of the quadrangle. The deformation increases trend of the Ozark uplift. Associated with each tion except at the borders where the rocks are Creek Valley and near the Kansas City Southern in a southeasterly direction across the general of these basins on either one side or the other, or, locally flexed downward because of dragging on Railroad. All of the localities are in the bottoms trend of the uplift. In the northern part of the in one instance, on both sides, are normal faults. the down-thrown sides. Longitudinally the strata of valleys or lower slopes of hills, and it is con­ quadrangle the tilting toward the southeast is With one exception these faulted folds occur in the incline gradually downward toward the south­ sidered that except in the two largest areas, located very slight. Southward the inclination of the central and western parts of the quadrangle. From west. A fault similar to the one just described, near Bunch and Marble, the rock is not accessible strata increases by a succession of tilted and faulted the central part northwestward there are five such but smaller, bears more easterly from the vicin­ for successful quarrying. synclinal folds. The southern half of the quad­ faults, which are downthrows toward the north­ ity of Bunch. These two faults mark the north­ Certain marble-like limestone beds occur at the rangle includes the southwest end of the Boston west, and are separated by basin-shaped faulted west side of the Boston Mountain monocline. base of the Boone formation. These have been Mountains, where the rocks are tilted southeast­ blocks inclined southward. The deepest parts of Southeast of these faults the strata are more found at only two localities, both on Barren Fork ward in monoclines, locally increased by faulting. the basins are coincident with the greatest down- steeply tilted toward the south and continue with east of the Kansas City Southern Railroad, sur-

J 7

rounding small areas of Chattanooga shale. This CLAY. land of transported soil distributed along the larger of agricultural value except in the few level tracts limestone occurs in even and moderately thin beds Clay shales occur in abundance in the Tyner, valleys, are formed in place by the weathering of in the tops of the ridges near the eastern border of and its texture is fine. Its situation near the river Chattanooga, Fayetteville, Morrow, and Winslow the rocks beneath them. The geologic map, there­ the quadrangle, in the table-land of Brushy Moun­ level, however, will prevent its successful quarry­ formations. All of these clay-shale deposits vary fore, may be considered as a soil map also. tain, and in the district south of Blackgum post- ing on a large scale. Certain limestone beds on in their different parts in percentages of lime, sand, The St. Clair, Tyner, Burgen, and Chattanooga office between Vian Creek and Illinois River. In the top of the Boone formation are adapted to use and iron, but none were found of sufficient purity formations come to the surface in small tracts in these tracts the soil is a light sandy loam and is as ordinary building stone. The beds occur in to produce a clay of high grade. A large part of narrow valleys or steep slopes where soils of any best adapted to the cultivation of vegetables and moderately thin strata. The rock is light blue the Tyner formation consists of greenish or bluish importance are not permitted to form. fruits. Elsewhere the formation is too hilly and and hard. This limestone occurs above the chert clay shale. There are thick beds of moderately The Boone formation produces two kinds of soil. the surface too stony and steep to serve any valuable beds and as a whole varies in thickness between 0 soft, even-textured shale of this formation exposed The first and more fertile of these is formed by the purpose except to support a forest. and 30 feet. It is included in the basal part of in the valleys of Illinois River and Barren Fork limestone at the top of the formation. Consider­ the Fayetteville shale and crops out in belts sur­ northeast of Tahlequah. able level fertile areas of this soil occur about WATEK. rounding the localities of this formation in the The Chattanooga shale is invariably an even, Westville and Stilwell, and smaller tracts are The ground-water supply of the Tahlequah northern half of the quadrangle. hard, laminated, siliceous clay shale containing an found in many places on the level upland and near quadrangle is limited almost entirely to the area The Pitkin and Morrow formations contain intimate mixture of finely divided bituminous the edge of the Fayetteville shales. Elsewhere, and of the Boone formation. The rocks above the .-deposits of limestone very similar in bedding, matter. On burning or long weathering it. changes over the larger part of the quadrangle, the Boone Boone formation, which consists chiefly of sand­ color, and hardness to that overlying the Boone for­ to whitish hues. The Fayetteville shale is similar formation produces a cherty soil. On weathering stone and shales, are practically impervious to mation. These limestones vary to a small extent in in character to the Chattanooga, but less homo­ the chert breaks into angular blocks and fragments water and afford no springs. quality in different parts of the formations. There geneous and softer. It contains less bituminous and, because of its great durability, forms a surface The Boone formation, on the contrary, while are also changes in thickness and character from matter in the upper part, but more iron, which layer. The little soil it produces is fertile, but is originally an impervious deposit of siliceous lime­ place to place across the quadrangle, which are occurs in the form of ocherous concretions. carried downward and away by the rains or forms stone, is intersected by underground solution chan­ discussed in the geological description of the for­ The shales of the Morrow formation occur in the a substratum toward the base of the weathered nels that extend both across and along the bedding mations. The occurrences of these limestones are middle and upper parts. Those in the middle lie chert zone. Thus over a large part of the Boone of the rocks. The water from many of these under­ shown on the geologic map. between beds of limestone and probably contain a formation, especially in the more hilly districts, the ground channels comes to the surface in the valleys The Winslow formation contains some sandstone large percentage of lime. The shales of the upper soil is at too great a depth to be accessible to agri­ and issues as springs, while that of others rises, beds which may be utilized for foundations and part are thicker, but more variable in constituents cultural processes. The soil under these conditions probably in joint fissures or faults in the rocks. ordinary farm improvements. The sandstones are of lime and siliceous sand, being interstratified with can be of service only to the "forest, which thrives The group of large springs at Tahlequah and one brown, of generally fine texture, and moderately both limestone and shaly sandstone beds. .There seemingly in accumulations of loose stone. In cer­ on the fault 2 miles south afford a large volume of hard. Certain beds in the upper part of the for­ are beds of even-textured shale, however, which tain areas that have remained flat for a long time water. Large springs occur also at Parkhill, Wau- mation, exposed near the southern border of the may produce a brick clay. the soil is at the surface or sufficiently near it to hillau, Stilwell, Bunch, and many other localities, quadrangle, are even bedded and will cleave It is estimated that one-half of the Winslow for­ be cultivated. This is the case about Tahlequah affording an abundance of fresh water. A group of in^ suitable dimensions for building purposes. Good mation consists of shales, which occur chiefly in and Parkhill and in other smaller tracts on the saline springs occurs at the outcrop of the Boone exposures of such stone occur along the Kansas City, the lower and upper parts. They range from very level divides in the northern part of the quadrangle. formation near the head of Salt Creek, opposite the Southern Railroad 1 to 2 miles from the southern sandy deposits to clay shales which may be utilized The Fayetteville shale forms a thin and poor east end of Brushy Mountain. The rocks here are border of the quadrangle. in the production of bricks. Clay shales of the soil and its area is not sufficient to require further steeply upturned and the springs appear to issue better quality outcrop in Skin Bayou Valley. consideration. from the bedding planes of the chert and lime­ LIMESTONE. They invariably contain a percentage of dissemi­ The Morrow formation produces the most fertile stone of the Bobrie and Morrow formations. These Certain of the beds of limestone in the forma­ nated iron, but are believed to be almost free from soil in the region, even on steep slopes, where much springs have a small but unfailing flow of saline tions referred to as containing building stone may lime. That part of the Akins member of the Wins- of the rock is exposed. Its fertility is attested by and sulphur waters, the quantity of common salt be used in the manufacture of lime. It is believed low which is exposed in the Tahlequah quadrangle the luxuriance of the forest and the occurrence of (sodium chloride) being of greatest abundance, vary­ that the St. Clair marble is the best adapted for this consists almost entirely of shales, a large part of walnut, locust, and other trees that are found natu­ ing in the different springs from a small percentage purpose. The limestone at the base of the Boone which are similar to the better grades found in the rally only on fertile soils. The topographic fea­ to a quantity sufficient to produce strong brine. formation exposed on Barren Fork east of the upper part of the Winslow formation. These shales tures of the Morrow formation, however, are not Apparently the sulphur issues entirely as a hydro­ Kansas City Southern Railroad is of similar disintegrate readily, forming clay soils, and are not favorable for the utilization of its soils, being con­ gen sulphide gas. The water of one of the springs grade. The limestone at the top of the Boone usually exposed. fined almost entirely to hilly tracts. The Hale issuing from the Morrow formation throws down a and in the Pitkin and Morrow formations is vari­ sandstone member of the Morrow formation pro­ crimson precipitate which becomes black on long able in quality and of generally lower grade, but SOIL. duces a fertile sandy loam that is especially well standing. This water has "a bitter as well as a certain layers may be of sufficient purity to pro­ The soils of the Tahlequah quadrangle, with adapted to fruit culture. common saline taste. duce lime. the exception of very limited tracts of bottom The Winslow formation contains but little soil March, 1904. Talilequah.