DESCRIPTION OF THE FAYETTEVILLE QUADRANGLE.

By George I. Adams and E. O. TJlrich.

INTRODUCTION. Plains has been given. In Cretaceous time there this stream, erosion has removed a great thickness nizable, except as indicated by the general elevation was a subsidence in the Gulf region, and sediments of the rocks which were the equivalents of those PHYSIOGRAPHY OF OZARK BEGION. of the higher points. The hills which rise above were deposited which concealed the southern bor­ in the northern slope of the Boston Mountains, the plateau are of two kinds those which protrude General features. -Broadly defined, the Ozark der of the Ouachita Mountains. A later oscilla­ and the river now lies within a narrow gorge in through the strata forming the upland surface, and region embraces the southern half of Missouri, a tion caused the eastern extension of that mountain the lower rocks. those which are remnants of higher formations. very small corner of southeastern Kansas, the range to be buried under sediments of Tertiary The valleys of the streams exhibit two phases of Of the former type are the hills and peaks of crys­ northeastern part of Indian Territory, and the age. This region, which is covered by Cretaceous development, both of which are represented along talline rock which are found in the southeastern northern part of Arkansas. On its borders are and Tertiary sediments, is in general low lying, many of the larger streams, and which grade into part of Missouri and form the St. Francis Moun­ the cities of St. Louis, Jefferson, Marshall, Sedalia, and is known as the Gulf Plains. Just how these each other without sharp distinction. The older tains. The second group are residual areas of the and Joplin in Missouri, Galena in Kansas, Wag­ oscillations affected the Ozark region is not readily and simpler phase is an open trough bordered by rocks which originally overlay the surface, but oner in Indian Territory, Fort Smith and Bates- determined. There were undoubtedly warpings of hills and without rocky ledges adjacent to the which have been largely carried away by ero­ ville in Arkansas, and Poplar Bluff in southeastern the strata as the sea in the Gulf region retreated, stream. This condition is usually exhibited in sion. They are outliers from the main area of Missouri. In a general way Mississippi and Mis­ advanced, and again retreated, but the structure the upper portions of the streams. The valley Mississippian limestones farther west. souri rivers bound it on the northeast and north, which was developed at these intervals has not yet is generally covered with residual cherts and the Springfield structural plain. This is essentially Spring, Grand, and Arkansas rivers approximately been differentiated from that produced by the pre­ stream bed is floored with them. The channel is a structural plain developed on the surface of the limit it on the west and south, while the upper vious faulting and folding. The generally even not occupied by water, except during the time of Mississippian limestones. The drainage of the portions of St. Francis and Black rivers mark its sky line of the plateau portion indicates a time protracted rain, and it is not bordered by bottom upland in its broader part, namely, in south­ southeastern margin. during which the area was worn down to a low­ lands. The other phase, found in the lower por­ western Missouri and in Indian Territory, is in Fig. 1 illustrates the relations of the Ozark land. This was probably the condition in late tion of the streams, is the canyon phase, and where general in the same direction as the dip of the region to the surrounding physiographic prov­ Tertiary time. Since then the region has been this prevails there are many tributary springs and rocks westward and south westward. The larger inces, and also indicates the divisions of the region. elevated and the streams have carved deep val­ there is usually sufficient water to render the streams streams begin near the eastern border of the area leys. Remnants of the old lowlands now consti­ perennial. In this part of their course some of the and have their upper courses in shallow, trough- tute uplands, and along the stream narrow lowlands streams have developed flood plains, and furnish like valleys; they cut deeper as they flow farther are being developed. rich, although usually narrow, bottom lands. The down the slope, and in some places expose the it.Louis ILL. Divisions of Ozark Region. best example of this condition is found in White underlying Ordovician rocks, which rise in anti­ River, which lies from 250 to 500 feet below the clines and low domes. Adjacent to Grand River BOSTON MOUNTAINS. general surface of the upland. Tributary to the the border of this area is very much dissected by The Ozark region may be considered as con­ canyons are numerous short stream valleys, which numberless short streams whose valleys are deep in sisting of two divisions, the Boston Mountains owe their depth to the grade of the larger stream. proportion to their length. The streams that flow and the Ozark Plateau. The Boston Mountains They are formed by sapping back from the main eastward and pass through the Burlington escarp­ occupy the southern portion. Their northern channel and have little headwater drainage. Along ment have but a small portion of their course on border forms an irregular escarpment overlook­ the main valleys numerous smaller streams have the Springfield upland. They have deep channels, ing the plateau, above which th^ey rise from 500 dissected the plateau, and the country is broken by due to the fact that they pass over the edges of the to 700 feet. They may be described as consti­ narrow points extending out from the general area Mississippian limestones, in which they have cut tuting a highland having in general a mono­ of the upland surface. These form a complicated a ragged fringe. clinal structure. The dip of the rocks is to the series of hills and ridges, over which the soil is The Springfield structural plain extends into south, and the southern slope of the mountains shallow. Indian Territory westward to Spring River and blends with the Arkansas Valley. The trend of On the general surface of the plateau, where Grand River. Along Illinois River it forms, in FIG. 1. Diagram showing relations of Ozark region to sur­ the Boston Mountains is approximately east and broad undissected areas exist, there is a peculiar the area of Pennsylvanian rocks, an embayment rounding physiographic provinces; also the principal west from Batesville, Ark., to within a few .miles form of drainage that is without definite channels. which, as a result of the dip of the strata, has divisions of the Ozark region. of Wagoner, in Indian Territory. The formations It exists in areas known as "flatwoods," and also the peculiarity of extending down the stream. In In its northern portion the region is to a large which constitute them are principally sandstones in untimbered areas where the water largely dis­ southeastern Kansas and in the western part of extent a simple rolling plain; in its southern and and shales, and the resultant topography is largely appears under residual cherts and in sinks and Missouri it grades off into a lowland country, more rugged part the broken character is evidently of the terrace and escarpment type. The area is underground channels. approximately along the contact of the Pennsyl­ the result of erosion by streams which have deeply very broken as a result of dissection by the streams. vanian formations. DIVISIONS OF THE OZABK PLATEAU."* dissected a generally even surface. As compared Illinois River, in northwestern Arkansas, rises with the Mississippi Valley, the region is an ele­ OZAEK PLATEAU. The Ozark Plateau is divided into the Salem on the northern base of the Boston Mountains and vated one. To the north and west of it lie the The plateau portion of the Ozark region is platform and the Springfield structural plain by flows northward, then westward, then southwest- Prairie Plains and to the east and southeast are deeply dissected in its central and eastern parts, the Burlington escarpment. This escarpment is ward. In its northern course it flows away from the Gulf Plains. To the south is the Arkansas and in places the topography is rugged, but the the border of the Mississippian limestones, which the Boston Mountains into the border of the Valley region, and beyond it the Ouachita Moun­ elevations rise to approximately the same general constitute the country rock of the western part of Springfield plain, while in its southwestward tain region, both with different types of structure. horizon, so that, viewed in its entirety, it has the the plateau. The escarpment limits the Cambro- course it cuts through the Boston escarpment. Considered in its broader relations the geologic shape of a low elliptical dome, ranging in eleva­ Ordovician area to the west, and in crossing it It flows in a deep, well-defined valley, and, judg­ history of the Ozark region is complex. At the tion between 1000 and 1500 feet above sea level. there is a noticeable rise, although the increased ing from its course with respect to the Boston close of the Paleozoic era a thick mass of sedi­ In the southeastern part of Missouri, in the elevation is not maintained, since the dip of the escarpment and its relation to outlying areas and ments which had accumulated over southern Mis­ vicinity of Pilot Knob and Iron Mountain, the rocks is away from it. That the Mississippian headlands of the Carboniferous sandstones and souri, Arkansas, and parts of Indian Territory and surface features of the plateau are of an excep­ limestones have been eroded from over a large shales, it formerly stood at a much higher level. Kansas was lifted above the level of the sea, pro­ tional character. Within an area approximately part of the Salem platform is shown by the The northern part of the Springfield plain is ducing an elevated region which in its southern 70 miles square, known as the Iron Mountain small residual areas of those rocks and the accu­ crossed by Osage River, which has a very tortuous part has a folded structure. The force which country, there is a group of peaks, to which the mulation of cherts derived from them by weath­ course, probably due to meanders which were caused the folding was compressive. The eleva­ name St. Francis Mountains has been applied. ering and erosion. The escarpment, where well developed before it eroded its channel into the tion may have been a coincident or a later effect. The rocks which form them are crystalline, and defined, has an altitude of from 250 to 300 feet. Mississippian limestones. The western border of In central Arkansas and eastern Indian Territory erosion has developed a type of topography dif- To the east of Springfield, near Cedar Gap, it the Springfield plain is indefinite, especially where the compression resulted in the Ouachita Mountain erent from that which prevails generally over the stands at a greater elevation than in any other it is coincident with the outcrop of the soft Coal structure, which is characterized by close folding plateau. part of the region, inasmuch as at this point it Measures shales and sandstones which form a low­ and faulting. To the north of this it produced The drainage of the Ozark Plateau is believed is farthest up on the divide of the Ozark Plateau. land in Missouri and Kansas. In Indian Terri­ the wide and open folds which are exhibited in to be consequent, the arrangement of the streams In Arkansas, White River and its tributaries have tory its border follows the valley of Illinois River the Arkansas Valley. Farther north is the Ozark being radial that is, down the slopes of the dome. cut a wide embayment into it. It extends in its to the Boston escarpment. Beyond that point the region, in which the forces developed a less com­ While this is true of the higher portions of the southern portion in an approximately east-west lowland continues along Arkansas River, where it plex structure. The Boston Mountains, on its region, along its borders there are seeming depart­ line parallel with the northern escarpment of the forms the southern border of the Boston Moun­ southern border, are of a monoclinal type, while ures from this arrangement. One of the most con­ Boston Mountains. tains and becomes coincident with the lowland of the plateau portion, or northern part, has the spicuous examples of what might appear to be a /Salem platform. The eastern portion of the the Arkansas Valley region. form of a low dome with local faulting and minor modified phase of drainage is given by White Ozark Plateau -is the Salem platform. Its surface Physiographic Relations of Fayetteville Quadrangle. undulations. The structure produced during this River. This is formed by a number of streams is that of a general plain interrupted by the val­ mountain-making period gradually dies out to the which rise along the northern slope of the Boston leys which have been cut into it and by occasional The Fayetteville quadrangle, in northwestern west and north, where the formations are inclined Mountains, and is joined by others which flow hills rising above it. The streams flow in steep- Arkansas, lies principally in the Springfield plain. at low angles, dipping away from the Ozark Pla­ southward from the higher parts of the Ozark sided, narrow valleys, some of which reach a depth The mountains and hills which near its southern teau, and the topography is characterized by step Plateau in Missouri. This flows northward, then of 250 feet or more. Where the country is not border rise above the general level of the country or escarpment features, such as are usually found northeastward, and finally southeastward, its course dissected it is an undulating upland; but along the are the northern fringe of the Boston Mountains. in nearly horizontal rocks. To this region, which evidently having been determined by the Boston lower portion of White River and its tributaries, The narrow lowland in the valley of White River, extends around the northern and northwestern escarpment, which in former periods occupied a and along some of the other large streams, dissec­ along the eastern border of the quadrangle, is an border of the Ozark Plateau, the name Prairie position farther north. Since the establishment of tion has gone so far that the plain is scarcely recog­ arm of the Salem platform. \

GENERAL GEOLOGY OF OZARK REGION. Geologic Relations of Fayetteville Quadrangle. stone and exposed the underlying Devonian shales, a few scattered pine trees. The hard wood is cut a number of springs are found just above the shale extensively to supply the demand for railway ties. The formations represented in the Ozark region, The larger portion of the Fayetteville quadran­ bed, which acts as an impervious stratum. The In the more level portions of the quadrangle there when grouped for the purpose of general discus­ gle, which is essentially a plain, is developed on the springs issue at the contact of the St. Joe limestone are natural prairies of considerable extent. sion, correspond closely with the physiographic surface of the Mississippian limestones. This series member with the Chattanooga shale, where the dip Agriculture. The principal industry of the features. They have a somewhat concentric dis­ is in places cut through by erosion, exposing the is such as to bring the circulating water to the point country is farming and fruit growing. The farm tribution. The oldest rocks are found in the St. underlying Ordovician rocks; for instance, along of outcrop. Where there is a surface covering of products usually grown are corn, wheat, and oats. Francis Mountains, while those younger and geo­ the valley of White River. In the southern border detrital material these springs are sometimes con­ The forage plants, clover and grasses, grow luxu­ logically higher occur successively farther south­ of the quadrangle Pennsylvania!! shales and sand­ cealed for short distances and issue at a lower level. riantly. Orchards are a common feature of the west. stones are found in the hills and mountains consti­ There are a number of shallow caves formed at the landscape, and the growing of apples and small Igneous rocks. The igneous rocks constitute but tuting the northern edge of the Boston Mountains. base of the limestone by the solution of the rock fruits is carried on to a very large extent. The a small factor in the geology of the region. There along the joint planes and by the shelving down cherty-limestone soil is well adapted to grape grow­ are but three areas in which they are known to GEOGRAPHY. of the beds along the underground watercourses. ing and a large number of vineyards are success­ occur. The most important of these is the St. At Sulphur Springs there are springs which are fully cultivated. Francis Mountains, in southeastern Missouri. The Location and general relations. The Fayette­ noted for their medicinal qualities. They issue at Culture. Portions of two counties are embraced exposures have the form of rounded bosses and ville quadrangle lies between parallels 36° and 36° a lower horizon than those heretofore described; in the quadrangle. The northern two-thirds be­ domes which protrude through the sedimentary 30' north latitude and meridians 94° and 94° 30' viz, from the Ordovician limestones. At Electric longs to Benton County, while the southern third series and constitute a scattered group embraced west longitude, and embraces, therefore, a quarter Springs, just east of Rogers, water issues from the is a portion of Washington County. The county within an area about 70 miles square. The of a square degree. It measures approximately 34 Boone limestone at a number of places. There are, seat of Washington County is Fayetteville, and rocks are granites and porphyries with several miles from north to south and 28 miles from east no doubt, many other springs within the quadran­ that of Benton is Bentonville. Along the line of varieties of basic rocks that occur as dikes. The to west. It is situated in the extreme northwest cor­ gle which have similar properties, but the pictur­ the St. Louis and San Francisco Railroad, which exposure represents but a small portion of the ner of Arkansas. The Missouri-Arkansas bound­ esque location of the above-mentioned springs and passes through Fayetteville, are the towns of great mass which forms the basal member over a ary, as established, falls just south of the 36° 30' the facility with which they can be reached have Johnson, Springdale, Lowell, Rogers, Avoca, large area. The age assigned to these rocks is pre- parallel, so that a strip of Missouri approximately contributed to their popularity. and Brightwater. The St. Paul branch of the Cambrian, since they are overlain by sedimentary one-fifth of a mile wide is included in the quad­ Caves. There are, as is usual in a limestone St. Louis and San Francisco Railroad runs east­ rocks of Cambrian age and there is no sign of rangle. country, numerous caves and sink holes. None ward from Fayetteville through Baldwin and Har­ contact metamorphism. That portion of the Arkansas-Indian Terri­ are of great extent, but many can be entered and ris, while the Bentonville branch, formerly the The second area of igneous origin is found in tory boundary line which lies to the west of the explored for short distances. Those which occur Arkansas and Oklahoma Railroad, extends west­ the northeastern part of Indian Territory, near the quadrangle has a west of north direction. The in the upland often have their entrances on spurs ward from Rogers through Bentonville and Gra- mouth of Spavinaw Creek, where there is a gran­ southwest corner of the quadrangle approaches between small ravines. Such caves are above the vette and into Indian Territory. Another branch itic dike about one-fourth of a mile long. The within 1J miles of Indian Territory, while the level of ground water and are dry. They contain of the Frisco System extends southwestward from third is a dike consisting of graphic granite or northwest corner is 7^ miles east of it. Accord­ dead leaves which have been blown in, and the Fayetteville to Tahlequah, Ind. T., passing through pegmatite, having an actual exposure of only a few ingly, a small triangular portion of the State lies floor is strewn with rocks which have fallen from the village of Farmington and thence out of the square yards. It is located in the southern border to the west of the quadrangle. the roof. Usually .they contain dirty stalactitic Fayetteville quadrangle. The Kansas City South­ of Camdei! County, Mo. The rocks of the second Drainage. The quadrangle lies on the divide of and stalagmitic growths which form botryoidal sur­ ern Railway runs through Sulphur Springs, Gra- and third areas are intrusions probably of post- the Ozark Plateau. This watershed crosses the faces on the limestone. In some places clean cal- vette, Decatur, and Gentry. The country is well Carboniferous age. southern border of the quadrangle at Kessler cite and dolomite crystals are found. The floor settled, especially in the level portions, and there Cambrian and Ordovician. The great mass Mountain and trends northward past Fayette­ usually slopes at a low angle, and the caves are numerous small country towns, post-offices, of magnesian limestones, dolomites, and interbed- ville, Springdale, Rogers, and Avoca, where it appear to have originated by solution along the and mills. The University of Arkansas, which ded sandstones forming the floor of the Salem turns eastward and passes over the border on joint planes of the rocks and by the breaking is the principal educational institution of the State, platform belongs partly to the Cambrian system the narrow ridge between Little' Sugar Creek and down of the roof. The lower point of outlet can is situated at Fayetteville. and partly to the Canadian series of the Ordo­ White River. The principal streams of the quad­ not usually be discovered. vician. As at present defined these two systems rangle are White River and Illinois River, which Another class of caves consists of those from GEOLOGY. can not be separated satisfactorily in the Ozark in their upper courses flow northward from the which springs issue. They occur in the valleys DESCRIPTION OF FORMATIONS. Plateau. The lowest formations surround the Boston Mountains on either side of the above- and are not much above the level of the water GENERAL RECORD OF SEDIMENTATION. pre-Cambrian ,area and are exposed on the flanks mentioned divide. Illinois River, after a course in the streams. Some of them are high enough of the St. Francis Mountains.. In general they of about 11 miles in a northward direction, turns to be entered, and the streams of water are occa­ The rocks of the Fayetteville quadrangle are all dip away from these mountains, their margins to the west and leaves the quadrangle, beyond sionally, of sufficient volume to be available for of sedimentary origin. They are nearly horizontal therefore being buried by later rocks. Younger which its course is around the western end of the water power. In a few cases there are sinks above beds which, except in a few localities, have been Ordovician pure limestones and shales> corre­ Boston Mountains to its confluence with Arkansas the place of outlet which indicate the course of the but slightly disturbed since their deposition. The sponding in age to the Trenton limestone of River. White River, which flows northward in a underground streams. Low, shallow caves occur in complete series can not be seen at any one locality, New York and the Richmond formation of Ohio very tortuous course along the eastern border, leaves the valleys of Butler Creek and Little Sugar but from the sections which are exposed their and Indiana, are found rather generally along the quadrangle east of Rogers. Its course farther Creek, at the contact of the limestones with the sequence has been learned and the general sec­ the eastern border of the plateau and more locally on has a broad curve northward, thence southeast­ shales, at which horizon springs also issue. They tion established. This is shown graphically on on its southern margin. The contact of these late ward and around the eastern end of the Boston are formed by solution and {breaking down of the the columnar section sheet. Ordovician deposits with the older magnesian rocks Mountains to its confluence with Arkansas River. limestone where the ground water flows over the During the progress of deposition there were is always unconformable. The remaining important streams of the quadran­ impervious shale. They sometimes extend upward many important changes in the life of the sea in /Silurian. Rocks of this age occur in very lim­ gle-are Spavinaw Creek, which flows westward to along joint planes as a result of the widening of which the sediments were deposited. Some of the ited exposures on the northeastern and again on Grand River in Indian Territory, and Butler Creek the fissure by solution. shells of the animals which existed at the time the the southern and southwestern flanks of the Ozark and Little Sugar Creek, which flow northward into Relief. The northern portion of the quadrangle formations were laid down have been preserved Plateau. In the latter area they consist almost Missouri, where they are tributary to Elk River, has the general appearance of a plain dissected by as fossils in the rocks. Since each period of the entirely of a single formation composed of crystal­ which is an affluent of Grand River. The coun­ deep stream valleys, while the southern portion is earth's history has been characterized by certain line limestone, to which the name St. Clair marble try is well watered. These streams have numer­ semimountainous. The northern or more level forms of life, their fossil remains afford a means has been applied. ous tributary springs, and are perennial, except in part is a structural plain developed on the surface of determining the age of the formations. Accord­ Devonian. Formations referred to the Devo­ their upper portions. The valleys of the main of the limestone formation. On the divides the ing to such evidence the rocks belong to the Ordo­ nian have a limited outcrop along Mississippi and streams dissect the plateau and the short streams altitude ranges between 1250 and 1450 feet above vician, Devonian, and Carboniferous periods of the Missouri rivers, but sediments of this age are have a dendritic arrangement which gives a rug­ tide. The valleys of the larger streams are about Paleozoic era. During the whole of the Silurian apparently wanting in a large part of the remain­ ged character to the country, especially near the 250 feet lower. The lowest points are where the period and the early part of the Devonian no sedi­ ing portion' of the region. There are, however, larger valleys. principal streams leave the quadrangle, and are ments were deposited, or if they were they were numerous small areas in northern Arkansas. In In that portion of the quadrangle which is semi- approximately as follows: Illinois River, 950 feet; eroded before the later Devonian and Carboniferous these the Devonian rocks consist of the black mountainous and is considered as belonging to White River, 1050 feet; Little Sugar Creek, 950 rocks were laid down. Chattanooga shale and of the Sy lam ore sandstone the Boston Mountains the streams have tortuous feet; Butler Creek, 900 feet; and Spavinaw Creek, Varying conditions of deposition have given rise member, which usually underlies the shale. courses and the smaller tributaries an irregular 1000 feet. to several lithologic units. The rocks which con­ Carboniferous. The rocks of the Springfield arrangement between the isolated hills. In the In the semimountainous parts the higher points stitute these units either are uniform in character structural plain are principally limestones with plateau portion the streams have in their upper rise from 250 to 500 feet above the structural between their upper and lower limits or, when interbedded cherts belonging to the Boone forma­ parts a shallow trough phase, and in their lower plain. They constitute a part of outlying areas changeable, consist of beds which are uniformly tion of the Mississippian series. courses, especially along the larger streams, there of the Boston Mountains. Elkhorn Mountain, in varied in character. The units are called "for­ The rocks which outcrop in the north escarp­ is developed a canyon phase. These two phases the northeast corner of the quadrangle, and Cal- mations," and their extent is shown on the map ment of the Boston Mountains and constitute this grade into each other. lahan, French, Webber, Price, Fitzgerald, and by different-colored patterns. The subdivisions division of the Ozark region consist of shales and Springs. A very noticeable feature of the quad­ Twin Mountains, are conspicuous because of their of the formations which can not be distinguished sandstones with unimportant interbedded lime­ rangle is the large number of springs which are isolation, although they are not over 250 feet throughout the field are discussed as members. stones, and may be ^conveniently grouped in. found well distributed. In the vicinity of Fay­ above the general level of the surrounding coun­ Some of them, however, which are important and accordance with their prevalent lithologic char­ etteville, in the area which consists principally of try. The highest points in the quadrangle have are well defined, have been mapped as lentils acter. They include in their basal portion Mis­ sandstones and shales, the springs issue from under elevations approximately as follows: Kessler Moun­ within the formations in which they occur. sissippian formations and extend up into the beds of interstratified limestones, the joints and bed­ tain, 1750 feet; Round and East mountains, 1700 Ordovician Rocks. Pennsylvania!! series. They are in sharp con­ ding planes of which furnish channels for the cir­ feet; Robinson Mountain, 1800 feet. trast with the rocks of the Springfield upland, culation of the water. In the limestone country, Timber. The country is covered generally with The oldest rocks which are found within the both in the character of the sediments which where the streams have cut below the upland, a growth of oak over that portion wkich is level, quadrangle are of Ordovician age. They are more constitute them and in the position which they springs issue from between the heavy beds of lime­ but along the borders of the streams and on the or less cherty magnesian limestones and are to be occupy. They rise above the structural plain of stone, and some of them have a large flow. Along benches of the mountains there are a large number seen only in valleys which have been cut deeply the Mississippian limestones and constitute a deeply Illinois River, Little Sugar Creek, and Butler of other hard-wood forest trees. Near the Missouri into the upland. The areas in which they occur dissected highland. Creek, where erosion has cut through the lime­ border in the vicinity of Sulphur Springs there are have usually a low anticlinal structure. The streams have eroded the higher formations, uncov­ being traceable or recognizable from Lake Erie to however, are not uncommon, and may, if not described in Professional Paper No. 24 of the ering Ordovician rocks, and to these facts the northern Alabama and thence westward to Indian always, at least usually, be found where the mem­ United States Geological Survey. On a recent exposures are due. Such outcrops are found on Territory. In this quadrangle it consists of a per­ ber is reduced to a thin conglomerate. visit to Noel, Mr. Ulrich procured evidence White River and on Illinois River. sistent bed of black shale, generally underlain by The name of the member was proposed by the demonstrating the Devonian age of the black

a more or less phosphatic, conglomeratic sandstone. Ogeologists o of the Arkansas Survev.«/ It is derived shale, and proving its distinctness from the green­ YELLVILLE FORMATION. Locally this basal member attains considerable from Sylamore Creek, in Stone County, Ark., ish shale at Eureka Springs, with which it had This formation, of which only the upper part is thickness, and in such cases it has been distin­ where it is well developed. been correlated. exposed in the Fayetteville quadrangle, consists of guished as a mappable lithologic unit under the During the course of work in the Fayetteville, Where the basal sandstone member is wanting, magnesian limestone and dolomite, in rather evenly name Sylamore sandstone. Eureka Springs, and Yellville quadrangles this as at a number of points in the vicinity of Sul­ bedded layers varying in thickness from a few iuoties sandstone was at first erroneously considered as phur Springs, the Chattanooga shale rests directly to several feet. These layers exhibit some variation CHATTANOOGA FORMATION. the equivalent of the Ordovician upper or "First upon the eroded surface of the Yellville limestone. in composition, and more in physical characters. As stated above, this formation consists of a saccharoidal sandstone" of Missouri. The older The usual absence in this region of at least the The beds containing much lime and little silica persistent black shale generally underlain by a sandstone is described under the name Key sand­ lower members of the Kinderhook group suggests weather with an even surface and have a soft variable bed of sandstone, known as the Sylamore stone in Professional Paper No. 24 of the United an occasional and probably always inconspicuous gray color. The more siliceous varieties are of a sandstone member. States Geological Survey, published in 1904, but unconformity also at the top of the shale. darker, leaden color, have uneven bedding planes, The name of the formation is derived from Chat­ as the sandstone at the localities in this quadrangle Carboniferous Rocks. and generally exhibit angular faces and close joint­ tanooga, Tenn. From this point it has been traced from which the name Key sandstone was derived ing. Strata in which the silica is irregularly seg­ northward through Kentucky and Ohio. In these proves on examination by Mr. Ulrich to be Devo­ The lowest formation of Carboniferous age is a regated weather with a pitted surface. Many layers States the formation is much thicker than in Ten­ nian in age, and identical with the Sylamore sand­ bed of limestone followed by siliceous limestones after long exposure to atmospheric agencies have nessee, and is known as the Ohio shale. West­ stone, the name Key sandstone must be abandoned. interbedded with cherts. These rocks constitute the superficial appearance of sandstone, the surface ward from Chattanooga the formation extends as The Sylamore sandstone occurs at numerous the Boone formation, which forms the upland over being made of small grains of dolomite partially a continuous band around the truncated dome of points in northern Arkansas and in neighboring a large part of the quadrangle. They lie nearly freed by the solution and removal of some of the middle Tennessee, and finally dips out of sight parts of adjoining States, but it does not appear to horizontal, and on their upper surface is developed more soluble components of the rock. Layers con­ under the later deposits occupying the Mississippi have been laid down as a continuous sheet. There a generally even plain. They are succeeded by taining numerous small rounded grains of quartz embayment. On the west side of the embayment can be, however, no reasonable doubt that the iso­ sandstones and shales in the southeast corner of frequently occur. Traced laterally in one direc­ it comes to the surface again in northern Arkansas. lated outcrops are practically contemporaneous. In the quadrangle, where the country has a semi- tion, the grains in such a layer may become so Here it forms an intermittent band around the some places the phosphatic constituent occurs in mountainous character. The Boone formation, abundant as to constitute a calcareous sandstone, southwestern slope of the Ozark uplift. Wherever sufficient quantity to make the rock commercially Batesville sandstone, Fayetteville formation, and while in the opposite direction they may soon fail the formation has been recognized it retains very valuable. It is essentially the same horizon that Pitkin limestone represent the Mississippian series. entirely. As a rule these quartz grains are asso­ strictly the same lithologic character. In western affords the valuable deposits of Devonian phosphate The Morrow formation and the Winslow forma­ ciated with oolitic granules. Thin, irregular beds middle Tennessee a more or less highly phosphatic rock in middle Tennessee. tion belong to the overlying Pennsylvanian series. of oolite, now almost invariably silicified, abound sandstone and conglomerate, corresponding at least The greatest thickness measured was nearly 75 BOONE FORMATION. in the upper part of the formation as represented in position to the Sylamore member of the forma­ feet. This occurs in the bluff on the south side of in this quadrangle. tion in Arkansas, occurs very commonly at the base White River just east of the mouth of Hickory This formation consists of limestone, cherty Chert is much more abundant in the upper than of the formation. Creek. Here the lower beds are massive and the limestone, and beds of chert. The lower portion in the lower part of the formation as here exposed. Sylamore sandstone member. This is a friable upper ones thin and somewhat laminated. The consists of even-bedded limestone, distinguished As a rule it is very hard and compact, of a dark- sandstone, and when struck with a hammer or exposures in the bed of Hickory Creek are of the as the St. Joe limestone member. gray color, and occurs in the form of irregular crushed it often falls into a loose sand, as a latter class. Small and not very well exposed areas St. Joe member. The limestone forming this masses and concretions. The masses are frequently result of the small amount of cementing mate­ of Sylamore sandstone occur along Illinois River, member succeeds the Chattanooga shale. It is brecciated or conglomeratic, and in this respect cor­ rial present. Because of its white and sugary on Clear Creek, and on the small stream south­ even bedded, quite free from chert, and usually respond with many of the limestone layers associ­ appearance, and since it nearly always rests west of Decatur. A small development of the outcrops in a distinct ledge. Its thickness ranges ated with them, from which they were formed upon the Yellville limestone, it is often mistaken member is indicated also on Little Sugar Creek from 20 to 50 feet, with an average of 30 feet. by replacement. The part of the formation con­ for the upper "saccharoidal sandstone" of the by loose bowlders of sandstone lying on ledges The limestone has a soft gray color, and when taining the lenses and irregular beds of oolite are Missouri geologists. The true saccharoidal, or of Yellville limestone, which outcrops along this freshly quarried shows a bluish cast where broken. usually fossiliferous. The fossils, while not uncom­ St. Peter, sandstone, however, is much older, stream. The upper beds are often full of crinoid stems, mon, are rarely in a satisfactory state of preserva­ being Ordovician in age, and seems to have been Black shale. The most common phase of the which weather out on exposed surfaces. In places tion. They consist almost entirely of small coiled entirely removed in this quadrangle by erosion Chattanooga formation is a bed of black carbon­ there are small nodules of pyrite disseminated Gasteropoda, generally less than one-half inch in prior to the deposition of the Sylamore. It appears aceous, often fissile shale, varying in thickness through the lower, thinner beds. The contact diameter. highly probable that the Sylkmore sandstone is from 30 to 70 feet and averaging about 50 feet. between the 'underlying Chattanooga shale and This formation occurs principally in two areas; largely derived from the detritus of the older sand­ At the top there are usually a few inches to a foot the limestone is usually marked by a few inches the larger is 5 miles east of Rogers, on Prairie stone. of green shale. The outcrops are in slopes and of greenish-gray shales or soft calcareous beds. Creek and White River, where the latter stream Though the color of the Sylamore sandstone is under ledges, and the shale is consequently largely The St. Joe limestone member forms a conspic­ leaves the eastern border of the quadrangle; the usually white, its surface is often brown, from a covered by detrital material, so that it is to be seen uous horizon, since the weathering and erosion smaller is on Butler Creek near Sulphur Springs. staining of iron. The constituent grains of quartz only where erosion is active. It is argillaceous, and of the shale which lies below it cause it to jut The base of the limestone is not exposed within are translucent and nearly always rounded. Very has a jointed structure and a tendency to break up out in a prominent ledge. Occasionally the ledge the quadrangle, and the total thickness is not commonly the rock includes variable quantities of into prismatic blocks. It contains considerable breaks down into large slabs and blocks, which are known. The vertical section of the formation light-gray or black pebbles that on examination iron pyrite in certain localities, and this weathers found lying on the slope below. Its occurrence is south of Prairie Creek is estimated at 100 feet. prove to be more or less phosphatic. These phos­ out as nodules and concretions, and although of no thus favorable for quarrying, and its even beds The best exposures are in ledges and bluffs along phatic pebbles range from less than one-eighth of value has attracted considerable attention because and jointing make it a convenient building stone. White River, and present vertical sections of 20 to an inch to several inches in diameter. Locally of its yellow metallic appearance. The shale has Underneath the jutting ledges there are low caves 50 feet. North of Sulphur Springs, along the the sandstone contains numerous large and small, a fetid odor, and has been thought by some to caused by the breaking down of the limestone railway, there are ledges which aggregate 50 feet rounded or angular pieces of chert. These chert contain oil. It has been passed through in both along underground water channels, and these often in thickness. In the immediate valley of Little pebbles and bowlders were derived from the wash shallow and deep wells in many places, but no oil extend upward along joint planes which have been Sugar Creek there are two small areas in which of the underlying Yellville limestone, which, for a has been found in it. The occurrences of the shale widened by solution. limited exposures of this formation may be seen. long time preceding and during the deposition of which are most often seen are those where wagon The upper limit of this member is defined by The top of the Yellville limestone forms an the Sylamore sandstone, was raised above sea level roads pass over and wear down into it. The black the presence of chert in the super]acent beds and is unconformable contact with the succeeding for­ and subjected to subaerial decomposition and ero­ color has suggested to some that coal might be asso­ not marked by any decided variation in color or mation. In this area the rock usually over­ sion. This condition is clearly shown in the vicin­ ciated with it, but this assumption is wholly unwar­ change in the texture of the limestone; evi­ lying the Yellville is the Sylamore sandstone ity of Sulphur Springs, where the chert pebbles are ranted. The shale is very uniform in character, dently there was no interruption in the sedimenta­ member of the Chattanooga formation of the Devo­ often decomposed, leaving cavities whose thin walls and, being impervious, forms a lower limit to the tion at this horizon. nian system. Locally, however, this sandstone is are formed by the siliceous sand that filled the circulation of the( ground water. Its upper surface Cherty limestones. The upper part of the Boone wanting, in which case the black-shale portion interstices between the pebbles. The rock in such is accordingly the horizon of many springs, where formation consists of cherty limestone, beds of chert, of the Chattanooga rests on the Yellville. The cases has a honeycombed or cavernous appearance the dip of the rock is such as to cause the water to and thin and massive bedded limestone, which vary stratigraphic hiatus indicated by the uncon­ that may falsely suggest the cutting of the rocks flow to the place of outcrop. in character in their lateral extent and are not formity therefore represents the time in which by a network of quartz seams. Fossils are always rare in the Chattanooga shale. sharply differentiated in vertical section. The the later Ordovician, all of the Silurian, and the The Sylamore sandstone is very clearly uncon­ Occasionally a layer may be found containing lin- thickness of this portion of the formation, accord­ early Devonian deposits were elsewhere laid formable on the Yellville limestone, its bulk having guloid shells and perhaps minute teeth and plates ing to the records of deep wells and the measured down. During much of the time not repre­ locally sufficed to only partially fill the inequalities of the type known as conodonts. Pieces of fossil section, is about 325 feet. These are the most sented by deposits in this quadrangle the surface of the old land surface that was submerged beneath wood (of the genus Dadoxylon] are probably the widespread rocks in the quadrangle, their area of of the earlier Ordovician rocks was being sub­ the Devonian sea. In consequence its thickness most conspicuous of the organic remains. outcrop covering fully five-sixths of it. They are jected to erosion and removal. In consequence varies greatly, and sometimes very abruptly. Along The principal outcrop of Chattanooga shale in distinguished by the presence of chert, which is the top of the Yellville is uneven, and exhibits the north bank of Prairie Creek it is practically this quadrangle occurs near the northwest corner, seen in the exposures or, on the weathering of considerable local variations. For instance, in wanting in places, or is represented by a conglom­ in the valley of Butler Creek. It is especially well the rocks, is left upon the surface. As a result of the vicinity of Sulphur Springs, situated near the erate only a foot or so in thickness. The same is exposed near the mouth of the valley at Noel, Mo., this slow disintegration the cherts cover the slopes northwest corner of the quadrangle, it is estimated true in the vicinity of Sulphur Springs, where the which lies just north of the border of the quadran­ and floors of the valleys of the minor streams. In that during this time at least 100 feet of Yellville variations in thickness are sometimes so abrupt as gle. When the survey was made the black shale the perpendicular bluffs are the only outcrops rocks were removed from the top of the formation. to suggest that the deposition of the sandstone was at Noel was believed to be the same as the Eureka which are not more or less disguised by this resid­ at least locally confined to channels. shale of the Arkansas geologists. The name Eureka ual material. Devonian Rocks. On account of the unfavorable character of the being preoccupied, it was proposed to substitute the The chert when first exposed is compact, and The Devonian system is represented in this rock, fossils, especially of invertebrates, are diffi­ new name Noel for Eureka, and it is under this usually has a light-gray color. On weathering it quadrangle by the Chattanooga formation. This cult to find in the Sylamore. Fragmentary bones name that the early Carboniferous shale at Eureka becomes yellowish brown from staining by iron, formation has a very wide geographic distribution, of large fishes, chiefly of the genus Dinichthys, Springs and elsewhere in northern Arkansas is and the fragments are often very light and por- Fayetteville. ous. It has many diverse colors, such as black, best sections are to be seen are the ones which were which in these cases lies unconformably above bearing shale, and furnishes a reference horizon in green, and drab, and the more siliceous varieties not reduced by the first period of denudation and it. In other localities, especially near and beyond locating the coal bed, the latter lying from 15 to retain their compact texture and, being easily frac­ now remain covered by higher formations, or those the south border of the quadrangle, a bed of shale, 30 feet above it when present. tured, disintegrate into small angular fragments. from which the overlying beds have only recently ranging in thickness from a few feet to over 60 Above the Brentwood limestone are shales, more The chert, which is frequently fossiliferous, occurs been removed. feet, intervenes between the Wedington sandstone or^less carbonaceous and approximately 100 feet as concretions in the limestone strata, as lenses Fossils occur locally in considerable numbers, and the Pitkin limestone. This shale is regarded thick. They are sometimes decidedly arenaceous, interbedded with the limestone, and as massive especially in the more calcareous layers. The as the upper member of the Fayetteville formation. and where their upper limit is not marked by the beds. There is much silica distributed through fauna indicates that the formation is to be cor­ It is rarely so dark as the lower member, and is Kessler limestone they grade into the superjacent certain of the limestone beds, and on removal of related with the early formations of the Chester commonly of a gray or slightly buff color. sandstones. They contain the coal bed above the lime by solution the rock has a porous texture. group in the Mississippi Valley. referred to. The coal has been discovered at The term "cotton rock" is used locally to desig­ The name is derived from Batesville, Ark., where PITKIN LIMESTONE. many places, but is not very important. It is nate this variety. As its disintegration progresses the formation attains much greater thickness. The This formation is usually a light-gray limestone mined to a small extent for local trade, but inas­ such a rock will crumble into a white, chalky bed, Wyman sandstone of Symonds (Kept, on Washing­ varying in thickness from a few inches to 40 feet, much as it nowhere exceeds 14 inches in thick­ such as may be seen in the railroad-cut east of ton County, Arkansas Geol. Survey, vol. 2, 1888) and is rather highly fossiliferous. The limestone, ness it can not become of any great commercial Gravette. "Tripoli" rock, so called, which is is the same formation, the Batesville sandstone when of any considerable thickness, is conspicuous importance. The shales occur in the higher quarried and sawed for niters, is obtained from of this author being the Wedington sandstone in contrast with the shales and sandstones. Its mountains, well up the slope, and in the hill similar siliceous beds from which the lime has member of the Fayetteville formation as described outcrop, when traced, is found to follow the in the north part of Fayetteville. Their occur­ been removed by solution, thus rendering the in this folio. Symonds's erroneous identification benches of the mountains. It is not mapped rence at a lower elevation 7 miles northeast of rock porous. To be of commercial value the of these sandstones arose from the mistaken view continuously, because it is not persistent, or, if Fayetteville is due to flexing and faulting. Like­ rock must be free from flint concretions or nod­ that the Batesville was underlain by the Fayette­ so, is concealed by the debris of sandstones and wise, the outcrop in North College avenue in Fay­ ules, which would prevent its being cut and ville. shales. It is the highest formation of the Missis- etteville, near the ravine, and in the block northeast dressed easily. sip pian series, according to paleontologic evidence. of the St. Louis and San Francisco station are the The limestones of the Boone formation are FAYETTEVILLE FORMATION. The conspicuous fossil of this formation is the bry- result of local disturbances. often free from siliceous matter and occur both This formation consists principally of a bed of ozoan Archimedes swallovanus, the screw-like solid Kessler limestone lentil. This name is applied as thin and as massive beds. They are coarsely black or dark-gray carbonaceous shale, which is axes of which can be seen on the weathered surfaces to a zone in the upper part of the Morrow forma­ crystalline and usually have a light-gray color on usually thinly laminated. As a rule a more or of the limestone. Other, but generally smaller, spe­ tion containing from one to four thin beds of gen­ weathered surfaces. In places they are charged less definite bed of hard, dark-gray or blue, fos­ cies of the same genus occur, generally very spar­ erally dark, argillaceous, and frequently somewhat with bituminous matter, and when struck give siliferous limestone occurs at or a few feet above ingly, in the underlying Fayetteville formation and ferruginous limestones. The beds are separated by off a fetid odor. Usually the limestone is fos­ the base of the formation. Frequently also there Batesville sandstone. variable intervals made up of dark-gray or black siliferous, and there are some beds which contain are some highly fossiliferous thin layers of lime­ shales. The limestones generally weather out on numerous crinoid stems. The rock breaks with a stone near the top. The shales making up the MOKROW FORMATION. the slopes of the mountains in large slabs, which conchoidal fracture and is very tenacious. The middle part of the formation are perhaps always This name is applied to a succession of sandstone are found at a lower elevation than the ledges from more even beds furnish a good quarry stone and lighter colored than those constituting the lower and shale beds in which there are some limestone which they are derived. The ledges are difficult the purer varieties are burned for lime. third or half of the thickness. Commonly the lentils. The beds aggregate 400 feet, but the vari­ to trace, because they occur on steep slopes of the color of this middle part varies from gray to yel­ ation in the individual members is considerable, and mountains and are usually covered with sandstone BATESVILLE SANDSTONE. low, while its lithologic character ranges, according the vertical section is not uniform in character or debris. The maximum thickness of the zone may The Boone formation is succeeded by rocks to the proportion of siliceous matter contained in in thickness. In this quadrangle the full section be as much as 70 feet, but the individual bands which are more or less arenaceous. In certain it, from a shale to a true sandstone. Where the is found only in the higher mountains, such as rarely exceed 4 or 5 feet in thickness. localities there are sandstones and shales inter- latter phase predominates this portion of the for­ Round, East, and Kessler mountains. The inter- The highest beds of the Morrow formation are stratified with limestones. The sandstone beds mation is distinguished as the Wedington sand­ stratified limestones are mapped as members or usually sandy and carbonaceous shales, which have are yellowish and generally are rather soft. The stone member. lentils, since they are of minor importance and are a maximum thickness of 50 feet. These lie between more argillaceous ones have a greenish-gray color. The Fayetteville formation has a wide occur­ not persistent throughout the formation as definite the Kessler limestone lentil and the Winslow for­ The outcrops occur in small areas widely scattered rence in the southeast corner of the quadrangle. beds. They are not of special economic impor­ mation, but since they occur high in the slopes of over the quadrangle and are only remnants which Here its maximum thickness probably exceeds 200 tance, and probably only the Brentwood can be the mountain they are not usually well exposed. have been left by erosion. The best section of the feet, approximately one-half of the thickness being followed any great distance. WINSLOW FORMATION. formation is found on the northern slope of Elk- made up by the Wedington sandstone. The black The name is derived from the post-office of Mor­ horn Mountain, where it aggregates 90 feet in color of much of the shale has suggested to some row, in Washington County, Ark., just south of The base of this formation is characterized by thickness and consists of alternating beds of shales, the possibility that it might contain coal, but none which a high hill affords a nearly complete section the occurrence of conspicuous quartz grains and sandstones, and limestones. At this place it is has ever been found in the formation. In some of the formation. The formation is of considerable small quartz pebbles in the sandstones. Because capped by higher formations. localities the shale contains gypsum, which occurs scientific interest, because it contains one of the best of this fact the formation has been referred to as The small patches in which sandstones and are­ as individual crystals or as a coating of calcareous representations of an early Pennsylvania!! inverte­ the Millstone grit. The beds of which the forma­ naceous beds are found over the area of the widely concretions. brate fauna known in America. The Brentwood tion is composed vary in lateral extent, and it does distributed Boone formation have been referred to Fossils occur rather generally in the limestone limestone member in particular is highly fossil­ not everywhere carry quartz pebbles. It is found the Batesville from their relation to the underly­ layers included in the formation. In the sandy iferous. The Pennsylvania!! age of this bed is only on the tops of the higher mountains, except ing rocks. One of these just west of Bentonville, beds, however, their distribution seems to be much indicated by the presence of the brachiopod some small patches about 6 miles northeast of Fay­ which has a maximum thickness of 25 feet, con­ more local, though, as at the north end of the genus Hustedia and by numerous gasteropods etteville, in which only the basal portion of the for­ tains flaggy layers from 3 to 6 inches thick and railroad cut at Fayetteville, they are sometimes and pelecypods closely allied to later Carbonif­ mation is represented. A fuller section is found in some impure interstratified limestones. The rocks extremely numerous, both in species and in indi­ erous species. the Winslow quadrangle, near the town of Wins- are of a greenish-gray color and have been quar­ viduals. Excepting the upper limestone bands, The contact of the base of the Morrow with the low, from which place the name is derived. ried for flagstones. which abound in fossil bryozoa and brachiopods top of the formation next beneath is probably There appears to be an unconformity between Along the bases of Callahan, Fitzgerald, and closely simulating those in the Pitkin limestone, always unconformable. The unconformity, how­ the Winslow and the underlying formation, but it Webber mountains, near the town of Springdale, the fauna of the Fayetteville consists preeminently ever, is never conspicuous, and often difficult to is not well marked. In the absence of the Kessler exposures of the Batesville sandstone have been of mollusks. see, but its probable occurrence is convincingly limestone it is difficult to determine the base of the observed resting on Boone chert and overlain by There is perha*ps no unconformity at the base of indicated by the variation in the beds at the base Winslow, but in this quadrangle it is usually a the Fayetteville shale. The sandstone is but 2|- the Fayetteville when it rests upon the Batesville of the Morrow and at the top of the underlying heavy sandstone forming a ledge. to 3 feet thick in these exposures, and as it has sandstone. This sandstone, however, is frequently formation, shown in different sections. In a few not been found in Price Mountain nor to the wanting, and in these cases the shale rests upon localities pre-Pennsylvanian erosion seems to have HISTORY OF PHYSICAL CHANGES. southeast of this series of residual mounds it is the more or less eroded surface of the Boone for­ entirely removed the Pitkin limestone. The rocks which outcrop in the quadrangle were possible that the bed thins and disappears in this mation. The occasional unconformity at the top Hale sandstone member. This, the basal portion, laid down as beds of sand, mud, and ooze on the direction. of the formation has been mentioned. In a few consists of sandstones with some shale. This por­ sea bottom, and later, under the pressure of super­ Near Fayetteville the sandstone which has been localities where the Pitkin limestone is absent the tion is not separately mapped, but its upper incumbent deposits, and through chemical action, referred to this formation is a soft, yellowish, coarse­ Morrow formation rests on the Fayetteville. It is limit is the Brentwood limestone. The strata were solidified into sandstones, shales, and lime­ grained, and often calcareous sandstone a few feet not decided whether the absence of the Pitkin in which compose the Hale sandstone are usually stones. The earliest record we have of these pro­ thick. There are no limestones interbedded with these cases is due to nondeposition, because of local soft, thick-bedded, yellowish-brown sandstone and cesses within the quadrangle is toward the close of it. It overlies the Booue formation and is over­ land conditions, or is the result of erosion subse­ flaggy layers, with more or less carbonaceous and the earlier half of Ordovician time. The condi­ lain by the Fayetteville shale. The formation quent to its deposition and prior to the laying down light-colored shales. On weathering, especially tion which prevailed during the deposition of the thins and disappears also westward from Fayette­ of the Morrow formation. The latter explanation, in bluffs, the Hale sandstone generally presents lowest beds was that of a widespread submergence. ville, being absent in the adjoining quadrangles in however, seems at present to be the more reasonable. a characteristic honeycombed appearance. The The lowest deposit was a limy ooze, which is now Indian Territory. Wedington sandstone member. Typically this soil found on this lower sandstone is often red, the Yellville limestone. Following this a great Near the post-office of Wyman it is of a nature member consists largely of heavy sandstones, from the large amount of iron present, and this bed of white " saccharoidal" sand was spread by similar to that of the sandstone near Fayetteville the bed ranging from 50 to 150 feet in thick­ feature is in some places an index to the occurrence the action of the water. This is not now present and occupies the same relative position. Its occur­ ness. But northwest of the White River fault it of the member. in any of the outcrops of Ordovician deposits rence in such widely separated localities and its grades apparently from the base upward into sandy Brentwood limestone member. This is a gray within the borders of the Fayetteville quadrangle, varying character make it a somewhat problematic shales, the arenaceous constituent growing grad­ crystalline limestone, and usually is conspicuously but some of it remains in certain quadrangles far­ formation. Being an overlapping formation it may ually less, until finally no trace of the sandstone exposed. It abounds in fossils, a common one ther east. Its removal here occurred prior to the not have been deposited at all in certain localities. remains. The sandstone is found capping Wed­ being Pentremites rusticus. The member is some­ deposition of the Devonian beds, and it doubtless If, however, the Batesville originally covered the ington Mountain, which is the type locality, times separated into two divisions by the interca­ furnished the greater part of the material that con­ whole quadrangle it must have been entirely Elkhorn Mountain, and the mountains east of lation of sandstone and shale, and where this occurs stitutes the very similar basal sandstone of the eroded over considerable areas before the deposi­ Springdale. In the area east and southeast of the thickness may aggregate 80 feet. In the more Chattanooga formation. The additional beds, if tion of the Fayetteville shale. Recent erosion has Fayetteville it forms the lower bench of the prominent mountains it forms a conspicuous ledge any, which were deposited in the Ordovician sea removed it in still other localities, and now small mountains. In some localities the top of the and has a marked influence on the topography. are not known, for during a subsequent emergence patches only are to be found. Those in which the sandstone is defined by the Pitkin limestone, It is important as indicating the base of the coal- the rocks were subjected to erosion. This is shown o by the uneven upper surface of the Yellville lime­ have been true despite the fact that the north stone. It should be taken into consideration, there is a fault which is on the same strike with stone and by the abrupt variations in thickness, shore of the Pitkin sea, as is indicated by the however, that its upper surface has been largely the one above described, and is perhaps a continu­ or the total absence in certain- localities, of the general thinning and local absence of the lime­ eroded, so that its full thickness is not represented ation of it. Sylamore sandstone. Where present this Devo­ stone in that direction and by the wider distribu­ at all places, and that its lower limit is generally In the intervening distance the faulting is not nian sandstone is the first deposit following the tion of the preceding shale formation, was located exposed in local anticlines. From the geologic conspicuous or recognizable, because of its occur­ Yellville limestone, and its stratigraphic relations nearer this quadrangle than was the corresponding map it will be seen that its highest elevation is rence in the limestone country, where the surface to the latter show clearly that it served to fill con­ shore of the Fayetteville sea. along the eastern border of the quadrangle, from is covered by chert debris. East of White River siderable hollows in the limestone, and thus paved According to the evidence of the fossils the Pitkin Springdale to Elkhorn Mountain, and that it dips the downthrow is probably as much as 200 feet on the way for the more evenly spread Devonian shale. formation is the highest of the Mississippian series. very slightly toward the west. the south side of the fault; near Rhea it is about There is no record preserved within the quadran­ Prior to the deposition of the next succeeding strata In the southeast corner of the quadrangle it lies 100 feet in the same direction. In connection gle of sedimentation in the Silurian period, nor in in this area the Pitkin was elevated above the sea at a lower elevation than in other parts, as a result with the development of this fault there is con­ the earlier parts of the Devonian period, and it level and subjected to erosion that at certain points of the faulting and displacement which has taken siderable flexing of the strata. In the area of the is probable that the Ordovician rocks during that sufficed to remove the greater part if not the whole place. The occurrence of the areas of Ordovician Fayetteville shale, shown along Anderson Branch time formed the surface of a great land area in the of the limestone. Elevations of land surfaces and rocks indicates local doming and divergent dips, and Hamestring Creek, the structure is in the nature Ozark region and were wasted away under atmos­ corresponding restrictions of water areas like those but no definite system of folds can be made out of a shallow syncline. pheric agencies. which introduced this erosion interval in northern from a study of them. The faults and folds which A branch of the White River fault occurs along Toward the close of the Devonian period the Arkansas occurred over a large part of. America at occur in the southern part of the quadrangle, how­ the ravine in sees. 21 and 22, T. 17 N., R. 29 W. sea gradually encroached upon the land, and a bed this time. In consequence, the contact between ever, indicate two structural lines; viz, N. 30° to 40° In this case the downthrow is on the north of the of mud, preceded by an uneven bed of sand, was the Mississippian and Pennsylvanian formations E., and N. 60° to 80° E. The former is the direc­ line of fracture. The fault dies out in sec. 29. deposited. These beds are now known as the Chat­ is nearly everywhere in this country appreciably tion of the Chambers Spring syncline and the Price As a result of this structure in connection with tanooga shale and the Sylamore sandstone member. unconformable. Mountain fault and syncline; the latter, of the the main White River fault, a block has been The Carboniferous period began with a compar­ The Pennsylvanian series is represented in the White River fault. dropped downward, so that the shales which are atively brief, and perhaps local, recession of the Fayetteville quadrangle by sandstones and shales Chambers Spring syncline. The axis of this coal bearing and small areas of the Winslow are sea. This is indicated by the general absence of with some thin lenses of limestones. The Morrow syncline enters the quadrangle in see. 21, T. 16 found at a much lower elevation than they other­ deposits representing the earlier stages of the Kin- formation, which is the lowest of this series, exhib­ N., R. 33 W. It passes through Cincinnati, which wise would be. (See fig. 2.) derhook group. However, before the close of its frequent alternations in the character of its sedi­ lies just beyond the western border of the quad­ In the northern part of the quadrangle there is, the Kinderhook, the land to the north was again ments, for at one stage shallow-water conditions rangle. It extends through an area of the Fayette­ locally, evidence of folding and displacement, but submerged. In consequence of this advance, and prevailed, with local land areas, which permitted ville shale and Wedington sandstone, which is the structure can not be traced very far owing to the deepening of the sea occasioned thereby, the dis­ the growth of a layer of plant material that is now preserved as a result of the structure. The fold the surface covering of chert. At certain places tance from this area to the shore was increased, and found in the form of a coal bed. The youngest is a very shallow one and does not affect the dip the Batesville sandstone is found at a lower ele­ sedimentation changed from mud to limy deposits. rocks in the quadrangle are known as the Winslow of the rocks very far on either side of the axis. It vation than the Boone limestone of the surround­ This condition prevailed for a long time, and the formation. They consist of sandstones and shales, is in evidence near Chambers Spring, where a rem­ ing area and there are occasional small fault blocks sediments form what is known as the Boone for­ the lower sandstone beds carrying some quartz peb­ nant of the Fayetteville shale occurs. It does not and unusual dips, but in such cases the exposures are mation. The beds first laid down were nearly pure bles. The close of the record of Paleozoic sedimen­ appear to extend to the northeast far.beyond this not sufficient to allow a satisfactory explanation. lime, and now constitute the St. Joe limestone mem­ tation is not preserved within the limits of this area. point. Its direction is N. 40° E. On the head of McKisic Creek there is an out­ ber. After this there was an admixture of silica, In the Boston Mountains, farther south, there is a Price Mountain fault and syncline. Just south crop of the Batesville sandstone within which the which gave rise to the cherts of the upper part of great thickness of rocks which belong to the Wins- of Price Mountain there is a fault which has a structure is synclinal, although it is not very defi­ the Boone formation. low, but they have been so eroded that within the direction of N. 40° E. The maximum displace­ nite. Two miles northwest of Pea Ridge post- After the deposition of the Boone formation Fayetteville quadrangle the lower beds only remain ment near Price Mountain is about 300 feet, the office there is another small area which exhibits a the sea retreated once more. This retreat is indi­ to form the tops of the higher mountains. downthrow being on the south side. (See fig. 2.) similar structure. At intermediate points the sand­ cated by the restriction of the next following Since the Paleozoic era no additional subaqueous The fault is not in evidence very far to the north­ stone occurs below the general elevation of the Boone deposit, the Moorefield shale, to areas south and formations have been deposited, or if so there are east. To the southwest it follows the contact of limestone. On the road just south of Rago post- east of the Fayetteville quadrangle. The sea now no evidences of them. The next stage in the the shales and sandstones with the limestone to office a small block of sandstone has been dropped retreated at this time also from a large part of history of the area, the record of which can be sec. 20, T. 17 N., R. 29 W. In this portion of down, so that it abuts against the limestone. the Mississippi Valley, the erosion of the cor­ read with certainty, is in late Tertiary time. Land the fault the displacement is evidently between 100 This is apparently the result of a dip fault near respondingly increased land being indicated nearly conditions had evidently prevailed for a long period and 200 feet, but it can not be measured accurately. the axis of the syncline. The direction of the everywhere by the absence of certain deposits and and the higher formations in the northern part of Still farther to the southwest the fault has been syncline is N. 30° E., which corresponds with the by the unconformable contact formed between the the quadrangle had been eroded and the surface observed at a number of places in connection with direction of the Chambers Spring and Price Moun^ old land surface and the first deposits resulting reduced to a nearly even lowland plain that corres­ synclinal structure. tain structural lines. from the next submergence. In this area, presum­ ponded in a considerable degree to the upper sur­ The rocks in East Mountain dip to the west ably, land conditions prevailed during the whole face of the Boone formation. On account of their slightly, and at Fayetteville, in the hill on which MINERAL RESOURCES. of the epoch, submergence and sedimentation being nearly horizontal position and the unusually resist­ the university stands, there is a low dip to the east. resumed only about the beginning of the Chester ant character of the rocks of the Boone, this plain The axis of the faulted syncline passes between The Fayetteville quadrangle does not regularly epoch the Batesville sandstone, which rests on is partially preserved at the present time and con­ these two localities. The disturbance is greatest supply any mineral products to the general market. the Boone, being of the latter age. It seems prob­ forms to the generally even horizon of the uplands. in the northern part of Fayetteville, in the hill It, however, contains resources which are of local able, however, that this sandstone marks merely The semimountainous portion of the quadrangle on which the schoolhouse stands, and along the use. They could be more largely developed, but the beginning of the submergence of this area, and was somewhat more extensive than now and stood ravine to the north of it. The displacement and inasmuch as the same materials are found com­ that it was not laid down over the whole of it. at a relatively higher elevation. deformation are shown by a careful study of the monly throughout the surrounding region the cost With the continued advance of the sea came a Subsequent elevation of the Ozark region has Brentwood limestone and the Winslow sandstone, of freight prevents extensive exploitation. These bed of black mud, which on solidifying formed transformed the lowland into an upland, and the but can not be fully expressed in the mapping. resources are, besides the soil, clay and shale for a shale known as the Fayetteville shale. During streams have cut deep valleys which in places The sandstones and shales appear with diverse dips brick, stone for building and for burning to lime, the course of the deposition of this shale slight expose the Ordovician rocks, so that at the pres- and are considerably crushed. There is some local and a thin bed of coal.

Cwt Cfv White TUver Cwt C]

FIG. 2. Northwest-southeast structure section in southeastern part of quadrangle, from Price Mountain to Round Mountain. Oy, Yellville formation; DCS, Chattanooga shale and Sylamore sandstone; Cbn, Boone formation; Cbv, Batesville sandstone; Cfv, Fayetteville shale; Cwt, Wedington sandstone; Cp, Pitkin limestone; Cmr, Morrow formation; Cwl, Winslow formation. Horizontal scale: 1 inch=% mile. Vertical scale the same as the horizontal, or 1 inch=approximately 3500 feet. movements of the earth probably occurred, caus­ ent time the oldest formations are again the scene displacement at right angles to the axis of this Soil. The upland of the larger part of the quad­ ing elevation and the production of the coarser sili­ of geologic activities. structure. An example may be seen in the rail­ rangle has a soil which is residual from the decay ceous material that now constitutes the Wedington way cut north of the depot at Fayetteville, at which of the Boone limestone, and contains an admixture DEFORMATION AND STRUCTURE. sandstone member of the Fayetteville formation. place the Pitkin limestone abuts against the Fay­ of organic matter from the decay of vegetation of Evidently an erosion interval followed the depo­ The various formations, as originally deposited, etteville shale. the woodlands and prairies which existed before sition of the Fayetteville formation, since the upper were in nearly horizontal position. The main cen­ In sec. 31, T. 16 N., R. 30 W., at Cato's shop, farms were laid out. It is a strong soil, wejl part of the Fayetteville is locally absent in this and ters of the disturbances which influenced the Ozark the Pitkin limestone is seen to have a decided syn­ adapted to the growing of grains and general farm adjoining quadrangles. This emergence and con­ region have been at considerable distances from the clinal structure. South westward along the old wire products. The subsoil is usually a red clay which sequent erosion probably resulted from compara­ area here described, and the oscillations of level road the rocks dip to the southeast conspicuously. is sticky when wet, and where the drainage is tively local warpings and oscillations, which first resulted in but slight inclination of the strata The ravine in that vicinity lies in the axis of the imperfect the ground is apt to be cold and unpro*- contracted and elevated at least the borders of the within the Fayetteville quadrangle. Moreover, syncline. ductive; but this can be easily modified by ditching basins, and later caused them to sink again beneath the successive elevations and depressions have White River fault. There is a fault entering and cultivation. In places there is an admixture the waters of the sea. As the sediments that were tended to neutralize one another. The final result the east side of the quadrangle in sec. 18, T. 17 of sand from the small remnants of the Batesville accumulated during this later submergence con­ is that the rocks have a gently undulating struc­ N., R. 28 W. It trends westward with some devi­ formation. Along the valleys of the numerous sisted chiefly of the calcareous matter now forming ture, which in places is accentuated into low domes ation and crosses White River in sec. 22. In sec. small streams which dissect the upland the surface the greater part of the Pitkin limestone, it is pre­ and folds, and where the tension or stress was too 20, T. 17 K, R. 29 W., where the White River is largely covered by chert, the soil having been sumed that the oscillations occasioned sufficient great there are fractures and faults accompanied by fault crosses the Price Mountain fault, the dips are washed away. The transportation of the soil con­ changes in the relief and drainage of the adjacent vertical displacement. diverse. Farther westward, on Hamestring Creek, tributes to the enrichment of the valleys, and where land to cause the comparatively quiet- and clear- The formation which is of widest extent and its trend is along the northern limits of the Fay­ they are level enough to be cultivated there are water conditions that must have prevailed during affords the best datum for studying the broader etteville shale area. In the vicinity of Rhea post- good farms. The valleys of White River and the the deposition of limestone. And this seems to structure of the quadrangle is the Boone lime- office, in the east slope of Wedington Mountain, Illinois, and even of the smaller streams, contain Fayetteville. 6 fields which are constantly enriched and renewed and tiling, but the cost of operating is too great obtained from the more massive upper beds of the erable depth they penetrate the magnesian lime­ by the overwash from the hills. Where the Chat­ considering the present local demand and the con­ Boone formation, which are here free from chert. stones of the Ordovician rocks. Oil or gas has, tanooga and Fayetteville shales outcrop the soil dition of the general market. Another kiln is in operation at a point about 1^ however, not been found. In passing through the would be poor and thin if it were not for the addi­ Building stone. The St. Joe limestone is an miles south of Sulphur Springs. This is conven­ Chattanooga shale, which is usually about 50 feet tion of material which has been transported from even-bedded stone which is well adapted for iently situated and the product of the kiln is thick, the cuttings of the drill commonly give off neighboring hills. walls and heavy masonry. Its occurrence at Sul­ said to be of excellent quality. The stone used is a fetid odor, and this has been an encouragement In the area of the sandstones of the Morrow for­ phur Springs is favorable for quarrying, and it is limestone of Kinderhook age that "here forms the to the prospector. The Chattanooga shale is, how­ mation the soil is usually a light, sandy loam. there conveniently near the railroad, so that it can basal part of the St. Joe member of the Boone ever, not known to be oil bearing, and the rocks' The presence of the limestone lentils where they be shipped. It has been used to a limited extent formation. above and below can not be expected to contain form heavy ledges mo dines this character consid­ and quarries are already open. This limestone has Coal. The coal which is mined in sees. 20 and either oil or gas. erably, since the washing of the surface water dis­ also been quarried on Little Sugar Creek, where it 21, T. 17 N:, R. 29 W., in the vicinity of Lem- The Boone limestone, which is so widely distrib­ tributes over a considerable belt the soil resulting forms a conspicuous ledge. At many places there mons bank, is a hard, lustrous, bituminous coal. uted over the quadrangle, is the formation which from the decay of these limestones. In decompos­ are quarries in other beds of the Boone limestone The bed is only 14 inches thick, and its thinness contains the lead and zinc deposits of southwestern ing, the shales, which are interstratified, receive to supply the local demand. Sandstone is also prevents its being worked on any large scale, but Missouri, and the finding of small quantities of such an admixture of sand from the higher slopes commonly employed in building, since it is soft considerable coal is supplied to the local trade. lead and zinc has induced many people to prospect that they do not form a distinct class of soils. The and therefore easily dressed and quarried. There Mines are also ojperated near the summit of Rob­ with the hope of finding larger bodies of ore. areas of alluvial soil are the richest farming lands, is an abundance of it in tile southern part of the inson Mountain,' where the same formation occurs, Thus far ho one has met with success. Usually but they are of limited extent, since none of the quadrangle, and in some of the smaller areas of and the coal there is of similar character and thick­ the prospects have not been located with respect streams have extensive flood plains. This class of the Batesville formation in the northern part it has ness. There is little prospect that beds of com­ to fault lines or fissures. Judging from results soil is found principally along White and Illinois been quarried for building blocks and for flag­ mercial importance will be developed within the obtained in neighboring mineralized regions, it rivers. stones because of the facility with which it can be quadrangle. may be worth while to prospect some of the local­ Clay and shale. Brickkilns have been operated worked. Prospects, drill holes, and shafts. Considerable ities in the quadrangle in which the rocks have to supply the local trade, but their production has Lime. Small limekilns have been operated at money has been spent in drilling wells, with the been disturbed. The conditions which brought never been large,O ' owingO to the facilityv with which many places wherever there has been a demand hope of finding oil or gas, and a number of shafts about the deposit of lead and zinc in southwest­ building stone can be procured. Thus far only the for the product. Half a mile south of Johnson have been sunk in prospecting for lead and zinc. ern Missouri do not, however, seem to have pre­ surface soil and clay have been used in the kilns. there is a kiln which is situated on the railway at The records of the drill holes conform with the vailed in this quadrangle. In the southern part of the quadrangle shales are a point that is convenient for quarrying and ship­ general section of the rocks as exposed within the available which could be utilized in making brick ping. The stone which is used at this place is quadrangle, and where the holes reach a consid­ February, 1905.

GENERALIZED SECTION FOR THE FAYETTEVILLE QUADRANGLE. SCALE: 1 INCH=200 FEET.

SYSTEM. SERIES. FORMATION NAME. SYMBOL. COLUMNAR THICKNESS SECTION. IN FEET. CHARACTER OF ROCKS. CHARACTER OF TOPOGRAPHY AND SOILS.

Winslow formation. Cwl 100 + Brown sandstone and variegated shale ; fine quartz pebbles near the Mountain tops. base in certain localities. Stony and sandy soil. PENNSYLVANIAN '. '-.-. ' : '-.'. '. : .''. .':

(Kessler limestone lentil.) (Ck) Gray and yellowish shale, and carbonaceous shale, with thin coal bed and zone of thin lenticular limestones. Morrow formation. Cmr 200± Mountain slopes and irregular surfaces. Soil sandy, with small amount of clay. (Brentwood limestone lentil.) (Cbr)

^r^^: ;.;;; ..vv.^v£vS Thin beds of limestone and shale; underlain by sandy shale. UNCONFORMITY Pitkin limestone. Cp / T .-. - .!.'. T ' ' v 0-15 Gray fossiliferous limestone of variable texture. Forms a ledge and contributes lime to soils lower on slopes. ( Wedington sandstone member. ) (Cwt) Tops of low mountains or hills and on mountain benches. CARBONIFEROUS Heavy brown sandstone with thin yellow shale locally at the top. Sandy soil. Fayetteville formation. Cfv 20-350 Black, fissile, carbonaceous shale containing calcareous concretions, Exposed near the bases of slopes. with thin lenses and beds of dark limestone near the base. Soil poor except where covered with overwash.

, 1111,11) , | -i-..- .£.._. ._..; . " ."-=-. ' Batesville sandstone. Cbv 0-90 Yellowish and gray thin-bedded sandstone, locally shaly and very At bases of slopes and on small flat areas. ' Mf^f^ss^^^m calcareous. Soil sandy. MISSISSIPPIAN | c=> | es* |. t 1 ' ** 1 .1 * » ^'^H T^ 1 0 1 0 <=»)«=><= 1 <=>

o <=> | c=> => | ca | ) ^>\<^\ «|.ce, Boone formation. Cbn = 1 l=>i 1=>I ' 3254- Ligl^t-gray siliceous limestone, cherty limestone, and beds of chert. Generally level surface, broken by stream valleys. cs 1 c= 1 G> |oo|oc> Good limestone soil, but often stony.

c* | <=> «» I «=» |o cs |o ea'j ) 0 - «=> | «= | es | | <=> 1 !<=> 1 1 ,0 | \CZ=>_\ <=> )c= o| |=»«=|o»j => « (St. Joe limestone member.) (Csj) 1 1 I 1 (20-30) Light-gray, even-bedded, noncherty limestone. In ledge at bases of valley slopes. No soil retained. -1 1_____ 1 =aiaesss=£=31 1 Black, carbonaceous, fissile shale, with joint structure. In valley slopes. Poor soil. > DC UJ Chattanooga formation. 20-145 White to light-brown friable sandstone in massive beds, locally con­ Q (Sylamore sandstone member.) (Ds) / (0-75) glomeratic, with chert, limestone, and phosphatic pebbles. In valley slopes and floors. Sandy soil. UNCONFORMITY i i i 2;£ ORDOVICIAN 0 | <=> | CO I => |0.. I Yellville formation. Oy 100+ Light- to dark-gray magnesian limestone and dolomite, even bedded i <=> i ^~Y i r«=> and locally siliceous or cherty. - In stream valleys, usually as bluffs. 0 I «3 1 e= 1 1 «= 1