cincinnati society of natural...

18 Cincinnati Society of Natural History.

THE CINCINNATIAN SERIES AND ITS BRACHIOPODSIN THE VICINITY OF CINCINNATI

By E. Lucy Braun

TABLE OF CONTENTS

PART I

I. IntroductionII. Stratigraphy

A. Lithology of the Cincinnatian Series1.2.3.

4.

Utica—FultonEdenFairview and McMillan (Maysville)

Mt. HopeFairmountBelle vueCorryvilleMt. Auburn

RichmondArnheimWaynesvilleLibertySaludaWhitewaterElkhorn

B. Structural features of the Cincinnatian1.

2.

OriginalWave-marksMud-ballsSun-cracksWorm borings

SecondaryThe Cincinnati anticlineLocal folds and faultsJoint cracks

The Cincinnatian Series and its Brachiopods. 19

III. Geologic and Physiographic HistoryA. Paleozoic Era

1. Cincinnatian epochEden stageMaysville stageRichmond stage

2. Silurian periodB. Post-Paleozoic Time

IV. History of the NomenclatureCorrelation Table

V, Bibliography

PART II

I. General Discussions of the BrachiopodsA. Value as Horizon MarkersB. Progressive EvolutionC. Table of Range and Relative Abundance of Thirty

SpeciesD. Complete List of Brachiopods reported from the

Cincinnatian Series of the Vicinity of Cincinnati,Ohio

II. Description of Species

PARTII. Introduction

The region about Cincinnati is underlain by a series ofalternating shales and limestones. This series, to whichthe name Cincinnatian has been given, is of Upper Ordo-vician age. The city of Cincinnati lies to the north of thecenter of a low dome. To the east, north, and west of it,are younger rocks; to the south of it, are older rocks. Thequarries about Cincinnati, the steep valley-sides of theOhio River, and especially the beds of the smaller valleys


present numerous exposures of all but the lowest beds ofthe series. Fossils are exceedingly abundant at manyhorizons, and they are as a rule very well preserved. Thesoils of this region are to a large extent derived from thedecay of the bed-rocks, the limestones yielding a muchmore fertile soil than the shales. Glacial and loess depositscover a considerable portion of the area, modifying thecharacter of the soil and often concealing the bed-rock.

The present paper is a study of the rocks of the Cincin-natian series in the vicinity of Cincinnati, and of the brachi-opods of this series—a class of fossils more abundant andbetter represented than any other, except the bryozoans.The discussion of the rocks is based on the literature of theCincinnatian series and on field observations made by thewriter through a period of several years. In the work onthe brachiopods, the literature and all available specimensin the Museum of the University of Cincinnati were studied.The bibliography of each species is as nearly complete aspossible. In the treatment of the different species, theoriginal description (if available) is given except where somelater one was considered better. This is followed by adiscussion of the distinctive characters and notes on theoccurrence and abundance at Cincinnati.

The paper was prepared in 1911 and 1912 in partialfulfillment of the degree of Master of Arts in the Departmentof Geology of the University of Cincinnati. It is a pleasureto acknowledge to Professor J. Ernest Carman my apprecia-tion of his many helpful suggestions during the progressof the work.

II. Stratigraphy

A. Lithology of the Cincinnatian Series

The rocks of the Cincinnatian series are made up of thinbeds of shale and limestone. The shale beds vary in thick-ness from a few inches to several feet; the limestone stratafrom a fraction of an inch to eight or twelve inches. The


proportions vary in different formations, but the generallithological characters are quite uniform throughout theseries. The shales are blue and calcareous, thin-bedded,and poorly consolidated. In place, they are firm and com-pact, but soon crumble on exposure to weathering. Al-though in general, the shale contains a rather poor fauna,specimens of some of our rarer fossils which are seldomfound in limestone strata, have been found beautifully pre-served in the shale.

The Cincinnatian series is divided on lithological andfaunal grounds into five formations, each of which is againsubdivided, as shown in the following table. The classifica-tion used here follows Bassler for the Eden, Fairview, andMcMillan formations, and Cumings for the Richmond.

Richmond* . . . . •

McMillan1 . . . . <

Fairview^

Eden+

. Utica

ElkhornWhitewaterSaludaLibertyWaynesvilleArnheim j Oregonia

[ SunsetMt. AuburnCorryvilleBelle vueFairmountMt. HopeMcMickenSouthgateEconomyFulton1

*Cumings: Ind. Dept. Geol. Nat. Res., 32nd Ann. Rep., 1907, p. 621.fBassler: U. S. Nat. Mus., Bull. 92, 1915, vol. 2, pi. 2.JFor the use of this term see Bassler: Proc. U. S. Nat. Mus. xxx, No. 1442, 1906, pp. 8, 9;

Foerste: Science, N. S., vol. 22, 1905, pp. 150, 151; Ulrich: Bull. G. S. A., vol. 22.1911, pp. 296, 297.

Cincinnatian. .


1. Utica.—The name Eden was proposed by Orton in1873 for a succession of alternating shale and limestonelayers comprising about 250 feet of strata at the base of theCincinnatian series. In 1897, Winchell and Ulrich^ re-placed this term by Utica, believing this formation to bethe equivalent of the New York Utica. The five feet ofstrata at the base of the Eden, as defined by Otron, containTriarthrus becki, which is characteristic of the New YorkUtica. The major part of what Winchell and Ulrich calledUtica does not contain fossils characteristic of the trueUtica, and is no longer correlated with the Utica, but is nowknown as Eden. The lower five feet of strata are referredby Bassler* to the Utica formation, and given the nameFulton, from the type locality—Fulton, in the East End ofCincinnati. He describes the rocks of the Fulton as "darkgray or drab-colored shales which contrast very distinctlywith the overlying Eden shales. "̂ This formation, whichoutcrops at 45 to 50 feet above low water of the Ohio atCincinnati (432 ft. A. T.), is the oldest formation of theCincinnatian. It is underlain by Trenton," the oldest rockoutcropping in the Cincinnati region.

2. Eden.—The Eden at Cincinnati is approximately 230feet thick, and is made up of a series of thin-bedded, cal-careous shales, interrupted at intervals of several feet bylimestone strata varying in thickness from a fraction of aninch to six or eight inches. The formation is characterizedby certain fossils which are restricted to it, or which occurabundantly in it. Among these are Climacograptus typicalis,Heterocrinus heterodaciylus, Callopora onealli sigillarioides,Dalmanella multisecta, and Plectambonites sericeus. Besides

*Orton: Geol. Surv. Ohio, vol. I, pt. I, 1873, p. 372.tWinchell and Ulrich: Geol. Nat. Hist. Surv. Minn., vol. 3, pt. 2, 1897.JBassler: Proc. U. S. Nat. Mus., vol. 30, No. 1442, 1906, p. 9.§Bassler: loc. cit., p. 8.||The strata outcropping along the Ohio River bank at West Covington, Ft. Thomas, and

Pt. Pleasant, which have been usually correlated with the Trenton of New York, havebeen shown by J. M. Nickles (Ky. Geol. Surv., bull. 5, 1905, p. 18) to be continuouswith the Winchester of central Kentucky. He considers them to be of Cincinnatian,rather than Mohawkian age. Bassler (U. S. Nat. Mus. Bull. 92, 1915, pi. 2) however,refers them to the Mohawkian.


these fossils, which may be considered as characteristic ofthe Eden as a whole, there are certain other fossils, whichare characteristic of one or more of its members.

The members of the Eden are: lower or Economy (50 ft.)>middle or Southgate (120 ft.), and upper or McMicken(60 ft.). These members are characterized by certainBryozoa: the Economy by Aspidopora newberryi; theSouthgate by Batostoma jamesi; the McMicken by Deka-yella ulrichi. Lithological distinctions between these divi-sions are not clearly marked. The Eden is a formation ofmuch greater uniformity than any of the succeeding forma-tions.

Besides the typical bryozoan of each member, otherfossils which are easily recognized, but not as uniformlypresent, may be mentioned. In the Economy may befound: Dalmanella emacerata, Leptaena rhomboidalis gibbosa,Pholidops cincinnatiensis, Plectambonttes plicatellus, andTrinucleus concentricus. The Southgate contains a moremeager fauna than the Economy and is not sharply differ-entiated from the beds above or below it. Dalmanellaemacerata, Pholidops cincinnatiensis, and Trinucleus con-centricus are here also, and Rafinesquina squamula, whichdoes not occur again below the Fairmount (see table,Part II), is occasionally present. The McMicken containsa rich bryozoan fauna, and but few representatives of theother classes.

Exposures of the Eden around Cincinnati are not com-mon. On Elberon Ave. and on Straight St. are good ex-posures of the higher beds; the lower strata are exposedonly in a few stream beds near the river level.

About 210 to 220 feet above the base of the Eden is aprominent horizon marked by two massive limestone strataseparated by about eight or ten feet of shale. The lowerlimestone stratum is 5 to 8 inches thick, and contains few

*Nickles: Jour. Cin. Soc. Nat. Hist., vol. 20, 1902, p. 69.


fossils. The upper is 8 to 16 inches thick, and its uppersurface is usually well covered with Dalmanella multisecta.A few inches of the shale just beneath the upper stratumis often almost entirely composed of the shells of this brachio-pod. In places, the upper three feet or more of the shalebed is largely limestone, in which case this becomes a prom-inent limestone horizon. The most marked spring horizonof the region is just beneath the lower limestone stratum.Above this stratum, the rocks are porous, allowing thedownward passage of ground-water; below, they are quiteimpervious, necessitating a lateral movement of ground-water. This results in seepage at many places along theoutcrop of the upper shale layers, which often is sufficientlyconcentrated to form permanent springs. The upper lime-stone stratum, which is the highest horizon containingDalmanella multisecta, is regarded as the top of the Eden.

3. Fairview and McMillan (Maysville).—Until recently,the rocks of the Fairview and McMillan formations weregrouped in one formation, the Maysville, which was sub-divided into five members. In both the Fairview and Mc-Millan, alternation of shale and limestone is the most promi-nent characteristic, more prominent even than in the Eden.The limestone totals about thirty per cent of the thick-ness; and strata six inches thick are common. The shaleof the Fairview and McMillan is often of a lighter bluecolor than that of the Eden, and much of it is of a coarsertexture, and less compact; the limestone, although alwaysimpure, is more compact and crystalline here than at anyhorizon of the Eden.

Fossils are much more abundant in these formations thanin the Eden. The surfaces of many of the layers of crys-talline limestone are almost completely covered with fossils.Throughout these formations, brachiopods and bryozoansare by far the more numerous fossils, while all the otherphyla of invertebrates with the possible exception of theProtozoa, are represented. A number of species are per-


sistent throughout both the Fairview and McMillan; amongthem are Lepidodiscus cincinnatiensis, Hebertella sinuata,and Platystrophia laticosta. Certain genera are character-istic of the two formations as a whole. Platystrophia,which is rare in the Eden, is very abundant and charac-teristic; Plectorthis is, with the exception of a single species,P. plicatella, restricted at Cincinnati to these formations;and Zygospira and Refinesquina, although found quitefrequently in the Eden and Richmond, are most abundantin the Fairview and McMillan. Cyclonema, Lophospiraand Byssonchia are also common.

The Fairview is divided into two, and the McMillaninto three members, based mainly on faunal content. Themembers differ considerably in lithological character.

Mt. Hope.—The Mt. Hope, named from its typicalexposure on Mt. Hope Road near the foot of Price Hill,where the entire member is beautifully exposed, containsabout seventy-five per cent of shale. It resembles theEden, but the proportion of limestone is considerablygreater. As exposed on Straight St., west of the University,the Mt. Hope has a thickness of about 50 feet. The typefossil is Amplexopora septosa^ A single stratum containingStrophomena planoconvexa marks the contact between "theMt. Hope and the next higher member, the Fairmount.*On most exposures, the contact is difficult to locate, as thisfossil is not always present.

Fairmount.—In the Fairmount limestone forms aboutthirty-five per cent of the total thickness. About half ofthis is suitable for building stone, and it is the limestone ofthis division which is most commonly quarried in the vicinityof Cincinnati. The Fairmount is the highest divisionexposed on many of the lower hills about Cincinnati, as atFairmount, Hyde Park, and Avondale. It is also the

*Nickles states, Ky. Geol. Surv. Bull. 5, 1905, p. 32: "No Platystrophia has been notedin the Eden," but a few have been found in the Eden at Cincinnati.

fNickles: Jour. Cin. Soc. Nat. Hist., vol. 20, 1902, p. 76.JNickles: loc. cit., p. 77.


highest bed-rock on the hills back of Newport and Cov-ington. On Straight St. where a good section is exposed,this division is about 60 feet thick. While fossils are lessabundant in this member than either above or below, thenumber of species represented is far greater, and the speci-mens are better preserved. The bryozoan Dekayia aspera*is the type fossil of this member, while Glyptocrinus deca-dactylus, Callopora dallei, Constellaria constellata, Platy-strophia crassa, Modiolopsis modiolaris, Cyclonema mediate,and Lophospira ampla are characteristic.

Bellevue.—The lowest member of the McMillan forma-tion is the Bellevue, a division lithologically and faunallydifferent from the underlying and overlying strata. It hasa thickness of only 20 feet. The lower 15 feet is composedalmost wholly of limestone which is made up largely of afrondlike bryozoan, Monticulipora molesta. This horizonis more resistant than the upper part of the Fairmount onwhich it rests, so that it stands out prominently on the facesof many of the bluffs around Cincinnati. The upper 5 feetof the Bellevue is composed of thin-bedded shales and shalylimestones. These shaly limestone beds are made upalmost entirely of single valves of Rafinesquina alternatafracta, with clay partings between the shells. On weather-ing, the clay partings break down leaving a jumbled massof poorly preserved shells. This horizon, known as the"fracta zone," is one of the most easily recognized horizonsof the entire Maysville. It is less resistant than the lowerpart of the Bellevue and usually forms a steep slope at thetop of the projecting cliff. The type fossil of the Bellevue,Monticulipora molesta, is present, although not as abundantas in the lower fifteen feet. Platystrophia laticostais commonthroughout the "fracta zone," and Hebertella sinuata,Rafinesquina alternata, and a number of molluscs are abun-dant in the lower part of this horizon.

Corryville.—The Corryville member of the McMillan,which is 60 feet thick, includes a series of thin limestones

*Nickles: loc. cit., p. 77.


and yellowish shales. Of itself, it is not a distinctivehorizon. It is only because of its marked contrast withunderlying and overlying members of the McMillan forma-tion, that the Corryville is easily recognized. In the field,it is usually identified by means of its position with relationto other members, or by means of the characteristic bryozoanof the member, Chiloporella nicholsoni. The Corryvillebeds are exposed on the higher hills around Cincinnati.Fossils are abundant: Platystrophia lynx is quite large;pelecypods, Anomalodonta and Byssonchia, are plentiful;and the bryozoan, Callopora ramosa, is very abundant andwell preserved.

Mt. Auburn.—The Mt. Auburn is composed of a nodularcalcareous shale or shaly limestone, 20 feet thick. Thetype fossil of this member is the large gerontic form ofPlatystrophia lynx. This is especially abundant throughoutthe lower 5 to 12 feet, and may be found throughout theentire member. Other fossils' are not abundant. Thismember is represented at Cincinnati only by its basalpart, which is the highest bed-rock on several of the highesthilltops, as at Fairview Heights (Clifton Ave. and McMillanSt.), Price Hill, and West wood. The Mt. Auburn is thehighest division of the McMillan, since it is now known thatthe overlying Arnheim (Warren), which was formerly placedin the Maysville should, because of its faunal relations, beclassed as basal Richmond.

4. Richmond?—-With the exception of the lower strataof the Arnheim, the Richmond formation is not foundnearer than about thirty miles to the east, north, and westof Cincinnati. To the south, it is even farther removed,because the center of the Cincinnati anticline is to thesouth of Cincinnati, in Jessamine Co., Ky. At certainhorizons, the Richmond formation resembles the Eden more

*Nickles: Jour Cin. Soc. Nat. Hist., vol. 20, 1902, p. 83.tThe discussion of the Richmond formation is taken largely from Cumings' paper, "The

Stratigraphy and Paleontology of the Cincinnati Series in Indiana," Ind. Dept. Geol.Nat. Res., 32nd Ann. Rep., 1907; and Nickles, "Richmond Group in Ohio and Indiana,"Amer. Geol. xxxii, 1903, pp. 202-214.


than it does the Fairview or McMillan, for it is in generala shale formation. In one division, the Liberty, the lime-stone is however more massive and more evenly bedded thanthe limestone of the Fairview and McMillan formations atCincinnati. Faunally the Richmond is more closely relatedto the Eden, representing a return to conditions existingduring the Eden stage. The presence of corals in thisformation is a distinctive feature. Columnaria, Tetradium,Streptelasma and Protarea, are common. The Richmondformation is divided into six members.

Arnheim.—The Arnheim is 80 feet thick and has beendivided by Foerste into a lower unfossiliferous division, theSunset, and an upper richly fossiliferous division, theOregonia. The basal part is exposed in a cut on theC. & O. Ry. about one mile south-west of Cheviot. This isthe nearest exposure to Cincinnati. Homotrypa bassleri isgiven by Nickles, (loc. cit.) as the type fossil of the division.

Dinorthis retrorsa, which has a very restricted verticalrange occurs 35 feet below the top. Leptaena rhomboidalis,(Richmond form), Rhynchotrema dentata, Streptelasma, andColumnaria, indicate the advent of a Richmond fauna, andunite this division more closely with the overlying thanwith the underlying strata.

Waynesville.—Lithologically the Waynesville, (the lowerRichmond of Nickles), is largely clay or clay shale of anintense blue color, with a few thin limestone layers, 2 to 5inches thick. It is characterized by the presence of Dal-manella meeki in great abundance throughout the zone.Calymene callicephala is abundant, and Leptaena rhom-boidalis, which is present near the top of the division, ex-tends upward into the Liberty.

Liberty.—The Liberty is composed largely of limestonebeds, which sometimes reach a thickness of 8 to 12 inchesbut average about three inches. The limestone, although

*Foerste: Ohio Naturalist, vol. 12, No. 1, Jan. 1912.


forming the predominating rock of the division, is inter-bedded with thin layers of shale. The base of the Libertyis marked by the first appearance of Hebertella insculpta.Strophonema planumbona* from which the Liberty is calledthe Strophonema zone, Rhynchotrema capax, Plectam-bonites sericeus, Bythopora meeki and Rhombotrypa quadrataare present in large numbers. The upper layers containfewer fossils, and in places become argillaceous and are-naceous.

Saluda.—The Saluda division is even more markedlyargillaceous or arenaceous than the upper layers of theLiberty. The typical exposure of this division is at Madison,Indiana, where it is chiefly a sandy limestone, or calcareoussandstone. Northward, it becomes more calcareous, andcoarse sediments are lacking. At Richmond, Indiana, it isrepresented by only a few feet of massive limestone. Onthe east side of the Cincinnati anticline, the Saluda ischiefly a shale horizon. In the southern area of its outcropin Indiana, ripple marks and sun cracks are common in themore shaly layers. Reef building corals, Tetradium minusand Columnaria alveolata, are very abundant. Two coralreefs are present, separated from each other by several feetof argillaceous rock. In the southern portion of the areaboth are composed of Columnaria. If these are tracednorthward, the upper is seen to be replaced by Tetradium.The Tetradium reef is much more persistent than the Co-lumnaria reef, but is absent at Richmond, Ind. Both coralsbecome much less abundant in the northern part of the area.At Madison, Ind., the Saluda is separated from the Silurianby 20 feet of mottled limestone, which represents only thelower portion of the Whitewater. Cumings^ interprets theSaluda as a shore deposit related to the Whitewater andElkhorn, which overlie the thin calcareous representative ofthe Saluda in the more northern sections, as at Liberty andRichmond, Indiana. Many authors consider the White-

*S. planumbona (Hall). See Nickles: Am. Geol. xxxii, 1903, pp. 214-217.tCumings: Ind. Dept. Geol. Nat. Res., 32nd Ann. Rep., 1907, p. 673.


water to be the immediate successor of the Liberty, nothaving recognized the thin, more northern representativeof the Saluda. The Saluda contains a very poor fauna,except towards the top, where certain brachiopods andbryozoans which are common in the Whitewater, begin toappear.

Whitewater.—The Whitewater is composed of nodularand concretionary shales and impure limestones, often of abrownish or yellowish color. It contains a much richerfauna than the Saluda. The predominate fossils arebryozoans, which are very abundant. Rhynchotrema capaxwhich is common in the lower part of the member is replacedby Rhynchotrema dentatum near the top. Platystrophiaacutilirata and Hebertella occidentalis are characteristicfossils.

Elkhorn.—The upper 50 feet of the Richmond containa fauna very different from that of the preceding Whitewater,and are designated by Cumings as the Elkhorn division ofthe Richmond.* The lower 15 feet of this member is shale,containing few fossils. The fauna of the Elkhorn is madeup of recurring Fairview and McMillan types. Hebertellasinuata, Platystrophia laticosta, and other species withtheir closest relatives in the Maysville. The division ischaracterized by a form of Platystrophia lynx known asP. lynx moritura.

B. Structural Features of the Cincinnatian

The structural features of the Cincinnatian are of twokinds: original features, those which show conditionsexisting during the epoch: and secondary features, thosewhich indicate subsequent events.

1. Original.—Under the first class of structural featuresmay be considered wave-marks or "giant-ripples," mud-balls, sun-cracks or mud-cracks, and worm borings.

*Cumings: Ind. Dept. Geol. Nat. Res., 32nd Ann. Rep., 1907, p. 678.


Wave-marks.—Many limestone layers of the Eden andFairview formations have undulating upper surfaces andplane lower surfaces. Such undulations are wave-marks orthe so-called "giant-ripples." The crests and troughs ofthe wave-marks are in general approximately parallel. Thedistance from crest to crest varies from two to four feet.The thicknesses of the wave-marked strata vary from oneto three inches in the trough, to three to six inches at thecrest. The material of which these wave-marked limestonesare composed is, as far as has been observed, always frag-mental. The wave-marked strata are usually overlain byshale, which is sometimes laminated, but more often homo-geneous. Where laminated, the laminae usually conformto the wave surface of the limestone stratum, the wavesgradually dying out before the next bedding plane is reached.

The direction of the wave-marks is not uniform. Insome cases waves have been observed to trend at almostright angles to those of other strata but a few inches aboveor below. Of fifteen wave-marked strata observed, tenhave the crests and troughs extending in directions includedin the northeast-southwest quarter of the compass, and fivehave the crests and troughs extending in a general north-west-southeast direction. That is, in general there seemsto be a division into two groups, (1) those with NE-SWtrend, and (2) those with NW-SE trend. One slope of thewave-marks is steeper than the other. Five examples ofthe first group (NE-SW) were observed for position ofsteeper slope, and one of the second group (NW-SE). Inthe first group the steeper side was toward the southeast;in the second, to the northeast. This indicates that thewaves moved in a southeasterly direction when formingthose wave-marks having a NE-SW trend, and in a north-easterly direction when forming those with NW-SE trend.The southeasterly movement appears to have been the moregeneral.

The following table records observed data for sixteenwave-marked strata.


Altitudeof

stratum

450'530'530'530'540'565'565'661'665'

715'730'731'760'760'

Horizon

TrentonEdenEdenEdenEdenEdenEdenEdenEden

FairviewFairviewFairviewFairviewFairviewFairviewFairview

Directionof

wave-marks

N7O°W-S7O°EN-S

N7O°W-S7O°ENW-SE

N-SNW-SE

N27°E-S27°WN80°E-S80°WN55°E-S55°WN80°E-S80°WN12°E-S12°WN45°E-S45°WN50°W-S50°EN45°E-S45°WN2O°E-S2O°W

Distance,crest to

crest

4'3 '

2' 6"2'2'

2' 8"2 ' 6 "2-3'4'3'

\y%-2>2-3'

2' 3"-2' 6"2' 9"1' 8"

Height ofcrest above

trough

4-64'2'1'2'3'

2-2..3'

1.51.5

a

-it

i

2.5"

2.5"

Steeperside

SES

SE

SENESE

These waved-strata indicate that the water was not toodeep for the sediments to be moved by the more powerfulwaves, and the fragmental nature of the material of thestrata shows that it had been much worked over before itwas finally left with a waved surface, to be covered with adeposit of mud and thus preserved. None of these wave-marked strata have as yet been shown to be continuous overany considerable area, but they have been observed in allparts of the area, and at various horizons in the Eden andFairview formations. They may have been formed eitherin shallow water near a shore line, or in shoal water whichwas independent of a shore line. Many of the wave-markstrend approximately in the same direction (NE-SW),indicating the possible existence of a land mass not fardistant. There are, however, a few prominent exceptionsto these in strata but a few inches above or below, whosedirections could not have been controlled by the sameshore line. It therefore seems more probable to the writerthat they were formed in shoal water, and that their directionwas controlled by the wind.


Mud-balls.—In some limestone layers there are roundedmasses of shaly material, varying in size from one to threeinches in diameter. The material is very different from thatof the containing stratum, being best shown when in lime-stone made up of comminuted shells. Upon weatheringthese masses are in some cases released from the containinglimestone and may be found free on the surface. Thesemasses are interpreted as fossil mud-balls. They wereprobably formed from irregular masses of mud broken offby waves from mud layers nearby or just beneath the newlyforming sediments. After being worn and rounded by thewaves the mud-balls were dropped and became imbeddedin the finer sediment being deposited.

Sun-cracks.—Sun-cracks are not known to exist in theEden or Maysville formations, but are quite prominent insome of the shale layers of the Saluda member of the Rich-mond. They indicate extremely shallow water conditions,with short emergences, allowing the mud to dry partiallyand crack, before being covered with another layer of sedi-ment.

Worm borings.—Many of the more shaly strata arecuriously marked with what are thought to be worm borings.These worm borings are of two types:—(1) those extendingalong the bedding planes, and (2) those passing into andthrough the beds. The first type probably represents thepath of worms crawling along the sea-bottom; the second,of worms burrowing into the mud.

2. Secondary.—Under this class of structural featuresare those indicating subsequent events. They include theCincinnati anticline, local folds and faults, and joint cracks.

The Cincinnati anticline.—The strata of the Cincin-natian series at Cincinnati appear to be horizontal. Theyare, however, part of a low broad anticline extending fromNashville, Tenn., northward through Kentucky, to Cin-cinnati. Near Cincinnati the anticline divides into twobranches, the one extending northwestward toward Chicago,the other northward through western Ohio. This anticline


is divisible into two domes—the Nashville dome of Tennesseeand the Jessamine dome, culminating in Jessamine Co., Ky.The whole uplift is known as the Cincinnati anticline.

Local folds and faults.—The rocks of the Eden andprobably of the Maysville are locally distorted by lowanticlines, which are only a few feet across. Thrust faultsare in many cases associated with these folds, the faultplane running in the direction of the axis of the anticline.No faults are known to exist in this region except in connec-tion with anticlines. These faults have a throw of severalinches and a hade of 25° to 35°. There appears to be noaccordance of direction of the axes of these folds and faults.

Thirteen small folds and faults have been noted by thewriter within the area of the Cincinnati quadrangle. Ofthese eight are at an altitude of from 620 to 640 feet A. T.or from 30 to 50 feet below the Eden-Fairview contact,that is, are found in the McMicken member of the Eden.Five of the observed folds affect the shale bed and limestonestrata just beneath the Eden-Fairview contact.

In all the folds and faults of the lower series (those of theMcMicken), but a small section is exposed, so that it is notknown to what extent the distortion affects the stratavertically. All are in stream beds, and while cross sectionsof the folds or combined folds and faults are usually exposedin stream banks, it appears that the axes trend in the samegeneral direction as the stream valleys in which the foldsare found. One faulted anticline which was observed1 isexposed in the undercut bank of a meander curve. The faultwhere exposed in the stream bank has a hade of 30° andthrow of six inches. Upstream, the fault dies out in a lowalmost symmetrical anticline, whose sides have a dip ofalmost 10°. The fold extends only about 25 feet in thesame direction before disappearing entirely. Its extent inthe other direction is not shown.

*Matson: U. S. Geol. Surv. Water Supply Paper 233, 1909, p. 26.tThese altitudes are judged from the topographic map of the Cincinnati quadrangle.JOn the west branch of Sycamore creek, north central part of section 22, Symraes township.


The folding of strata just below the Eden-Fairviewcontact is usually of a very irregular nature, thus differingfrom the folding at the lower horizon, which is much moreregular. At this higher horizon the axes are parallel to thestream valleys. Only two or three feet vertically are affectedthe distortion seldom extending upward to the Dalmanellalayer.

Two possible explanations of these folds and faults inthe Eden shales present themselves: (1) lateral compressiondue to dynamic action during the formation of the Cincinnatianticline; (2) buckling due to removal of load in streamvalleys in recent times. The observed folds seem to beseparable into two groups—or possibly three groups ifthose reported from the Maysville be considered—differingin regularity of folding and extent of distortion. The firstgroup includes those folds of the Eden shale (McMicken)found at horizons 30 to 50 feet below the Eden-Fairviewcontact. The axes of these folds are apparently somewhatparallel to the stream valleys (or to the general trend ofthe valleys), and are without accordance of direction.These folds are usually quite regular and sometimes almostsymmetrical. The second group includes those folds foundat the top of the Eden, with their axes parallel to the streamvalleys. These are always very irregular, and the strataseem to be crushed and broken rather than distinctly andregularly folded.

Considering first the folds and faults of the lower series(McMicken), uniformity of horizon would favor the firstexplanation, as it would seem probable that these folds ata common horizon, should have a common origin. Lack ofaccordance of direction of axes is opposed to it, as lateralcompression, working over the area through which thesefolds are distributed, would produce a general parallelismof axes. Their existence in stream valleys would suggestthe second explanation, affecting possibly an inherently

*For a known example of buckling due to a similar cause, see Bull. Geol. Soc. Amer. vol.,20, p. 625.


weak horizon, a fold occurring whenever this horizon isproperly situated topographically. Their direction, moreor less parallel to stream valleys is favorable to the hypothesisthat they have resulted from buckling due to removal ofload in the valley.

The second group, at the top of the Eden, seems to beadequately explained by the hypothesis of buckling. Here,the axes are parallel to the stream valleys. In all cases

• where folding exists at this horizjon, the stream bed is sud-denly cut deeper just beneath the Eden-Fairview contact.This horizon lies just beneath a formation which contains arather large proportion of limestone and is therefore strongerthan the shale beneath. When this support is removedbuckling may occur, as the shales cannot withstand thedownward force on either side.

Joint cracks.—In the Cincinnati region the rocks areaffected by two very persistent systems of vertical joints,having general east-west and north-south directions. Thesejoints are not uniformly spaced, varying usually from aboutone to three feet apart. Both systems extend far beyondthe Cincinnati region, as indicated by the following statementfrom Matson: "In the Blue Grass region there are two well-developed systems of vertical joints at approximately rightangles to each other. These joints have general north-southand east-west directions and are apparently very per-sistent."* It is probable that these two systems of jointsare coextensive with the Cincinnati anticline. They affectboth shales and limestones, but are more prominent in thelimestones. These joints are taken advantage of in quarry-ing the limestone strata, the joints forming easy fractureplanes often doing away with the necessity of blasting.Weathering first takes place along these joint planes, mani-festing itself in the yellow oxidized borders of the jointblocks. The joint cracks greatly facilitate the circulationof ground-water, and become much enlarged by solution inthe purer limestone strata.

*Matson: U. S. Geol. Surv. Water Supply Paper 233, 1909, p. 28.


A number of limestone sinks are known in the Cincinnatiquadrangle in places immediately underlain by the Bellevue,which contains some of the purest limestone strata of theseries. They probably owe their existence to the falling inof the roofs of caverns which were formed by the solutionof the Bellevue limestone.

III. Geologic and Physiographic History

A. Paleozoic Era

1. Cincinnatian epoch.—During the Cincinnatian epochthe interior of the continent was a vast epicontinental sea,with land to the east, north, and west. Toward the closeof the Mohawkian epoch the sea became shallow enough toaffect the character of the sediments. The Winchester andLexington limestones (Mohawkian) of central Kentuckyand the Bromley and Pt. Pleasant (Trenton) of northernKentucky and southwestern Ohio, which contain upwardan increasing amount of shale, give evidences of the shallow-ing of the epicontinental sea in the Cincinnati region. Thewave-marked limestone layers composed of fragmentalmaterial and the mud-balls of the Pt. Pleasant indicate thatthe sea had become quite shallow. A slight disconformityexists at the top of the Pt. Pleasant, pointing to a shortemergence of this area at that time.

Eden stage.—Throughout the Eden stage the sea re-mained quite shallow and a large part of the materialdeposited was mud. The mud-balls and wave-markedlimestone layers of this formation previously described alsoindicate shallow water deposition. The amount of materialdeposited (230 feet) was far greater than that of the twosubsequent stages, and almost equal to that of the Rich-mond. The life of the Eden stage was meager for the muddywaters were unfavorable to abundant life. Bryozoans,though not abundant, were fairly well represented, andtrilobites (Calymene and Isotelus) and pelecypods (Bysson-chia) were not uncommon.


Maysville stage.—During the Maysville stage, the supplyof mud was lessened, as is shown by the increased proportionof limestone upward in the formation. It is not knownwhether this clearing of the seas was due to an actualdiminution in the amount of mud supplied, or to a deepeningof the sea which would reduce the amount of terrigenousmaterial brought to this place. But we do know that attimes the sea was quite shallow, for in the Fairmount.mem-ber where limestone is relatively more abundant than atany lower horizon in the Cincinnatian, there are severalwaved limestone strata. As these are composed largely offragmental material, they could not have been depositedat a depth greater than that at which such material can beagitated by the waves. The Maysville stage was a timefavorable to the existence of abundant animal life, andespecially to such forms as brachiopods and bryozoanswhich inhabited clear waters.

Richmond stage.—During the Richmond stage, con-ditions changed frequently, as is shown by the alternationin the character of the rock. These varying conditionswere probably produced by epeirogenic movements. TheArnheim (basal Richmond) was a time of deposition ofshaly limestone and of shale. The change from clear waterconditions of the McMillan stage to the muddy waters ofArnheim time affected the life of the seas very strongly asis shown by the scarcity of fossils in the lower division ofthe Arnheim (Sunset). Later in the Arnheim time (Ore-gonia), life became abundant, but the species and even thegenera were largely different from those of the previousstage. The Arnheim time was transitional between theMcMillan and the Richmond stages. Muddy water con-ditions inaugurated during the Arnheim time prevailedduring the deposition of the Waynesville, and in accordwith this, species closely related to those of the previousmuddy water stage, the Eden, appeared, such as Dahnanellameeki, Leptaena rhomboidalis, and many bryozoans. Follow-ing the Waynesville time the seas again cleared, inaugurating


the most pronounced limestone making age of the entireCincinnatian, the Liberty. This was characterized by anabundance of brachiopods whose nearest relatives lived informer limestone making epochs—-Trenton and Maysville.After 35 feet of calcareous material had accumulated, theclear seas were suddenly terminated by a return to muddywaters, and an extensive shoaling of the sea. It is probablethat at the time of the formation of the coral reefs of theSaluda and the deposition of its coarse terrigenous sedi-ments, a part of the Cincinnati anticline had emerged, andthat the shore features of the Saluda were caused by thepresence of this land. Some of the shaly strata of theSaluda bear sun-cracks, showing that a part of the areaoccupied by these rocks was occasionally even above thesurface of the sea. Terrigenous material was still suppliedduring the deposition of the Whitewater and the Elkhorn,but it was less coarse than that of the Saluda. At Madison,Ind., the highest beds of the Richmond formation areabsent and the Clinton rests unconformably upon the lowerportion of the Whitewater. This shows that the area ofthe land did not remain constant, but at times diminishedin size permitting the overlap of younger sediments.

As has been indicated, the Richmond stage was a time'of epeirogenic movements in the eastern interior of thecontinent. The sediments of the Medinan series of NewYork indicate that this epoch was a time of epeirogenicmovements in the east. The Richmond is a formationknown only in the interior basin; the Medina and Oneidaformations of the Medinan of New York are known onlyin the Appalachian district. Both represent a time ofchanging depths of seas, and shifting land masses. Becauseof the peculiarities of their distribution, the movementsaccompanying their deposition, and the character of theirsediments, a question has arisen as to the possible equivalenceof the Richmond and basal Medinan formations, and ifthey are equivalent, to what system, the Ordovician or


Silurian, they belong. Cumings* considers that the move-ments of the Richmond and Medina stages were related,and that the Richmond is equivalent to a part of the Medina.Bassler places the Richmond formation in the vSiluriansystem, evidently in accordance with this idea of its con-temporaneity with the eastern formations.

2. Silurian period.—That an emergence of the Cincinnatianticline occurred late in the Richmond or early, in theSilurian is further indicated by the different nature of thelater Silurian formations to the east and west of the anti-cline. The Clinton of Ohio and Indiana is very similarfaunally and lithologically'1' thus precluding the existenceof any extensive land mass at that time, but the Waldronof. Indiana^ and Tennessee is not represented by any similarformation in the area to the east of the anticline, whichmight be interpreted by assuming that a land barrierexisted between these two basins. It is probable that dur-ing the subsequent periods of the Paleozoic, this area wasgenerally above the sea, but was low lying and sufferedlittle erosion.

B. Post-Paleozoic Time

At the close of the Paleozoic, all the eastern interior wasraised above sea level, and there was extensive deformationin what is now the Appalachian Mountain region. Longcontinued erosion then followed resulting in the formationof an extensive peneplain in Cretaceous time. Evidence ofthis peneplain still remains in the mountain regions, but hasbeen obliterated from the great interior areas underlain byless resistant rocks, where it was no doubt also formed.After the formation of the Cretaceous peneplain, there wasan uplift which inaugurated a second great period of erosion,again resulting in the formation of a peneplain in Tertiary

*Cumings: Ind. Dept. Geol. Nat. Res., 32nd Ann. Rep., 1907, p. 687.tBassler: Proc. U. S. Nat. Mus., xxxix, 1911, pp. 509, 517; U. S. Nat. Mus. Bull. 92, 1915,

vol. 2, pi. 3.JFoerste: Amer. Jour. Sci., vol. 18, 1904, pp. 321-342.gKindle and Barnett: Ind. Dept. Geol. Nat. Res., 33rd Ann. Rep., 1908, p. 401.


time. This peneplain which was only partial in the moun-tain regions, was almost completed over vast areas of theinterior of the continent.* At this time the area at Cin-cinnati was peneplained. This Tertiary peneplain is rep-resented by the level crests of the hills about Cincinnati.Upon this plain, stood a few low-lying monadnocks, whichnow show a very low swells above the flat-topped uplands.The Tertiary peneplain was uplifted, and then began thedevelopment of the present topography of the region. Atthe beginning of the Pleistocene period, most of the presentstream valleys were formed, and the topography was similarto that of today. During the Glacial Epoch the topographywas modified by changes in drainage, by the deposition oftill, and by out wash deposits. Post-Pleistocene erosion hascompleted the development of the existing topographicfeatures.

IV. History of the Nomenclature

Early in the nineteenth century, the "Blue Limestone"as the Cincinnatian series was then called, became wellknown because of its wonderfully abundant fauna. Manyattempts have been made to correlate it with the formationsof the eastern states, resulting in the application, at differenttimes, of various names. At one time it was considered byJames Hall to be the equivalent of the Trenton of NewYork (including Trenton, Hudson River, and Utica slate),and throughout Volume I of the New York Paleontology,reference is made to the Cincinnatian series as the "Trentonlimestone." Nickles, in 1903, in his paper, "The Geologyof Cincinnati"^ gave a concise and adequate account of thehistory of the nomenclature up to that time. At that time,the names Utica and Lorraine were accepted terms. Laterinvestigations have shown that the Utica of New York isrepresented by only the basal five feet of the formationformerly called Utica at Cincinnati. To this five feet the

*Campbell, Richmond Folio (No. 46); Fenneman, U. S. Geol. Surv., bull. 348, p. 43.tNickles: Jour. Cin. Soc. Nat. Hist., vol. 20, 1902, p. 52.


term Fulton has been applied* and the major part of theformation formerly called Utica is now known by Orton'sterm Eden.* The Fairview and McMillan formations haveuntil recently been included under one formational name.For many years, this series of strata was considered to bethe equivalent of the New York Lorraine, and was knownby this name. Later, as it became evident that thesestrata were not the exact equivalent of the Lorraine, thename Maysville* was proposed. This name was used forseveral years, bat is now being superseded by two names,Fairview and McMillan, which Bassler* has proposed forthe two divisions of the Maysville which he raises to forma-tional rank. These two formations, together with the Edenand Utica, he included in the Covington group. Recentlythe Richmond has been referred to the lower Silurian.

The following table is intended to show the scope andequivalents of the various names which have been appliedto parts of the Cincinnatian series in the vicinity of Cin-cinnati.

*Bassler: Proc. U. S. Nat. Mus., xxx, No. 1442, 1906, p. 9.tWinchell and Ulrich, Geol. Nat. Hist. Surv. Minn., vol. 3, pt. 2, 1897, p. cii.JFoerste: Science, N. S. vol. 22, 1905, p. 150; Nickles: Ky. Geol. Surv. Bull. 5, 1905, p. 15;

Cumings: Ind. Dept. Geol. Nat. Res., 32nd Ann. Rep., 1907, p. 621.§Bassler: loc. cit. p. 10.HBassler: Proc. U. S. Nat. Mus. xxxix, 1911, p. 509-517; U. S. Nat. Mus., Bull. 92, 1915,

pis. 2, 3, 4.

i •

Early

Authors

Orton, 1873,Ohio Geol.Surv

vol. 1, p. 371

Winchell & Ulrich,1897

Minn. Geol. Surv.vol. iii, pt. 2,

p. lxxxix

Nickles, 1902Jour. Cin. Soc. Nat. Hist.

vol. 20, pp. 64-98

Nickles, 1903Amer. Geol., vol. 32,

p. 218

Foerste, 1905Science N. S., vol. 22,

p. 151

Nickels, 1905Ky. Geol. Surv., Bull. 5,

p. 15

Bassler, 1906Proc. U. S. Nat. Mus. 30, No. 1442,

p. 8

Cumings, 1907Ind. Dept. Geol. Nat. Res.

32d Ann. Rep., p. 621

Bassler, 1915

U. S. Nat. Mus., Bull. 92, pis. 2 and 3Present Report

ThicknessNickles \ 1902

1903

ThicknessBassler,

1906

Approximate ht.above low waterof the Ohio,

A. T. 432 ft.Bassler, 1906

Elevation A. T.of

upper contact,Straight St.

section

Lebanon. Richmond. Richmond

Upper.

Middle.

Lower.

Richmond

Madison

Whitewater.

Liberty

Waynesville.

Hill Quarry(in part)

Lorraine.

(Warren

Mt. Auburn

Lorraine.. Corryville

Bellevue

Fairmount

-Mt. Hope

Warren

Mt. Auburn

Lorraine.. v. Corryville

Bellevue

Fairmount

Mt. Hope

Eden(in part)

Utica. {Upper

Middle

]

Utica

. Lower

(Upper

\ Middle

I Lower.

Richmond

Saluda.

Versailles.

Waynesville.

Arnheim

Mt. Auburn

Maysville - Corryville

Bellevue

Fairmount

I Mt. Hope

Eden.

Garrard

Middle Eden

Lower Eden . .

(Fulton layer)

Saluda(Madison)

Richmond- Whitewater.

Liberty

Waynesville.

Arnheim(Warren)

Mt. Auburn

Maysville , Corryville(Lorraine) j

Bellevue

Fairmount

Mt. Hope

Eden(Utica)

Upper

Middle

Lower.

Richmondgroup

Saluda

Whitewater

Liberty

Waynesville.

Richmond

Arnheim.

Elkhorn

Whitewater 1

Saluda. . . . J

Liberty

Waynesville.

Arnheim....

Elkhorn (Belfast)

f Whitewater—

( Saluda (Madison & Fowler)

LibertyRichmond

( Blanchester |Waynesville j Clarksville >

( Ft. Ancient)C Oregonia ~|

Arnheim -I \ • • •( Sunset. . I

( Elkhorn

Whitewater. .

Saluda

Liberty

Waynesville..

Arnheim

45'-50'

30'-40' east side ]

40'-60' west side j35'

SO'

80'

40'

35'

35'

50'

80'

Cbvingtongroup

(Mi. Auburn

McMillan I Corryville

Fairview

Eden

Utica

Bellevue

Fairmount

Mt. Hope

r McMicken

Southgate

I Economy . .

Fulton.. . . .

Maysvilleor

Lorraine

Upper

Middle

Lower

Eden. .

McMicken(Upper)

Southgate(Middle)

Economy(Lower)

Maysville

Eden. .

McMillan

Fairview

Mt. Auburn

Corryville(Gilbert)

Bellevue(Tate)

Fairmount

Mt. Hope(Up. Garrard)

Mavsville

rMt. Auburn.

McMillan< Corryville. .

Fairview

Bellevue. . .

f Fairmount.

Mt. Hope. .

20'

60'

20'

80'

50'

35'

35'

15'

50'

45'

'McMicken.(Paint Lick)

Southgate )> Million

.Economy )

. Fulton

cMcMicken.

Eden. . < Southgate.

I Economy . .

Utica .Fulton

60'

120'

80'

60'

120'

50'

5'

625'-665'

665'-7OO'

59O'-625'

540'-590'

46O'-54O'

425'-460'

390'-425'

375'-390'

325'-375'

280'-325'

220'-280'

100'-220'

50'-100'

45'- 50'

855'

795'

775'

7O5'-713'

673'


V. BibliographyBassler, R. S.

1906—A study of the James types of Ordovician and SilurianBryozoa. Proc. U. S. Nat. Mus., vol. 30, No. 1442,pp. 1-66.

1911—Corynotrypa, a new genus of tubuliporoid Bryozoa. Proc.U. S. Nat. Mus., vol. 39, No. 1797, pp. 497-527.

1915—Bibliographic index of American Ordovician and Silurianfossils. U. S. Nat. Mus., Bull. 92, vols. 1 and 2.

Campbell, Marius R.1898—Richmond Folio, Ky.

Cumings, E. R.1907—The stratigraphy and paleontology of the Cincinnati Series

in Indiana. Ind. Dept. Geol. Nat. Res., 32nd Ann.Rep., pp. 605-1189.

Fenneman, N. M.1911—Geology and mineral resources of the St. Louis Quadrangle.

U. S. Geol. Surv. Bull. 438.

Foerste, August F.1904—The Ordovician-Silurian contact in the Ripley Island area

of southern Indiana, with notes on the age of the Cincinnatigeanticline. Am. Jour. Sci., 4th ser., vol: 18, pp. 321-342.

1905—The classification of the Ordovician rocks of Ohio andIndiana. Science, N. S., vol. 22, pp. 149-152.

1912—The Arnheim formation within the areas traversed by theCincinnati geanticline. Ohio Naturalist, vol. 12, pp.429-457.

Kindel, E. M. and Barnett, V. H.1908—The stratigraphic and faunal relations of the Waldron

fauna in southern Indiana. Ind. Dept. Geol. Nat. Res.,33rd Ann. Rep., pp. 395-416.

Matson, George Charlton1909—Water Resources of the Blue Grass region, Kentucky.

U. S. Geol. Surv. Water Supply Paper 233.

Nickles, J. M.1902—The geology of Cincinnati. Jour. Cin. Soc. Nat. Hist.,

vol. 20, pp. 49-100.1903—Richmond group in Ohio and Indiana. Amer. Geol., vol.

32, pp. 202-218.1905—The Upper Ordovician rocks of Kentucky and their Bryozoa.

Ky. Geol. Surv. Bull. 5.Orton, Edward

1873—The Cincinnati Group, or Blue Limestone formation Geol.Surv. Ohio, vol. 1, pt. 1 chapt. 13 pp. 367-418.


Ulrich, E. O.1911—Revision of the Paleozoic System Bull. Geol. Soc. Am.,

vol. 22, pp. 281-680.

Van Horn, Frank R.1909—Landslide accompanied by buckling, and its relation to

local anticlinal folds. Bull. Geol. Soc. Am., vol. 20,pp. 625-632.

Winchell, N. H. and Ulrich, E. O.1897—The Lower Silurian deposits of the upper Mississippi province:

a correlation of the strata with those in the Cincinnati,Tennessee, New York and Canadian provinces, and thestratigraphic and geographic distribution of the fossils.Geol. Nat. Hist. Surv. Minn., vol. 3, pt. 2,

(To be continued)

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