GEOLOGY OF OLMSTED QUADRANGLE Institute of Natural Resource Sustainability William W. Shilts, Executive Director PULASKI COUNTY, ILLINOIS Illinois Geologic Quadrangle Map ILLINOIS STATE GEOLOGICAL SURVEY IGQ Olmsted-G E. Donald McKay III, Interim Director W. John Nelson, F. Brett Denny, John H. McBride, and Laura Williams 2009

CYPRESS 8 MI. R. 1 E. R. 2 E. 2.6 MI. TO ILL. 169

S J 140 N K 250 " 350 k 350 N Kom e" Kom J 37 br T QTm Kom 350 400 T. 15 S. 400

350 Qe

360 Qe J N Qe 33 QTm 32 QTm N J 31

400 32 33 34 Kom 400

35 400

400 400

J N 36 48 T k" N J 400 C 24 Kom Kom 0 k" 210 40 66 350 e" "k Kom br

T. 14 S. N J Kom 38 Kom QTm K 0 T. 15 S. 350 T N J N J 380 T. 15 S.

Price C 56 N "

J R k A o 350

400 a Kom

N J d Kom Kom C 60 350 QTm 400 k" C 66 400 N J T Tw k" N J Kom 5 S N J K 400

185 J

Kom N

430 e"

N 450 J br 350 4

6 350 N 400 J N J 400 N J 350 4 360 5 N J 3 C 24

" 400 J k

C 54 2 N Kom N J k"

Kom T 1 350 N J 85 N J k" 400 Kom QTm N J 450 T 450 Qe 450 N J 380 C 72

J 400

N k" N

J QTm

QTm K N

400 J N J 280 Qm k" S N J br 400 k" 81 66 N J k" QTm GEOLOGIC UNITS 400 Kom Qe K 350

J 350 N N Qe J 400

N J 450 380

N J 9

N J N J T

300 sm Bethlehem Road 8 Surface mine (clay)

K

J N

N 450 J k"79 N J

K T N

Kom J 450 260 N J 450 N k" J 350 Holocene

450 br Qc

N J Kom 400 350 450

J N N N J J 310 C Qc Cahokia Formation

k" 205 400 k" 310

T k" N

Kom J 65 Kom N J 400 N J Tpc br 285 C 40 Tpc k" QTm k" 470

Kom e" br 8 N

150 J 150 K 9 Tpc e" K Ck" 60

Kom Tpc N J Quaternary

N J

Tpc 10 250 J N Qm 11k"Kpc Clark Road Wisconsinan N J 250

N N J " J e Qe

QTm 12 br Equality Formation N 52 7 J k" T N

450 450 J 400 Kom Unconformity

J 350

N Tpc 370 J

K QTm N N J 450

450 N J N 37 J Illinoian 450 Metropolis Formation 450 Qm

3885 C 84 T and older J N N 47 J 450 k" N J 440 ª k" QTm

St. Peter Kom N J QTm 90 N J J k" 450 N Km 115 Tpc Komk" 44 400 330 K k"Tpc QTm J N k" N J Mounds Gravel

Kom K 70 Pliocene and

N N J J k

J Tpc N 300 Miocene 420 Unconformity k"66 d K QTm N J Dam 53 Roa

450 J 400 N

N J 105 N J 70 k" e" 400 18 Tw Wilcox Formation Tpc Tpc Tpc Eocene 450 Qm S 150 Tertiary 450 k" Kom 310

400 T 450 63 150 350 17 T S Unconformity 450 " N J Komk 69 k" Kom

J k"

N J 16 N

k" 981 U.S. War Dept. N Kom B J 15 S k" Dcc Tw 225 13 Kom k" Porters Creek Clay and k 14 150 Kom Tpc Paleocene 400 450 149 Clayton Formation 64 Kom N J Qc k" 310

N J

PULASKI 5 MI. 5 PULASKI Tpc J

252 N Unconformity

N J C 400 k" Kom 260 300 320 "k310 k k Tpc AЈ 400 Kom Kpc 400 Kom 450 Owl Creek and S 189 Kom N 450 Cretaceous Maastrichtian K J k" McNairy Formations

N J 400 J Kom

N T J N N N J Tpc J T 320 O 400 T l 400 d S N J Fe N J k" 22 Note: Loess units are not mapped.

a Tpc T

N J sm

th J N N

J 450

e Tpc 0.8 MI. 0.8 Tw OW r Tpc Tpc Tr 400 Qc QTm 450 400 Tpc a N J

i

N J l 400

N J

N J T 24

J N J N QTm 450 K 430 Kom 400 473 N J 320

Qm EYEBR MONKEYS Symbols

20 N J Qc QTm N

Tpc QTm J Qm

N J 400 21 T

N J J 22 N 300 T 23 502 400 122

N J 68 C

Tpc Tw Kom k"

Ck" k"Kom 400 Mfp Vertical joints

64 Ck"

T

56 e" k" Kom C 115 Â N J 66 55 " J e" k Qc

N Kom þ ü þ Kom Kom þ S 261 Mfp

J ^ ü sm

N k" ^ 1150 þ Mfp C 525 Inclined joints or fractures Qm Ba k" C lt N J Tw ª C 43 im C k"120 o sm k" Dgt Mfp 310 Dcc 350 k" r 320 K e K Dna 398 350 Kom R N J N J 400

J N 370 o 330 a Drill Holes T d

N J 80k" 330 from which subsurface data were obtained 76 37 S 1000 br Qc C k" 350 K k" 85 Tpc Dcc k" N J N J br 350 92 N e" J Stratigraphic boring Ck"138 k"br Tw Dna 95 320 N J k"br

Qm C 121 k"105 320 320 e" Water well

350 k" Dsl br 320 N J Tpc 370 Â 26 S 44 Qm sm e" Engineering boring 350 k" N J BЈ 330 Ko29m 350

350 28 Oil test hole 27 T ª Sk"41 J 310 Kom N 320 Labels indicate samples (s) or core (c). k" 57

Kom 330 J N Numeric label indicates total depth of boring in feet.

Qc 350 K Unit label denotes formation at bottom (br = bedrock

350 SC 225

J N k"

J N Tpc (formation unknown), Kpc = Post Creek Formation, 330 Mfp = Fort Payne, Dna = New Albany Shale, Dsl = 350

Tw St. Laurent, Dgt = Grand Tower, Dcc = Clear Creek).

J Qm Qm N 320 Dot indicates location accurate within 100 feet. Tu rn 320 QTm Tpc e

J N r

La

J n N d in g Line Symbols R o 330 a 330 dashed where inferred, dotted where concealed 32 34 K d J

33 N

J 400 350 N 320 Contact

330

J N

J J

N Normal fault; bar and ball on downthrown side N T. 15 S. 320 K K Displaces top of Paleozoic bedrock and at least

T. 16 S. 50

J the lower part of Cretaceous McNairy and Owl Creek Formations, k" N Qc

350 QTm

J N but not overlying Tertiary strata

J k"80 Sk" 76 N QTm QTm 350

330 473

J N T Normal fault; bar and ball on downthrown side N J

330

J 320 N Displaces Tertiary strata in addition to Cretaceous and Paleozoic

K

J N

J 320 N Line of seismic reflection profile N J 4 3 330 MI. 3 ANA 5 350 340 1105 BAND

350 A AЈ Line of cross section

J 330 N N J

K Note: Well and boring records are on file at the ISGS Geological

350

J N N J Records Unit and are available online from the ISGS Web site.

320 350 350 37

330 MOUND CITY 4.8 MI. 4.8 CITY MOUND

Qm K

J Qc N N J 75 k" Tw

Qc 350

J N N J 320 79 310 k" 310 QTm 350 340

350 10 N J 370

Qm 8 9 370 330 350 380

320 310 k"55 350

350

350

330 370

300 350 17 16

1105 310

R. 1 E. BARLOW 6 MI. 3.4 MI. TO KY. 358

Base map compiled by Illinois State Geological Survey from digital data (Digital Line SCALE 1:24,000 Geology based on field workby W. John Nelson, F. Brett Denny, John H. McBride, and Graphs) provided by the United States Geological Survey. Topography of Illinois area 1 1/ 2 0 1 MILE Laura Williams, 1996–2004. by photogrammetric methods from aerial photographs taken 1965. Field checked 1967. 1000 0 1000 2000 3000 4000 5000 6000 7000 FEET Planimetry of Kentucky area by photogrammetric methods from aerial photographs taken Digital cartography by Jane E. J. Domier and Shannon Geegan, Illinois State Geological 1952. Topography by planetable surveys 1954. Revised 1967. Photoinspected 1975. 1 .5 0 1 KILOMETER Survey.

North American Datum of 1983 (NAD 83) The Illinois State Geological Survey and the University of Illinois make no guarantee, Projection: Transverse Mercator expressed or implied, regarding the correctness of the interpretations presented in this 10,000-foot ticks: Illinois State Plane Coordinate system, west zone (Transverse Mercator) BASE MAP CONTOUR INTERVAL 10 FEET document and accept no liability for the consequences of decisions made by others on the and Kentucky coordinate system, south zone NATIONAL GEODETIC VERTICAL DATUM OF 1929 basis of the information presented here. The geologic interpretations are based on data 1,000-meter ticks: Universal Transverse Mercator grid system, zone 16 that may vary with respect to accuracy of geographic location, the type and quantity of data available at each location, and the scientific and technical qualifications of the data sources. Maps or cross sections in this document are not meant to be enlarged. Recommended citation: © 2009 University of Illinois Board of Trustees. All rights reserved. Nelson, W.J., F.B. Denny, J.H. McBride, and L. Williams, 2009, Geology of Olmsted Quad- For permission information, contact the Illinois State Geological Survey. rangle, Pulaski County, Illinois: Illinois State Geological Survey, Illinois Geologic Quad- rangle Map, IGQ Olmsted-G, 2 sheets, 1:24,000, report, 10 p.

1° ROAD CLASSIFICATION ADJOINING 1 2 3 QUADRANGLES MA TR 1 Dongola NOR GNETIC Primary highway, Light-duty road, hard or UE NOR UE 2 Cypress hard surface improved surface 3 Karnak 4 5 Secondary highway,

4 Pulaski TH hard surface Unimproved road For more information contact: 5 Bandana T Institute of Natural Resource Sustainability 6 Cairo H Illinois State Geological Survey 6 7 8 7 Barlow 615 East Peabody Drive 8 La Center, KY APPROXIMATE MEAN State Route Champaign, Illinois 61820-6964 DECLINATION, 2009 (217) 244-2414 http://www.isgs.illinois.edu

IGQ Olmsted-G Sheet 1 of 2 A Cahokia Formation Silt, sand, and gravel. Silt is mottled in light to me- nated. In some cases, rhythmic lamination suggests tidal action. The Wilcox Subsurface Only THICKNESS STAGE FORMATION GRAPHIC COLUMN dium gray and brown; sand is mostly light gray to buff and fine- to coarse- thickens southward from an erosional feather-edge in the central part of the (FEET) UNIT grained. Most sand is loose, but some is cemented by iron oxide. One or more map area. It is the youngest marine deposit of the Mississippi Embayment M Post Creek Formation Chert gravel. Two water-well drillers’ logs record SERIES SYSTEM upward-fining sequences, grading from gravel at the base to sand at the top, within Illinois. The lower contact is unconformable. “gravel.” Other logs report “chert” underlying sand or clay of the McNairy For- commonly are present. On the Ohio River floodplain in Kentucky, the Cahokia mation but do not distinguish between chert gravel that might be Post Creek HOLOCENE Cahokia 0–100 A Y Peoria 6–12 C rests on an irregular erosion surface and is as thick as 94 feet. Long arcuate I Porters Creek Clay Clay is dark gray, silty, and micaceous; it breaks and bedded or massive chert of altered Paleozoic bedrock. In nearby areas, Equality 0–50 B Wisconsinan Roxana 2–8 D ridges, evident in the field and on the topographic map, represent former point with a blocky or conchoidal fracture. Bedding generally is indistinct, marked the Post Creek is largely white to gray chert gravel in which the pebbles have Loveland Silt 4–7 E Illinoian bars and longitudinal bars. These are separated by swales, many of which are by sandy layers and iron stains. Pryor and Ross (1962) reported radiolaria, dull surfaces, lacking polish or patina. OCENE TERNAR lakes or wetlands where organic-rich silt and clay accumulate. Along small hystrichospheridae, foraminifera, casts and molds of pelecypods and gas- A Metropolis 0–55 F streams in the Illinois part of the map area, the Cahokia is generally less than tropods, and abundant fish scales and shark teeth. The lower part becomes N Fort Payne Formation Cherty limestone and siliceous rock. Where QU Pre-Illinoian

PLEIST 20 feet thick and contains a large component of silt derived from upland loess. increasingly sandy, glauconitic, and burrowed. Wayne Pryor (1958, ISGS unaltered, the Fort Payne is composed of dark gray, micritic, siliceous lime- G PLIOCENE Mounds Gravel 0–45 field notes; available from ISGS library) reported abundant sand dikes in an stone containing numerous chert nodules. Where altered, the rock is a dark MIOCENE Y B Equality Formation Clay and silt, minor sand and gravel. Sediment col- outcrop southeast of Levings (SW¼ SW¼ SE¼ Sec. 12, T15S, R1E). Near brown, porous residue that resembles siltstone. This material is porous, low EOCENE Lower or Ypresian Wilcox 0–15 H ors vary from greenish and bluish gray to olive and yellowish brown. Texture Olmsted the Porters Creek has been mined extensively to manufacture ab- density, and bedded or laminated. Sponge spicules, crinoid stems, and shell TIAR Thanetian varies from soft and plastic to stiff; structure massive to finely laminated. Thin sorbents. Maximum thickness is about 70 feet in Illinois and 120 feet in Ken- fragments are rare. Layers of dull, opaque, banded, dark-colored chert are 2 PALEO- Porters Creek Clay 0–70 I TER CENE peat layers and plant matter are locally present, as are weakly developed tucky (Olive 1969). The lower contact is gradational. to 4 inches thick and spaced several feet apart in cores. The lower contact is Danian Clayton 6–18 J soil horizons. Sand and gravel occur as lenses, mostly in the lower part of sharp. Owl Creek 3–9 K the formation. Pebbles are mostly chert and quartz derived from the Mounds Thomas and Murray (1989) reported that the Porters Creek from Olmsted and Formation, but include fragments of ironstone concretions derived from the elsewhere is largely calcium montmorillonite or smectite, along with lesser Note: Mississippian units younger than the Fort Payne probably occur within McNairy Formation. This unit occupies bottomlands of streams tributary to the proportions of kaolinite and illite. The kaolinite portion increases upward the Olmsted Quadrangle, but no information on such rock units is available. Cache Valley in the northern part of the map area. The unit represents slack- through the formation and northward in the Embayment. Non-clay constitu- water sediments that were deposited outside the main valley during times of ents include quartz and lesser amounts of mica, feldspar, and siderite. The O Springville Shale Shale and siltstone. Dark gray and greenish gray silt- Maastrichtian high glacial meltwater runoff. Cahokia Formation generally overlies Equality, Porters Creek is interpreted as marine sediment that records a rapid trans- stone in the upper part grades downward to greenish gray shale in the lower McNairy 90–600 L but the two units are difficult to differentiate in the field. The lower contact is gression followed by gradual regression. part. Both contacts are sharp. CEOUS

A unconformable. J Clayton Formation Sandy clay to clayey sand is greenish gray to nearly P Chouteau Limestone Limestone and siliceous rock. Light to medium CRET C Peoria Silt Silt is mottled in light to medium yellowish gray to yellowish black when fresh and weathers to an orange-brown. The sediment is mas- brown, microgranular limestone containing few fossil fragments is partially UPPER OR GULFIAN brown and lacks stratification. The Peoria has lower clay content than the sive, mottled, heavily burrowed, and highly glauconitic. It is commonly iron- altered to a gray, porous, and spongy siliceous residue. Both contacts are Campanian Post Creek 0–30+ M Roxana. The modern soil is developed within this unit. The Peoria is at the cemented and contains small limonite concretions. Chert pebbles and oc- sharp. ground surface in uplands throughout the map area and is not shown on the casional cobbles as large as 8 inches across occur in the lower part of the geologic map. This unit is loess, deposited by the wind. The lower contact is unit. Collecting fossils mainly in the now-abandoned Golden Cat clay pit on Q New Albany Shale Shale is greenish and olive-gray to black, moder- gradational within a few inches. the north side of Olmsted, Cope (1999) reported an extensive fauna of bryo- ately to very fissile, pyritic, and contains a sparse fauna of conodonts and fish Fort Payne zoans, annelids, bivalves, gastropods, crabs, lobsters, sharks, rays, ratfish, remains. Three members can be identified with reference to Cluff et al. (1981). 0–200+ N D Roxana Silt Silt is weakly mottled in medium to dark yellowish brown crocodiles, and turtles. These fossils signify brackish waters, as in an estuary. The Selmier Shale Member at the base is 75 to 80 feet thick and consists of

GIAN Indicates altered or and in some cases has a reddish cast. Layering is absent. The Roxana has A potassium-argon date from glauconite 3 feet above the base of the Clayton layers of black shale alternating with layers of greenish to olive-gray shale that silicified OSA limestone a higher clay content than the Peoria and holds water better; fresh core sam- yielded an early Late Paleocene age of 60.6 ± 1.3 million years (Reed et al. is partly silty and pyritic. Overlying the Selmier with a sharp but conformable

ALMEYERAN OR or dolomite ples tend to be plastic. The weakly developed Farmdale Geosol (ancient soil) 1977). The lower contact is unconformable and, in the Olmsted area, repre- contact is the Grassy Creek Shale Member, 75 to 100 feet of uniformly very V MISSISSIPPIAN Springville Shale 15–45 O is in the upper part; it is expressed by mottles, clay skins, and manganese sents a hiatus of approximately 5 million years. dark gray to black, pyritic, well-laminated shale. At the top is less than 10 feet oxide pellets and stains. Scattered sand grains and granules are present. The of greenish gray, calcareous shale probably belonging to the Hannibal Shale KINDER- Chouteau Ls 3–5 HOKIAN P Roxana underlies the Peoria in uplands throughout the quadrangle. The unit Mapping the Kentucky portion of the Olmsted Quadrangle, Olive (1969) com- Member. In some cores, the New Albany contains laminae and thin interbeds is not shown on the map. This unit is loess, deposited by the wind. The lower bined the Clayton and McNairy Formations into a single unit. Partly he did this of microgranular limestone and dolomite. The lower contact is unconformable. Famennian contact is gradational within a few inches. because many well records were insufficiently detailed to separate the two units. However, Olive’s description of the Porters Creek Clay includes highly R St. Laurent Formation Cherty and shaly limestone is largely medium E Loveland Silt Silt is strongly mottled in gray, yellowish brown, and or- glauconitic, burrowed sand containing chert pebbles identical to Clayton to dark gray, microgranular to bioclastic (lime mudstone, wackestone, and New Albany 150–180 Q ange. It has a high clay content and tends to be stiff. The lower part becomes Formation as outlined herein. Olive examined outcrops on the Illinois shore of packstone), with thin layers of dark gray to black shale. Bedding is thin and

UPPER Shale sandy and contains scattered small pebbles. The strongly developed Sanga- the Ohio River and cited pollen analysis that equated glauconitic, pebbly sand commonly wavy to nodular. In some cores, this unit has been leached to a Frasnian mon Geosol (ancient soil) is within this unit and is shown by intense mottling, with the lower part of the Porters Creek. In view of the findings of Reed et al. residuum of clay and chert fragments. The lower contact was not observed weathered appearance, and blocky structure with abundant clay skins. The (1977) and Cope (1999) and others, we stand behind our identification of the but generally is sharp. Loveland occurs throughout upland portions of the map area but is not shown Clayton Formation.

ONIAN on the map. This unit is loess, deposited by the wind. The lower contact gen- S Grand Tower Limestone Limestone and sandstone. Light gray, fine- to Givetian St. Laurent 37–75 R erally is gradational and irregular. K Owl Creek Formation Sand and silt are light greenish gray to brown, coarse-grained, bioclastic limestone (skeletal packstone and grainstone) is DEV medium- to coarse-grained, cross-bedded, and glauconitic. The upper part the dominant rock type. It is commonly sandy and contains numerous trilo-

MIDDLE F Metropolis Formation Clay-rich silty sand and sandy silt with gravel. is more clay-rich and finer grained, more glauconitic, and riddled withOph - bites, brachiopods, and other marine fossils. The Dutch Creek Sandstone Grand Tower Eifelian 40–100 Limestone S This unit is yellowish orange and yellowish brown, strongly mottled with gray, iomorpha and other burrows. The Owl Creek is interpreted as littoral (shore- Member at the base is white, fine- to medium-grained sandstone composed brown, and locally with bright reddish orange. It typically comprises a series line) to shallow subtidal, marine. A potassium-argon age of 65.7 ± 1.4 million of rounded, frosted quartz grains cemented by calcite. In some wells the of upward-fining sequences with stratification weakly developed. The sedi- years, obtained from pelletal glauconite 2 feet below the top of the Owl Creek, limestone has been dissolved away, leaving a residuum of clay and chert ments are thoroughly burrowed, and multiple soil horizons are developed. The is very close to the end of the Cretaceous Period (Reed et al. 1977). A weath- fragments overlying loose basal sand. The lower contact was not observed; in

WER Emsian Clear Creek 550 T upper part is dominantly massive silt that resembles loess but contains scat- ered zone reportedly occurs at the top of the Owl Creek (Pryor and Ross most of southern Illinois, it is unconformable. LO tered sand and pebbles. Portions are calcareous and contain abundant small 1962). The lower contact is gradational in some places and scoured in other calcite concretions. Gravel occurs as lenses and discontinuous layers. The places, marked by rip-up clasts derived from the McNairy Formation below it. T Clear Creek Formation Limestone and chert. The upper part is entirely gravel is dominantly composed of chert pebbles derived from the Mounds but chert that is white to buff, opaque to translucent, and dense to porous; it con- abraded and bleached, losing much of the original bronze patina. L McNairy Formation Sand, silt, clay, and lignite. Sand is white to light tains casts and molds of dolomite crystals. This material probably was origi- gray, buff, orange, and red; very fine- to medium-grained, and weakly lithified nally cherty limestone that underwent dissolution. In some wells, the lower In Kentucky, Olive (1969) identified the Metropolis as an “upper silt and sand to tightly cemented by iron oxide. Silt and clay vary from nearly white through part is light gray, very fine-grained limestone that is cherty and fossiliferous. unit of continental deposits” and noted its equivalence to “terrace deposits” all shades of gray to black. Abundant muscovite mica is characteristic of the mapped in Illinois by Pryor and Ross (1962). (Pryor and Ross incorrectly as- McNairy. Sand, silt, and clay commonly are interlaminated; rhythmic planar Only one well, the R.G. Williams Number 1 Richey (or Rickey) oil test (in Sec. signed Wisconsinan age to the terrace deposits.) On Olive’s map, the terrace lamination indicates tidal activity. Thicker sand units can be cross-bedded 9, T15S, R1E) penetrated strata below the Clear Creek Formation. The follow- in the southeast corner of the Olmsted Quadrangle was mapped as loess. and, in many cases, contain rip-up clasts of light-colored clay. Both upward- ing summary of deeper formations in the Richey well is based on a sample This terrace is composed of Metropolis Formation mantled in loess, as shown fining and upward-coarsening sequences are developed. study by ISGS geologist Frank E. Tippie, 1941: by the outcrop on the left bank of Clanton Creek 1.6 miles northeast of Os- car. The terrace is mapped as Metropolis Formation on our map, which omits The McNairy contains much more organic matter in the Olmsted area than Formation Thickness Description loess units. elsewhere in southern Illinois, including highly carbonaceous clay and silt (feet) along with stringers and beds of lignite as thick as 2½ feet. Fossil plants are Backbone Ls (?) 70 White to light gray crystalline, cherty lime- The Metropolis underlies loess on low terraces that border the Ohio River in common; W.A. Pryor (1959, ISGS field notes; available from ISGS library) stone the northeastern, southeastern, and southwestern parts of the map area. It is identified foliage of walnut, willow, wax myrtle, and pondweed from an outcrop interpreted as sediments of small, meandering streams that occupied the low- near Lock and Dam 53. These leaves indicate environments ranging from Grassy Knob Chert 630 Cherty and siliceous light gray dolomite, silt ermost Ohio River valley while the main flow of that river was diverted through aquatic to well-drained uplands. Pryor and Ross (1962, p. 19) gave the name and Bailey Ls and clay increasing downward; green near the Cache Valley, north of the Olmsted quadrangle (Nelson et al. 1999). The Levings Member to an interval of lignitic silt and clay, stating that this member base lower contact to the Mounds Gravel generally is gradational. occurs throughout the northern Mississippi Embayment. We have been un- Moccasin Springs 140 Reddish brown to green very silty limestone able to trace the Levings away from its type area and interpret it as a local St. Clair Ls 30 Light buff to pink limestone with red fossils G Mounds Gravel Gravel and sand. Gravel is composed principally of well- facies rather than a widespread, tabular unit. rounded chert pebbles, mostly smaller than 1 inch but reaching 2 inches or Sexton Creek Ls, 92 Micritic limestone and dolomite, darker more. These pebbles bear a distinctive, glossy bronze to yellowish brown pa- The ISGS Johnston test boring (SE¼ Sec. 22, T15S, R1E) penetrated 455 Girardeau Ls downward; upper part cherty, lower part tina of iron oxide that permeates outer layers of the pebbles. Quartz granules feet of Cretaceous sediments without reaching the base. The upper 160 feet shaly. are common in the finer fraction. Gravel is crudely stratified, with lenticular comprises burrowed and laminated, micaceous clay, silt, and sand of typical Maquoketa Sh 185 Silty shale and siltstone, nearly black; 18 bedding and low-angle accretion surfaces. Sandstone boulders as large as 6 McNairy aspect. Downward this unit grades to darker, highly organic sedi- feet of sandstone near the middle, phos- feet and balls of clay are locally present. Sand of the Mounds is red to brown- ments that include many stringers and thin beds of lignite. There are multiple phatic at base ish orange, coarse and poorly sorted, and commonly cross-bedded. Gravel rooted zones and layers of kaolinite that represent buried soils. White chert Kimmswick 155 White to light brown, medium to coarse and sand are partially cemented by iron oxide, particularly at the base of the gravel near the bottom of the hole resembles that of the Post Creek Forma- (“Trenton”) Ls dolomite unit. The Mounds underlies loess on hilltops in upland areas, and it underlies tion but is underlain by more clay and lignite. Fossil pollen from lignite layers the Metropolis Formation in lowlands. This unit represents alluvial, braided- at depths of 61, 219, 328, and 490 feet was examined by Norman O. Fred- Plattin 844± Gray to dark brown, micritic to very fine- stream deposits. The lower contact is unconformable. eriksen of the U.S. Geological Survey. Frederiksen reported (written commu- grained limestone and dolomite with few nication 2003) that all samples are Maastrichtian age—coeval with McNairy fossils In Kentucky, Olive (1969) identified the Mounds as a “lower gravel, sand, Formation and younger than the Campanian pollen age reported for the Post Joachim Dol 142± Sandy dolomite, very fine, beds of white and silt unit of continental deposits.” His detailed lithologic descriptions leave Creek (Harrison and Litwin 1997). Evidence strongly indicates that the John- sandstone no doubt that the lower and upper continental deposits of Kentucky equate, ston borehole penetrated a fault block that rapidly subsided during Maastrich- Dutchtown Ls 169± Very dark brown dolomite and limestone, respectively, to Mounds and Metropolis Formations in Illinois. The gravel is as tian time, trapping a thick succession of terrestrial sediment in advance of lithographic to very fine, shaly interbeds, thick as 95 feet in Kentucky (Olive 1969). initial marine transgression (Bexfield et al. 2005). See cross section B–B9. base sandy St. Peter Ss 10+ White, medium-grained dolomitic sand- H Wilcox Formation Sand, silt, and clay. Sand can be white, yellow, In Kentucky, Olive (1969) reported only local “fragments of lignitic plant mate- stone. orange, or red; fine to coarse; with granules of chert and quartz; and with clay rial” in the McNairy Formation. Only one well in the Kentucky portion of the rip-up clasts. The chert granules are gray, brown, and black, well rounded and Olmsted Quadrangle completely penetrated the McNairy. In that hole, which See accompanying report for references. polished, but lack an iron patina. Clay and silt come in many colors, including is not shown, located on the north side of Turner Landing Road just west of pink, brown, magenta, and ochre. Clay, silt, and sand are commonly interlami- Mitchell Lake, the McNairy is 220 feet thick with the top eroded.

West East A AЈ Elevation (feet)

600 600

S. R. 37 Olmsted Fault Zone Water Water QTm Tpc QTm Well QTm Well QTm Feather Trail Fault Zone QTm Qe QTm QTm Tpc Tpc QTm U.S. War 400 Qe 400 Dept. Kom Tpc Kom Qm Ohio River Qe Kom Kom Kom Kom Kom Kom Qc

200 200

Pz Pz Pz Pz Pz Pz Pz

0 0

West East B BЈ Elevation (feet)

600 600 Feather Trail Bierbaum Fault stratigraphic Olmsted Zone borehole Fault QTm Tw S.R. 37 QTm QTm Johnston Zone QTm 400 Qc Qc stratigraphic Tw Ohio River 400 sm Qc sm Qc Tpc borehole Qm Tpc Army Corps Tpc Qm Qc of Engineers borehole

Kom Kom Qc 200 200

Kom Pz Pz Horizontal scale: 1 inch = 2,000 feet Vertical scale: 1 inch = 200 feet 0 0 Vertical exaggeration: 10ϫ

Porters Creek Clay sm Qe Equality Formation Tpc Surface mine QTm Mounds Gravel and Clayton Formations Pz Paleozoic bedrock

Owl Creek and Kom Qc Cahokia Formation Qm Metropolis Formation Tw Wilcox Formation McNairy Formations

IGQ Olmsted-G Sheet 2 of 2