Prepared and Published with the Support of COUNTY ATLAS SERIES THE MOWER COUNTY BOARD OF COMMISSIONERS AND ATLAS C-11, PART A MINNESOTA GEOLOGICAL SURVEY Plate 2—Bedrock Geology D.L. Southwick, Director THE MINNESOTA DEPARTMENT OF NATURAL RESOURCES, DIVISION OF WATERS

° R 18 W 93 00' B' R 17 W R 16 W 92°45'

Omaq 56 1 6 6 1 6 1 Ogal R 15 W R 14 W 92°30'

Odub er v Odub 16 i Dspl 00 R 1100 reek 11 UDOLPHO 1150 C 7 oot Omaq k BEDROCK GEOLOGY R ree 8 Ogal 1 Omaq PLEASANT C AA y AA' Waltham re Odub Dspl VALLEY a C Dclp By 1 Sargeant 63 T 104 N A' n so 90 in Omaq John H. Mossler ch b n o a R Br Dspl 1250 SARGEANT T 104 N 1100 1998 C Dspl e Omaq

d

a WALTHAM 12 218 r 20 RACINE Dclp 00 1 STRATIGRAPHIC COLUMN 1050 12 50 North Dclp U 31 R 36 31 31 iv 56 36 31 36 31 36 D 36 e Racine r Group, Natural Gamma Log 1250 Era Formation, Lithology Increasing count

BB Unit N BB' o Series Member r 0 100 th R Omaq Unit Symbol o 6 API-G units 6 b 1 6 1 Hydrostratigraphic LANSING 1 erts 1 6 Thickness (in feet) Lansing Creek 6 1 43°45' Dclp 7 Bear 43°45' 2 Ostrander Fork Member Kwos Dspl Creek Upper Omaq 250 Iron Hill Fe Fe 20Ð35

DEXTER Windrow 2 1 (<100 m.y.) Kwih

Brownsdale Formation

Cretaceous Member Omaq MESOZOIC

D 1050 Dclp Lithograph Dclp k U ee City Dcuu Cr Dspl Formation k r Up to 50

1000 ree GRAND ea Odub Wolf C B Dclc MEADOW th Fork Ramsey ou 1100 S Coralville Mill Pond Creek T 103 N T 103 N Deer Formation Dspl D RED ROCK Dexter Grand 57Ð61 Ogal Dcum 16 16 Dcum U U Meadow D k 1050 1100 16 e 20 e Hinkle & Mur r Dcum

phy 1150 C Dclc Eagle CC C CC' re Center Mbrs 25Ð35 e 1050 k U D

U Cedar Valley Group ins FRANKFORD Chickasaw 1100 D b Dclc Dclp b Member o Dclp Maple View D Dspl 15Ð43

1150 8 Dspl Bassett

36 31 31 1200 14 Member 36 31 36 31 36 31 40Ð70 1100 1100 Dclc Dclp Pinicon 16 90 1250 Dclc Dcum Elkton Ridge 6 1 6 1 6 1 6 1 6 1 Formation 20Ð47 90 Middle (387Ð374 m.y.) ek re r C ee er 3 Dclc Dclp D Riv Dcum Spillville Dspl 1050 Formation

Dclc 21Ð84 3 Dcum Root Wapsipinicon Group DD 1000 DD' Austin 56 Dclc Dcum Branch 1050

O 1000 7 r c h 105 South a Maquoketa r 3 Omaq

T 102 N d CLAYTON 1100 T 102 N C Formation

AUSTIN 36Ð85 r

C Dclp e Dcum

e MARSHALL k

BENNINGTON Dubuque Dcuu 3 Odub Formation 23Ð40

Dclp 1150 D U Dcuu 1050 Dclc 4 Dcuu

1050 1200 Varco er Rose v er WINDOM i U er iv Creek 4 4 R D iv R R a R o w s e Creek o a Stewartville Dcum I w r Io Formation e 218 p 75Ð85 31 ar 31 36 31 36 31 p 36 31 36 Dspl d 36 1100 e Dclc U C EE EE' Group 56 7 Dclp Ogal

6 1 6 Dclc 1 6 nch 1 a 6 1

6 r 1 e tl

Galena Prosser B it L h Limestone Adams t 1000 r 40Ð50 o 1000 Dcum N Dclc 5 Dclc Taopi 5 1000 LE ROY 11 Cummings- ville 7 Dspl

U Formation 70Ð75 p p 950 er 950 Dcum Little U LYLE 5 5 Fe Fe T 101 N NEVADA D T 101 N Upper (458Ð444 m.y.) Decorah 1000 Dcum Dcuu

Dcuu LODI Shale 950 Cedar Dclp Dcum Dcum 56 45Ð50 105 Dcuu Odpg Dcum Platteville Iowa 14 Dcum Formation 20Ð30 FF W R FF' Glenwood Ph o iver Ph o 900

Dclc 5Ð6 d 900 Formation Ph b ur 1100 Fe Fe y C R O i reek v Dcuu er t 0 ter 105 6 Creek 6 6 St. Peter Ostp Dcuu Sandstone

Le Roy 70Ð80

Lyle 31 31 36 7 36 31 Dcum 31 36 31 36 C' 36 Dclc 43°30' 43°30' 93°00' R 18 W B R 17 W A R 16 W 92°45' R 15 W R 14 W 92°30'

Digital base modified from 1990 Census TIGER/Line Files SCALE 1:100 000 Cartography by Joyce Meints and Philip Heywood of U.S. Bureau of the Census (source scale 1:100,000); Graphic design by Philip Heywood 1 0 12345 MILES county border files modified from Minnesota Department of

Transportation files; digital base annotation by Minnesota 1 0 12345 6 7 8 KILOMETERS Shakopee Geological Survey Formation Universal Transverse Mercator Projection, grid zone 15 1927 North American Datum

INTRODUCTION The Bassett Member, though very thick bedded to massive, is jointed and pump sand). Also, a low-permeability regional confining layer at the bottom Many zones of well-cemented siltstone and shale may reduce yields of The map on this plate shows the bedrock formations that crop out or lie immediately contains a few large, open vugs. This relatively permeable unit forms a minor of the formation—found farther north and west in the state—is missing in wells developed in the Mt. Simon. The effect of bedrock highs beneath sediments. The information used to create this map was compiled from aquifer (J.A. Green, pers. commun., 1997). The medial limestone member of Mower County (Woodward, 1986). Confining layers may be present locally. and structure on unit thickness is uncertain, but they may dramatically reduce Opdc

Pinicon Ridge, which farther south in Iowa is broken, possibly brecciated, and Opdc Prairie du Chien Group (Lower Ordovician). the amount of sandstone available for well development: to the south in Cerro PALEOZOIC examination of exposures of bedrock and from subsurface data, including water well drillers' 320Ð340 cavernous (Libra and Hallberg, 1985), may form an aquifer. Shaly dolostone Shakopee Formation—Dense to finely crystalline, light-gray to light-olive-gray Gordo County, Iowa, the Mt. Simon is absent locally due to nondeposition logs, geologists' descriptions of water-well cuttings, wireline geophysical logs, engineering drawings, and geotechnical logs. Unpublished sources that were consulted include geologic and shale in the upper and lower parts of Pinicon Ridge have been interpreted dolostone. Locally sandy (medium to coarse quartz sand grains); siliceous (Hershey and others, 1970). Prairie du Chien Group field notes by R.E. Sloan (1954–1960), D.W. Kohls (1959–1960), Nikola Prokopovich to be confining units (Libra and Hallberg, 1985). oolites present locally. Oolitic dolostone possesses moldic porosity in places. Fond du Lac and Solor Church Formations (Middle )—Not penetrated (1955), and W.E. Parham (1966). J.A. Green, Minnesota Department of Natural Resources, Dspl (Middle Devonian)—Finely crystalline, light-brown to grayish- Minor amount of white chert. Thickness about 150 ft. by any wells drilled in Mower County. Interpreted from adjacent areas to orange dolostone; abundant -moldic porosity; dog-tooth calcite spar in —Very light gray to yellowish-gray, finely crystalline, consist of red-brown siltstone, sandstone, and shale having low permeability. Oneota

and G.N. Meyer provided the author with locations and descriptions of outcrops and sinkholes. Dolomite For further information on the bedrock geology of Mower County, see Mossler (1998). larger vugs. Very thick to thin bedded. Basal few feet are sandy to silty and nonfossiliferous. Thickness, about 170 ft. may contain minor amounts of shale or shaly dolostone. Middle to upper parts Coon Valley Member—Heterolithic basal unit; medium- to coarse-grained quartzose Lower Ordovician (505Ð478 m.y.) of unit have thin-bedded, light-olive-gray, dense dolomitic limestone. Unit sandstone, very fine grained, feldspathic sandstone and siltstone, and sandy to Contact—Approximately located; generally concealed. DESCRIPTION OF MAP UNITS thickness is as much as 78 ft in eastern Mower County; unit thins in western silty dolostone. (Upper ?)—The Windrow Formation unconformably Mower County, where it is 21–66 ft thick. Most permeability and porosity in the Prairie du Chien is related to fractures D Fault—Inferred; U, upthrown side, D, downthrown side. overlies Devonian carbonate rocks; the contact is generally marked by a zone Fracture porosity and permeability dominate upper part of unit; fossil- (joints, bedding planes), but intergranular porosity is present in sandstone U of weathered rubbly rock several feet thick at the top. The mapped extent of moldic, vuggy porosity is prominent in lower part. The basal shaly dolostone beds. Fractures near the sub–St. Peter unconformity are possibly solution Anticline—Showing trace of axial surface and plunge of fold.

the two members as shown on the map and sections is approximate. of low permeability may function as confining unit locally, as studies suggest enhanced through weathering that occurred prior to deposition of the St. Peter. Coon Valley Member Kwos Ostrander Member—Conglomerate consisting of rounded pebble-sized clasts of it may in northern Iowa (Witzke and Bunker, 1985); however, gamma logs Strongly cemented, very fine grained sandstone and siltstone beds in the basal

Syncline—Showing trace of axial surface and plunge of fold. quartz and chert set in matrix of fine to coarse quartz sand grains. Generally indicate the zone is discontinuous in Mower County. Coon Valley form a leaky unit of relatively low permeability (Setterholm and very friable and unconsolidated; some thin siltstone and very fine sandstone Omaq (Upper Ordovician)—Mostly silty, fine to medium crystalline, others, 1991). Jordan Line of equal elevation on the surface of the Maquoketa Cjdn layers. Goethite cement imparts distinctive brown to orange color. Generally light-olive-gray, slightly fossiliferous dolostone; scattered beds of light-olive- Cjdn (Upper )—Total unit thickness, 65–70 ft. Sandstone 1100 65Ð70 less than 10 ft thick. Commonly overlies Iron Hill but may lie directly on gray shale and very light gray dense limestone. Vugs are lined with drusy Quartzose facies—Fine- to coarse-grained, very light gray, very friable sandstone; Formation—Contour interval 50 ft; ticks point into area of lower

older strata. The unit labeled (Kwos) is only shown on the cross sections. quartz. Scattered light-olive-gray chert nodules. Principal : crinoids trace of calcite cement. elevation.

Kwih Iron Hill Member—Clayey, noncalcareous, white to variegated light-brown, grayish- and brachiopods. Unit thickness, 61–78 ft. Feldspathic facies—Very fine grained, very light gray sandstone; calcite and minor orange, and yellowish-green siltstone in scattered occurrences throughout most The dolostone in the upper part may have enhanced permeability owing to pyrite cement. AA'Line of section shown on this plate—Vertical exaggeration x 20. of county; includes some iron-formation (mainly goethite and minor hematite), fracturing and brecciation that are related to the development of the pre– Porosity and permeability are intergranular. The Jordan, which is considered especially in extreme eastern Mower County. Generally 5–15 ft thick. Middle Devonian unconformity on Ordovician rocks (Witzke and Bunker, 1985). an important regional aquifer, is generally much thinner in Mower County AA AA' Line of section shown on Plate 4—Vertical exaggeration x 40. The Ostrander is generally very porous and permeable, though locally goethite The many thin shale beds in the lowest part are similar to those in the underlying than where present to the north and east in Minnesota. The permeable quartzose St. Lawrence Formation Cstl cementation may occlude porosity. Much of the Iron Hill is clayey siltstone, ; together, the lower part of the Maquoketa and the Dubuque facies is possibly only 20–25 ft thick in most of the county. The tight feldspathic G 110Ð120 REFERENCES CITED giving it relatively low permeability; it may form confining unit. The unit form a regional confining unit. facies has low relative permeability (Runkel, 1996). G labeled (Kwih) is only shown on the cross sections. Odub Dubuque Formation (Upper Ordovician)—Light-gray limestone; subordinate Cstl St. Lawrence Formation (Upper Cambrian)—Very finely crystalline, very light Delin, G.N., and Woodward, D.G., 1984, Hydrogeologic setting and the potentiometric G Dcuu Lithograph City Formation (Middle Devonian)—Limestone and dolostone layered dolostone. Limestone interbedded with thin to medium beds of light-olive- gray to light-olive-gray, silty dolostone; glauconitic, especially near base of surfaces of regional aquifers in the Hollandale Embayment, southeastern Minnesota, G in thin to medium beds; a few scattered 1–3-in-thick gray-green shale beds. gray to light-gray calcareous shale; fossiliferous (abundant echinoderms, unit. Minor gray-green shale and light-brown-gray, sandy siltstone beds 1970–80: U.S. Geological Survey Water-Supply Paper 2219, 56 p.

Dolostone is very finely crystalline, yellowish-brown. Limestone is yellowish brachiopods). Unit thickness, 23–35 ft thick. interspersed in dolostone; thin, light-brownish-gray silty shale about 20 ft Green, J.A., Mossler, J.H., Alexander, S.C., and Alexander, E.C., Jr., 1997, Karst hydrogeology Reduced G gray, has distinctive, very fine grained equigranular (lithographic) texture. Ogal Galena Group (Upper Ordovician)—Total unit thickness, 200–205 ft. thick at top. Generally 110–120 ft thick. of Le Roy Township, Mower County, Minnesota: Minnesota Geological Survey Open- scale

Limestone forms upper part of unit. Unit thickness as great as 50 ft near Le Stewartville Formation—Dense limestone and finely crystalline dolostone; mottled The carbonate rocks of the St. Lawrence are tightly cemented and have few File Report 97-2, 2 plates, scale 1:24,000. G G 50% Reno Roy, thinner or eroded elsewhere. yellowish gray and pale olive gray. Few fossils compared to overlying Dubuque. open fractures; therefore, the formation is relatively impermeable. Hershey, H.G., Wahl, K.D., and Steinhilber, W.L., 1970, Geology and groundwater resources and The unit contains many joints, fractures, and bedding planes enlarged by Thickness, 75–85 ft. of Cerro Gordo County, Iowa: Iowa Geological Survey Water Supply Bulletin 9, 75 p. G Tomah Libra, R.D., and Hallberg, G.R., 1985, Hydrogeologic observations from multiple core Members dissolution (Green and others, 1997) and possesses high permeability. Prosser Limestone—Fine-grained, fossiliferous, yellowish-gray limestone. Fossils THE FOLLOWING APPEAR ON THE STRATIGRAPHIC COLUMN ONLY G

Dcum Coralville Formation and Hinkle and Eagle Center Members of Little Cedar in thin coquina layers (some silicified). Thickness, 40–50 ft. (Upper Cambrian). holes and piezometers in the Devonian carbonate aquifers in Floyd and Mitchell Counties, G 155Ð160 Formation, undivided (Middle Devonian)—Dolostone, shale, limestone. —Yellowish-gray dense limestone, green-gray, calcareous Reno Member—Slightly micaceous, glauconitic, light-olive-gray siltstone; minor Iowa: Iowa Geological Survey Open File Report 85-2, Part 1, p. 1–19. G

Dolostone is thin to thick bedded, generally finely crystalline, yellowish gray shale; fossiliferous (bryozoans, articulate brachiopods). Chert nodules, particularly amounts of green-gray shale; 75–80 ft thick. Mossler, J.H., editor, 1998, Contributions to the geology of Mower County, Minnesota: G Franconia Formation or light brown. Light-gray lithographic limestone is very minor component. in the upper part. Thickness, about 70–75 ft. Minnesota Geological Survey Report of Investigations 50. Tomah Member—Green-gray, micaceous siltstone, shale; 25–30 ft thick. G Unit thickness as much as 61 ft in Le Roy area. Owing to its shale beds, the Cummingsville is less permeable than the Birkmose Member—Light-olive-gray, highly glauconitic siltstone and very fine Runkel, A.C., 1996, Geologic investigations applicable to ground-water management, Rochester Birkmose Gray and gray-green shale beds as thick as several feet are present in upper Prosser and Stewartville, which together form a unit of relatively greater sandstone; 35–40 ft thick. metropolitan area, Minnesota: Minnesota Geological Survey Open-File Report 96-1, 27 Member G

G and middle Coralville; they lack sufficient continuity to form regional confining permeability; however, enhancement of fracture permeability and porosity by Together with the St. Lawrence, the Franconia forms a relatively impermeable p., 4 plates. G unit (Libra and Hallberg, 1985). Most permeability is fracture related, present karst-related dissolution of carbonate is spotty and is probably best developed Setterholm, D.R., Runkel, A.C., Cleland, J.M., Tipping, R.G., Mossler, J.H., Kanivetsky, unit in Mower County. Vertical flow in the Franconia is impeded by many Ironton and as joints or bedding planes; significant fossil-moldic, vuggy porosity present where the formations were subjected to pre-Quaternary–Holocene nearsurface silty and shaly beds (Delin and Woodward, 1984). R., and Hobbs, H.C., 1991, Geologic factors affecting the sensitivity of the Prairie du Galesville

in lower Coralville. Dissolution-related permeability is less developed than in weathering, as in the northeastern and northwestern corners of the county. Ironton Sandstone and Galesville Sandstone (Upper Cambrian)—Fine- to coarse- Chien–Jordan aquifer: Minnesota Geological Survey Open-File Report 91-5, 18 p., 12 Sandstones 40Ð45 Lithograph City (Coralville dolostone much less soluble than Lithograph City Odpg , Platteville Formation, and (Upper plates.

grained, friable, silty, yellowish-gray quartzose sandstone; minor amounts of G limestone). Ordovician)— Total unit thickness, about 70 ft. Witzke, B.J., and Bunker, B.J., 1985, Stratigraphic framework for the Devonian aquifers in green-gray shale partings. Total unit thickness, 40–45 ft. Dclc Chickasaw Member of Little Cedar Formation (Middle Devonian)—Silty, light- Decorah Shale—Green-gray shale; thin beds of commonly fossiliferous limestone; Floyd and Mitchell Counties, Iowa: Iowa Geological Survey Open File Report 85-2, Part The presence of intergranular porosity and permeability warrant investigation gray to medium-gray shale. In southeastern Mower, where it is 36–43 ft thick, about 45–50 ft thick. of the two units as a possible aquifer in Mower County; however, they may 2, p. 21–32. G G the Chickasaw Member may form an important confining unit owing to its Platteville Formation—Fine-grained, fossiliferous, yellowish-gray limestone; 20– lack the permeability present farther north and east in the state, where average Woodward, D.G., 1986, Hydrogeologic framework and properties of regional aquifers in

very low permeability (Green and others, 1997). Unit thins westward and is 30 ft thick. sand size is greater (Woodward, 1986). the Hollandale embayment, southeastern Minnesota: U.S. Geological Survey Hydrologic G G

only 15–20 ft thick in western Mower County, where it is also dissected by Glenwood Formation—Green-gray, phosphatic, sandy shale; some quartzose (Upper Cambrian). Investigations Atlas HA-677, 2 sheets, scales 1:1,000,000 and 1:2,000,000. G G buried stream valleys. sandstone beds; generally 5–6 ft thick. Upper part—Green-gray, glauconitic siltstone and shale; 75 ft thick. G G

Upper Cambrian (523Ð505 m.y.) G Eau Claire Dclp Bassett Member of Little Cedar Formation and Pinicon Ridge Formation, Taken together, the three formations have low permeability because of Lower part—Light-brown, very fine grained sandstone, shale, and siltstone; 120– Every reasonable effort has been made to ensure the accuracy of the factual data on which this map

Formation undivided (Middle Devonian)—Total unit thickness, 75–85 ft. their high shale content, but the Platteville may have minor permeability along 125 ft thick. interpretation is based; however, the Minnesota Geological Survey does not warrant or guarantee that 200 Bassett Member of Little Cedar Formation—Finely crystalline, thick-bedded to joints and bedding planes. The many shale beds and tightly cemented siltstone beds give the Eau there are no errors. Users may wish to verify critical information; sources include both the references very thick bedded dolostone; light gray to brown gray; 40–70 ft thick. Ostp St. Peter Sandstone (Upper Ordovician)—Very fine to medium-grained, light- Claire low permeability; in Minnesota it forms an important confining unit listed here and information on file at the offices of the Minnesota Geological Survey in St. Paul. In addition, effort has been made to ensure that the interpretation conforms to sound geologic and cartographic Pinicon Ridge Formation—Mainly finely crystalline, silty or sandy dolostone; gray sandstone; poorly cemented; quartzose. Regional unconformity at base. (Delin and Woodward, 1984). principles. No claim is made that the interpretation shown is rigorously correct, however, and it should not light gray to yellowish gray; 20–47 ft thick. In its medial part are nodules of Generally 70–80 ft thick. Mt. Simon Sandstone (Upper Cambrian)—Not penetrated by any wells in Mower be used to guide engineering-scale decisions without site-specific verification. light-gray chert, thin beds of gray shale and siltstone, and minor beds of dense The St. Peter is considered an important regional aquifer, but drillers in

County. To the west in adjacent Freeborn County, the Mt. Simon is fine- to yellowish-gray limestone. Mower County report that its fine sand grain size and friability make well coarse-grained, light-gray to yellowish-gray sandstone containing many scattered completion difficult (sandstone is hard to screen off and wells commonly beds of siltstone, very fine sandstone, and shale. Total thickness in Mower

County estimated less than 200 ft.

A A' Quaternary 1400 Deer Creek Grand 1400 Adams Kwih Meadow deposits

C-C' Kwos Kwih Bear Creek N O T S H W M A P R E C I Little Cedar River Section Dcuu Racine Quaternary deposits Kwos Mt. Simon Dcuu Dclp

Sandstone 1200 Dcuu Dspl 1200

Dcum Dclc 200 or less Quaternary deposits Omaq Dcum Dclp Odub Dclc Dclp Dspl Ogal 1000 1000 Dspl Omaq Omaq Odpg Odub 800 Odub Ogal Ostp 800 Opdc Elevation in feet Elevation Elevation in feet Elevation Ogal Middle Proterozoic rocks, undivided Odpg 600 600 (about 1200Ð900 m.y.) Odpg Ostp Unmeasured Vertical exaggeration x 20 Opdc 400 400 Goethite-hematite ore LIMESTONE Ph Phosphate pellets

DOLOSTONE Algal mats

Algal domes; stromatolites B B' SANDY Fossiliferous; fossils (symbols not 1400 1400 Cedar SANDSTONE used in limestone and dolostone

VERY FINE TO FINE

C-C' River Cedar Lansing units) Section River Lyle Dclc Austin Kwih Dclp FINE TO MEDIUM Worm bored

Kwos 1200 1200 Dclc Pebbles (gravel in Dcum Quaternary deposits Dclp Kwos Dclp Quaternary deposits Dclp Dspl MEDIUM TO COARSE unconsolidated units) Dclp Dclp Omaq Flat-pebble conglomerate Dspl Omaq Dspl SHALY Dspl Omaq 1000 Dspl 1000 Cross-bedded (festoon)

Odub SILTSTONE Omaq Ogal Cross-bedded (planar to tangential) Odub Ogal Ogal SHALE Odub Ripple cross-laminations 800 Odpg 800 Ogal Odpg Odpg Vugs (commonly filled with Dolomitic Ostp coarse calcite) Calcareous Ostp Chert Elevation in feet Elevation

Elevation in feet Elevation Contact marks a major erosional 600 Odpg Ostp 600 K-bentonite bed (altered volcanic surface Ostp ash bed Opdc Facies change Oolites Low permeability and porosity; 400 400 G Glauconite horizontal bar shortened where lateral extent is limited Fe Iron stain Moderate to high permeability Vertical exaggeration x 20 Cjdn and porosity Cstl 200 200

C C' 1400 Minn. 56 1400 A-A' Upper Iowa River Little Cedar River Section Upper Iowa River

B-B' Kwos US 218 Le Roy Section Kwih Cedar River Varco Dcuu Dcuu Quaternary deposits Dcuu 1200 1200 Dcum Dclp Dcum Dclc Dspl Dclc Omaq Dclp Dclp 1000 1000 Odub Dspl Dspl Omaq Omaq Ogal 800 Odub 800 Ogal Odpg Ogal Elevation in feet Elevation Elevation in feet Elevation Ostp Odpg 600 Odpg 600 MOWER COUNTY Opdc Ostp Ostp Opdc Vertical exaggeration x 20 Opdc 400 400

©1998 by the State of Minnesota, Department of Natural Resources, and the Regents of the University of Minnesota The University of Minnesota is an equal opportunity educator and employer GEOLOGIC ATLAS OF MOWER COUNTY, MINNESOTA