R03W R11W R10W R09W R08W R07W R06W R05W R04W o Ops Ops Ops Ops o Ogp # 92 00' # 43 30' R14W R13W R12W Dw Dw ### # Kw Dw # Kw # o # 43 30' # # # # Ops # ALLAMA# KEE Dc Ogp ### Ops # # # # Dc # # # # # # Dw # # # # # # r WINNESHIEK # # HOWARD e Om # # iv ## # Ops # # # # R # # a ## # # # w # # # Io # Dc r # Ops # e # # # # Ops T100N p # # Ogp # p # # U # Dc # # # # # Ops # # # Om # # # # # ## # Om # # # # # # # # Cjl Cw # # # # Om # # # # Cjl # 52 # # # /( # Ogp # # # # # # # # # # # # # 63 # ( Ogp r # # / # e # # # Ogp # iv # # Dw R Ops Dc Dc # # # # Dw # a ## # w # # o Ops Ops # # I # # # # # r # e # # p # # # # Om# p # Ops U # # # Ogp # # # Ops # Ogp # # # # # # # T99N # Cresco # # # # # # ## # DIGITAL GEOLOGIC MAP OF IOWA # # # # # # # # # # # Ogp # # Dw # # 9 !"9 # # !" # # # # M # # # # IS PHASE 2: NORTHEAST IOWA # # S # Ogp # IS # # # # S Ogp ### # IP # PI # # # R # # IV ## # # # # E # Dc # # # # # R # # # # Ogp # Prepared by # Ogp # # Decora# h Ogp Ops # # # # # # ## # # Dc # # Dw # # # # # # Brian J. Witzke # T # # # Ogp u # # # r Ogp # # k # Dc # # Greg A. Ludvigson # e # # y # # # # # # # # # # # # ## # # # R # # # # # # Dw # # # # i ## # # Robert M. McKay v # # # # # # # # # e # # # T98N # Ogp Kw # Dc r # # # # # # # C # Ogp # # # Ops Raymond R. Anderson # r # 9 ## # a # !" Kw Ogp n # ## # # e # # ## Bill J. Bunker # Waukon C # # # # # Cjl # # r # # # # # e # Om # # e Dc # # # James D. Giglierano # k # Dc # Ogp # # # # # # # John P. Pope # # # Cw # # 9 # Kw # " # # # ! Ogp # Adrian E. Goettemoeller Dc # # # # # # # Ogp # # # # # # # # # # Om Maureen K. Slaughter # # # # # Ogp # Dw Dw # # Dw # # # # # # # # # # # Cjl # # # # # # # T97N # # # # # L Energy and Geological Resources Division

W Dc # I Dc Dw # Ogp # i # # t # # # # a t # le # p # # Geological Survey Bureau # # # # s CHICKASAW T Dw # # # # Cjl i # u # # p # r # # # # # i # # k # # # n e # # # # # # i # # y c # # # R Dw # o # # # # # i # August 1998 n # # # v # # # # # # # # Om e # # # R r # # # # # ## # i v # # # # e # ## # L Dc # # Ogp # r 63 # ( # # # i / # # t Dw # # # Produced under the STATEMAP program, in cooperation with the # t # # # l # e # # Ops # # Yel W # # low # # # R U.S. Geological Survey, Department of Interior, Supported by Dw # iv a # 52 # er # # # /( p # # # # 15# 0 # # # # s " # # Ogp ! # i # # assistance Award No. 1434-HQ-97-AG-01719 T96N p # # ### "24 # i Dc ! # # n ## Om # # # Ogp # c Dw # # Dw # o Sls # n # # R # # Cjl # Dc # Om i # # Ogp v Dc Sls # # # # e Om # Om r # Dw # # # # # # # # Sls # Sls # # # # New Hampton Dc # # # # # # # # # # # # # # # # Om ## ## # # # Ogp 18 # FAYETTE # # # ( # # # # # # # / # # # # # # # Ops # # CLAYTON # E Dw # # a # s # t Ogp # # # # B Sls # # # # # # # r Sls # # # # # # # W # # T95N # R # # Ogp # a o # # # p # b # # s e # # # r 18 # i # # ( p / # t i Shb s n # # C # o # i # Shb # # # # # # c # r # # # o e # Om # 43 00' # (18 e # n / # # # k Om o # R i Dw # v # 43 00' e Dc # # # # # # r Shb # # # # Shb # Dw # # #

# # # Shb # # # West Union # Sls # # # # # Cjl # # # # # # # # Om ### # # # Shb # (18 # # # / # # # ## # Dc # # # # # # # Om # # Shb # # Om # T94N # # # # # Dw # # # # Iowa Department of Natural Resources # # Dc D#w # Om T # # # # u # Om # rk Sls e # # y # # # # Ri # # # Shb ve # Larry J. Wilson Shb r # Sls # # # # Dw # # # # # # Dw # Shb # # # # # Sls # # # # # # # # # # O# gp # # # ## # # # # ## # # # BREMER # Om Shb /(52 Dc # Om ACKNOWLEDGEMENTS # # # Om Om Shb # # # # Cjl # # # Om # # Om Elkader # Recognized for direct contributions to the map’s production: Donald L. Koch, Jackson L. Gilmore, T93N # Dw # 218 # /( Om # # # # # Lynette S. Seigley, and Orrin W. Plocher of the Iowa DNR Geological Survey Bureau # # # # # # ## ## # # # Shb # # # # # # # Shb Om # # # # # Dw Vo lg # # # a # # # R # # # iv # Om # er # ## # Om # # # # # # 150 Dw !" # # # # # Om # Ogp # # Dw # Om # # # Shb 63 Om # # ( / # # # L C # Dc "13 Shb i ! e Dw t t # # d l # # # e a # # # r # # # W T92N R a i # # v p e # s r # i # Shb Ops C p # ## Dw # r Dw i Om # # # n ## a # # # i Om o n c # # # # e Shb 91 00' o # n Om # C Om # # R r # e Shb Waverly# i # e v # ## k e # r # # Ogp # # # # # # # Om 3 # !"3 !" # # # # # # # # # Om # # Shb # # Ops # Ogp # # 3 # # Shb !" # # Om Dc # # # # # # # Om # # T91N # # # # # # # Om # # M # # IS # B # # SI # # SS # u # IPP # # # I R c Shb Om IVE Shb # Ogp R 218 k # # ( C Dw Dw # / # # # Shb r # # e # # # # # # Shb e # # # # # k # !"3 # # # # # # # # Dc Ss # # # # DUBUQUE # Ss # # # # # # # # Om # # # # # # Dw # # Om # # Dc DELAWARE # # # Shb # # # Shb # # BUCHANAN # # # # # Dw # # Ss # BLACK # # # # # # # # # Dc # Ss # Om # # # r # ## # # # e Om HAWK # # v # # # # i # # R (52 # # / T90N # # a # # t # ## # # # # e # ## # Ss # k O# ps # # # # # # # # o # Om # u # # q # # # # a # # Om # # (63 # # / # # M # # # # # # # # # # # Dc 150 # # # # k # # # " # ### # # ! r # # # Sls # # # o ## # # Om Om # # # # # Dw # F # # # # # # # # # M # # Ss # N Ogp # # Om # a Ss # # # # # # ## Ogp # q # # # # # # ### # u # Shb # # o # # # r # # k # # # e # e # # Shb # # # v # # # Dw # t i # # # a # # # # R # 61 # # ( # / R Ss # Dubuque # # # # ta # # ## # W i # # # # a v e # # o # # p k # # s Sls # e # o # # # i # r # 42 30' p # # Shb u Om # # i Ss # # # # # # n # q # # # # # # # i Manchester Sls # a # # # # c # # # o # # # n # M# # # # # # T89N # # R e # # # i Ss # # l # # # # Shb v # # t # # # e # t # # o # r # i # # # # # # # # I # C # # # # # # # 42 30' # ## # # # L # # # e # # # d # # # # # ## Ogp # # # # # ## # #a # ## ### # # # r # # # Cedar Falls R # # # # # Ss # i # # Dc # # # # # # # # # # # v # Ss # ## # # # # # # e # # Ss # # # # # r # # # # # 20 # # # /( # # # # # ## Waterloo Shb Independence # # # # # ## # # Ss Ss # # # # # Dl ## # # # Shb # # # # 20 # # # # ( # # / # # # # # # # # # # # 20 # # # # # # ( # # # # # # Shb / # # # Sls Ops # Sls # Sls Shb # # Sls # Om (20 # # # / # # # # 20 B # ( # Om # / # # # # # # ## # # # # u # # ## # # # # ## # # ## f ### # # # # f # # ## ## # # # # # # a # # # Sls # ### # # # # # l 13 Ss # # # # # o !" # # # Ogp # # # # # # # Ss # # # # Dl # ## C Ss # # # # # # # # # # # r # # # # # T88N # # # e # # e # # # # # # # # # # # Ops # # k # # # # # # # # # # ### ## # # Sls # # # # # # # # # Ss # # ##### # # # ##### # # # # # # # # # # # # # # # # # # # # # # # # # Ss # # # # # # # Dc # # ## # # # # # # # Dw # # # # # # # D# l 380 # # 218 . # # ## # - # # # , # ( # # / # # # ## # # # ## # # # Ss # # Ogp # # # # # Sls Om # # # # # # # # # # # Om Sls # # # # Dw ## # # 52 # # # # # Ss ( # # # / # # Ss # Dw # # # # Sls Sls # # # # # # 151 # # # ( # / # # # # # # 63 # # # Ss ( # # Om # # / # # # # # # # # # # # # # # # # # # # # # # # # # # ## Ss # # # # Ss # # # # # # # # # # # # # # 61 # # # ( # # # / # Dw Shb # # # # # Ss # # # # Ogp T87N # # # # # Dc # # # # # # ## # # Shb # # Ss # # # # Dc # # # # # # # # # # # # Dw # Ss Ss # Dl Ss # # # # # # # # # # # # # ## # # # # ## # # # # # S# s 150 # Shb # # # # # # # # # # # " # # # ! # # # # # Ss # # # # # # # # # # # # # # # # # # # # Shb # # # # Ss # # # # # # # # # # # # # # # # # Sls # # # # # # # # # # # # # # # # # # # # ## ## # # # JACKSON o # Ss # # # # # # # # # # # # 91 30' # # # # # # # # # R11W # # # # # R13W R12W # # # # R14W # # # # # # # # # # R09W LINN # # R10W JONES # # # # Dc # # # Ss Dw # # # # # # # # # # # # # # ## ## # # # Dw #### # # ### ## # # # # Ss # # # # Ss # # # # # # T86N # # # # # # # # Shb Dc # # # # Ss # # # # Ss # # Ss # # # # Ss # # # # # # # # Ss # # # # # # # # # # # Ss # # # # # # # Ss Dw # # # # # # # # # Ss # # # # # # # # Dw Sg # # # # # # # # # ## # ## # # # # # # # ### # # # Dw # # # # # # # # Ss # # # # Ss # # # # # # # Dw # Dc # # # # # LEGEND # # # # Ss Om Dc ## 151 # # # #( / # # # # Ss # # Ogp # # # # # # # # Ss # # # # Ss # # # # Shb # Sg Dw # # # # # # # # # Ss # # # # # # # # # # # # Dc Dc Sg # # # # Dw # Pcc Ss # # # # # # # # # # # # # # # # # # # # # Pcc # # # # Ss # # # # Description of Map Units # # # # # # # # Shb Ss Ss T85N # # 61 Ss # # # /( Ss # # # # Dw # Dw # # # # # # Dw # Ss C # # # # # Ss Ss # # Sg Dw # # Ss 52 e # # /( # Sg # # # d # # # # Sg # # # # Ogp 1# 3 # # # # # a !" # # S# s # Shb # # # r # # # # # # # R # # # # # # # # i # # # v # e Sg # # # # # # # # # r Dw # # M # # Ss # # # ## # # # aq # u Ss # Ss # # Ss Dw # # # o # # # # # ke # # # Ss# ta # # # # # R # Ss # # Ss i # # # # Shb # ve # # # WINDROW FM.; Iron Hill and Ostrander mbs.; mid Cretaceous (?upper Albian and/or Cenomanian). # Anamosa r # Dw # # # # # # # ult Zone Kw # # # er Fa # # Pcc Riv # # D Ogp Maximum thickness: 40 ft (12 m). Primary lithologies: sandstone, part pebbly to conglomeratic, part cemented by iron oxides. Secondary lithologies: mudstone; massive iron # Ss # Plum # # # # # # # U # # Ss # # # ore, silty to sandy. # # Shb # # # # # # ## ## # # # # # # # # # # # # # # # # # # # # # # # # Ss # # # ### # # # # # # Ss Sg # # # # Pcc # # Dc Dw # Pcc Om # Om # ## # # Sg # ## # Shb # # # 64 Ss # # # # Sg #### W " # # # # # # ! # # # # # # # # # Shb 380 # # a # # # . # # # # # # # # # # # # # # - # ## p # # # # , # T84N # # # Ss # # 64 # # # s # # # " # # # ! # # # # # # # # i # # # # # # # p # # # # ## # # # # i # # # Dc # # n # # # Sg Om # # # # # # i # Dw ## # # # # c Maquoketa # # # # Ss 151 ( o # # Shb # # # / # # # # # # # # Dw n # # # Pcc# # # # # Ss # # # # # # # # R # # # # # CHEROKEE GROUP AND CASEYVILLE FM. undifferentiated; Lower and Middle Pennsylvanian (Morrowan, Atokan, Desmoinesian). Maximum thickness: 250 ft (75 m) # # # # # # Dc # # # # i # Pcc # # # v# Ss # # # # e # # Shb in Scott Co. Primary lithologies: shale, m-dk gray, part micaceous, part sandy; sandstone, vf-m. Secondary lithologies: shale, black, carbonaceous; siltstone; coal; underclay, # # Ogp # Dw # r # Mario# n # # Sg # # # # # ## # # # # ## ## # # # # Dc # # # Pcc # ## # # # # pale gray. Minor: sandstone, f-c; conglomerate; shale, red to pink; siderite pellets and concretions; limestone; pyrite. # # Ss # Om # # # # # # # Pcc o # Sg # # # # # Dc # # # Sg # CLINTON # # # # Sg # 42 00' # # # # # # Pcc Sg ## # # # Sg # # # # # # # # # # # # # # S# g # Pcc # 38 Ss # # Shb # # " # Ss # # ! # # # # # # Ss D # # Pcc Shb Dc # Pcc ## # Sg # # ## Dc # # # # # ## # ## U # Ss Ss # # # # # Ss # # # # # # # # # # # # o #Pcc # # Cedar # # Sg Pcc # # Shb # Ss 42 00' # # # Shb # Dc# Dw Sg Ss LIME CREEK FM.; Upper Devonian (upper ). Maximum thickness (Black Hawk Co.): 125 ft (38 m). Primary lithologies: shale, green-gray to gray, calcareous. # # # # # Shb Ss # Dl # Rapids # # # # # # # Secondary lithologies: limestone, fossiliferous, part argillaceous. T83N # # # # # # # Om # Deep Creek ## # Dw # Om # # # # # # # # Ss # Ss # # # # Sg # # # # 61# # # # ( # Sg # / ### # Dc ## # # Shb # ## Sg # # # # # # # # # # Dc # # Sg # # # # 67# # # e # /( Ogp # # on Pcc # # # CEDAR VALLEY GROUP; Lithograph City, Coralville, Little Cedar fms.; Middle to Upper Devonian (upper -lower Frasnian). Maximum thickness total interval: # Sg # Dw ult Z Shb # 30 Fa # # Dc /( D er # # # Ss iv # # # # # R # # # 250 ft (75 m); max. Little Cedar (Hinkle, Eagle Center, Chickasaw, Bassett, Rapid, Solon mbs.) 115 ft (35 m); max. Coralville (Iowa City, Cou Falls, Gizzard Creek mbs.) 70 um # # # # U Pl # # # # # # Sg # Pcc # ft (21 m); max. Lithograph City (Andalusia, Idle wild, Thunder Woman, Osage Springs mbs.) 80 ft (24 m). Primary lithologies: dolomite, -moldic to vuggy; limestone, # # Pcc # # Ss # # # # ## # # # # # ## Dc # # # # variably dolomitic, fossiliferous to sublithographic, part argillaceous. Secondary lithologies: chert; shale, gray, dolomitic. Minor: glauconite; sandy dolomite or limestone. # Sg # Pcc # # # # # # ## Sg # # # # Sg Dc # Dw # # ## # # # # # # CEDAR # # # # # # # # # # # # # # Ss Dw # # # # Shb # Dc # # # Ss # # # # # # Dc # 30 Sg # WAPSIPINICON GROUP; Pinicon Ridge, Spillville, Otis, Bertram fms; Middle Devonian (upper -lower Givetian). Maximum thickness total interval: 160 ft (50 m); /( # # # # # # Shb Dw Sg # # # # max. Bertram 100 ft (30 m); max. Spillville 100 ft (30 m); max. Otis 52 ft (16 m); max. Pinicon Ridge (Kenwood, Spring Grove, Davenport mbs.) 82 ft (25 m). Primary # # Sg # # ## # Sg # # W # # # Ss # # # # a # lithologies: dolomite, fossil-moldic to vuggy; dolomite, laminated or sandy; limestone, dense to sublithographic, partly to wholly brecciated. Secondary lithologies: shale, # # Ss ## # Sg Sg p ## T82N s # # # # # # Sg ip # dolomitic to sandy. Minor: chert and chalcedony; sandstone. Dc # # # i # n Pcc # # # i # # c # Dc # 30 # o # # # # Dc /( n # Sg # # R # Sg # # # i # Sg # # v Sg # e # # r # # Pcc # # # # # Dc# ## # # # # # # # # # Dw # # # # Pcc # # # GOWER FM.; Anamosa, Brady, LeClaire mbs.; Wenlock-?Ludlow. Maximum thickness: 180 ft (55 m). Primary lithologies: dolomite, evenly to irregularly laminated Sg Dw # # # Clinton # Sg # Ss Ss # # Ss ## # (Anamosa Mb.); dolomite, fossiliferous to vuggy, commonly brachiopod-moldic, mounded facies (Brady Mb.); dolomite, fossiliferous to vuggy, part sparsely skeletal, part # # # # # R07W R06W # # # # # ## R08W # # ## R05W # # # # # # # crinoidal, includes mounded facies (LeClaire Mb.). Minor: chert; dolomite, intraclastic. Sg # # # # # # # 30 # Om # /( Sg # # # # # # # # Sg ## ## # # # # # # # # # # # # # # Ss # T81N # SCOTCH GRO VE FM.; Welton, Buck Creek Quarry, Waubeek, Palisades-Kepler, Johns Creek Quarry mbs.; upper Llandovery-mid Wenlock. Maximum thickness: 240 ft # # # Ss # # # (73 m); may locally reach thicknesses in excess of 300 ft (60 m). Primary lithologies: dolomite, fossil-moldic to vuggy, part very crinoidal (Welton Mb.); dolomite, cherty to # # # # # # # # Sg # # very cherty, dense (Buck Creek Quarry Mb.). Secondary lithologies: dolomite, mounded facies, part very fossiliferous to vuggy, part very crinoidal (Johns Creek Quarry, # Sg # R07E # # Palisades-Kepler mbs.). Minor: dolomite, slightly argillaceous; quartz druse, chalcedony. # Tipton # Om C # e d # # a # r # Description of Map Symbols # R Dw # # # i # # # v # # HOPKINTON AND BLANDING FMS.; includes Tete des Morts and Mosalem fms. in northeastern outcrop; to upper Llandovery. Maximum thickness total e # Pcc # Shb r Shb interval: 330 ft (100 m); max. Hopkinton 160 ft (50 m); max. Blanding 65 ft (20 m); max. Tete des Morts 30 ft (9 m); max. Mosalem 100 ft (30 m). Primary lithologies: # # Sg # Ss # ## # dolomite, fossil-moldic to vuggy, non-cherty to very cherty. Secondary lithologies: dolomite, argillaceous (Mosalem); chert, nodular to bedded (Blanding, lower Hopkinton). # Ss GEOLOGIC UNIT CONTACT # SCOTT # # Sg # # # R06E U # Dw # Dw # FAULT TRACE # # D # # Pcc # SILURIAN LIMESTONE facies; LaPorte City and Waucoma fms.; to lower Wenlock. Maximum thickness Waucoma Fm. 80 ft (25 m); maximum thickness T80N # Sls # # LaPorte City Fm. 60 ft (18 m). Primary lithologies: limestone, fossiliferous, dense, non-cherty to slightly cherty (Waucoma); limestone, fossiliferous, dense, cherty to very # # # # BEDROCK WELL DATA POINT # # 38 67 " # /( # ! cherty (LaPorte City). Secondary lithologies: interbedded calcitic dolomite and dolomitic limestone; chert conglomerate/residuum (upper LaPorte City). Minor: shale, # # # Pcc # (61 # # / calcareous. # # Ss Dw # Sg Pcc # Dw # # # # # COUNTY BOUNDARY OR TOWN # # # # Pcc # # # # # ## Dc Pcc # # # # Pcc # Pcc # Ss # Dw # # MAJOR HIGHWAY ## # # Dc # # # # # # Pcc # ### # Sg # Sg # # # # Sg MAQUOKETA FM.; Neda, Brainard, Fort Atkinson, Clermont, Elgin mbs.; Upper Ordovician (Richmondian). Maximum thickness: 275 ft (85 m). Primary lithologies: 80 # # # # . # Interstate Route # # # # ,- # Om . # ,- Shb # # shale, green-gray, dolomitic; dolomite and limestone, variably argillaceous to cherty; limestone fossiliferous, part cherty. Secondary lithologies: shale, brown, graptolitic Dw # # # # # # # # ## # # (lower part). Minor: phosphorite and phosphatic dolomite (basal part); oolitic ironstone and red mudstone (locally at top). # # # US Route Dc # # ## # # /( # Pcc # Dw T79N Sg # Pcc # # Sg # # Dw # # # State Route # # # # # # Pcc ## # GALENA GROUP AND PLATTEVILLE FM.; includes thin interval of Glenwood Shale at base; Middle and Upper Ordovician (Blackriveran, Chatfieldian, Edenian, Dc # # # # Ogp # 80 # # # . # - # # , Maysvillian, basal Richmondian). Maximum thickness total interval: 320 ft (98 m); max. Galena Group (Dubuque, Wise Lake, Dunleith, Decorah fms.) 275 ft (85 m); max. # # Ss # # 6 # # # Dw /( # # # TOWNSHIP BOUNDARY # # # # # Platteville (McGregor, Pecatonica mbs.) 55 ft (17 m); max. Glenwood 10 ft (3 m). Primary lithologies: limestone, fossiliferous, variably dolomitic, part cherty; dolomite, # # # # # # # # # # # # fossil-moldic to vuggy. Secondary lithologies: shale, green-gray, calcareous (Decorah); shale, green-gray, non-calcareous, part sandy (Glenwood); limestone, argillaceous; # # # # # # Dw # # # RIVER OR STREAM # Bettendorf # # nodular chert. Minor: dolomite, part sandy (Pecatonica); shale, dk brown, organic (Decorah); sandstone, vf-m (Glenwood). Sg # # # o # # Pcc # # Ss 91 00' # ### Sg # R01W R01E Dw # # # R03W R02W # R04W # #

Dw # # Pcc PRAIRIE DU CHIEN GRO UP AND ST. PETER SANDSTONE; includes upper Jordan Fm. (Coon Valley Mb). Lower Ordovician (Ibexian, Canadian) and Middle # Pcc # # Ops T78N 74 # Ordovician (Chazyan-lower Blackriveran). Maximum thickness total interval: 400 ft (122 m); max. Prairie du Chien Group (Shakopee, Oneota fms.) 290 ft (88 m); max. St. . # # R05E ,- Dw # # # # # Peter 220 ft (67 m); max. upper Jordan 50 ft (15 m). Primary lithologies: dolomite, part vuggy, part cherty (Oneota); dolomite, variably sandy, cherty, oolitic, intraclastic, and Pcc # Dc # # # stromatolitic (Shakopee, Coon Valley); sandstone, vf-m (St. Peter). Secondary lithologies: sandstone, vf-m (Shakopee); chert, nodular, part oolitic. Minor: shale, green-gray; ## # ## # # # # # # # # chert conglomerate. # # ## # # # # 280 # # . # ,- # # Sg # Davenport # Pcc # ##

CAMBRIAN # o # # R04E 41 30' Pcc # # # R # E JORDAN SAND STONE, ST. LAWRENCE FM., LONE ROCK FM.; Upper (Trempealeauan-; Sunwaptan-Steptoean). Maximum thickness total 5 0 5 10 15 Miles # # IV Cjl # # R interval: 360 ft (110 m); max. Jordan (Waukon, Van Oser, Norwalk, Waukon mbs.) 125 ft (38 m); max. St. Lawrence (Lodi, Black Earth mbs.) 120 ft (37 m); max. Lone Rock # I # P T77N # P 140 ft (43 m). Primary lithologies: sandstone, vf-m (Jordan); siltstone, dolomitic, and silty to sandy dolomite (St. Lawrence); sandstone, vf-f, silty to argillaceous, glauconitic # SI IS greensand (Lone Rock). Secondary lithologies: sandstone, f-c (Van Oser Mb.); shale, gray to green, part glauconitic (Lone Rock). # S # IS 5 0 5 10 15 Kilometers D# c # # M Sg Cw WONEWOC FM. AND SUB-WONEWOC Cambrian units (Eau Claire and Mt. Simon fms.); Upper Cambrian (-lower Franconian; Marjuman-lower Steptoean); lower Mt. Simon could be Middle Cambrian. Maximum thickness total interval (to basement): 700 ft (213 m); max. Wonewoc (Ironton, Galesville mbs.) 135 ft R02E R03E (41 m); max. Eau Claire 160 ft (49 m); max. Mt. Simon 405 ft (123 m). Primary lithologies: sandstone, vf-m and f-c (Wonewoc, Mt. Simon). Secondary lithologies (Eau Claire): sandstone, vf, and siltstone, dolomitic, micaceous, part glauconitic; shale, gray to green, micaceous, part dolomitic. Secondary (Mt. Simon): sandstone, m-vc. Minor: Scale 1:250,000 dolomite, argillaceous to sandy (Eau Claire); shale, maroon to green-gray (Mt. Simon). when printed at 36" x 48" format

INDEX SHOWING AREA OF GEOLOGIC MAPPING

Prepared by the Iowa Department of Natural Resources, Geological Survey Bureau, May 1998. Open File Map 98-7

Universal Transverse Mercator Projection, UTM Zone 15, North American Datum 1927