errr as mnt. WO ta aatnes Am Ree as etre ann ae nhac 0 net eae wae ve as Se mw SCF, BT pa ge a ar wer eeea reap ET mE Ty egg bm A LS Ee lin Ha) ANG i Mi Bi iN ny vy a aia ie eat utes wt LM DEPARTMENT OF THE INTERIOR MONOGR APHS UNITED STATES GEOLOGICAL SURVEY NV ONE MEM eX XOxOVeET WASHINGTON . GOVERNMENYT PRINTING OFFICE 1899 UNITED STATES GEOLOGICAL SURVEY aes CHARLES D. WALCOTT, DIRECTOR AC Jel Jab PEpeNOre GRACIAL LOBE BY FRANK LEVERETT WASHINGTON GOVERNMENT PRINTING OFFICE SIONS CONTENDS: Page IME RTE RSORRTRANSMUTIALiy ee nae Sac lomo sie ame San ernie cele ect ese Ate melee scciee cde tine eis ase x INESTRAC THO RRO UM gametes series c\qto nicl saat ise rsh einie e ere ey Safe ae cee etne iocresenisee cee cic. GXMIL (CHEMISTS sa GANG Y DL GLORWON Goce asco coe cob noes Geneenueoeon cuny Sap Scnenea bode case dess bo5p ceenee 1 CHarrrr Te —PrySICAl) HEATURES ese sseeee eee eet eaee 7 CHaPptTerR III.—OUTLINE OF TIME RELATIONS OR GLACIAL SUCCESSION ....---.---------------- 19 CHAPTER IV.—THE ILLINOIAN DRIFT SHEET AND ITS RELATIONS.......----------------------- 24 Cloner] GIMUOMGNU os sed cues code SopnodSbee SodaCE bodooo cosede Snonos DoEe Suas0n BoaodoneHeos 24 Relation to outlying and underlying drift 24 Relavionstoytheplonvannduilktisheetwyscseeese seen eaeraceeiaareleermcicnerecinectcltacisiseiaeer 24 Culmination of the Illinois lobe at the Illinoian stage..--..-.....--....----.----.----- 25 General aspects of the Illinoian drift sheet..............-.-.---..-----+--------------- e+e 25 DENTON OLE HWS Cag NOSES = 55 655655 ocddGucoeess Sooo bond ods caaado ashe Sods baepseudaoodepes 25 TO) COERADNIC GN ORI OM ss oS 406 Seco cebcee ades boo docs Hace cose eo dont daSs Seances csosbaEs 26 Thickness of the drift 27 Stricturevofathednittasssecemacenaee ae sate cee re aecion seciave eee ree ere coe reer eee 27 Gam OnE?) eache saison cinere cis ote sere rade oe ae erent miois cinisieinlere bstorer Sages sieeelsieeis sieve ee re ciate 28 Sectionssofetherlilin olanyciniditeeeessiseseeeeene reece nee eiceeteeeer eee cecaaecne 33 ANiya .abetne hanks too dsuaneonacGas pace conouaHESseS cOodon Gdbu dbp5 GuoS saneos daoSneabe cons sone 34 DASA HRUIO MNS 64565 cooSde decnbs Shot boohoo ebe eobsconseu babe Soon eeBS SOUndbESShe> asun 6645 3 I OGG Gh. soo cscacsdoce senses edonsosoEseeGnaces cecous peemas ssuood ceeSee 38 Structurerotathe aritcybord eremcrcmic nc ctsisccisetastn tells aisles elses ee eeieieee eieinieia stele islacitere see 40 Characterotetheroub washer sersc) casa vareey sare vatcis tetas cient alte ala gay serala|sectey Ts oectats erro 70 Dhexridced driftiot the Kaskaskia; Basim =) 52-7 = <= 5) one ia yeysiclsiel laine am ee aininiel icicle maim 71 IRIE Op aN IONS Saqo Bad edcosd CseoRe dadcod SHUO5S BaASes Sere HabopraHes daseemdoasdeoese 74 Eskers or gravelly ridges of northwestern Illinois ...-....---...--.. ------------:---------- 76 THeateRiveLrrOryAG OlUNE.eS RET Say fo sae ee ge eee mieten ese eee acters leiem tee ie ete te ee ean ae 76 Mazellhurstyeskerpe cscs tea era Se eee stele eereielatare eno ates elese sie sere ote tert are 78 GardentPlainieskery.cc seer ase calc aa eee lone wichenwe sleleciicterin= siete nein alse syeiias eee 79 Recatonicarcskersy Stems serssni=oseiee eee satstisieiietscctecerisceeiaiseieecie eee eee steers 80 Cedanvalllenb ehtx reese oe ecisic sors ale are eke eos a rsiece te Stercinjaieswivismerelb ier semeise Sere emiaeeioeaar 81 Onamcenillle hallitgs cone ceo> ono neo nesbos Scoop nosbee code conees ESsboosess cheecu ceases osee 81 Genenwhobservation sts. ie sees sec face ce ei aiinle eats aa ie ioiniee Spore ismicicce seem ete Ase caeee 82 iransportedyrockwled ceswe sre wee eters rats tee aa sealer sera erat neice este isete eye eieiniee 82 CEU emer SIC er eas St a ne eC eR A ee eS eee RE 84 Effect of the Illinoian ice invasion on the outer-border drainage. -...--...----.---.-------- 89 Temporary displacement of the Mississippi River 89 Changes of drainage in southwestern Indiana-....-.---- 97 Pleistocene deposits beneath the Ilinoian till sheet......-.....---.--..-----.-------------- 105 AK Cea TAH TDD a ie aria a ACR as obese areal hms ot AN ISS Detar a om hs Net See SA ie ek elds 105 Pre-llinoianebilllandsassociatedidepositsa=sce sane se es eae ee eens eae eee eee 107 Silvexriai@?) tormationyandtother/ silt deposits aes. 222254222. -i- aes See ee eae === 111 CHAPTER V.—THE YARMOUTH SOIL AND WEATHERED ZON 119 Weathering of the buried Kansan drift -....-.-.----------------------- adneaeseas a) BUTHedl Oil; THOM CWO seceded 205 beados boss does s55550 SoDcaoS GUS ED boas Ese See Heeone Seas 120 HTOSTONKO tau Lem WwansanrdrinuiGheeteeeeereeeee te eeeeee cise cei site rem ecince eee eete cee cei 121 Ons MANe MEWAINS 545554 c0bccs seecéo osesbs Se bbes 6oGes bbcode Sa50 soS5 beeEos seeeus Sobacoas 123 ws ju 4 VI CONTENTS. Page. CHAPTER VI.—THE SANGAMON SOIL AND WEATHERED ZONE..-...---..---.-.---..-------.---- Ge CHAPTER VII.—THE IOWAN DRIFT SHEET AND ASSOCIATED DEPOSITS.-.--..---.------.-------- 131 Mhenlowansheetoseshewllan ol Spo Cee ers see ee ease eae ee 131 Distribution or extent .----- -- Pete eta CERIO SUISOs 6 Sonn SaRaeoee east Sere waoSe 131 Topographic expression. .--------------------- ---- ---------- ---- -------- =------+------ 134 Mhickmessvo fi thev wilt menace ecm ee eel ee eee ee ee eeetietetaaerletoininse 136 HEA eMOle COM eta g eee esen Sooo on ta easoee ees Sado reso aches SaoeRU ots cee saceoe 137 ORE Geena oees CL oedevorricaa tooUmasoronsesmeacantd aise cote asdbocss once ace meceadiaace 140 Probable extent of Iowan drift sheet beneath the Wisconsin ....-....---.----------------- 141 Probable extent of Iowa portion of Iowan drift. .-..-..-.--..--.------------.------------- 144 Relationvofatheulllino1shn dslow:aan Cen Oe pst ester teeta earl 151 ANG) OMEN Oke soane cmisceo Sacees seecte Oooneo ceseatSousds Seote ses eren sees coda sees seecisoe 153 IDO HOA aan oe sos CoeSas Sacisee ao Seer ebee senso choses oso erSosoeesaoses asesraseeo 153 A AMEN Hoya TIKES cage conecosace SoUeae ests Hos osoSese caob ess Spee sS toScotSeescee5 155 Ghrenonnte, oon eoe sebacolgddosenesans oneoee 6565 so0nce suse scoop OSs SoS SSssso nsonseeSse scceso 156 Interv es SARE os ase ceo esocmaacaoonocae scence dsebins odoose coceco opeS sede seo eons 4epaa5 165 WIGS GE GENO NS cana Sach okoricson ongees =aoece bscees sees Sac see dees ecooeeeSaeEose cess 176 Cuaprer VIII.—THAE PEORIAN SOIL AND WEATHERED ZONE (TORONTO FORMATION?) --------- 185 Generales tacemve rita ete ieee ee ae ee ae eee ott 185 Soil and peat between the Iowan and Wiscons*n drift sheets ---.---..----------------- 185 Leached loess beneath the Wisconsin drift -.---...-..-----.--.------------------------ 187 Iowan outline compared with succeeding and preceding glaciations- --------.---------- 188 Change in attitude of the land--------..--------...---.++--+--------------------------- 188 Length of the Peorian stage..-.--.-----------------------------------+---------------- 188 TM NOM WO BMERGON: oo 56 case cadaos sSeSao Maceo Sooo se neon ado SoSeS ose sopanerS cseSes: 189 @HAPTER 1X.—THE EARLY WISCONSIN DRIFT SHEETS.---------------- -.-. ---- === 191 Generales tater emtje na sete ete rate ale eal la et ee em mtn ale ama 191 Section I. Shelbyville morainic system ..-..---.------------------------------------------ 192 Bixtenbiotethersnel biyawallll 6 is Nee titer ee ay ae eet 192 Shelbiyavaille pm oan eye ete a ee a alae a ete ee eee 192 IDIOMS 5 ooo sho ss ooeS HSecos cone bed S255 0005 ES Sebo sesso sSssocsss esse sscesa cece 193 TRO tos weoeead socesd nous soau Conon eEEe oso desea epeEsoasosas Bosnosce ones poesed 194 TENS) Wa OVUM) cae see ece obo pep eEds oslo o> eseaes HSecEsOneescosacso cbea secs OSes 194 SBE MOUS) = peek ones ose esem pba aerISaesS Sse scsds sorbesebSc oooeceeseeacocce 195 Sirnchumeran dat 1c kn eSsyo ta Celt ee bys ane ee al eer 197 @haracterlosowiwash) ceesereee ee eeee ee ee Cee eee eae See er ae eee eee 208 Thabareyes oy eK WAAOE sob oooaee Con dee Hooded ceos sesbcesg Sods esos odposeSo cede He csclicsobds 213 Topography ---. .--- --<- - 22 - << -- <22 = 22 = a nm nw nn ne = = nnn 213 TNA MAST Oe Chav iadeo Sess case coos Sear anue Meas pags Doss oaed cose qaeeoceenssensccsscs © WIG} Structure of (rifts sic tece eee ae oe Se eran. SER Ee eS eee ores eeree rises sae LS: GerrorGord ommolalme meer eee eee ite ee ate eee eee ae eee ere 218 Distribution 218 Mopooraphiclex pressions. 2 cee! 75 sae e seo = eee ee a ee eee 218 Struchuroro te hlrerdritte assets te ee ere eae ae eens cnet ele eee 219 @haracterio tou twashiee cease eae ete sete eae eee le eee ee eee ete 221 Tree loorte Gyr TPN as isos ose ssS oceans Seoces beech s Sond Sods ceo egmceed coooen secs neeate 222 Section II. Champaign morainic system ------ 2-222 2- sone on ne ee ns aoe 223 IDE MMH So oa4 oes Sosa bose ce Saccee Soot osores sfoe sess sess este oreo obec sstscccoas 223 IID! 55 soto ce caso Sasa seegssen coo cies asesas sess dSse ses thes necodens sesscscocs 225, Rance nnya bv d temas eine) ae ae an eee eee eee 226 STN EES) COONS) S50 Seco epee see meee casos cossosed os edooss SpeSesco rsee osesse sass 227 MhicknessandispLuCtuLerOl Olt peas eet eee eae eae tae ae a eee 231 Character of outwash 237 Associated till plains ----- ---- -------- ---- -- 22-22 ne ne nn 239 Section IJJ. Bloomington morainic system ---..----.-----------. --------.-----------.----- 240 IDWS MNOS | Sos Coded Oba Sos ce see Ses Sor cosas cogeSsee SoeSceSeas commence so seed cess 241 IRIS 5 seas socemo doses ctocae Seobhs cocaine csicd Gost ogee cand obSescenas | Socusoosess 244 CONTENTS. CuHarTer IX.—THE EARLY WISCONSIN DRIFT SHEETS—Continued. Section III. Bloomington morainie system—Continued. Rema) TH AVAGO. 6 Sono cesoos ceeewdccomeashocse -sed Reno Smeadoc ancecicoceSeseOs oor SI ENES, COMIMUETS Go. socdadosaq dads acsagosche pe osce SH pUseSeee seosboka Does ooeS podsop Between western Kane County and the head of Bureau Creek ..-..-...---..--- ImpBuresul Creelkudrainac eyb asim see eeyser eer eee a rama ee tae = neta ee tora a InsBureauwMarshallandseeoria counties sees sen sees eee sae eee ae a Bet weenstheslllinoistandeMackinawerlviersteesiscssee = eters cise siesieleie astepete ete Between the Mackinaw River and Ford County reentrant. -.....---.-.-------- Mhewmeen brant mn Vora © OM Mbyte eee lea ie isles teal ete ete ee ae Eastward from the Ford County reentrant to western Indiana. ....--..-------- The portion covered by the late Wisconsin drift ..---..----------------------- The weak moraine in eastern Iroquois County, Illinois..---..----.-----. soous? OfRnseny IIMS .cod sons coo cde caaeesos ads pond nQHEeG CEeass snoSoconUeHBacensace OINATONTOR CANA, INI Con 6 seco conc coo onbbso cess Beso HodgneoseS sess deeemer iDemere TeCalGxs) Ore (CoP NE TOS Cao poosoe code Sone SSeb Seeesdeoso ces msennoEs core TIC ken OSSHO hes CULES eee eet ete eso ate eet ot tae hee eesti eisieiec osele sami oor ores Série trimer oun chin trey eters aero are eee eta ayer eee op ane Spiele hese te oie FENG te ChpMEXeNSe Ole CUE wodc Sancisos boss Hoes Gadbliesao eos Saeclicoeane noasoe KeeaGabesaae ThA MNOMENNTNG THROWS. «cses cosa ude ceeee aces coop mcocoscsbe Ueeo uous Hoob sewaoseeestoea. coe IDG SOMO Ni Oke Ge Nios coe cecsencoce Boca desaddauos podo eboeusd aoe kee.onesce ees abode (OG O LR E Pete se adda case noReuoiesonseldeomeconsore bbodos OS HeeH Aasoadeaseiaoce THic knessno te cil benter es ee epee ese eee ons cenes ssa yaaa semeie mean ele mee VOR Gi? Ghelin seco peas cooeHoBSE conc scsecoEe CoSU mene oboone Sons nobeos caceen osbeno Kanevillevesiervandidelltacpocs «Soe cere see laa en ee ane Meee eee oeiae Inttlosockwesker vor Devils sbackbonewess == nena = serene eens eee tela OOy/Gll INIMGS sn0 SoSnbo soot es Bocode boscce sons pone cogent edocs Coe ase cEor seeSs5 Gamano Onarga Ridge) sete ere eee ee ane tte etal alain ole ee e/a = sla miele wial oleae meinem min Section IV. The composite morainic belt of northern Illinois..-----.----..----------------- Marengo Ridge. .--..------- ---- ---- +--+ +--+ -- +--+ ---- +++ +--+ 22 2 nnn eee ee IDIOMA. Sas Seo moses oddbeaosn Seceoo bees soseaseH seuss) deeds Meche eee emeeter SMFS COM UOWINS 5 6 ed aces ses esos Sood seo noneeda cnemeD ocecopesuabe sontccoeos RSDBRe AMO eGR Gie GhebRIS cae Saosscecos soad GaSe ao omen Sco SenUcenoSHenaa Baesay bocosesese RiAHeS Ole GUA go ooseosoobopadedcesas HosoOU beoaoH ecuSbs cecods Cooues eascaa SeaGbq (CiipmRACIG! CH? Ooi, Hoo soe 55uaSccu sasd dea dos Kocaed bobsedaede uadoeddoeoer oseeee Innersporderphenomlen tye meseree seme eee iee a\ele eee mee eater fae ee arial COMO NI o465 eso0 sdbocsetdsedis Seas Sao cagsoopsaese deceoooaadoe veeneSeedeissaoes Portion of the composite belt west of Fox River.....-....---.---.---.---------------- (Somennlitiminysshscesuseuuceodes eee eeedn eodr dada ie Guo Chose See poHemE saEcaainodo sone Sreucwine @F Ghali csec codecs cone comach Sees basd beds doSolds S6 cb soso Hoy oceeeESS so eess Cooney 45 sosccadscu Sancuso anaese 6500 odde GenneAsososbbSccubesceds. cossos sacs Portion of the composite belt east of Fox River. -..-....---.--------------------------- Distriputlonvanduconnechions sseci=eeeeece ese eee e eee ene eee eae @onenall {enitniesoo ods Base aac coaessce Soaade Snee cena sacoSa Subassop aac > pepbadosSeed FIMO MNSS Ot Glavtie do- best seoobeus Soceod aa oe dea oneens scee. Suen cose cuSacesHeca5 cose CeO OF Ginthy Sod SdeceSskseee code seeds conaop Smee Gobo Babe Gobo qenenoteadooress Sections MIELheyMarselllesmmoraln 6 seme ere eee eesti ae ate a eee Onan det a coe ede Ghbd Soe ee csoues Sad] Gots case Sénb0s bSabenboUSbese eSebescnoe Range in altitude ..-.-.------.------------------------- +--+ +--+ 2-25 2-22 e222 2 ee IRONS? oo coc ebkeeet bus toetesces Secale shes noacte Go Sdeastance nosbed senecoeradomeros RIT TACD COMIN S 245 soc oneobes cedhesinsoe sae Geod secccesepNpeoeeebods HeeaeenSacanoe THO RAGAS Gi? GliNhE 656 oad Soo bns Sabese sodecubsooes cond HeooHe oadood depseSs paciace Scat Simei OF Gb 46 sonees Sou Sho Gubees Koco 5655 eden sobs Hodes eed bonesdeseeoseodsE Ciramaciae OF Ouliniel Ks 5 bees Bask ageeeo tho sencose esteaeeeseeaes se coden Stee seems Teese Us NENNEs os eec5 Sane po ebcobeceoe SE eens SoS6 5665 SbOn SeSoUcee bese es Sa eoopo pwwwhy wy a yoy wl oe bo co 00 OU Gt St St Gt Gt Tt Tt ww wy 7) —} VILE CONTENTS. Page. CHAPTER X.—THE LATE WISCONSIN DRIFT SHEBTS.-.-.--..-.---------------- Season 317 Basis for separation from the early Wisconsin. ...-..------.---- Bi ways Sai 317 Outlinetofsthelateawasconsimubordersecee eee ese see eee eee ee eee eee eee epee ete 318 Section lbewvian OO ksuruulilitsy cl oe apse se a a rere 319 IDET SIU Nes ee Set aaso ese osoe heed Seon bensos Stes bcos chide Goce baos cops GcosCdes 319 Probublewineoticontinuahlonere see oe ees eee eee eee eee Ee eee eee aeEee eae 319 IOS Bie eee eR cin eeemce BAR OROO Mas ORb oon eae Ssatee Genesee cae DRS OCEn 320 Mhrekmessio fi Gritty yee te ee ete an nee ate ee eet epee ree ere eee eee et 320 Senet hub gee Gb00 (Re Guee aah Spectre ecemmeGOnbOn DoS So colo CoEEeoUnCowe se cum aoaaoe 321 Characteriofithetoutwashy soos scestecer a cee sect ee eel een ee eee eee 321 Innere yop Ralere HNL THEN oh cos sch eedacs so sesb edecoddaressiodos Scop ke soepeo cehe sess uoss 324 Section il. Bowlder belits =: 50 e 2. cee Se se eee eee ee Se eee emi ese seen ser 325, Section iil ake: Manivakee: ysis peels ne ete ee emery mere aparece nT ete 328 Maxton trotethersam is acl to aecic ey somata Berea eee ee eterna sere ee enon ete & 329 Range in altitude of the bordor of the sand.---.-...----.-----.------.------------ 331 Sumfalcencomtovrs eee ee ete re ete ae eae aera ee eee 332 Mhieknessiofethersan dee. 2 sete ele ioe tel eve ae eee fone te ee terete ete poe pte ars eee ree ee 333 VaTiat ONS Ni COATSENESB) feo ojeea oe eee eee ene ee ere ee ere tee ree ee ere ene ce BBB ILA RUAN MOWS) =e Soda daca chem soocss oosdsebacesceacess soousHedes LenB csaemasoe oaas 334 Sections iver Dhenvial paraiso moran Cisiy, Se Me ee eer rae eee erent 339 Distributions: <2 85 ee eee ee oe Sie ee Se ene ee eee ree ete oe nes pee eee gee 339 Border between the Lake Michigan and Saginaw Bay lobes ..-_-..-.--.----------- 340 Rees) shy VNMUIGY coco scsses case tondhaas RoeaSe ca06 Sesccdod osesas SoeeeoEo SSeS aaases 343 Sob BIAS) GOMOD seas esqa agen ade dee HEU OSes poooed 0565 Soon CoD Das SonUSEE bboETS dobooS 345 Detailed description of the Michigan portion _._...........---.-----.------------- 348 “THOME Or? WAG Globe So ces cand poadoueR ebboss of on son Dasa Sace GEdS SooE GSeoNSoN Sé0e 353 Structures f thevdritthera sept seers e i eC ere eee eRe erie sree einen em 356 @haracter ofitheroutwas bias seer reece eee Cee Co eee eee Rer eee eee eee 375 Sectionsvenlne lake-bordermorainicisy Stell === => sere en ener ea arene ee Ene earner 380 Till ridges of Lake and Cook counties, Illinois .--.---.-------------------.------------ 380 ANA CWUKEP OP WEG WHEE. 5 oS iee6 sees sees ocad canbe Hoo DoD SHbSeS Seco ce eSeeeSeoDESEs 380 Tay) moniGlellle mIGxs) = 3-5 occ sSs5 beds esoesn Baud cooo Sees see uScoESg Dees Hes USScesteooooes 381 TING) CESUTIGIGD§ Seocot se sace acebecoss toss qadone sescecosee _somesdoo coco sesdocense ctor 381 Probab] GxcomPin mah OWS ycerse cee rs rates ae eee teeter 382 JOON S46 Sas 5S one acoosn daedne poatan cbenpolbceeincas sscelon phos nHSSdd Dade Se Gate oeeace 38h THICIMESSLOLGATIE tps pa seis ches Spee oy le ee ee nee Eee ete peter tele aes ete 384 RYOUKO NU RsIONe Gh wha hee creo oo eH COREE TORE ins 35-16 coe oSMemagone eran ecuaacecsse 385 Till ridges on the southeast border of ake Michigan.--------------------------------- 386 MONG OUP WOES) sescss cesses sce ees se sene Bass chooses o060 coo dns soctSabedecdce Porson 386 Chants NCIC s So sonsee osborc aaeces pouuES Hanes acess onDbas acd Sooubcosaeeacesocos 388 AROEG TCO S55 coo5 occas saeco cnet SSeSed one bemenosoedes sesecoGens soso segs cacmss 390 INSTI tals He Bene On eSsb ond Ges Sees OSeT Soe BeOS OO Earn btse Gone HeteoaeEer cESaoossmeda 391 INANE: Th AUMUOIIG) 35 seb oSo coo essg besos Sooo Ssar odao Read SRoo bao Sa ceSd cece Sebd ones 391 “AN OloVSz6) Ce Clalit Sop ao Heats socboe enon eoad EsoeeacoUN Sd odDS AcEmas cope se dere boene 392 Structurerotadpiitecs cts sare et states eet anda slate sete terete etait ete ere eee tee eee 393 @Heractertotathevo ut was Depo sseee eee nase ees cere se eee eee eee ee eee 403 NERO UE AULT HENS 32-5 25 boss soso eda Sens sono sooo eat oseasepesececcssassassccoosss, Chih Aine, Amel SIQWES. --oa55 s5Sec0 Soneso Saesisooe SaisSS sSmosS coo saSSSsesecSs esos cess 404 MhickmessoMmavitt ssesesece cess eee eee eee ee eee eee ee eee eee eee 406 CyTAOLTR RS) Ore GbN Othe e cee coco psaoco sees Hood Sooace ShSnoq HES Sod BeGaE nd condo scseesEs 407 Section VI. Striwe within limits of Shelbyville moraine -....-..---...----.---------=-.---- 412 CHAPTER XI.—THE CHICAGO OUTLET AND BEACHES OF LAKE CHICAGO....-..--------- soncee 418 IERENAIOWIS MARU So SoS Koceso obosed SI5She c505 ssosapooe See ceas csngsaassobse0 bods eteseb S550 418 The Chicago Outlet .-..------.---------------------+----+------+--------------------- ---- 420 The glacial Lake Chicago ------.----------------------- -----------+-+-------------------- 427 Upper, or Glenwood, beach. --.--.-----. ----------------+-------+---+--+--+---+------------ 428 CONTENTS. CHAPTER XI.—THE CHICAGO OUTLET AND BEACHES OF LAKE Curicaco—Continued. The glacial Lake Chicago—Continued. IntrAPEMl Ore GUNG RUSN Os soccer cbsecs SoSe ss eosued cooeboc se deenes sobone Essa see eaBeeeaeee Hossibleysecondte meng ence meet era eiey eta eter eee tere net eae ea ‘Malial, Or ANON EUOM, IDEN 6365 scaces co nces Secs ped dnseeneser sos cees shocnee sees eeeeee snbeypresentgbeaclmorelalcepNti chic an eee epee et eet te ys ere ena eee oe CHAPTER XII.—INPLUENCE OF THE DRIFT ON DRAINAGE Deflection past th MS AND DRAINAGE CONDITIONS... C) ILUQCENIE) OHM Noe, TAGS. ssoceeoee cede conese adesoo seeeese see Jeoe Reestablished stream between upper and lower rapids--.-.--..........-.....---.-.---- Deflection at the 1 OWL TAPES yas er tse ayscniyne seiaee) eae ees ta ele a Jacidigacwentnecs sei Reestablislred stream below the lower rapids-...--..............-..-...-.------------- Deflectionsssouthyoteelacialmboundanye ese eeer eres naee eee eee eee ee oe eee Rock-flooriand) presenitjstreamicompared se tases aee eee ese eee eee eens sco es eee MinorstributariesiofitheyMississip ppleesses seen serene eee re ree ee ee eee eereaee eee eeee Apple River.... .- Plum River ....-.- Flint River ..---- Lost Creek. --..-.- Bear Creek. ...-.-. Bay Creek 2... .- Big Meadow channel . Ines NAL hE Eye ANS ooecoosdes beonon ssonadinecs ocSsaeducHos Aes EBS E AB eae mae ecner Rhetpreglacialidrain ace se sats o 5 rece tees eee ete Ieee ae oe Se ae eee oe net: Present: courselo lo Glo Rivie nse nce epee esa yey ce epi jer oet yee epee tune alan Green River.-..... Rockieorcesioinorthwesterne illinois =sserereee ss see seer ees eseet ecnee es eee eee Hlinoisghiner drain ace pb as inter. oy. eater ea aN oe ys RR Veep atta eben The lower Illinois The upper Illinois Des Plaines River Mazon Creek, ete. Vox River......-- Kickapoo Creek. - Harm Creek ._-_-- Quiver Creek. ..-- Copperas Creek -.- Spoon River... ---- Sangamon River. .- Crooked Creek . .- McKee’s Creek ~~~ Indian, Mauvaise Terre; and Big: Sandy creeks. ................---------2---22---+-2--- Apple Creek.-...- Macoupin Creek. - Otter Creek ...-.. Le ae ne ee ee) © © OO ¢ Ce ew kh le = D or Ot OT Sl OF OT Ot OF St Ot St OF ¢ or or or 1a} b WwW le or or or lo x CONTENTS. CHAPTER XII.—INVLUENCE OF THE DRIFT ON DRAINAGE SYSTEMS AND CONDITIONS—Cont’d. IRESRASRGy IRI Creathm nee) WHS bh Ae Code dom becema seen se ae Aso Soe ated madd seceisae scene ICSE Sh IO Ea eerie s ses cp oso Sa Sha seeS soa aeosapmoodasotscHee ddoscsnS cons cede See Sooynll (Cielo s Ss swogeotasetseesdndiedo cose asentese sh renders senses sere sdest oppsinticineoees Silver’ Greelestue ceca ss cbtimec ome s ceecee Ge Sotnie a Se cise eee yas Smee mee tet ot one ey oes art Leyes Nu hokehys Mrbwteye bebe KAG) Wns hele aoe cess coemos Sese agoc oso oes S650 sec6 Bsa sono seceeooeee SAIIG Ls Or Chm Baa ME: ooo cs noeee ote sooo Sere SoootS BadeOe Be coas Soecad oto Badane (OEY ST ati ty 12) Dea, ae eee i IER Sh Sst a arte ae eels Mc th mime orale a Shar ls toe | ea ea Wabashshivendrainage Dasinee: assem near ne ae a 3am ies ee Seer ee ee ene Steere es Eee TPnGed eral ERIS WECN Ss 3-52 = cosoos'ssnane sosest asso oseces Sisco seed osoceasosasqosence Minor deflections of the Wabash. ----.---....--.--------.--- SE nae res ot a ay TittlesWwabash River: 22-- =... ete Sacks neces sn Sem eeetaes cee sas Seeee eee eee Eee see PB OMMIPAS UYU OL eae setters ete ere tee ere ee SL Senet (PabolcavhiLVereiccsc cic aoe usec eae aes aie ree Ric ares SS eee tale eee Sa eS note WV) INVER os Se oeetaaeeee secs cesclercossonssusessese ox 2 S00 GSSe SOBA esou sans GoSseewoSsite DORA ay ale a San oe serene se eos San aces Cos So bSneetoSeocSs asoocy mectmnsoose oonaossoS IBWEREeONC) te Se aso Soa a aRe See Ben ece cma Snes Been GoSd sob achon cacaeanoe aaockbosociaciods Takis IEMA HOO OIRO ooo 5 Sects one ears copsasaa ssh coas Osco casbor cuss eeds sogacwas seo0 2008 NSRP (CIRO Aa 65 nos SSsucs ooseeS esse song GSensd Seam sSsnce Goad esos sesdasseetedastsoassce Wier INT Gis Scans cacs Sods coos catmede cas dear Scoensoro= Sseseass SonSee Saaicoo soos5¢ IbpY RG) MO MnGEy A (EME WAS N ep nos cose eccees Saseco sesh eso cacs osededae ea ao ce seco co scise (Chivicnyaoy IRIN@Ps ce ceede acd cessed stecso seesee Cootge conmose seb seSsta snes ssee Soescedese (Chniltrinnyn IMIWGIP 6 coe e ste b cod don cosas SonSoS eddie dese tects consee Shee elses ceetos csc AREA CREGs jsossdlosoeee Sesh Boos cass se cece cedd sose Soe dscees esse cos sese soso cose sepece (CHRO IRIN Guid socatsup sone Goss asco dsoo paso uotS Seece dec cot ocean oeeSEEseksel sobs anes Sirs OECTA IOP oe Seas onde seston eScenees Sbodied sesoss Sess edo esed sedo esos doce céco TPayqoblun RUIVGI « sShene peae dose Sesdsond cern osos satco co esoridisus cede Saat coaSnoososeo dace THRO Ii eosoe nance eesdcese cadm cociacd papeoe secess soSccu gene Sebase GunesS cess caso ones Kalamazoo River - --- CHAPTER XIII.—AVERAGE THICKNESS OF THE DRIFT IN ILLINOIS -..-..-..---..--------------- (COVA, SOY SAIC oy) Ties ONKOVIS) Sa ess oSoReaasod sao so Sae ssismosdocosagsescosanc S56 TARO Goce eseeeo asnsbe Gatsde aaeon6 Bescau petieee sabe coud soaden gusdasoesus osedsosese> Classification of underground waters.--------..-----------.---+-----. ---------------- NG) EOGYENO HORTONS) os sa5 does a5 SSeS coscas possse oc Seca sce caccea Sosscasaasesss JATRANIGY ONE TING) BUDA mie ose eebeec asco cosase Gausoa sens Sones ees9 Seno pneees bosons sessed PISKeN tial CONGIELOUS LOM ALLESLADN wWOLLS mera ee saya eee lee arent RelationopsthelarintmbOrOLdiN al yiaw Cll Sessa sete yee an ae a ee eee Gir 6 dap Soccacnaso cade He caau ceoeon ee seueE Seon sescco compe cadosobaoScnbesedsss Mabulationof sourcesitor city, waver SUPDPLV~ --ce<- sa - eee eee ee ee eas ee DEON GHECTESIOM -o 6 32 so desc bocca de eoo shod Sans se Sean ded ssesss co nbem esesoSsesacszonc TO WATE COMA 7c oon os setts Ang Sosece Soo ose nsos SH obesorsoribe docoso Soke sees cdes eases Stephenson omnis ee oe oe ee am a ale mw a al ll Whinnebavo) County. 22-5 1D a1 St Shay a Sa OF Wr & 1-1 oo EU Skea ONS PLATE I. Map showing the several drift sheets and the present glaciation of North America. II. Map showing base lines and principal meridians in the district covered by the HMLinoisyolAcialp 0 bela cay acy ae ener t sya se eters eee oe oe eaeersesjc een ate III. Topographic map of Illinois and western Indiana -......-...---...----. 22.2... IV Map showing areas between 100-foot contours -.-.....-......-.----.-----.------ Wo EROTIC) eno ss IDET) MMO. -cogessenoccoses canese coca canoer coco bees DOOREE Wb. Cleon iano Git JNUNMONS TE WONG. S555 code coonde p66 Saoson coosog bosses cosa nemone WALT ow, derabedtatii the progress of the investigation have been unusually intimate, and it has been a pleasure to contribute to the work such data and suggestions as my studies in this and other regions permitted. I trust that the monograph will prove a valuable contribution to the complex problem presented by the gla- cial series of the Northern United States. Very respectfully, yours, T. C. CHAMBERLIN, Geologist in charge. Hon. Cuarues D. Waucort, Director United States Geological Survey. AIBSMNgetOs Ol) WOO INDE, CHAPTER I. INTRODUCTION.—The Illinois glacial lobe formed the southwestern part of the great ice field that extended from the high lands east and south of Hudson Bay southwestward over the basins of the Great Lakes and the north-central States as far as the Mississippi Valley. It overlapped a previously glaciated region on the southwest, whose drift was derived from an ice field that moved southward from the central portion of the Dominion of Canada as far as the vicinity of the Missouri River. This southwestern part of the eastern ice field, being mainly within the limits of the State of Illinois, has received the name Illinois Glacial Lobe. The results of earlier studies by Chamberlin, Salisbury, and others are noted, and the plan of investigation is set forth. A brief explanation of the method of num- bering townships is presented. CHAPTER II. PHYSICAL FEATURES.—The variations in altitude are set forth in a topographic map and also in tables, and the marked increase in altitude of certain parts of the region because of drift accumulations is considered. The conspicuous reliefs of the rock surface are briefly touched upon, and the preglacial valleys receive passing notice. Profiles and maps are extended across the bed of Lake Michigan as well as border districts, and the inequalities of the lake basin are briefly discussed. CHAPTER III. OUTLINE OF TIME RELATIONS OR GLACIAL SUCCESSION.—A sketch of the major and minor divisions of the drift sheets and of the intervals between them is accompanied by a brief explanation of the basis for the classification adopted. CHAPTER IV. THE ILLINOIAN DRIFT SHEET AND ITS RELATIONS.—The I]linoian is the most extensive drift sheet formed by the Illinois glacial lobe and receives its naine because of its wide exposure in the State of Illinois. The evidence that the Ilinoian drift sheet should be separated from the outlying and underlying drift and also from the lowan drift is briefly set forth. The aspects of the Ilinoian drift sheet are then discussed, its topography as well as its structure being considered. In connection with this drift sheet a very adhesive clay, known as “ gumbo,” which caps it, is described and the questions of its relation to this drift sheet and to the overlying loess are considered. > o &, ° S is be 5 - o 4 » 5 \ 4 2 | pan SS at ‘ “ af C “a iN rR. V0 Sie ~f eS KG 2 ¥ 1 ne 9 oe nid ~Cer eae GULF OF ME ee BSG = a0e:. has . Seo > eno eae il ese ce ga OS aia ees peso q ae es ea oo : ae aL 2 INDIES | YY » £ Wisconsin and later drift sheets <]> O oH hp N 5 B £ Q « {B 2) Be cay Existing glaciers andice sheets 7 cAR | NOS 4 ( : Hh TRAL| | e (ou Quaternary lakes (Bonneville,Lahontan and Glacial Lake Agassiz ) A Ie 1 \ YS Glacial currents known by strize Q Dea Eas WY \, | Glacial currents known by drift transportation or otherwise inferred == UNE fe WV | ¢ fee ime WA L I ‘ = 40° 30° Longitucle West 20° from Washington JULIUS BIEN & CO.LITH Nv. MAP OF THE GLACIATED AREA OF NORTH AMERICA. (Modified from Upham’s map Plate XVI Monograph XxV) BY FRANK LEVERETT 1898 Scale, about 550 miles to an inch Teas vate A2 wis ete ai 0 hes eG THE ILLINOIS GLACIAL LOBE. - By FRANK LEVERETT. © HEAGE TERS I: INTRODUCTION. The Illinois glacial lobe includes a portion of the great ice sheet which extended from the highlands east and south of Hudson Bay, southwestward across Michigan, the Lake Michigan basin, and Illinois, to the axis of the Mississippi Valley in southwestern Illinois and southeastern Iowa (PI. I). It finds its natural limits on the northwest at the border of the Driftless Area of southern Wisconsin and northwestern Illinois. On the west it overlaps a region previously glaciated, but its extent there is readily deter- mined, for it has usually a definite border in a belt of ridged drift. On the south and southeast it extends to the unglaciated tracts of southern Illinois and southern Indiana. From central Indiana northward it seems to have been merged with the eastern portion of the great ice sheet, except in shrunken stages. In the last stage here considered it extended but little beyond the borders of Lake Michigan and was then distinct from lobes to the east lying in the Saginaw and Maumee basins. The present report discusses the deposits made by the lobe south from the latitude of the Illinois-Wisconsin line, in Illinois, Indiana, and Michigan. The drift deposited by this ice lobe has received considerable attention from the geologists of the several State surveys, and also from several students of geology not connected with official surveys. The early publi- eations furnish numerous sections of the drift, of which mention is made below, which throw light on its structure and thickness. They contain MON XXXVII——1 1 2 THE ILLINOIS GLACIAL LOBE, only occasional references to the topography of the drift surface. Appar- ently the first clear recognition of the import of morainic belts in this region was that by Prof. T. C. Chamberlin, who began his investigations in the Wisconsin Survey in 1873, and who in 1876 presented a map, before the Wisconsin Academy of Sciences, showing the distribution of the moraines of eastern Wisconsin. This was followed by one in 1878 show- ing moraines then recognized in the United States.t It soon became apparent to Professor Chamberlin that sheets of drift of widely different age occur, the later of which are characterized by stronger morainic lines than the earlier. Prior to the recognition of the morainic belts and of drift sheets of widely different ages the published sections of the drift presented many puzzling features. But with this recognition the sections published by the early students became of service in making interpretations. The later students are thus able to build upon the work of the earlier. The disad- vantages under which the earlier students worked, on account of the less complete knowledge of the glacial features, can scarcely be appreciated by those who are furnished with the present facilities for study. Any erroneous interpretations resulting from the restricted acquaintance with such features merit a most charitable construction. For example, the writings of Profes- sor Worthen of the Illinois survey are full of the hypothesis of deposition of the drift by icebergs. The early reports of the geologists of the Indiana survey contain a similar interpretation of the drift. In the light of present knowledge of the moraines, with their attendant valley trains of gravel and other features demonstrating the presence of land ice, the iceberg hypothesis must of course be set aside, but this study of moraines has largely taken place during the fifteen or twenty years since the reports referred to were published. The present report is an outgrowth of studies entered upon by Pro- fessor Chamberlin prior to the publication of his paper in the Third Annual Report of this Survey.” In that paper it is shown that the State of Hlinois is traversed by several morainic lines lying outside the great moraine which is the theme of the paper. These lines, together with others not then 1 Trans. Wisconsin Acad. Sci., Vol. 1V (for 1876-77), 1878, pp. 202-234; with two maps. 2 Preliminary paper on the terminal moraine of the second Glacial epoch, by Thomas C. Cham- berlin: Third Ann. Rept. U.S. Geol. Survey (for 1881-82), 1883, pp. 291-402. INTRODUCTION. 3 known, have been mapped in detail and a large amount of data concerning them have been collected. The detailed studies were begun in the spring of 1886, and the follow- ing statement concerning them was made by Professor Chamberlin in his report to the Director for the fiscal year 1886-87: Messrs. lL. C. Wooster, R. D. Salisbury, F. Leverett, and myself have under- taken a work that is measurably new, though a part of the general plan of work previously inaugurated. In the region about the head of Lake Michigan and between it and the Hrie basin is a tract which was invaded by successive glacial movements from both these great basins, these movements being more or less inharmonious and conflicting, resulting in exceptionally complicated phenomena. There arose from this a need for detailed study and the development of more refined methods of investiga- tion than those demanded by the simpler drift tracts.! During the tield season of 1886 the study was extended out for a dis- tance of 50 to 100 miles from the head of Lake Michigan in Illinois and Indiana, a division of the district being made so that each person worked a separate area. Since that season the field work has been largely carried on by Professor Salisbury and the writer, though Professor Chamberlin has constantly superintended the work and has from time to time visited the field. Professor Salisbury’s work, since the first season, has been largely in southern and western Illinois, while the writer's has been mainly in the northern half of the State. During the autumn of 1892, however, the writer was detailed to collect soils and prepare a soil map of Illinois for the Illmois Board of World’s Fair Commissioners. This study necessitated a reconnaissance of the southern portion of the State. This reconnaissance has been supplemented by more detailed studies in 1894 and 1896. The field work carried on by the writer in the region under discussion has been done mainly in the field seasons of 1886, 1887, 1892, 1894, 1896, and 1897. In the intervening years the same line of study was extended into bordering districts, and the broadening of the field has resulted in a better understanding of the features of this region. In the preparation of this report, and also throughout the field study, Professor Chamberlin has given constant advice and direction. The report really embraces the information obtained by Professor Chamberlin in his early reconnaissances, and the best fruits of his wider studies, and of the studies of his other associates, as well ‘Eighth Ann. Rept. U. S. Geol. Survey (for 1886-87), 1889, p. 141. 4 THE ILLINOIS GLACIAL LOBE. as the data directly obtained by the writer. It is with gratitude as well as with pleasure that this acknowledgment of indebtedness is made. In this investigation there have been several distinct lines of observa- tion, which supplement one another in throwing light upon the glacial succession. (1) The work began with a mapping of moraines, and this map- ping has been carried to completion, i. e., each moraine has been followed throughout its entire course with sufficient zigzagging to learn its breadth and general features as well as the position of the crest. (2) With this study of the moraines there has been carried on an investigation of the stratigraphy of the drift, shown by well sections or other exposures, both artificial and natural. Several thousand well sections have been collected, many of which appear in tabulated form in this report. The mode of deposition of the glacial drift is such that a simple study of the drift sheets in a vertical series can not, in many cases, furnish index of the glacial suc- cession. The mapping of the moraines has often aided greatly in working out the full glacial succession. (3) Coupled with the stratigraphic study and the mapping of the moraines there have been a few measurements and estimates of the relative amounts of erosion or other surface changes in the drift in different parts of the drift-covered area, a study which aims to throw light upon the relative ages of different drift sheets. Since the townships are frequently referred to by number and range, rather than by the civil name applied to them, a brief explanation of the method of numbering townships in this region is here presented, together with a map (PI. IL) showing base lines and principal meridians. The expla- nation begins with the Second Principal Meridian adopted by the United States Land Survey, since the First Principal Meridian (which follows the State line of Ohio and Indiana) was not used as a basis for laying out any portion of the region under discussion. The Second Principal Meridian leads north to south through west- central Indiana from the line of Michigan to the Ohio River, and is situated about 2 miles east of longitude 86° 30’ west from Greenwich. The base line crosses the southern portion of Indiana within 1 or 2 miles south of latitude 38° 30’. The townships are numbered both north and south from this base line. he State of Indiana only extends to T. 9 S., but reaches T. 38 N. of the base line. The ranges are numbered both east and west from the Second Principal Meridian. Those on the east extend to the State MONOGRAPH XXXVIII PL. IIL. IS Wliolalalzlels|4 |—. Ipo, —| MIC El GaAUNe| Ll i IN any Beeps Pt | | | (s]2 Sees tt ays | a Ss | Way as NG ee ee Oe eT ee eee eee ee FAovsvLe,, A | a PRANKFORT SHOWING BASE LINES AND PRINCIPAL MERIDIANS IN THE DISTRICT COVERED BY THE [ILLINOIS GLACIAL LOBE SCALE OF MILES AO GO = 20,10 0 20 80 100 120 — = JULIUS BIEN &CO._LITH NvY. INTRODUCTION. 5 line of Indiana and Ohio, while those on the west have an irregular boundary. From the head of Lake Michigan southward nearly to latitude 41° the west boundary is at the State line of Indiana and Mlinois, but south from this line it extends west into Hlinois about 25 miles, being very near longitude 88°. The Third Principal Meridian leads north from the mouth of the Ohio River to the Wisconsin line. It is about 8 miles west of longitude 89°. The base line is a direct continuation of the base line of the second merid- ian survey in southern Indiana. It enters Hlinois from Indiana just north of the city of Mount Carmel and touches the south part of Centralia and Belleville, coming to the Mississippi River immediately below St. Louis. There are 17 townships south of the base line and 46 north of it. From the north line of the State south to the Hlinois River at Peru the ranges lie — entirely east of the Third Principal Meridian, but south from that stream the ranges are numbered both to the east and to the west. T’o the east they extend to the western limits of the survey based on the Second Principal Meridian; to the west they extend to the Hlinois River above the mouth of that stream and to the Mississippi River south from the mouth of the Illinois. The Fourth Principal Meridian leads from the Illinois. River at Beards- town north to the Mississippi River about 8 miles above Rock Island, and is continued in western Jo Daviess County. The base line leads directly west from Beardstown to the Mississippi River, 6 miles above Quincey, and is situated about 2 miles north of the fortieth parallel of latitude. The townships south of the base line reach the number 14, while those north reach 29. ‘The ranges are numbered both to the east and to the west of the principal meridian, north from Beardstown; south from that city they are numbered only to the west. In Iowa and Missouri, together with several other States west of the Mississippi, the land surveys are governed by the Fifth Principal Meridian, which leads from the mouth of the Arkansas River north through eastern Arkansas, eastern Missouri, and eastern Iowa. The base line crosses cen- tral Arkansas, passing just south of the city of Little Rock. From this base line the townships are numbered to the south as far as the line of Arkansas and Louisiana. They are numbered to the north as far as the international boundary in western Minnesota’ and north Dakota. Eastern 6 THE ILLINOIS GLACIAL LOBE. Minnesota and Wisconsin are laid out from the Fourth Principal Meridian, the townships being numbered from the State line of Illinois and Wisconsin northward to the international boundary in Minnesota and Wisconsin, and to the line of Michigan and Wisconsin in eastern Wisconsin. The State of Michigan is laid out from the Michigan meridian, which leads from Sault Ste. Marie south to the Ohio State line. The base line follows the parallel 42° 30’. The numbering of townships north from the base line harmonizes with those laid out from the Fourth Principal Meridian in Wisconsin and Minnesota. The ranges aré numbered both to the east and to the west of the principal meridian as far as the limits of the State. In each township there are 36 sections, numbered back and forth in tiers of six, the numbering beginning at the northeast and terminating at the southeast corner of the township. 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Il. 59" @Manchester Magus Anamosa ze _ Maquoketa: i] Monroe =) Clintons Sqlumbus Je\z, Wapello) Yarmouth South Have: _@ oor (Pleasant R' rlinigtorig pmark o YWesrRoin = ie Mexico (39) =e = AT jeardatown lo > Farid, ( dg) y C inston; (Covington ebano iCarmel.. 49. 0, Sap apomenwan Tg Princeton af Jasper™ tnslish § Soe Be at 4S heagenivaifth rmeetown =" maps | | | NOTE: Data from Illinois obtained from unpublished contour howing 10 feet interval Prepared by ©. W Rolfe in li Data from Indiana based upon railway attitides personal aneroid determinations and notes furnished by the Indiana survey, In TUinois the 50 feet contours ap- pear except inthe southern end of the state and in the portion north of Rock river wherel00 feet contours are Siven Only 100 feet contours appear in Western Indiana and South vestern Michigan Scale TOPOGRAPHIC MAP OF BY FRANK LEVERETT 1898 ILLINOIS AND WESTERN INDIANA Ho} Counties ILLINOIS {4 WHITESIDE 15 ROCK ISLAND. 16 MERCER 25 1ROQUO!S 26 FORD 27 UVINGSTON 34 HENDESSON 35 HANCOCK 36 MEDONOUGH: 37 FULTON 38 MASON ‘39 TAZEWELL 40 MCLEAN $1 VERMILION 42 CHAMPAIGN 48 SCHUYLER 49 BROWN 50 ADAMS 5) PIKE 52 SCOTT 53 MORGAN 54 SANGAMON 55 CHRISTIAN 58 DOUGLAS 59 EDGAR 60 CLARK 6) COLES 62 CUMBERLAND 63 SHELBY €% MONTGOMERY: 65 MACOUPIN 66 GREENE 67 CALHOUN 68 JERSEY (GALLATI 96 HARDIN 97 POPE 98 JOHNSON © 99 UNION 100 ALEXANDER 101 PULASKI 102 MASSAC |} asp INDIANA LAKE PORTER LAPORTE. sT JOSEPH MARSHALL STARKE NEWTON JASPER PULASKI FULTON CASS WHITE BENTON WARREN TIPPECANOE CARROLL CLINTON HOWARD. TIPTON HAMILTON SCONE MONTGOMERY FOUNTAIN VERMILION, PARKE PUTNAM. HENDRICKS: Oo + Ont DN— SULLIVAN GREENE MONROE BROWN JACKSON 9 LAWRENCE MARTIN DAVIESS 2 KNOX S GIBSON PIKE DUBOIS ORANGE WASHINGTON FLOYD) a HARRISON GRAWFORO VAMOERBURG ry 55 POSEY ne + are it CHEPACP SER 1: PHYSICAL FEATURES. Before entering upon a discussion of the glacial deposits, the leading physiographic features of the region will be outlined. The region invaded by the Illinois lobe occupies the midst of the great interior basin which on the east rises to the Appalachian Mountains and on the west to the Rocky Mountains. The State of Illinois has the distinction of being the lowest of the North-Central States. Its mean elevation has been estimated by Mr. Henry Gannett to be about 600 feet above tide, while that of Indiana is 700 feet, Michigan 900 feet, Wisconsin 1,050 feet, Iowa 1,100 feet, and Missouri 800 feet." Including the south end of the Lake Michigan basin, the region coy- ered by the Illinois lobe shows a range of not far from 1,200 feet, the bottom of the lake opposite Racine, Wisconsin, being at sea level, while the highest rock surfaces of Illinois covered by glacial drift are nearly 1,200 feet above sea level. It is not unlikely that glacial erosion and differ- ential depression have increased this range, but there is reason to think that in preglacial times the lake basin was at least several hundred feet lower than the highest ridges of the border districts and that it had a controlling influence upon the course of the ice movement.” The State of Illinois has been covered by a careful barometric survey conducted by Prof. C. W. Rolfe, of the University of Illinois, a survey which had for its object the preparation of a topographic model of the State for the Columbian Exposition. Professor Rolfe used as datum points the altitudes of railway stations which had been determined by surveyor’s level. These are found at intervals so frequent in nearly every county of the State that there is but little room for error in his maps. He has exercised great 1The average elevation of the United States, by Henry Gannett: Thirteenth Ann. Rept. U.S. Geol. Survey, 1892, p. 289. 2See discussion by R. D. Irving: Geol. of Wisconsin, Vol. II, 1877, pp. 632-634. Also T. C. Chamberlin: Ann. Rept. Wisconsin Geol. Survey, 1878, pp. 23-32. 7 8 THE ILLINOIS GLACIAL LOBE. care in reducing to a minimum errors arising from barometric fluctuations. He has kindly allowed the writer to trace from his unpublished map sheets such contours as are represented on the accompanying map (Pl. HD). In the hilly-driftless tracts in the northwest corner, and in the southern end of the State, the surface is so uneven that only 100-foot contours are intro- duced. But the altitude of the greater part of the State is represented by contours with 50-foot interval. For very small areas, covering but a frac- tion of a square mile, the contours must necessarily be omitted on a map of so small scale. A few such areas occur in the hilly districts in the north- western and the southern portions of the State. In Pl. IV the areas between each 100-foot contour are shown in color, and the bottom of Lake Michigan is also represented. In a general way the altitude decreases from north to south in the State of Illinois, there being four counties on the north border (Jo Daviess, Stephenson, Boone, and McHenry) in which points rise 1,000 feet above tide. Near the southern border of the Coal Measures basin the average altitude is below 500 feet. There is, however, south from the Coal Meas- ures basin a prominent ridge which rises nearly to the altitude of the northern portion of the State, its crest reaching at one point an altitude of 1,047 feet (Rolfe). A reference to Pls. II and IV will make clear the altitudes and slopes of Illinois and also of the portions of southwestern Michigan and western Indiana embraced in this discussion. The highest point in Illinois (1,257 feet) is Charles Mound, on the Hlinois-Wisconsin line, in the northwest county. The lowest points are near the junction of the Ohio and Mississippi, and fall slightly below 300 feet at low-water stages of the stream. At high-water stages none of Illinois is below 300 feet. It appears from the table below (p. 12) that only 125 square miles, or an area of less than four townships, rises above the 1,000-foot contour, and that only 10,747 square miles, or less than one-fifth of the State, falls below the 500-foot contour. About 20,000 square miles, or more than one-third of the State, stands at 600 to 700 feet above tide, or at about the average altitude of the State. The thickness of the drift is so great in the northeastern fourth of Ilimois as to convey a false idea of the altitude of the rock surface in that region. Were the drift coating entirely removed, the average elevation would prob- ably be as low as the surface of Lake Michigan (580 feet above tide), and AVIS £E GONV1HOIY 92 SONSYMY1 SZ adOsMV YO +L YadSve EL WVHONI443 22 BLLBAVS IL GNOS OL NOSIGVW 69 AaSH3P 89 NNOHIVO 19 3N33uD 99 NIdnOOVW 9 AYAWOOSILNOW +9 AST3HS £9 GNY1IN3HWND 29 $3109 19 MHV19 09 yuvod3 69 sy1onoa es BINLINOW 2S NOOWW 9S NVILSIYHO SS NOWVONYS +5 NVOHOW &¢ 4109S 2g 3XId 1S SWVGv OS NMOS 6b Y3TANHOS SSVO Lr GQUVNAW 9+ NV901 Sb LLIM30 +b Livid oF NOIWdWVHO 2 NOMIWY3A Ih NV3TSW Ob T13M4aZ¥1L 6f NOSYW ge NoLINd Le HONONOGSW 9 HOOONYH Se NOSY30N3H +o NayuWM Ee XONM Ze vidoad If MYvLS Of Q40iG00M 62 TIVHSUYA 82 NOLSONIAIT Lz GHO4 92 siondoui sz BINVHNYY bz TIM £2 AQNNUD zz TVON3H 12 39) x ; y ef eee I B , t's 311vsv1 oz at = y / ; ise 2 ep aS] AIL) B WYNind ) é 5 nvaune AUNH u30NaW GNWiSI 4904 301S3LIHM. > ay cS) spidey .repd 6 8! LI 91 S| +1 TIowNvo EI 337 21 PSOureUy ; 3190 II B1YN30 O} ANY 6 a9vdna 8 009 £ 341 9 AUNH SWS 3NO08 + OOVB3NNIM £ NOSN3Hd3LS Z ss3lAvaor | SIONTTT senuno,) | = \= | i } d oTAsouey}} 5 | OTANI : -68 ; js aljoury\\o Al 1d IIAXXX Hd VYSONOW ASZAYNS 1V9ID01039'S'N - 5 TIPPECANOE 6 CARROLL z a — = Oo w A er 6 8, S220 692 as Won Ose 22 0 ze0 eu Zre =z FweOwRZSeuEz Ozenx ubortougs wow puz< SP Heo Sz G0uzZoxe weESongEaacPporre® pi eS Sr eco ss year lyse Fy Sef gee so sno TzS =< E rr HWS Ose EESSHOTaSS Surface of lake 579.6 feet Sea /eve/ Pleistocene 640 feet —_ ER x Profile across Lake Michigan in latitude 44° 15 Devonian shale320 feet Devonian limestone Litle Sable Pr wD Old shore Sheboygan Surface of lake 579.6 feet. Beg RYE a ee, Oe aaa Profile across Lake Michigan from Sheboygan to Little Sable Point Sea /eve/ Surface of lake 5796 feet Pt Washington BENTON HARBOR SS Maskegon Lake Se pee eS Sere Bed of lake Se. < a Jevel« fo-Carboniferous faverly sandstone and shale Profile across Lake Michigan from Port Washington to Muskegon Surtace of lake 579.6 feet. =) fprore: Dunes Grand Haven Bed of /ake D stocene| _\Oritt /79 feet £6-Carboniterous\— Sandstone 76 feet Sea level Profile across Lake Michigan from Milwaukee to Grand Haven Till ridge Till ridge Old shore Surtace of lake 5796 feet. , f eeolate Till ria; Old shore Covertridge Bed of lake Sea /ave/ Profile across Lake Michigan from Racine to Holland Des Plaines R. Surface of Jake 5796 feet. Magara group. Bed of lake a Ison River Sroup Sea /evel Devonian shale Profile across Lake Michigan from Fox Lake to Keeler Vajparaiso oraine mM C—O See Surface of lake 5796 feet. Covert ridge Benton Harbor q ff 134. Bed of lake Upper Silurian\ _\Niagara group Lower Silurian plasonik ven eroue Sea /eve/ Blue shale Black sha/e Hamilton limestone Devonian Profile across Lake Michigan from Chicago to Benton Harbor PROFILES ACROSS THE BED OF LAKE MICHIGAN (Based onsoundings given in the United States Lake Survey Charts. ) BY FRANK LEVERETT 1898. JULIUS BIEN 6 CO, LITH N.Y. PHYSICAL FEATURES OF THE REGION, 13 of drift (see Pl. V). The first two profiles show a gradual slope from the west side to points beyond the middle of the lake, followed by a somewhat abrupt rise to the east shore. The amount of drift on the east shore is somewhat greater than on the west, the rock floor at St. Joseph being but 456 feet above tide, or 124 feet below the lake, while on the west shore it rises in many places 20 or 30 feet above the lake level and generally is not far below it. ‘The next profile leading eastward from Racine passes across the deepest part of the basin in the southern end of Lake Michigan, and shows no essential difference on opposite sides of the lake in the slope of the lake bottom. The slopes and bottom are very smooth compared with those shown in profiles farther north. The profile leading from Milwaukee to Grand Haven shows a much shallower part of the basin than that east from Racine, the altitude being nowhere below 200 feet above tide, while opposite Racine it reaches sea level. This line between Milwaukee and Grand Haven seems to mark nearly the summit of a ridge between two basins, both of which, together with the dividing ridge, are covered by the lake. In the profile a few miles to the north, leading from Port Washington, Wisconsin, to Muskegon, Michigan, the lake bottom is shown to be singu- larly irregular. The appearance presented is that of a series of escarp- ments facing westward, similar to the escarpment of Lockport (commonly known as Niagara) limestone a short distance west from Lake Michigan, but it is not entirely certain that they are rock escarpments. Were the drift to be removed from the eastern border of the basin the profile would be quite different. A well at Muskegon, reported by the Michigan Geo- logical Survey, has 235 feet of drift, which brings the rock floor down to an altitude but 360 feet above tide, or only a few feet above the crests of the ridges in the midst of the lake. The dotted line at the right of the profile indicates the depth of the drift at that point. The profiles north from this line show irregularities of lake bottom which give it the appear- ance of being channeled longitudinally. Whether these irregularities are due to drift accumulations or to rock ridges is not manifest from an inspec- tion of the lake charts. The remarkable thickness of drift at Manistee (640 feet) is worthy of note, and indicates that the abrupt border of the lake there is of drift. Evidence that the present smooth bottom of the Lake Michigan basin in its southern end is due to the planeness of the drift surface instead of the 14 THE ILLINOIS GLACIAL LOBE. smoothness of the rock floor is found in borings near Michigan City. Three borings in a line leading from Michigan City westward 2 miles show a ridge capped by Devonian shale at the middle boring, which stands 70 or 80 feet above a rock floor of limestone at the other wells. Taking the basin as a whole, interesting contrasts appear. The remarkable depth and the smoothness of the south-central portion of the basin shown in the profile east from Racine seem to favor the view that glacial erosion was there an agency of much consequence. The preserva- tion of the shale at Michigan City (a few miles to the south) and the apparent preservation of old escarpments in the midst of the basin a few miles to the north, both being in more prominent and apparently better exposed situations for effective erosion than the deep part between them, seem to show comparatively little erosion. The evidence therefore as to the amount of glacial erosion is somewhat confusing, and it will be found difficult to eliminate this factor if an attempt to restore the preglacial features of the basin be made. 7 The reliefs of the region covered by the Illinois lobe are seldom of a bold or conspicuous type. On the contrary, they are so gradual as to give the impression that they are less than the instrumental determinations indi- cate. There are, however, a few ridges with rock nuclei which are of sufficient prominence to merit notice. The most prominent ridge of the region is found in the southern por- tion of Ilinois, at the southern border of the glaciated district. This ridge crosses the State in a direction nearly due east and west from the bend in the Ohio River just south of the mouth of the Wabash to the Mississippi River near Grand Tower. Its crest ranges from about 700 to 1,047 feet above tide (Rolfe), and its breadth ranges from 5 or 6 to 10 or 12 miles. It stands 300 to 600 feet above the lowlands on the north, their altitude being but 400 to 550 feet above tide, and an even greater amount above the lowest parts of the district on the south. This ridge seems to have limited the extension of the ice sheet, for the drift was carried well up toward the crest on the north slope, but no decisive evidence has been found that the crest was overridden. From the western end of the ridge just noted, northwestward along the Mississippi to St. Louis, an elevated limestone belt separates the river valley from the Coal Measures district to the northeast. This belt is but PHYSICAL FEATURES OF THE REGION. 15 5 to 10 miles wide and stands 650 to 750 feet above tide, while the Coal Measures district bordering it stands only 450 to 600 feet above tide. It is interrupted by gaps 2 miles or less in width where the Big Muddy and the Kaskaskia pass through it to the Mississippi; otherwise it forms a continuous belt. Its altitudes are no greater than those of the district across the river in Missouri. On the contrary, there is a rise in that direction to the [ron Mountain district of southeastern Missouri. It seems remarkable that the Mississippi should have taken a course across this limestone belt, and as yet no satisfactory explanation for this feature has been found. The stream is apparently in a preglacial valley. Its course seems, therefore, to be inde- pendent of glaciation. This belt, like the ridge of southern Ilinois, seems to mark the limit of the ice sheet. Drift in small amount occurs over most of its surface, but, so far as known to the writer, does not extend beyond the Mississippi. Near St. Louis, however, where the limestone border passes to the west side of the river, drift is found in small amount. Passing up the Mississippi to the mouth of the Illinois, a narrow axis of upheaval is found, trending nearly east and west, along which the altitude is somewhat greater than on bordering districts. Just east of the mouth of the Illinois there are a few points where the rock surface rises to about 800 feet, while on the plain north of this ridge the rock scarcely exceeds 650 feet. West from the Illinois the altitude is not markedly greater at this axis than to the northward, there being a narrow limestone ridge between the Mississippi and the Ilinois through the entire length of Calhoun County, whose crest is generally 700 to 750 feet above tide. The altitude of the ridge west of the Illinois is fully 100 feet greater than that of the blutts immediately east of that stream. These elevated limestone ridges, and similar ridges on the Missouri side of the Mississippi, near the town of Louisiana and southward, carry very little drift and, as noted some years since by Salisbury, may not have been completely covered by the ice sheet." Of the three belts just described two have been sculptured very deeply by surface erosion, viz, the ridge crossing southern Illinois and the ridge near the mouth of the Illinois. The remaining belt (along the Mississippi below St. Louis) is less deeply sculptured because in much of its extent underground drainage through sink holes and caves has been established. 1 Proc, Am. Assoc. Ady. Sci., Vol. XL, 1891, pp. 251-253. / 16 THE ILLINOIS GLACIAL LOBE. There is not even a well-developed system of ravines and tributaries on its surface, but ravines partially developed often discharge their waters into sink holes and have no surface indications of connection with other lines of drainage. In the northwestern part of Illinois a few conspicuous outlying mounds of Lockport (Niagara) limestone appear. Some of these are situated in the drift-covered region and others in the Driftless Area. They rise 75 to 300 feet above border districts. The majority of these mounds rise above the 1,100-foot contour, and one of them, Charles Mound, as noted above, forms the highest point in the State (1,257 feet). They vary in size from a fraction of a mile to several square miles. In the latter case a chain of mounds oceurs, rather than a single mound or ridge. These mounds lie but a few miles north and gast of continuous Niagara formations and were apparently onee joined with them, their separation, as long since stated by Worthen, being due to denudation.’ The greater part of the district among these mounds has been denuded of the Hudson River or Maquoketa shales as well as of the Lockport limestone, thus exposing the Galena limestone. East from the district just discussed is the broad drainage basin of Rock River, which has no conspicuous ridges or remnants of higher strata capping its present surface formations, though the latter are thoroughly sculptured by drainage lines. Between the Rock River drainage line and Lake Michigan there is a somewhat elevated belt of limestone, which extends curvingly in a direction east of south into western Indiana. It is generally so heavily covered with drift that its lesser features can only be conjectured. Borings indicate that variations of 100 feet or more in altitude occur within a distance of a few rods. It was in all probability thoroughly sculptured by drainage lines. The rock surface has its greatest altitude at the north, being 400 feet above Lake Michigan at the Ilinois-Wisconsin line, while in the vicinity of the Indiana line it rises only 100 to 200 feet above the lake. The Fox, Des Plaines, and Kankakee rivers now cross this limestone belt from the low belt bordering Lake Michigan into the old Rock and Illinois drainage basin, thus extending the latter at the expense of the former. In southern Indiana there is a comparatively elevated region along the east border of the Coal Measures formed largely by the Conglomerate Geology of Illinois, Vol. T, 1866, p. 4. PHYSICAL FEATURES OF THE REGION. 170 sandstone. This was partially covered by the ice sheet. The highest points within the glaciated portion seldom, if ever, exceed 900 feet, but with this altitude they stand 200 to 300 feet or more above the general level of the rock surface near the Wabash, only a few miles to the west. This sandstone forms the western border of a broad tract of elevated land, which is greatly eroded and hence is called the “hill country” of Indiana. Its northern portion has had the irregularities greatly softened by glaciation. The southern portion was less heavily glaciated and is nearly-as rough as the unglaciated tracts. The district occupied by the Coal Measures, both in Mlinois and in Indiana, has a general altitude somewhat lower than that of the bordering limestone or sandstone. Prior to the ice invasion its surface had been greatly eroded, leaving narrow divides at the water partings more or less dissected into low hills, while the streams occupied broad shallow troughs. These features are only partially concealed in southern Illinois and south- western Indiana. As already noted, streams which flow from the Coal Measures into the lower Carboniferous limestone show a marked reduction in the size of the channel upon entering the limestone. This is true not only of small rivers like the Kaskaskia, but also of large streams. The valley of the Illinois is reduced in breadth from 8 or 10 miles to scarcely 3 miles on entering the limestone on the border of Pike and Greene counties. The preglacial Mississippi, now partly filled with drift, is narrowed in breadth from 10 or 12 miles, or possibly 15 miles, in the Coal Measures of Louisa County, Iowa, and Mercer County, Illinois, to only 5 or 6 miles on entering the limestone a few miles above Burlington, Iowa. Where streams do not enter the limestone a gradual widening occurs toward the mouth. The Wabash occupies a preglacial valley in which the breadth increases gradually southward and reaches 10 or 15 miles in the vicinity of its mouth. Below Terre Haute the breadth varies from 5 or 6 miles to 15 miles or more, and in places the bluffs are very poorly defined, owing to the fact that the strata of the bordering districts have broken down nearly as rapidly as the valley was deepened. The several tributaries of the Wabash in southern [lmois—the Embarras, Bon Pas, and Little Wabash—have broad trough-like valleys 2 to 4 miles in width in their lower courses, and their bluffs are often vaguely defined, like those of the main stream. MON XXXVIII w 18 THE ILLINOIS GLACIAL LOBE. Occasional basin-like expansions of river valleys appear outside the Coal Measures. One formed in the Hudson River or Maquoketa shales and anderlying formations along the Pecatonica River near Freeport has a breadth of about 4 miles where widest, though usually it is but 2 or 3 miles. This basin has been discussed recently by Mr. Oscar Hershey as a peneplain,’ but to the writer it appears too immature to be thus classed. A similar basin borders Elkhorn Creek in Carroll and Whiteside counties. | The Mississippi Valley also has an expansion where it crosses these shales on the borders of Carroll County, Illinois, and Jackson County, Iowa, being fully twice as wide as it is where cut in the Galena or in the Lockport (Niagara) limestone. These contrasts in width are well shown in the Clinton, Savannah, and other topographie sheets covering this part of the ' Mississippi Valley. The Clinton sheet appears as PL. XVIII of this report. Most of the streams in this region have courses independent of the preglacial drainage lines. It is only in the western half and southern third of Illinois and in southwestern Indiana, where the drift is compara- tively thin, that the course of preglacial drainage can be confidently indi- cated. Even here the larger valleys only are traceable, for the valleys of the smaller streams have usually been completely filled, and deep borings are too few to supply data to map out their position and connections. The effect of glaciation on the drainage will appear in the progress of the discussion. ‘Am. Geologist, August, 1896. CHAPTER TWiT. OUTLINE OF TIME RELATIONS OR GLACIAL SUCCESSION. _ In the progress of the studies of glacial deposits the complexity of the glacial history has been gradually unfolded. After the abandonment of the iceberg hypothesis, the early students approached the study with the hypothesis of a single and practically continuous period of deposition, in which the ice sheet at one time covered the entire glaciated area. This period was supposed to have terminated with a single high stage of water, attending the melting of the ice, which was termed the Champlain epoch. It soon became apparent that this simple hypothesis could not be made to cover the complicated glacial history. Evidences of a succession of reces- sions and advances of the ice sheet have appeared, and a sharp controversy has arisen concerning the importance of these oscillations, it being held by some students that they are of minor importance and mark short or partial retreats and advances in a single epoch of glaciation, while others have contended for the necessity of recognizing two or more ice invasions between which were very extensive and prolonged deglaciation intervals. The studies upon which the present report is based have developed evidence which, it is thought, has an important bearing upon the question in dispute. The writer, like others who have studied this region, has been greatly impressed with the evidence of prolonged intervals of deglaciation, and an attempt will be made to set forth the nature of this evidence. The several sheets of glacial drift which this and neighboring regions contain have received geographic names, as have also some of the inter- glacial beds. Names of this class were proposed by Chamberlin as a sub- stitute for time phrases which had arisen and which were of controverted appheation." They have already come into wide use in glacial literature, and are employed by students who hold the divisions to be of minor impor- tance as well as by those who consider them of great importance. The ‘See Geikie’s Great Ice Age, third edition, 1894, pp. 754-774. Also Jour. Geol., Vol. III, pp. 270-277, and Vol. IV, pp. 872-876. 19 20) THE ILLINOIS GLACIAL LOBE. divisions to which Chamberlin has applied names appear to have the rank of the main divisions of the Glacial period, whatever that rank may prove to be. Other names are necessary to denote the subdivisions. In the present report several names are thus introduced to designate the moraines associ- ated with the older as well as the newer sheets of drift. The name selected is usually that of a town located on the moraine. In most cases the names have come into use in the office and in correspondence with other glacialists, as a convenient form of reference. The selection thus made seems suitable for general use. In the outline given below it is aimed to cover the events between the deposition of the oldest-recognized drift sheet in North America and the final recession of the ice sheet or sheets into the region north of the Great Lakes. The main divisions appear to be much longer than the secondary ones. It is concerning the former that the value of time intervals is a mat- ter of dispute. The secondary divisions of the drift deposit are not thought by any students to be marked by intervals sufficiently prolonged to merit the application of the term epoch. It is probable, however, as shown farther on, that some oscillation of the ice front occurred, so that the moraines on which these subdivisions are based do not mark simply halts in the recession of the ice, but rather readvances after recessions of minor consequence. To.avoid the use of the controverted term epoch, it is thought best to employ the term stage, which gives a less definite time value. Outline of the drift sheets and intervals. Stage 1. Oldest recognized drift sheet—the Albertan of Dawson, including, also, the sub-Aftonian of Chamberlin. Stage 2. First interval of deglaciation—Aftonian of Chamberlin. Stage 3. Kansan drift sheet of the Iowa geologists. Stage 4, Second interval of recession or deglaciation—Yarmouth of Leverett. Stage 5. Illinoian drift sheet. Stage 6. Third interval of recession or deglaciation—Sangamon of Leverett. i=] t=) Stage 7. Iowan drift sheet and main loess deposit. Stage 8. Fourth interval of recession or deglaciation—Peorian of Leverett, possibly equivalent to the Toronto Formation of Chamberlin. Stage 9. Early Wisconsin drift sheets. § Shelbyville moraine. ? Cerro Gordo moraine. Outer ridge. Substage 2, Champaign morainie system < Middle ridge. Inner ridge. Bloomington or outer main ridge. Substage 3. Bloomington morainic system < Normal or inner main ridge. Subordinate ridges. § Marseilles moraine, ( Possibly Minooka till ridge. Substage 1. Shelbyville morainie system Substage 4. Marseilles morainie system TIME RELATIONS OR GLACIAL SUCCESSION, 21 Stage 10. Fifth interval of recession, unnamed; shown by shifting of ice lobes. Stage 11. Late Wisconsin drift sheets. Substage 1. Great bowlder belts and accompanying moraines, including, perhaps, the Minooka till ridge. Substage 2. Valparaiso morainic system. Substage 3. Lake border morainic system. Stage 12. Lake Chicago submergence. Stage 13. Emergence of plain covered by Lake Chicago. Stage 14, Partial resubmergence of plain covered by Lake Chicago. Stage 15. The present stage of Lake Michigan. The outline just presented differs from the one last presented by Chamberlin’ in the separation of the Wisconsin drift series and lake history into the several substages, and the introduction of names for three inter- glacial stages. Except for the introduction of names for the interglacial stages, it is essentially the same as an outline presented by the writer in a recent bulletin of the Chicago Academy of Sciences.’ Mr. J. B. Tyrrell of the Canadian Geological Survey, who has studied widely in western Canada, favors the separation of the Albertan and sub- Aftonian stages. In a letter to the writer dated July 9, 1897, which discusses the outline given in the bulletin just referred to, he makes the following statement: The Albertan drift sheet of Dawson is older than any till of the Keewatin glacier seen in the plains of northwestern Canada, while the Upper and Lower Bowlder Clay of our Reports seem to correspond closely with your Kansan and sub- Aftonian. I should, therefore, completely separate the Albertan and sub-Aftonian. In the present stage of investigation the correlation of the Upper and Lower Bowlder Clays of the Canadian Reports with the Kansan and sub- Aftonian of southern Iowa is not worked out satisfactorily. The full extent of either the Kansan or sub-Aftonian in districts lying between Iowa and the Canadian boundary is not determined. It therefore may be hazardous to venture definite correlation, though the balance of probabilities, as sug- gested by Tyrrell, seems to favor this correlation and the transference of the Albertan to an earlier stage. The complexity of the glacial history is still further increased by the occurrence of more than one gathering ground or center of dispersion of the ice. The explorations of the Canadian Survey have shown that there 1 Jour. Geol., Oct.—Nov., 1896, Vol. IV, No. 7, pp. 872-876. 2 Pleistocene features and deposits of the Chicago area, by Frank Leverett: Bull. Chicago Acad. Sci. No. 2; issued May, 1897. s 2? THE ILLINOIS GLACIAL LOBE. were three main centers of dispersion aside from Greenland. The Cordil- leran region of western Canada contained one ice field from which there was dispersion in all directions. The province of Keewatin, west of Hudson Bay, contained another ice field which spread in all directions and reached the glacial boundary in Missouri and States to the southwest. The third ice field occupied the highlands east and south of Hudson Bay. It spread to the borders of the Atlantic on the north and east, and to the borders of the Mississippi and Ohio on the southwest and south. The two ice fields bordering Hudson Bay probably for a time coalesced to form the Lauren- tide ice sheet of Dawson.’ But they were apparently distinct and inde- pendent centers for a considerable part of the Glacial period. The names Keewatin and Labrador seem appropriate for these independent centers of glaciation, the former being a name proposed by Mr. Tyrrell, and the latter one which has been used by several glacialists in correspondence and to some extent in print. The name Cordilleran has been applied by Dawson to the ice field in western Canada. There appears to have been less com- plete coalescence of this ice field with the Keewatin than that between the Keewatin and Labrador ice fields. The Cordilleran ice field, as shown by Dawson, occupied a portion of the Rocky Mountains and extended eastward into the province of Alberta, in the early stage of glaciation, when the Albertan drift sheet was deposited? This advance long preceded the maximum westward extension of the Keewatin ice field. Whether the sub-Aftonian or any other deposits of the Keewatin ice sheet are as old as the Albertan, as noted above, is not satisfactorily determined. The Keewatin ice sheet apparently reached its farthest limits on the borders of the Mississippi at the Kansan stage of glaciation. The recogni- tion of the sub-Aftonian—an older deposit than the Kansan—in southern Iowa is based upon the exposures of this drift sheet under a somewhat fresher sheet of Kansan drift. The extent of the sub-Aftonian toward the south and west compared with that of the Kansan is not yet determined. In a paper presented at the twelfth annual meeting of the Iowa Academy of Sciences, in December, 1897, Dr. H. Foster Bain, of the Iowa Geolog ical Survey, gave a careful review of the features of the sub-Aftonian and 1See Am. Geologist, Vol. VI, 1890, pp. 153-161. 2Bull. Geol. Soc, America, Vol. VII, pp. 31-66; issued November, 1895. TIME RELATIONS OR GLACIAL SUCCESSION. 23 descriptions of the weathered zone between this till sheet and the overlying Kansan. The extent of weathering appears to him scarcely sufficient to warrant a separation into a distinct glacial stage. He, however, suggested that the sub-Aftonian sheet may have been formed during one of the hypothetical minor advances of the ice sheet preceding its maximum extension.' The portion of the Labradorian ice field to which the name Illinois Lobe is applied, reached its farthest limits on much, if not all, of its border at the Illinoian stage of glaciation. The Illinoian drift sheet, as indicated in detail farther on, passed some distance into territory which had been occu- pied by the southern extension of the Keewatin ice sheet at the Kansan stage. Since the Illinois ice lobe reached its farthest limits on much of its border at the Illinoian stage of glaciation, any earlier deposit made by this ice lobe must be largely concealed by the deposits of this stage. Attention is called below to deposits in Illinois which may prove to be sufficiently older than the Illinoian to be referable to a distinct stage, though the evidence as yet is rather fragmentary. Concerning this matter Professor Chamberlin has sug- gested” that the two great ice fields may have alternated in their invasions in such manner that the sub-Aftonian preceded the sub-Illinoian and the latter preceded the Kansan, much as the Kansan is known to have preceded the Hlinoian. There is, however, as yet no decisive evidence of such a rela- tionship. Possibly the sub-IIlinoian will prove to be of about the same age as the Kansan. With these preliminary statements we pass at once to the discussion of the Ilinoian stage of glaciation. 1 Proc. Iowa Acad. Sci., Vol. V, 1898, pp. 86-101. 2Communicated to the writer. CaEASP yl Er Ra ive THE ILLINOIAN DRIFT SHEET AND ITS RELATIONS. GENERAL STATEMENT. Relation to outlying and underlying drift—The first recognition and separation of the Illinoian drift sheet from an older sheet of drift which underlies it on the borders of the Mississippi was made by the writer in southeastern Iowa in the spring of 1894. The occurrence of a bowlder of red jaspery con- glomerate in Lee County, Iowa, had been noted some ten years earlier, but its significance was not recognized at that time. It is now found that bowlders of this class are not rare, and that they are in all probability derived from the ledges north of Georgian Bay. If so, they are an indica- tion that the southwestward movement of the ice from that region extended somewhat beyond the Mississippi River. The studies in 1894 developed other evidence that the invasion which brought in these bowlders from the northeast reached beyond the Mississippi, and that it occurred at a much later date than the general glaciation of southern Iowa and northern Mis- souri. The western limits of this ice invasion are plainly indicated by a marginal ridge. The evidence of a long interval is found in the greater erosion of the drift sheets outside the limits of the Illinoian, and in the prevalence of a soil horizon and weathered zone beneath the Illinoian sheet where it overlaps the earlier one. This interval appears to be of sufficient importance to be termed an interglacial stage and to justify the reference of the two sheets to distinct stages of glaciation. The intervening stage of deglaciation has recently been named the Yarmouth interglacial stage,’ and is discussed farther on. Relation to the Iowan drift sheet—'The question arises whether the Ilinoian sheet should be classed with the Iowan sheet, which, as shown by McGee in the 1In a paper presented by the writer at the twelfth annual meeting of the Iowa Academy of Sciences, December, 1897: Proc. Iowa Acad. Sci., Vol. V, 1898, pp. 81-86; also Jour. 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VI a | 4 | Counties )} ILLINOIS MONOGRAPH XXXVIII U.S.GEOLOGICAL SURVEY 14 WHITESION 1S ROCK ISLAND 16 MERCER wy WENRY. 18 BUREAU 19 PUTNAM 20 LASALLE 21 KENDALL 22 GRUNDY | 23 wit. 24 KANKAKEE if 25 inoquors 26 FORD 27 LIVINGSTON ‘34 HENDERSON 3S HANCOCK 36 MeDOKOUGH 37 FULTON 38 MASON 39 TAZEWELL 40 MCLEAN 41 VERMILION 42 CHANPAION 49 PIATT 4 DEWITT 45 LOGAN 45 MENARD 47 CASS 48 SCHUYLER 49 BROWN 50 ADAMS SI PIKE 52 SCOTT 53 MORGAN 54 SANGAMON 55 CHRISTIAN 56 MACON 57 MOULTRIE 58 DOUGLAS 59 EDGAR 60 CLARK z 61 COLES SS 62 CUMBERLAND | 63 SHELBY ie | 64 MONTGOMERY ie She] |B) 6 MACOUPIN sReauktoRL | | pore \ 4 CALHOUN oo | I Vote jf as sersey + yee 20, 69 MADISON aie || sae’ 4 Redan MY F er ‘ reesille § = 98 JOHNSON q 4 = Q 5 sta u UNION *® Mexico i A 4 as ‘ N } | 9 100 ALEXANDER v 10) PULASKI —— LEGEND — = TF: H be 8 eae ) Sea era” SUS || suas ee anv IND [ a |priruess anv INDI’ iF 1 LAKE PP) Glacial tiases | ) (chiefly moraines) 2 PORTER S = Kansan drift 3 LAPORTE 4 STJOSEPH 5 MARSHALL © STARKE 7 NEWTON 8 JASPER ® PULASKI {0 FULTON 1 CASS. 12 WHITE 13 BENTON [4 WARREN 15 TIPPECANOE 16 CARROLL 17 CLINTON 16 HOWARD 19 TIPTON 20 HAMILTON 21 BOONE 22 MONTGOMERY Probable Winoian Course of Mississippi at Iinoian invasion 29 FOUNTAIN 24 VERMILION 25 PARKE 26 PUTNAM 27 HENORICKS 28 MARION 29 JOHNSON 50 MORGAN 3) OWEN owan in lowa | lowan in Tlinois } Ridges of looss and sandontowan | drifborder(inapped ontyiniliois) 34 SULLIVAN awneetown 35 GREENE 34 MONROE 37 BROWN 38 JACKSON 30 LAWRENCE 40 MARTIN 4{ DAVIESS | i | Shelbwille till sheet | | Sand and gravel plains and 1} | lerraces of Wisconsin age Plake Qhicagoaren andlake outlet > also outlets lake Agassiz and lake Maumee ENC i Cape Girardeau me \ A \ <2 | | | Morseilles ull sheet | {Probable temporary lake areas / i 3 NOTE | | | Data from Minois obtained-from unpublished contour | _ maps showing 10 feet interval Prepared by CWRolfe in | 1893. Data from Indiana based upon railway attitudes, | 44 23 Giesom personal aneroid determinations and notes furnished | 44 Pine | | | Bloomington till sheet } Lake Kankakee area (early Wisconsin) I | leas a by the Indiana survey In Illinois the 50 feet contours ap 40 ORANDN pear except in the southern end of the state and in the portion north of Rook river where!00 feet contour a Only 100 feet contours appear in Western lodiana art | Southwestern Michigan | 46 ORANOE |] 47 WASHINGTON 48 MOYO 40 HAR RIGON AWFORD | (curly Wisconsin) i an 5) PERRY 52 SPENCER 53 WARRICK NOCABURG id } Iroquois till sheer (late Wisconsin than Wisconsin j Y rh tie: Valparaiso ii sheet | NQ |giacial suriae j (late Wisconsin) \ lhivial terraces older j Seale 70 MILES | GLACIAL MAP OF THE ILLINOIS ICE LOBE BY FRANK LEVERETT 1898 DOUS BIEN @ CO LITH GENERAL ASPECTS OF ILLINOIAN DRIFT SHEET. 25 Eleventh Annual Report of this Survey and in earlier papers, is separated from the underlying drift of eastern Iowa by a distinct soil horizon. It is found that a notable interval occurs between the deposition of the Mlinoian sheet of drift and the deposition of the main sheet of loess of the Mississippi Basin, an interval indicated by erosion, weathering, and the formation of a soil horizon. But this sheet of loess seems to be intimately connected with the Iowan drift sheet, as shown by McGee, a relation which subsequent studies by several independent investigators fully confirms. It appears, therefore, that the Illioian drift sheet is separated by a notable interval from the Iowan sheet as well as from the underlying sheets. Furthermore, a till sheet referred to the Iowan stage is present in northern Illinois which falls far short of reaching the limits of the Ilinoian till sheet. Like the Iowan sheet of eastern Iowa, it is found to be contemporaneous with the main loess deposition. The interval between the Illinoian till sheet and the Iowan loess and till has recently been named the Sangamon;' it is discussed in some detail below. A deposit termed gumbo, which lies between the Tllinoian till and the Iowan loess, is also described. Culmination of the Illinois lobe at the Illinoian stage —At the time of the deposition of the Illinoian drift sheet the southwestward movement from Labrador and the heights south of Hudson Bay appears to have reached a limit in western and southern Illinois beyond any earlier invasion. It is not as yet certain, though it is quite probable, that the Illinoian sheet extends beyond all older sheets in northwestern Ilinois and southern Wisconsin. In the absence of positive evidence to the contrary the present paper discusses the western and southern limits of the drift of the Ilinois lobe as a single line, occupied at the Illinoian stage throughout its entire length by the ice lobe. Its extent may be seen’ by reference to Pl. VI. GENERAL ASPECTS OF THE ILLINOIAN DRIFT SHEET. Extent of its exposures—'The I[]linoian sheet is extensively exposed to view outside the Iowan and Wisconsin sheets in Illinois and southwestern Indiana. In western and southern Illinois and in southwestern Indiana it constitutes the surface sheet (aside from a thin loess coating) over the entire interval between the glacial boundary and the outer moraine of the Wisconsin series. 1In a paper presented by the writer at the twelfth annual meeting of the Iowa Academy of Sciences: Proc. Iowa Acad. Sci., Vol. V, 1898, pp. 71-80; also Jour. Geol., Vol. VI, 1898, pp. 171-181. 26 THE ILLINOIS GLACIAL LOBE. The greatest width of this area is about 125 miles, and the width nowhere in western or southern [linois falls much below 75 miles. In southwestern Indiana it occupies a triangular-shaped area, broad at the west and narrow at the east, for the glacial boundary passes northward nearly to the edge of the Wisconsin drift in the south-central portion of that State. In the portion of Hlinois north from the latitude of Rock Island the Iowan drift occupies a large part of the interval between the glacial bound- -ary and the outer moraine of the Wisconsin series. A drift, tentatively referred to the Illinoian, forms the surface sheet in that region in Stephen- son County and parts of Winnebago, Ogle, Whiteside, Carroll, and Jo Daviess counties. A small area of this earlier drift in southwestern Wis- consin is exposed outside the limits of the Iowan, but the exact boundaries of the latter have not been determined. If the loess capping be disregarded, nearly two-thirds of the glaciated portion of Illinois has the Ilinoian drift as a surface sheet. The remainder of the State is mainly occupied by the Wisconsin drift sheet, the Iowan being exposed only in parts of a few counties. Topographic expression —The greater part of the Illinoian drift has a plane surface, destitute of the swells and ridges which usually occupy the Wis- consin till sheet. There are, however, a few belts of sharply ridged drift found within its area, and the border is ridged throughout much of south- eastern Iowa and western Illinois. The most conspicuous ridging is found in a strip about 20 miles wide leading southwestward through the Kaskaskia Basin from the border of the Wisconsin drift in Shelby County across southeastern Christian, eastern and southern Montgomery, western Fayette, Bond, Clinton, southeastern Madison, eastern St. Clair, and eastern Ran- dolph counties. This strip embraces a series of nearly parallel ridges, which are discussed in some detail farther on as the ridged drift of the Kaskaskia Basin. Another ridged belt is found in eastern Sangamon and southwestern Logan counties, and this is discussed below as the Buffalo Hart moraine, the village of Buffalo Hart being situated on it. A less conspicuous belt of ridged drift traverses southern and western Fulton County, touching eastern McDonough County near Bushnell, and apparently having its continuance into Knox and Peoria counties in a chain of mounds and short ridges. It has far less prominence than the two belts just mentioned, its relief being but GENERAL ASPECTS OF ILLINOIAN DRIFT SHEET. Pail 15 to 30 feet above the bordering plains, and the breadth of the main ridge one-half mile, more or less. In the northwestern part of Illinois, in Stephenson, Ogle, and Carroll counties, there are gravelly ridges, some of which are of esker type, and are discussed in. detail below. Aside from the ridged belts just mentioned, there have been found only occasional knolls, either isolated or in small clusters, and these seldom rise 50 feet above the bordering plains. The knolls are more abundant in western Illinois than in southeastern [linois and southwestern Indiana. In the latter districts entire counties have been traversed without the discovery of a knoll so much as 10 feet in height. Thickness of the drift—The well records obtained in the region occupied by the Illinoian drift indicate that the average distance to rock on the preglacial or original uplands is not far from 50 feet. In this 50 feet is included the loess, which is several feet in depth, and possibly also pre-Ilinoian drift. Along original valleys the thickness is 100 to 200 feet or more. There are extensive areas in the northwestern counties of Illinois and in the counties bordering the Wabash River, both in Illinois and in Indiana, where the ridges carry scarcely any drift, while neighboring valleys may be filled to a depth of 100 feet or more. In western and south-central Ilinois the ridges usually carry 30 to 50.feet of drift, the general amount of drift being greater than in northwestern Illinois or southeastern Illinois and southwestern Indiana. Throughout the area occupied by the Illinoian drift the main preglacial valleys are usually but partially concealed, though the small valleys and tributaries are often filled so completely that their position is revealed only by borings. In this respect the Hlinoian drift is in striking contrast with the Wisconsin, for where that sheet is present the main valleys are as com- pletely concealed as the lesser ones. Records of a large number of wells which have been sunk in the Illinoian drift area are presented in the portion of this report dealing with the wells (Chapter XIV). Structure of the driftt—Throughout the area occupied by the Illinoian drift till predominates, there being but a small amount of sand or gravel except in deeply filled valleys. The ridges above mentioned are usually com- posed of till, though pockets or thin beds of sand or gravel have been discovered in some of them. Upon passing toward the glacial boundary 28 THE ILLINOIS GLACIAL LOBE. the drift becomes more variable in its constitution than at points remote from the boundary. This variableness is set forth in the detailed discussion of the drift border below. The till which forms this Hlinoian sheet is usually of a yellowish-brown color to a depth of 15 feet or more, beneath which it assumes a gray or blue-gray color. In many places there is a transition from the brown to the gray, in which gray streaks remain in the brown till, or cracks stained a brown color extend down some distance into the gray till. In such places it is probable that the brown is simply an altered gray till, the oxidation of the iron haying produced the change in color. In places a thin bed of sand or gravel occurs at the junction of the brown and gray till, which gives them the appearance of being originally distinct. But it is not certain that the brown till in such places was not originally gray in color. The points at which there is a transition from till of one color to that of the other are so numerous that it seems highly probable that the brown till is generally but an altered phase of the gray. At least nothing decisive has been discovered to indicate that the brown and gray tills are referable to distinct invasions or to different modes of deposition by the ice. In portions of central Illinois, especially in the Sangamon and Kaskaskia and Embarras drainage basins, the well diggers and drillers report a marked change in the texture of the drift in passing from the brown to the gray tills. The gray till is said to be much harder to penetrate than the brown. Where wells are dug, they may be spaded without difficulty through the brown till, while in the gray till a pick is usually required to remove the material. This difference may be due to the effect of ground water or to some secondary change in the brown till which does not affect the underly- ing gray till, a change which is coextensive with the change in color. It may, however, prove to be an original difference and may be of significance in determining the glacial history. Possibly the gray till in these districts is sufficiently older than the overlying brown till, or sufficiently distinct from it in deposition, to be referred to a separate stage and considered pre-Hli- noian. But few exposures of this hard till were found, and in these no sign of a distinct interval between the brown and the gray tills was recognized. The available evidence is, therefore, of an inconclusive nature. Gumbo (?)—The Tlinoian till sheet, and also portions of the Kansan till sheet in southeastern Iowa and northern Missouri, are extensively covered GENERAL ASPECTS OF ILLINOIAN DRIFT SHEET. 29 me with a gummy or very adhesive clay, often several feet in depth. This clay is found at frequent intervals throughout the entire area in which the Illinoian sheet is exposed to view outside the limits of later till sheets, and has also been found under the later till sheets at some distance back from their margin in the central portion of Illinois. It occurs as far west as the writer has made examinations in Iowa, a distance of 50 miles or more beyond the limits of the Illinoian till sheet, and is known to be present over extensive areas in northern Missouri. Its extent and im- portance seem to have been unrecognized prior to the present survey. — It is not such a continuous deposit as the overlying loess, there bemg many places where the loess rests directly upon typical till. It is most conspicu- ous in the vicinity of the Mississippi Valley and in the southern portion of Illinois as far south as the glacial boundary. The region in which it occurs ranges in elevation from 400 feet up to fully 800 feet above tide. Possibly much higher elevations are attained by it in passing westward from the Mississippi. Like the loess, it seems to be independent of contour lines in its distribution. The color of this clay varies from ash or light gray to nearly black. The black portions are heavily charged with humus and in places present the appearance of a swamp muck. It is in this clay that the black soil so often seen at the base of the loess is usually developed. Where the loess rests directly upon till the soil formed beneath it is usually of a reddish- brown color. This gummy clay contains a few small pebbles. They seldom exceed a half inch in diameter and are far less numerous than in the typical till. It often bears a striking resemblance to the “gumbo” of the Hlmois and Mississippi River flood plains, which is deposited by flooded streams in the portions of the flood plains where there is but little current. It, however, contains more and larger pebbles than the gumbo of these flood plains. The origin of this deposit, and its time relations compared with the overlying loess and the underlying till, are questions of prime importance, but as yet no satisfactory conclusions have been reached. There is much in the appearance of the deposit to support the hypothesis of aqueous deposition. The pebbles may, perhaps, have been derived from neighbor- ing prominent points in the till during the progress of asubmergence. The action of floating ice may be postulated as an accompaniment of submergence 30 THE ILLINOIS GLACIAL LOBE. whether the water be shallow or deep, and this may have carried stones in sufficient number to have supplied the clay with the few pebbles that it contains. The difficulties arising from the great range in altitude which the deposit presents may not be fatal to the hypothesis of submergence. The hypothesis is, therefore, still entertained, especially simce none more satisfactory has suggested itself, but it can not be confidently put forward as a solution. In considering the time relations of this clay, there is decisive evidence that it was deposited at a much later date than the Kansan sheet, in the faet that it also overlies the Lllinoian, a younger sheet of drift. .The evidence is equally conclusive from its relation to terraces cut in the Kansan. The gummy clay, as well as its coating of loess, is found on terraces bordering valleys cut in the Kansan sheet, and also on the uplands occupied by that sheet. All the main valleys examined in southeastern Iowa had been cut to a depth of 50 feet or more into the Kansan sheet, and often to a width of 1 or 2 miles, prior to the deposition of this clay. If, therefore, it had been examined only in districts outside the limits of the Illinoian, it might have been demonstrated to be a much younger deposit than the Kansan. Passing to the Illinoian sheet, it is found that the changes effected in its surface prior to the deposition of the clay under discussion are less than in the Kansan, yet some change was apparently effected in its surface. In fact, the surface of the till has often the appearance of marked atmospheric reddening prior to the deposition of the gummy clay, and there is usually an abrupt change from gummy clay to the till. The till is also not infre- quently leached of its calcareous material for several feet below the base of the gummy clay. In places the gummy clay is mingled with the under- lying till, but it does not follow that the two deposits are contemporaneous. The Illinoian till sheet was not so conspicuously channeled by streams prior to the loess deposition as the neighboring portion of the Kansan, but the slight channeling which took place seems to have antedated the deposi- tion of the gummy clay as well as that of the overlying loess. This clay is apparently more conspicuously developed in small channels cut in the Tllinoian than on the bottoms or terraces of the broad channels. Not infre- quently these small channels are so greatly filled by the clay that the surface is nearly restored to its original planeness. The writer has found GENERAL ASPECTS OF ILLINOIAN DRIFT SHEET. Bil numerous exposures where such fillmg reaches a depth of 15 or 20 feet in districts where the general thickness of the gummy clay is scarcely 5 feet. The presence of so many exposures where there is evidence of an interval between the deposition of the till and that of the clay under discussion has led the writer to conclude that in the exposures where the two deposits appear to be blended there has been redeposition of the till in connection with the later deposit. In so commingled a sheet as till it is a very difficult matter to determine whether redeposition has occurred since the withdrawal of the ice sheet. In view of all the data now available the conclusion seems warranted that this clay is somewhat younger than the Ilinoian. No suitable name has as yet been found for the clay, although the name gumbo has been applied to it by residents of the region which it char- acterizes, because of its gummy character. This name is open to objec- tion for the reason that it has already been applied to other deposits of different age and different origin. There is a gumbo in the Cretaceous series of the Western plains. The term is also applied to the flood-plain deposits of the linois and Mississippi, which are still in process of accumu- lation. The name gumbo has, however, been used by McGee in his discus- sion of a compact phase of the loess found in southeastern Iowa and northern Missouri, and of a dark clay at its base, apparently the clay under discussion. It is his opinion that the loess there owes its compactness to derivation from the clay beneath itt Until the origin and time relations are more satisfactorily determined, it may be as well to leave unsettled the name for the deposit. It remains to consider the probable time relations between the clay under discussion and the sheet of loess that overlies it. The gummy clay, as noted above, has usually a blackened surface due to humus, a feature which indicates that it was exposed to conditions favorable to plant growth. The plant remains in this clay are seldom sufficiently well preserved to admit of identification. The writer, however, found bits of wood in an exposure along the Santa Fe Railway near New Boston, in Lee County, Iowa, which have been identified by Mr. F. H. Knowlton, of the United States National Museum, as a species of conifer. The specimens were too small and not sufficiently well preserved to enable him to determine the genus and species, though they appear to belong to the genus Picea (spruce). 1Eleventh Ann. Rept. U. S. Geol. Survey (for 1889-90), 1891, pp. 299, 414, 461-471, 508-510. 32 THE ILLINOIS GLACIAL LOBE. They consist of rootlets about 2 cm. in length and 2 mm. in diameter. They are, therefore, too small to afford good sections of the wood cells. The locality where these specimens were obtained is now a prairie region and the spruce tree is not native in the forests which border the streams, the only conifer present being the red cedar. Several instances of the oceurrenee of logs at the base of the loess in western Illiois have been reported to the writer by well drillers, but no specimens have been obtained. The evidence is, however, considered good that much of this region was forest-covered prior to the deposition of the loess. Whether this emergence and forest growth occupied a long period has not been satisfactorily deter- mined. Last season (1897) the writer found a fine exposure of muck and peat and wood, associated with silt, at the base of the loess in a cutting on the Toledo, Peoria and Western Railway, 4 miles west of Washington, Illinois, a photograph of which is presented in Pl. XI, B. It is several miles inside the border of the Wisconsin drift, and the loess is here covered by a bed of till of Wisconsin age. At this cutting the Wisconsin drift is only 15 feet in thickness, the upper portion having been removed by erosion. The section at the cutting is as follows: Section at a cutting on the Toledo, Peoria and Western Railway, £ miles west of Wash- ington, Illinois. Feet. ChMNGll sees cSdo sao b65e cooseoU Eoeeoy Gedsse onoda suSoSbeS.caa9 5 da6S sone san Song s4sseC coaS osedc5 6 Blwerculle@wasconsin)) esse eenee aces ereaseree ae See an oe e ee ate era 5 Se ge Oe Ne ee 8 Gray clay, laminated, pebbleless, very calcareous .---_.---...---.---. --2------- -=-=- ---- 2 == 1 Brown loess, probably of Iowan age, caleareous, and containing helix shells -.---.....--..----- 6 Peaty silt of brownish black color, containing a large amount of wood (Sangamon) .--.--..---- 5 Drab colored loess-like silt, becoming brown toward bottom, filled with mats of fibrous roots... 4-5 Reddish-prownleachedstill|(llinolan) esse a-s eo oe eee aes eesti eee ee see eee eee 4 Browniunleachedstulln@illinoian)fexposedWeecsseciees aceiee ch ceceeee ret eee ee Ene oer ee eee eee eS. TOQUE Caos cn5acesS soSede seco secs Bese Sede BES OS8d Gags oad sae Joosce snap ca5es0 caso so enas 42 Specimens of the shells in the loess, of the wood in the peat, and of the roots under the peat have been collected, but have not been specifically identified. The silt under the peat is somewhat similar to the deposit which overlies it, though it may prove to be of different origin. This series of beds seems to indicate that a land surface, which had been exposed to atmospheric action favorable for leaching of the till, was transformed into a swamp favorable to the growth of peat, and that this swampy condition was followed by the deposition of the loess. As the gummy clay just dis- GENERAL ASPECTS OF ILLINOIAN DRIFT SHEET. 3303 cussed is not represented in this section, the question naturally arises whether the silty material under the peat is not its equivalent. The question can scarcely be decided from such fragmentary evidence as is now available. This section appears to bring the loess into closer relation to the gummy clay than had heretofore been supposed. If the blackened, humus-stained surface of the gummy clay required but a few centuries for its development, it would seem not unlikely that the deposition of this gummy clay and that of the loess are to be referred to the same epoch of low altitude, an epoch attended by more or less complete submergence, with interruptions or partial emergence of the land. The reddened and leached’surtace of the Hlinoian till apparently signifies a long exposure to atmospheric action. The balance of evidence seems to favor a closer connection between the loess and the gummy clay than between the latter and the underlying Llinoian till. As the loess is discussed in some detail in connection with the Iowan drift sheet, with which it is correlated, only a general statement concerning it is made at this point. The entire surface of the Illinoian drift sheet appears to have received a capping of loess or loess-like silt at about the time of the Iowan ice imvasion, the deposit being found midway between the principal streams as well as along their borders, where it was first recognized. It is much thicker on the borders of the Ilinois and Missis- sippi than on the divide between these streams or in the region east from the Hlinois. In much of southern Hlinois the thickness is only 3 to 5 feet, and the average thickness in districts east of the Illinois and Mississippi is probably less than 10 feet. On the borders of these streams its thickness is frequently 30 to 50 feet, though a portion of the valley border near the corners of Iowa, Missouri, and Illinois is characterized by a thinner coating of loess than is found to the north or south, the average thickness being scarcely 10 feet. Aside from its thickening on the borders of the Illinois and Mississippi, there is also a thickening on the borders of the Iowan drift sheet in Carroll, Whiteside, Henry, and Bureau counties, as indicated in the discussion of that drift sheet. Sections of the Illinoian drift— or sections illustrating the structure of the Hlmoian drift sheet, reference may be made to the portion of this report devoted to the wells of Ilinois (Chapter XIV). The well sections are taken up by counties; but attention is called to the several drift sheets which are MON XXXVIII 3 34 THE ILLINOIS GLACIAL LOBE. penetrated by the wells in the various counties of the State. The structure of the portion of the Hlinoian drift in southeastern Lowa and western Illinois is set forth in the detailed discussion of the border of the Ilinoian drift sheet which follows. THE DRIFT BORDER. DiSTRIBUTION. The border of an old drift sheet, tentatively referred to the Ilinoian, emerges from beneath the Wisconsin drift im southern Wisconsin a few miles southwest of the city of Madison, and from that point southward to the Mississippi River it forms the eastern border of the Driftless Area of southwestern Wisconsin and northwestern Illinois. The border of this drift sheet probably crosses the Mississippi a few miles below Savanna, but, as shown in Pls. VI and XII, the presence of the Iowan drift sheet, together with the heavy loess deposit, both of which are later than this drift, has so obscured it that its limits can not well be determined in Clinton and Scott counties, lowa. In Muscatine County, lowa, the slightly ridged west- ern border of the Ilinoian drift sheet becomes visible, and is distinctly devel- oped from that county southward. It crosses the Lowa River just below Columbus Junction and leads southward through western Louisa County, the village of Cairo being within a mile and the village of Morning Sun within 3 or 4 miles east of the border. It passes thence in a course west of south across northwestern Des Moines County and southeastern Henry County, the villages of Yarmouth and New London beimg situated on the ridged border and the village of Lowell, in Skunk River Valley, being situated where the border crosses that valley. In Lee County, as shown in fig. 4, the course of the ridge is southward past the village of West Point to the vicinity of the Mississippi bluff, about 5 miles below Fort Madison. From this pomt south- ward to Keokuk the border apparently is nearly coincident with the course of the Mississippi River, though there may be slight deposits of the Ilmoian drift on the west side of the valley. Immediately south of Keokuk, on the Illinois side of the river, a distinct ridge of drift appears which marks the border; and this may be traced southward along the east bluff of the Mis- SISSIppl across Hancock and Adams counties, though in the southern portion of Adams County it lies back a mile or two east from the river bluff. In Pike County the border bears gradually away from the Mississippi bluff in THE DRIFT BORDER. 35 asoutheastward course and comes to the Hlmois River in the southeast part of the county; thence it follows the Illinois Valley southward to the mouth of the river, perhaps touching the west bluff in southern Calhoun County. The border then either follows the Mississippi bluff eastward past Alton, or continues southward across the projecting point of Missouri which borders the mouth of the Missouri River just above St. Louis. It is somewhat uncertain whether the drift found on the Missouri side of the Mississippi is of direct glacial deposition or a deposit made by streams; the greater part of it is assorted material. The presence of drift on the Missouri side of the Mississippi has been noted only in the district north from the city of St. Louis. Below that city the drift border apparently follows the line of the valley of the Mississippi closely as far down as southern Jackson County. The Mississippi River there turns southward, but the drift border passes eastward, following the north slope of the elevated ridge which crosses south- ern Illinois and entering Indiana in the extreme southwest corner of that State. The drift border, as indicated on PI. VIII, crosses the southwestern county of Indiana (Posey) in a northeastward course lying near the valley of the north fork of Big Creek. It cuts across the northwest corner of Vanderburg County and enters Gibson County in sec. 16, T. 4.8. R.11 W. Thence it passes northeastward, touching the village of Haubstadt and coming to Pigeon Creek in sec. 22, T.38., R. 10 W., at the junction of Sand Fork and Muddy Fork. From this creek the course for a few miles is northward to the divide between Pigeon Creek and Patoka River, which it crosses about 4 miles east of Princeton. It there swings eastward and comes to Patoka River near the line of secs. 32 and 33, T.18., R. 9 W. It enters Pike County about 1 mile south of Oatsville, in sec. 27, T. 1 S., R. 9 W. In that county it lies but a short distance north of Patoka River, and apparently follows nearly the divide between the small northern tributa- ries and Flat Creek, a large northern tributary, to the mouth of Flat Creek in western Dubois’ County. From this point eastward to the vicinity ot Jasper, and thence northward to East White River, there is a sand-covered plain in which the boundary is difficult to locate. Possibly this plain was covered by the ice sheet, since glacial pebbles several inches in diameter are found beneath the sand on its east border. The sand seems to have been deposited in a small glacial lake, Lake Patoka, which occupied this 36 THE ILLINOIS GLACIAL LOBE. plain and neighboring sections of the Patoka Valley while the present out- lets along the White and Wabash rivers were blocked by the ice sheet. For a few miles north from East White River the exact position of the glacial boundary is difficult to locate, for only scattering pebbles are found along the border. It seems, however, to pass near the village of Alfords- ville, in Daviess County, and thence to take a northeastward course to the bluff of East White River near Whitfield, in Martin County. The border follows the west bluff of East White River northward past Mount Pleasant to the bend near that village, from which point it continues northward, passing about a mile east of the village of Loogootee. The border then bears west of north and soon enters the western range of sections in Martin County and lies very near the Martin-Daviess county line for 10 or 12 miles. It makes a slight protrusion eastward at the valley of Furse Creek, in northwestern Martin County, and enters Greene County about a mile south- east of the village of Scotland. The course of the glacial boundary through Greene, Owen, and Mon- roe counties has been mapped in detail by Mr. C. E. Siebenthal, of the Indiana Geological Survey, and is represented in Pl. IX. From near Scotland it has a course slightly east of north to the valley of Plummer’s Creek, in sec. 9, T.6 N., R.4 W. North of this creek it makes an east- ward protrusion of about 2 miles into a lowland tract known as the Ameri- can Bottom, reaching sec. 36, T. 7 N., Rh. 4 W. North of this lowland the course of the boundary is west of north to the valley of Richland Creek, in sec. 9, T. 7 N., R.4 W. It follows the east bluff for about 3 miles and crosses to the west side of the creek in sec. 35, T.8 N., R.4 W. It follows nearly the west bluff to sec. 17, T. 8 N., R. 3 W., passing about a mile southeast of the village of Newark. The boundary makes an eastward protrusion of about a mile into Richland Creek Valley in sec. 16, from which the course is northward into Owen County. Entering Owen County in sec. 33, T. 9 N., R. 3 W., the boundary leads northeastward past Free- man post-office and crosses into Monroe County in see. 6, T. 9 N., R. 2 W. The course continues northeastward through northern Monroe County, the boundary being about 2 miles north of Ellettsville and 1 mile north of Modesto, and coinciding nearly with Indian Creek Valley from mouth to source. From the head waters of Indian Creek, in see. 3, T. 10 N., R. 1 W., the boundary leads eastward about 6 miles, near the Monroe-Morgan THE DRIFT BORDER. 37 county line, and there reaches its most northern point in Indiana. It is here that the limits of the portion of the ice sheet properly included in the Illinois glacial lobe should be placed. The boundary from there leads southeastward to the Ohio Valley, and is discussed in another report in preparation. The drift border shows no evidence of an overlapping’ at this reentrant angle of one lobe upon territory abandoned by the other, such as was noted on the west side of the Illinois lobe. The border south- east from the reentrant seems to be a direct continuation of that just traced. The length of the drift border thus outlined is about 700 miles, and the width of the lobe encircled by it is about 300 miles. The tracing of this border has been the product of several independent surveys. The portion in Wisconsin was largely determined by members of the Wisconsin Geo- logical Survey. The border in northwestern Hlinois was partly determined by members of the Hlinois Geological Survey, and subsequently with greater approximation by Prof. R. D. Salisbury, of the United States Geological Survey, but the precise limits have not as yet been mapped. The portion in Iowa, and also the portion from the southern edge of Towa southward to the vicinity of St. Louis, have been traced by te present writer. Salis- bury, however, made observations at an earlier date on the limits of the drift in Pike and Calhoun counties, Illinois, and discovered evidence sug- gesting that a portion of these counties is unglaciated. The deposits of drift on the Missouri side of the Mississippi, in the vicinity of St. Louis, were first described by Prof. A. H. Worthen! and later by Profs. G. F. Wright,’ J. E. Todd,’ and H. A. Wheeler.* The portion of the boundary from St. Louis southward to Jackson County, Hlinois, was mapped by Prof. G. F. Wright and discussed in Bulletin 58 of this Survey. Wright also mapped the boundary across southern Illinois, but this had previously been outlmed with a fair degree of approximation by Worthen.’ Wright also made a tracing of the glacial boundary in southwestern Indiana, which was published in Bulletin 58 of this Survey. But the posi- tion of the boundary in that region is found to be shown very inaccurately, the limits of the drift being from 5 to 20 miles outside the limits placed by 'Geol. of Illinois, Vol. I, 1866, p. 314. ? Bull. U.S. Geol. Survey, No. 58, pp. 72-73. ‘Bull. Geol. Soc. America, Vol. V, 1894, p.539. Missouri Geol. Survey, Vol. X, 1896, pp. 161-163. ‘Trans. St. Louis Acad. Sci., Vol. VII, No. 3, Feb., 1895. 5Geol. of Illinois, Vol. I, 1866, p. 27. 38 THE ILLINOIS GLACIAL LOBE. Wright. As indicated above, its position in Monroe, Owen, and Greene counties has been mapped in detail by Mr. C. E. Siebenthal, of the Indiana Survey. The portion between Greene County and the southwest corner of Indiana has been traced by the present writer. The portion mapped by Siebenthal has been reconnoitered by the present writer, and also most of the border in southern and southwestern Illinois. TOPOGRAPHIC EXPRESSION. The drift border in the portion examined by the writer, both in south- eastern Iowa and in western Illinois, is generally marked by a low ridge, seldom rising more than 60 feet above the outer border district, and averaging perhaps 40 feet. In Adams and Pike counties there are a series of ridges shown on the glacial map (Pl. VI), which have nearly parallel trend, but which are broken by wide gaps, and represent imperfectly the successive positions of the ice margin in these counties. The ridge forming the border seldom exceeds 2 miles, and is usually but a mile or less in width. On the eastern slope there are low swells, 10 to 20 feet in height, extend- ing out in places to a distance of several miles from the drift border, but seldom showing a disposition to form connected chains or ridges. The portion of the drift border along the east side of the Driftless Area in northern Hlinois and southern Wisconsin is in places slightly thick- ened beyond the usual depth of drift in districts to the east, but is in other places very thin. It may be possible to trace an ill-defined ridging more or less suecesstully near this border. The writer's observations touch it at only a few points, and are not sufficiently full or continuous to justify an opinion on this matter. From the point where the border crosses the Ilinois River in south- eastern Pike County, Illinois, southward to the Mississippi, there are occa- sional knolls, 20 to 40 and occasionally 60 feet in height, the majority of which are elliptical, with the longer axis trending ENE.-WSW., or about at right angles to the trend of the drift border. These knolls do not lie at the extreme border, but are situated 5 to 10 miles or more back from it. Their form is drumlinoid, but seldom assumes the regularity of the typical drumlin. The portion of the drift border touching the State of Missouri displays only patchy deposits of drift, usually in the valleys or depressions, and TOPOGRAPHIC EXPRESSION OF THE DRIFT BORDER. 39 seldom, if ever, aggregated in the form of knolls or ridges. As noted above, it is not certain but that the deposition was largely made by streams, rather than by direct glacial action. : Below St. Louis there is a less regular and lighter deposit of drift in the vicinity of the border than in districts to the north, and the border there, so far as noted, is without topographic expression, the drift bemg found largely in depressions, with only a thin veneering on the hills. As noted farther on, a prominent belt of drift ridges comes down nearly to the drift border from the northeast across southeastern Madison, central St. Clair, eastern Monroe, and northern Randolph counties, and there turns southeast- ward, taking a course nearly parallel with the drift border and scarcely 10 miles back from it. Upon turning southeastward this belt of ridged drift becomes ill-defined, but has been traced with some certainty to central Jackson County (midway between Ava and Murphysboro). As yet no line of ridges marking a continuation has been found farther southeast. It is possible that the sheet of drift which terminates at this belt of ridges may come to the glacial boundary in southern Illinois, and constitute that boundary from there eastward. In southern Tlinois occasional low knolls, 20 feet or less in height, occur in the vicinity of the drift border, and there appears to be a slight ridging in east-west direction in the southern portion of Williamson County, a ridging sufficient to influence the course of streams, as indicated on a later page (p. 527). In the vicinity of the Wabash River, near Ridgway, and thence northeastward to New Haven, Illinois, there is a belt of low sandy knolls and ridges, the origin of which is not clearly determined. Possibly they are entirely the result of wind action, or they may be due in part to glacial action. In southwestern Indiana a few places were found where the drift border and districts immediately back of it show a tendency to aggregation in low knolls and ridges. Perhaps the most conspicuous instance is found in Gibson County, near Fort Branch, where for a distance of about 3 miles along the east side of the Evansville and Terre Haute Railway there is a ridge of drift 30 to 50 feet in height and nearly a mile in breadth, whose surface is quite undulatory. From the southern end of this ridge south- westward into Posey County knolls 10 to 20 feet in height are of frequent occurrence, and in places become so closely aggregated as to give a 40 THE ILLINOIS GLACIAL LOBE. decidedly morainic expression to the drift surface. Occasional knolls and low ridges. of drift were found im northeastern Gibson and northern Pike counties, Indiana, lying usually within 5 miles of the glacial boundary. No knolls or ridges of drift were noted in the district north of East White River, nor have any been observed far back from the glacial boundary in southwestern Indiana and southern Illinois. Reviewing the above statements, it appears that the border is only in places marked by a definite ridge, and that there the ridge has mild expres- sion and slight dimensions compared with the expression and dimensions of the bulky moraines formed at the Wisconsin stage of glaciation. The expression is also much milder than that of ridges formed at some distance back from the drift border in southwestern Illinois, which pertain to the Illinoian sheet, descriptions of which are given below. STRUCTURE OF THE DRIFT BORDER. The drift border, as here discussed, includes a belt several miles in width, embracing a svfficient amount of territory to afford a fair index of the variations which are displayed in the immediate vicinity of the border, The discussion begins in Lee County, Iowa, which is the writer’s native county, since the sections of wells and also natural exposures have been studied more thoroughly there than at any other part of the drift border. This county is situated in the extreme southeast corner of Iowa. (See fig. 4). During the drought of 1894 and 1895 a large number of new wells were sunk, and the writer had opportunity to make many observations concerning the character of the drift penetrated by them. The Hlinoian drift sheet is found to be generally but 10 to 30 feet in thickness, though on the ridge which forms its western limit the thickness is increased to 50 feet or more. In several of the wells which were observed during excavation the Hlioian drift is composed of a brownish, pebbly clay, which has been so thoroughly leached that no response with acid could be obtained, even where the thick- ness is 20 feet. But in some of. the wells this sheet contains a very cal- careous till which has been leached only to a depth of 6 or 8 feet. This variability in the amount of leaching is thought to be due to difference in the derivation of the material. That which is leached from top to bottom is probably made up in large part of the surface portion of the older sheet of drift which is here overridden. That which is a typical calcareous ‘till STRUCTURE OF THE DRIFT BORDER. 41 was probably in part formed by the ice in passing over rock ledges and in part collected from the calcareous portions of the underlying sheet. It does not seem at all probable that the variations in the depth of the leached material are due entirely to leaching which has occurred since the Ilinoian sheet was deposited. The portions which are leached to great depth seem to be no more readily pervious to water than those in which the leaching has extended to a depth of only 6 or 8 feet. The ridge marking the western limits of the Illinoian drift, in Lee County, is in places thickly set with bowlders, but as a rule it appears to carry no more bowlders than the portion of the same sheet in the plain tracts immediately east. The bowlders and smaller rock constituents of the Illinoian drift are found to differ somewhat from those of the sheet that underlies it, there being certain rocks found in it that are not found in the underlying sheet, while other rocks differ in abundance in the two sheets. Several bowlders of red jaspery conglomerate, apparently from the Huronian outcrops north from Georgian Bay, have been found in this county on and east of the ridge that marks the western limits of the Illinoian drift, and these are thought to point decisively to the Labradorian invasion. There are also quartzite rocks present in the Ilinoian drift that have not been seen in the sheet beneath it and which probably were derived from sources not far distant from the Huronian that bears the jaspery conglomerate. The cherty beds of the Burlington limestone that outcrop along the Mississippi and its tributaries have been meorporated in the Illinoian drift sheet and transported westward to the extreme limits of that sheet. They point with certainty to the influence of the Labradorian invasion. : The Illinoian till sheet in Lee County, as also in counties to the north, is separated from the underlying Kansan till sheet by a weathered zone accompanied by beds of black muck and peaty material. This was first brought to the writer’s notice about ten years ago, in a well sunk near the village of Yarmouth, in Des Moines County. For this reason, and because it is not lable to be a source of confusion by duplication in other parts of the glaciated region, the name Yarmouth has been proposed to cover the interglacial interval between the Kansan and Ilinoian." The village of. 1The weathered zone (Yarmouth) between the Kansan and Illinoian till sheets, by Frank Leverett: Proc. Iowa Acad. Sci., Vol. V, pp. 81-86, 1898; Jour. Geol., Vol. VI, 1898, pp. 238-243. 42 THE ILLINOIS GLACIAL LOBE. Yarmouth is situated about 20 miles northwest of Burlington, the county seat of Des Moines County, on the line of the Burlington and Western Railway. It stands on the ridge which marks the western border of the Ilinoian till sheet. The well above referred to, which first suggested to the writer the occurrence of two distinct sheets of till in southeastern Iowa, was made by William Stelter, on the border of the village of Yarmouth. The writer visited the well soon after it was bored and made out the follow- ing section from the material exposed in the dump : Section from well of William Stelter, near Yarmouth, Des Moines County, Iowa. Feet. SoxlFan dil osm (Lona OCS) meee ame ene ate meal la eater ee 4 Brovenishiy ell opti (UOT am) em ie late ofa mw em al i la 20 (Gray nll (UMS EIN) > Soo soSecc cee Bpeecs seSSS5 Ste5 seme Soon sasoge Sate boceus soscbese ness sesoesseco 10 Peatibed with’ twicsand bones|\(Yarmouth))=2-=- << 2 oes en eee ae ela enna oe eee eee 15 Gray or ashy sandy clay, containing wood (Yarmouth) -------.---.---.-----.-------------------. 12 LOT) SAG (OVEN) 268 Scab So2 3 Sasa coon ea Sa erod mnas osSS oseSeS Sass SS dp cosb SSE Ss SHS SSaSHsSHe 16 Yellow sandy, till| with+few pebbles: (Kansan))-- <= 222 seeee nena see wla so eee ieee oe eee eae 33 ANNE GN IN Eleventh Ann. Rept. U. S. Geol. Survey (for 1889-90), 1891, p. 491; also fig. 77. STRUCTURE OF THE DRIFT BORDER. 45 streets. The occurrence of a distinct soil and weathered zone between the loess and the upper or Illinoian till sheet is a feature not noted by McGee; with this exception his description applies well to the exposure. The section, as determined November, 1897, is as follows: Section of drift at corner of Sixth and Harrison streets, Davenport, Towa. . Feet. HORAN Naess, MAW GOGIe OE SG Gooeds sauobN ceuS cosBeU sed aoe 9ecsos ednrisoscoR sone cease cecicas deSeae 8 Black soil 1 foot, with Ilinoian till surface leached and reddened to a depth of 3 feet in the San- gamon interglacial stage; total...--...-.--.---------------------- +--+ 22+ -- 2 2-2 eee eee 4 Brown calcareous till, with a few caleareous nodules; traces of horizontal bedding near bottom, but with few vertical fissures or seams, a characteristic Illmoian till. .---..---.-------------- Brown till, calcareous, with numerous vertical fissures and seams, and occasional horizontal sand partings, with tendency to break in cubical blocks, a characteristic oxidized Kansan till. 8-10 Blue-gray till, calcareous, with occasional horizontal sand partings and numerous vertical seams, also tendency to break in cubical blocks; bowlder-like masses of gravelly sand often 2 or 3 feet in diameter, in some cases showing crumpling of beds, occur in the lower part of the “1 exposure; a characteristic unoxidized Kansan till; entire depth.--..--.--.-.------..-------- 35-40 Fine sand, appearing only on Harrison street, at base of exposure...-..---...---.-------------- 3 Tonal) AMWOMtiodaboc casado sooSau susaor Uodb Baeuas esobSbicodsice sSun 6dao00 cuaN osbo Hobo Sanetsdod 70 The base of this exposure stands about 50 feet above the level of the Mississippi River, while the top of the exposure is nearly at the level of the uplands. In this exposure no leached zone appears at the junction of the Hlinoian and Kansan, probably because of removal by the Hlinois ice lobe. The change in physical character upon passing from the brown till of the Hlinoian to that of the Kansan is very striking. The Ilinoian may be denoted a friable or crumbling till, while the Kansan is a caking till where characteristically developed. The next exposure examined presented a weathered zone and evidence of erosion between the Ilinoian and Kansan, and also showed the Iowan loess in its full thickness. It is found along Highth street in a steep descent between Myrtle and Vine, and is as follows: Section of drift along Highth street, between Myrtle and Vine streets, Davenport, Iowa. Feet. TOI NOCH Sic boos hodace sossaocda6ss osoene cocosd seeebe sa aeeSccomes BBh0a50 8505 566060 Coco bSoDoc 30 Reddish-brown surface of Illinoian till sheet, leached and stained during Sangamon inter- @lacialistasessss esses esas eeee es ieee a cles aes sania oe enna amin nni~naininn ==") 28 UO) 1d Brown calcareous till, crumbling readily; a characteristic Ilinoian till .-..--..-.--.-------- 15 Ash-colored gummy clay with black streaks, apparently of humus, representing the Yarmouth interglacial stage ......----.--------- -----------+ --- + == 22 ene eee eee reece 2 to 3 Brown till, calcareous, fracturing in cubical blocks, color changing to grayish blue at 12 to 15 feet; characteristic Kansan till...-...-----.-----.-----------+ +--+ ++ +++ +22 tener eee etree 25 Teall, ANON eS Sabos adée cces ceed danced so escubs soden dene anced Senor GaeEHe Sesess poe oae 75 46 THE ILLINOIS GLACIAL LOBE. The surface of the Kansan appears to have been subjected to some erosion, for it drops down about 15 feet in a distance of 20 rods in passing toward the river valley. This sloping surface of the Kansan is leached and humus stained, and the Ilinoian till mantles it with a bed of nearly uniform thickness, thus presenting an upper surface nearly parallel with that of the eroded Kansan. In the autumn of 1894 the writer observed several exposures of a soil and weathered zone in ravines in western Scott and eastern Muscatine counties, between what are interpreted to be the Kansan and Ilinoian till sheets. They are not conspicuous in eastern Muscatine County, but may be seen both north and south of Blue Grass, in Scott County. The exposures noted are not sufficiently deep to show the lower till sheet to good advantage, but the upper is well displayed and has the characteristic appearance of the Illinoian. Its thickness is but a few feet—in some places only 6 or 8 feet, and seldom more than 15 feet. The Yarmouth soil and weathered zone is represented by a gummy black or gray clay, changing below to a reddish-brown till. The Sangamon soil and weathered zone is represented by a similar dark gummy clay and a leached and reddened till surface. The Iowan loess in this locality is only about 8 feet in depth, and is more compact than the bluff loess found in Davenport. . At Muscatine the party of geologists above mentioned examined exposures in the east part of the city, in the east bluff of Mad Creek, and east from there on or near Second street and on Park avenue. These all occur in a lowland tract bordering the lower course of the ereek and occupying the interval between the creek and Mississippi River. Its general elevation is about 80 feet, and the highest points barely reach 100 feet above the low water in the river. The latter are found in a low ridge following the bluff of the Mississippi. This lowland carries on its surface a nearly pebbleless silt several feet in depth, at the bottom of which there are occasional thin deposits of sand resting on till. The thickness of silt and sand is scarcely 10 feet, or less than one-half of the thickness of the Iowan loess on neighboring uplands. It seems doubtful whether the deposit is of lowan age or is to be correlated with the loess. The view that it is alluvial seemed to us more probable. The till beneath this silt and sand was found to carry numerous large bowlders, some of them being STRUCTURE OF THE DRIFT BORDER. 47 at its surface. It also presents the crumbling texture characteristic of the Tllinoian till sheet. It shows very little surface leaching, response to acid being readily obtained at a foot or less. This absence of a marked weathered zone was interpreted to be due to removal by a stream which deposited the sand and silt, rather than to the time interval being too brief for the development of a weathered zone. The slight inequalities in its surface appear to be due to erosion. This till is referred with some confidence to the Hlinoian because of its physical texture and characteristics. Its thick- ness, as exposed on Second street, is about 30 feet. Beneath the till there are beds of fine sand and silt, in the midst of which are thin layers of clay, bearing pebbles up to 2 inches or more in diameter. Similar beds in the southwest part of Muscatine separate the Hlinoian and Kansan till sheets, as shown below. | In the southwest part of Muscatine the altitude of the Mississippi bluff is 160 to 200 feet above the river, and a remarkably full series of drift deposits is, or has been, exposed. In 1894 a erading on Green street afforded an excellent exposure of the upper part of the series, beginning at a level about 165 feet above the river and extending down 50 feet, but this is now concealed by grass. The lower part of the bluff is still exposed in the large clay and sand pits west of Green street. The exposure on Green street was examined by the writer when freshly graded (in 1894), and those west of Green street were examined by the party of geologists in November, 1897. The sections are as follows: Section on Green street, Muscatine, Iowa. Feet. Iowan loess, partly eroded....-....---- -----------+ +--+ 22+ 2222 ee eccentrics nee 10 Brownish-black silt at base of loess....--.------------ ------ ------ ------ +0 --- cr reet roe 1ito 2 Pebbly black soil (Sangamon) .----..----.---- .---------2+ 22-25 0ccre seer eet tttrc re 3 EAGNGGL bro AUN Gillies) )oneoce cases ceases base coc=cee4 cosees ec aeice caseos coUahe cepcce= : 6 Brown till, unleached, many bowlders near base (iliiioehn) e33. bees seo nob ges woos eco noeeeoo 12 Gallcamcouspsilib ce cece soe lee eee ele eet seine el mini) alc UCR SABE BC aS ae Cos aCeEeEeDoaHe 6 to 8 Caleareous till of brown color, probably Kansan-..-..--------------------+------ errr rt etree 10 Section on Mississippi bluff west of Green street, Muscatine, Lowa. Feet. Loess, perhaps not in situ. .....------------------ 2-2-5 s222 oer eee nest 0 to 5 Till of brown color, eroded, of friable crumbling texture, characteristic of Ilinoian drift... 15 to 25 Beds of sand with even upper surface but uneven lower surtace, containing a few bowlderets and cobblestones, but not as a rule stony.----.--------------- ------+------rr ttre 5 tol12 Gray till, with vertical cracks lined with brown material, probably Kansan-.-.---..---- ---- 8 to 20 48 THE ILLINOIS GLACIAL LOBE. Section on Mississippi bluff west of Green street, Muscatine, Towa—Continued. Feet. Disturbed beds of sand with folds that appear to have a prevailing east-west trend, as if ROWE Gl N TNO VON Na oa ek Seas soe cones Geese Seno coo coos GaSe eeiscossy Secs seco acos ccos 4 to12 Blue-black till with fragments of wood, very thickly set also with small stones and very caleareous, not characterized by weathered seams, possibly pre-Kansan, exposed only a few HOGS Coo sao sobscacsedasacco decane co ecenscccoces dash don dad tosane DeSbas GoaSso Saas sees secos 0 to 8 Peaty bed, exposed "only for aifew, feet =~ — ene oe ee oe eens aie tto 1 Sand, perhaps from decomposed Coal Measure Sandstone .-.--..-..------------------------- 1 to 2 Coal Measure Sandstone exposed at bottom of pit at level probably 50 feet above river. The blue-black till at the base of this exposure is thought by Bain to be very similar in physical texture to some of the supposed pre-Kansan deposits of southern Iowa. The writer has observed several instances of similar material near the bottom of the drift series in southeastern Iowa. It is thought best not to include it in the Kansan unless these suspicions are removed. ; In the Museatine cemetery, on the bluff back of the exposures just described, at an altitude about 200 feet above the river, a well passed through 215 feet of glacial deposits, including loess and sand. The drift is mainly blue till, but beds of sand such as outcrop in the exposures near Green street were passed through. For a few miles in the portion of the Illinoian drift border adjacent to the southwestern flowing portion of Cedar River, in Muscatine County, sand dunes and a general coating of sand, drifted probably by wind from the plains bordering the Cedar River, form a mantle of considerable depth on the crest of the terminal ridge, and conceal the structure of the ridge, so that wells afford the only means for obtaining information concerning it. Several deep wells have been made which penetrate from 120 to 300 feet of drift, the least depth at which rock was found being 120 feet. These wells usually penetrate a large amount of till, but there are thin beds of sand associated with the till at various levels. In some cases a hard till is found at considerable depth, which, it is probable, is as old as the Kansan, and possibly is pre-KKansan in age. The following list of wells in Musca- tine County will serve to set forth the variations in structure and the great depth of drift. The list begins at the northeast part of the county and pro- ceeds southwestward along the ridge. For several of the sections the writer is indebted to Prof. J. A. Udden. STRUCTURE OF THE DRIFT BORDER. 49 Deep wells along Ilinoian drift border in Muscatine County, Iowa. Altitude | | Owner or location. above tide. Depth. Remarks. Feet. Feet. | S. Hayden, sec. 8, T. 78, R.1 E.-----| 800 | 120 | Mainly till; inflammable gas from near | | bottom of drift. Sock SUI Tei Min ere tan ae 730 261 | Clay, 80 feet; quicksand, 8 feet; coarse | sand near bottom. SK G} WS Us} Mig Wi SeShou cogcaneses 710 240 | Sand, orsandy till, 90 feet; blue clay, 140 | feet; sand and gravel, 10 feet. W. Feldholm, 2 miles south of | 750 100 | Silt, 5 feet; sand, with few pebbles, 30 Durant. | feet; hard blue till, 65 feet. Three miles south of Wilton.----- 720 300 | No rock entered. J. Denkman, sec, 12, T. 78, R. 1 W -- 770 158 | Clay, 140 feet; silt and sand, 18 feet; | rock at bottom. F. D. Wood, sec. 27, T. 77, R.3 W... 750 208 | Mainly blue clay with few pebbles; no j rock struck. A. Wiggam, sec. 10, T, 76, R. 3 W-..| 750 170 | Loess, 12 feet; yellow till, 38 feet; grav- elly sand, 25 feet; blue till, 25 feet; yellow cemented gravel, 10 feet; very hard blue till, 60 feet; sand, 8 feet. SecnoO i liGekoowWi-tsesiemiceec cee 720 154 | Mainly till; gravel at bottom. | L.Eppelry, 3 miles north of Letts-| 735 200 | No rock entered. | A. Cone, sec. 24, T. 76, R.4 W..._... | 660 200 | Till, 180 feet; very hard till, 60 feet; | sand at bottom, 10 feet. In northern Louisa County, near Letts, several wells have obtained inflammable gas in sand below till at depths of 100 to 150 feet. These wells are situated just within (south of) the ridge marking the limits of the Illinoian drift, at a level perhaps 50 feet below its crest, or about 675 feet above tide. It is reported by the residents that beds of black muck and peaty material are found closely associated with this gas, and it is probable that the gas is derived from the decomposition of organic matter in these beds. The horizon seems rather low for the Yarmouth beds, unless the Kansan till sheet has been eroded. Prof. F. M. Witter, of Muscatine, Lowa, has presented a brief discussion of these wells in the American Geologist.’ The drift in the vicinity of Columbus Junction may exceed 300 feet in depth. A well made by Dr. Daniel Overhalt in the Iowa River Valley, near Columbus Junction, at a level about 130 feet below the uplands, ‘Am. Geologist, May, 1892, pp. 319-321. MON XXXVIII——4 50 THE ILLINOIS GLACIAL LOBE. reached a depth of 164 feet without entering rock; the bottom of the well is estimated to be but 416 feet above tide. The following section of this well is reported by the well driller, L. Williams, of Columbus City: Section in well in Iowa River Valley near Columbus Junction. Feet JNA Boece ececon baacee ne He beens sed con as seer rdonoe acco scandenbao ceuaoUcbacccosescéds onsdos 8 Blue pebbly, clay. -+-- == -2-- -=-- 0-2 == = a a a a ne wm nin wre eli 72 Riinttl san Gadoxde no socdes naccns deep SESo pe cebe asada codec paadas ensdraodedgnancoad Soc0.nn0b caecds 2 IBY Obhy coe Socieso co vase saecas Hoe a BOSCEE SIUTEs sSneoe Gace EOStea cer oane boass5 oNeoco oS SacoooRCSS 14 SETI sca deco ccootibos Gacin a6 Gos Coe HOnS HE edSs Sao oeiceco opcode promec banca oeeksoreercecedscssascs6 68 SHOE Y eGeina SSO oe ORS BBE So BSB E Ee De MOReEsOcoe acsocte acs babteaaashomscadcas sonsse cecese 164 Dr. Overhalt has a well on the bluff back of Columbus Junction at an altitude 130 feet above the well just noted, which reached a depth of 166 feet. It penetrates about 35 feet of loess and yellow till, beneath which it is mainly in a blue till to within 6 feet of the bottom, where sand and gravel are struck. It is probable that the blue till in this and the following two sections is Kansan. A well made for Hon. J. W. Garner at Columbus City penetrated only 13 feet of loess and yellow till, beneath which 157 feet of blue till was passed through before a water-bearing sand was found. L. Williams’s well, in Columbus City, passed through 20 feet of loess and yellow till and then penetrated 108 feet of blue till before entermg water- bearing sand. Within 2 miles west or south of Columbus City rock is found at depths of only 20 to 40 feet, and the drift is largely a yellow till. Near Cairo, in Louisa County, Lowa, two wells on the crest of the outer ridge of the Hlinoian drift sheet, at an altitude of about 750 feet above tide, reached a depth of 130 feet without encountering rock. They are mainly through till, much of which is probably Kansan. On the outer face of the ridge, near the base, at an elevation of 50 feet below the crest, a well was sunk by R. Cotter which enters rock at about 50 feet. Rock is also exposed in the bluff of Long Creek, north of Cairo, beneath about 60 feet of drift, mainly till. Along the outer ridge of the Ilinoian drift in northwestern Des Moines County several deep wells have been sunk, some of which penetrate a bed of peat or muck at about the level of the base of the ridge and the surface of the Kansan sheet of drift. It is here that the Yarmouth section given above (p. 42) is found. In some places along the outer ridge of the Hlimoian drift wells have STRUCTURE OF THE DRIFT BORDER. 51 passed below the level of the outer border plain before entering the black muck which is thought to separate the Illinoian drift from the Kansan. In such cases the well is supposed to have struck into a valley which had been excavated in the earlier sheet of drift, though there is a bare possibility that an older soil horizon is struck. The following section of a well on the farm of F. Smith, about a mile south of Yarmouth, will illustrate the condition just mentioned: Section in well on farm of F. Smith, a mile south of Yarmouth, Towa. Feet Mellowstill Sbecomineyorayabelows (illanolan)) perenne) eee scien eae ee nicere sae see eee. 36 Sand, with thin beds of blue clay and also of cemented gravel, probably in part Illinoian and in PERU MIURIN sompoo sobs beomeo Ropabdo Son een cou ROSS Coons» aHabeD opuasU sus nee BeHectEEes poou eee 73 black muck ycontainin oywoodeG@varmo uth) oecelm saat eeeeeisceniaciece esse seer eee cen en ene 6 Shrel anal -przinall pROAbby Alle cooss sasnades Koo be Hb donu.cooouS soSbes bodoad obec noodouEoson 80 Gray silt, apparently pebbleless, probably alluvial...-..........---..----.---.------------------ 15 Jee TH CANE EIN) coosuooSos ebabas BanoocbGeSs dado obec 6500 abaEde Hooopd babeat pane pod aESEceeDTeEeEe 42 IDG PUNs50009 boo aos seus Goeees coEE SE bod GodEde SESS CacHasSHEEoEubRs baooSEoE esSSumESacoed eer 180 This well is on the crest of the ridge at a level 60 or 70 feet above the outer border plain. The black muck is therefore at a level about 40 feet below the plain. A well in the neighboring section on the south, at an ele- vation 25 feet lower, enters rock at a depth of 182 feet. One of the thickest drift sections found along this drift border is in a well made by Anton Totemeir near New London, Iowa, in sec. 19, T. 71, R. 4 W., which struck rock at a depth of 276 feet. The section of the well indicates that only the upper 40 feet should be referred to the Hlinoian drift _sheet. The section as reported by Mr. Totemeir is as follows: Section in well of Anton Totemeir, near New London, Towa. Pebbliysyellowaclayg (lin o1an) eemsmeters soe steen eeinstaciite ep atsie siete te siecle eeiaeiseioe eriee eee ssseacnee 3 iPebblyabluerclayAChilinoiam) mass sss scsscsaaea ae sey eee eee e nae ee iene -k eocuie a sasicceecsenmeccsce 10 Deeply stained; reddish-brown pebbly clay (Kansan) -------.---..--.-.-.--------¢--------------- 12 Blue pebbly clay, with thin beds of sand, possibly including pre-Kansan as well as Kansan...... 224 Dotaleecee ss ssoseces sidbdues doboor GodobH Kedoladhb cuopsone puad Beoeoodobree Scot Osea beer eeud 276 The well mouth being about 750 feet above tide, or 240 feet above the Mississippi River in Burlington, the rock floor at this well is but a little lower than the bed of the present Mississippi at Burlington. Of the several wells along this ridge in Des Moines County none have been found to enter rock at less than 120 feet, and probably at least half this drift is older than the [lnoian. 52 THE ILLINOIS GLACIAL LOBE. Along the ridge in southeastern Henry County, as in northwestern Des Moines County, wells not infrequently pass through a bed of muck or peat at the base of the Illinoian drift sheet. In a well made by Andrew Johnson, 14 miles south of New London, there were logs and wood, ocecu- pying a space of nearly 4 feet, found at a depth of 40 to 45 feet from the surface. The writer obtained specimens of the wood and of peaty material associated with it, which await specific identification. Mr. Johnson reports the section of the well to be as follows: Section in well of Andrew Johnson, 14 miles south of New London, Iowa. Feet YWellowsclaypnwathoutmpebbles\ (loess) eee == em atet= = yeni se nals eeiniaien a =ia)ole aie nislel= = oe eae 6 Brown clay with few pebbles (Kansan) exposed'---< --------- 8 oi eee -- 15 WN sa co.aqde pond eoabogunes noeo Hee eco baeedu naaaed odoo Gadns SeSb dasodibos Saou Sern Sado eeondeas 47 The deepest well section obtained on this ridge is at the residence of Andrew Foggy, sec. 16, T. 69, R. 5 W., and this differs from other well sections in that neighborhood in containing a large amount of sand in the lower part. From observations in a neighboring ravine and Mr. F ogey’s statements concerning material penetrated in the well, the following section is prepared: Section in well of Andrew Foggy, near West Point, Iowa. Feet biellowssilitzordloessi (low!) Meare eaascle eel aise Seer peinietece thse eee me eisisinte seein ieteiereeers 6 Black#soilmwauhsonayesubsolla(sang amon) eaeeeeere ese ate eep see see nsisiee eae nies rele eee 4 Ve one UBL CaN Neh Ate eS Sub aN eo ee oN ee Sere cara y ea Byes Ae ee et Sy ra ete 20 Sand eattordinopweakyvermyotwwater (llinolam) ene cer essaiseeisn ss =) ee ea eee ie ale s= elec 6 Bluextilly(illin ova) einem e vee is pe ee nina teats pagerneels (ak ntelee ea ta)= aie igs epteiele fe eeto see Sate 33 Sand and peaty material, underlain by « fine gravelly sand (alluvial and Kansan)..---.---.------ 50 TLACTHCROND (coos cao Se56505 Koad oboaSS0nO50 poos chop ec0b dob GooO DOOD ONOD aSoMeapa cEne cece. cooooda aHEs 12 IDEN, caon cseS ecan sons ose bccag sabe menu pHaE nee coobibsba 5sc0 9500 5085 CBSO ESad SSH SbsHoouanoeD, el It is probable that the [linoian drift extends to the peaty material at a depth of 70 feet, for the well stands upon probably the most elevated point on the ridge in this county, at a level nearly 70 feet above the outer border plain. A neighboring well in the same section, on the farm of I. Timpe, penetrated about 12 feet of loess-like silt and slightly pebbly yellow clay, at which depth a very calcareous, sandy, yellow till is entered. This 54 THE ILLINOIS GLACIAL LOBE. changes to a blue till within a few feet. A large amount of wood was in the blue till near the bottom of the well, at a depth of 25 to 30 feet. The wood, however, is incorporated in the till in the same manner as bowlders or pebbles, and does not indicate a soil horizon. The well appar- ently terminated in the [linoian drift. On the plain east of this ridge a black soil (Yarmouth), which separates the [Mlinoian sheet from the underlying drift, has been noted in wells at the following depths: Depth to black soil (Yarmouth) in wells on the plain near Denmark, Towa. | | eyaende | Depth. i | | Feet. Feet. CRAM ohrerysecslOVUNGO RD Wee ey acee salejoee eeee eee eats ee ee 725 | 30-32 Mei \Warklcawiioin SyS6CHibo 4D. OO piv o) AWW) artisan see tae eee tee eer eee | 715 | 16-20 1D5 IGN ANDIN, Sees PE MIRC} 188) NY conoes obo deosee S55 6555 Sees ooaSoSeoRS 725 35-40 ChHeBurtoniestate. secs25, Ds 69. SiWieseseee ae ne ee eeeee nee aeceee | 720 30-35 Mhomas;saunderson seco. el GU wh DW ieee eee eee eee eee ee eee eee eee | 720 20-22 Benjmkrebipielsecso0: choo whois eee eee bee eae eee eee ere 720 35-40 NBS TSUN STh My EOS BLO, AL SEY Mtoe EW) os So Geom sosadesedesoehoed cascanss | 725 | 45-48 SaiViaml urylres tabey Sec o0 lOO) hud Wieser ene es eer et eat a | 715 35-37 GeBaBrackett,Denmarkicscseeceslee ces sete este eee eee | 700 20-26 JamesiConarosDenmarky sue a2 shoe oe se ee See eee eee aes | 700) 19-24 eaWitllianeBlackintons Denman kes sae: eesece este ee eee ee ene eae | 700 26 IDye, Winllhnen Silom, IDEMMERNS o ooo co60 eso babs co aScs He Sane boocesesceee | 700 | 25 Publichwell Wen m amkyes aa. siee sees icea eee ee eee ace ee eee | 700 | 20-30 The wells at Mr. Flohrer’s and Mr. Hawkins’s pass through several feet of ash-gray clay, apparently a subsoil, immediately below the black soil. Exposures on ravines in this part of the county sustain this interpretation of soil and subsoil. The Van Tuyl well has the following series of beds: Section in well on S. Van Tuyl estate, near Denmark, Towa. Yellow silt or loess, slightly calcareous and containing a few small pebbles near base (Iowan). ---- U Brownish-yellow clay, with few pebbles and but slightly caleareous (Ilinoian)..............----- 10 Brownish-yellow till, pebbly and calcareous (Illinoian)).---...-..-. 2522-2 0222_. 22222) - se eee eee 8 Bluerolayeawathetewap ebb] esd lla ora) peer settee ete ee aera eee ee 10 Blackamnickyesoll await liyi0 Ode (Marin OU UL eee tasers ies reese sre ae oe eee 2 BrOwMish=y ell Owe crl Ul (Kcr Sam) erate erenete ee eter te eee aie etc ee 12 Isle Hl PahnKsy UL (KEN NEENN) caso ppoSod oasdac Goss Sas cous odocen duoomo sossesess codccaneessceseced ence 6 IDFING EO) codons Soocas ddoogS soSece Baboos SUSSoS Osmo He Sae on necuse Bedbod LeSoaky copoee mond edd ooemes 4 STRUCTURE OF THE DRIFT BORDER. 5D The well at Dr. Sloat’s penetrates the following beds: Section in well of Dr. William Sloat, in Denmark, Iowa. Feet Wallon, Bilior legss (OWE) socesenonooussoe Hassho soch cond Bae Shan n65600 SPGORe SSS G GSS RS ESSEC Ros 6 Brownish-yellow clay, slightly pebbly (llinoiam))s22s2-- ----2- --2- 2-22 - 2 = eee 20 Mucky clay, largely of gray color and containing a few small pebbles (Yarmouth, and possibly IKARIA) = St peo aue poseor pode Gra dan6NSs=55 BuOnSs SSgaS9 885508,.5000 OS5 SF EEG SSSR SODA CS SHy os oe 15 Brownish-yellow) till, (Kansam)/-- 7-22 22j22- ~~~ eee ane ooo aio a also aon cana eit 10 Dark-blue till, with beds of sand yielding water---.-.-- ------------------ 222-22 crt cette 5 ARON GRIN sacs coop coseeo beso seas ease S000 carb nano nes Sa p0 Soca RE Oe SeISSre EC Ao BSS ER Oa 56 The well at Mr. Conaro’s was carefully observed by the writer during its excavation, and has the following section: Section in well of James Conaro, in Denmark, Lowa. Feet. Yalour Gls Or IOGES (iGO) cosese asso coceco ceases seboCd SceO SSSR SSHG05 0SdRC nae DEG OOS ESS iss 9 Brown clay, not calcareous, with occasional pebbles, 3 inches or less in diameter (Illinoian) ..---- 10 Soil and grayish subsoil, slightly pebbly, not calcareous (Yarmouth)... .-.. -----------------+----- 5 Brownish-yellow till, leached for 6 feet at top, remainder very calcareous (Kansan)--------------- 25 GRAN GIG NIN. ss ceaqasenes sabdecuoosda sass ssbeed SUoRU aRaSDeecosolG0 SuakcS dasa See CoR cobb: 49 At Mr. Blackinton’s well, which was also personally observed during its excavation, the upper 20 feet is a thoroughly leached clay; the remainder is calcareous till of brownish-yellow color, which ineludes thin beds or pockets of sand and extends to the rock, which is struck at a depth of 54 feet. In this connection it may be remarked that several of the wells in the vicinity of Denmark penetrate yellow till below the Ilinoian drift sheet to a depth of 25 or 30 feet, there being little or no blue till above the rock. At the public well, however, a blue-black till occurs at 52 to 63 feet. Expo- sures on ravines both north and south of the village also have a dark blue- black till beneath the yellow at a level 15 or 20 feet below the top of the Kansan sheet of drift. Possibly this is pre-Kansan till. On the bluff north of Fort Madison a well made at the residence of Mrs. Heitz reached a depth of 315 feet without entering rock. Blue till was entered at 27 feet, which, with the exception of a thin sand bed, presents a solid mass 260 feet in thickness. Beneath this till, in the lower 26 feet of the well, there is a cemented gravel. Exposures in neighboring ravines indicate that the Illinoian drift sheet on the bluffs at Fort Madison is not more than 20 feet in depth. The thick bed of blue till passed through in the well is apparently as old-as the Kansan, and includes perhaps an earlier drift sheet. Along the Mississippi bluff above Fort Madison there D6 THE ILLINOIS GLACIAL LOBE. are exposures of drift 180 feet in height. The upper 50 or 60 feet consists of alternations of till with sand or gravel, and is referred mainly to the Kansan. The remaining 120 feet is a nearly solid mass of dark-blue till, which is, however, characterized by stony parts that give it the appearance of being interbedded with gravel and cobble. These bands of stony material are very nearly horizontal. It is not certain that this should be referred to the Kansan; possibly it is pre-Kansan. Many bowlders are accumulated along the base of this bluff. A strip covered with these bowlders, having a length of 8 rods and a width of 3 rods, was carefully examined. It in- cluded 107 bowlders, with an average diameter of about 3 feet. The largest three exceed 6 feet in diameter; the smallest included in the count were at least a foot in diameter. Upon classifying the bowlders it was found that red granite greatly predominates, there being 85 specimens. Of the gray or dark-colored granite only 6 were found. The greenstones are repre- sented by 10 specimens. The two remaining specimens were limestone. About one-fourth of the bowlders were glaciated on the sides exposed to view; probably many others are glaciated on the under side. The pro- portion of red granite is exceptionally large for this region, though it is probable that at least half the bowlders are of this class. These bowlders are probably largely from the dark-blue till. The artesian wells in the Mississippi Valley at Fort Madison enter rock at a level about 135 feet below low water in the Mississippi, or at about 365 feet above tide. The drift is mainly blue till, such as is exposed in the neighboring bluff. It is older than the Hlnoian, and possibly is pre-Kansan. This blue till is covered to a depth of 10 to 40 feet by alluvial sand, which in places extends to near the level of the river bed. The artesian well on the Mississippi bluff at Mont Clare, about 12 miles southwest of Fort Madison, penetrated 305 feet of drift. It is reported to be mainly through clay for a depth of 250 feet, beneath which there is sand extending to the rock. ‘This well, it should be noted, stands just outside the limits of the Ilinoian drift. The drift, therefore, like that at Fort Madison, belongs to an earlier sheet than the Ilinoian. The Hlinoian drift probably extends to the western limits of the upland’ in Hancock County, Illinois, throughout the entire length of the county. The drift, however, can not be referred entirely to the Hlinoian invasion, for there are southeastward-bearing striz in the western part of this county, STRUCTURE OF THE DRIFT BORDER. Or 7 which indicate that the earlier ice invasion, from the Iowa side, crossed the Mississippi into western Illinois. Instances of a soil between till sheets have also been found in this county, as in the counties of southeastern Iowa just discussed, and this soil is referred to the Yarmouth interglacial interval. The distance to which the Hlioian sheet overlapped the earlier one is not known. It is probable that the heavy deposits of drift found in central and southern Hancock County should be largely referred to the earlier invasion. A well made by William MeCuen on the east slope of the terminal ridge of the Hlimoian drift, about 4 miles south of Hamilton, has the fol- lowing section : Section in well of William McCuen, about 4 miles south of Hamilton, Iinois. Feet sYellowusiltxors oess) (Lowam)) Wee (eeetsaeh seeps eee niece ae eee eek ee ek 12 Soil and gray subsoil grading downward into a pale till (Sangamon and Iinoian).-._............ 22 THINS Wl GoD NON hy WUTC EM)) o66 38 pooded Sopa coca acood soueoe Eobeoe ee se ae ey Eee - eS 8 PeatyamuclawithawooduGprobaD lye arn out) sereeeeeisene tere aeeece ese a erenneeeae selene 4 Rebbivaclaysofabiliuishacolors@probablyskansan)) esse sestee eee stent eae en LOR MOU CN Nec aed ccoa cnededHaee sebopE nese deuadooueeisheodn secs Sageds Se GcLese BaSeeoe sae neee 74 Mr. McCuen reports that other wells in the neighborhood have pene- trated a similar buried peat. It seems probable that this peat is at the base of the [linoian sheet, though it may possibly be interbedded with other deposits. From near Carthage southward past Stillwell there is a filled valley whose position is revealed by the deep wells, the filling being so complete that there are no surface indications of the course. The artesian wells at Carthage penetrate 214 feet of drift, and several wells between Carthage and Stillwell reach a depth of nearly 200 feet without entering rock, and one a depth of 220 feet. A well at Owen’s mill in Stillwell enters rock at 207 feet. As the surface elevation at these wells is nearly 200 feet above the Mississippi River, those which strike rock enter it at about river level. Probably the deepest part of this filled valley is cut to a much lower depth, for the rock floor of the preglacial Mississippi is 100 feet or more below the level of low water in the stream. In nearly all these deep wells the drift is mainly a blue till similar to that exposed in the Mississippi bluff near Fort Madison, and, like that near Fort Madison, is probably older than the Ilinoian. In some wells the blue till is entered at a depth of only 20 to 25 feet, but in the majority it is struck at 35 to 40 feet. 58 THE ILLINOIS GLACIAL LOBE, On the portion of the Mississippi bluff above Hamilton the drift is only 20 or 30 feet in depth and is largely of*sandy constitution. It seems probable that some modification of the glacial drift has resulted through drainage connected with the melting of the Illinois glacial lobe. The evi- dences of a delta-like fillmg at the lower end of the Des Moines rapids, near Warsaw, are discussed on another page. In Adams County the Illinoian sheet has a series of ridges developed near the border. The outermost one lies but a short distance east of the Mississippi bluff, and is interrupted by wide gaps through which the streams find passage into the Mississippi. The inner ridges occupy a portion of the divide between the Illinois and Mississippi rivers in the central and south- eastern part of the county. These ridges differ greatly in structure from point to point. The portion of the outer ridge north from Bear Creek is composed largely of ordinary brownish-yellow till, but throughout its con- tinuation south of Bear Creek, from near Mendon southward past Eubanks, it contains a large amount of sand and gravel. The upper 30 or 40 feet, however, is often of clayey constitution, and this included, probably, the entire Illinoian sheet as it extends about to the level of the base of the ridge. In places the sand and gravel beneath this ridge is thought to be of pregla- cial age, and it seems not improbable that the portions which contain Canadian rocks or other erratics may be composed in large part of slightly modified preglacial material. The material thrown out from wells at Mendon was carefully examined and was found to be a quartz sand, of orange color, entirely free from calcareous material. But exposures of a similar sand near Eubanks were found to inelude occasional Canadian rocks in their upper portion, as if the sand had been worked upon by the ice sheet and redeposited, together with some of the material contained in the ice. Upon following this ridge southeastward to Mill Creek a change to till is found, and the valley of Mill Creek, at the point where the ridge crosses, is shown by wells to have been filled to a depth of 150 feet or more with a clayey deposit which from description appears to be till, there being numerous pebbles incorporated in it. A well made at the residence of Mrs. Thrig, on the west bluff of Mill Creek, in sec. 15, T. 2.5., R. 8 W., reached a depth of 155 feet without encountering rock. It was mainly through clay, except a few feet of.sand at the bottom. A well on the east bluff of the creek, in section 12 of the same township, is 200 feet in depth and is STRUCTURE OF THE DRIFT BORDER. 59 thought to have entered rock only 40 feet; it also is reported to have been largely through clay. On the elevated district near Payson wells penetrate alternations of clay and gravel to a depth of 60 feet or more. A well made by Mr. Barnard, 1 mile west of Payson, after penetrating 60 feet of clay and gravel, entered ared clay, apparently formed from the limestone which underlies that region. In some places the gravelly beds of the drift seem to rest directly upon undecayed rock surface. A small drift ridge is traceable southeastward from the village of New- ton (Adams post-office), on which wells have been sunk to a depth of 75 or 100 feet without entering rock. The town well at Newton is reported to be mainly through clay, with a few feet of gravel at bottom. A well at Mrs. Wittemeyer’s, on the crest of the ridge, about a mile southeast of Newton, reached a depth of 82 feet and apparently passed through a buried. soil between sheets of till. Exposures of a buried soil are to be seen near the level of the base of the ridge in the road leading south from Mrs. Wittemeyer’s, in sec. 35, T.2 S., R. 7 W., but at that place it is underlain by sandy gravel. The following is a section of the well as reported by the owner: Section in well at Mrs. Wittemeyer’s, a mile southeast of Newton, Adams County, Illinois. Feet. Yellow clay without pebbles (Iowan) -.---.------ .----------+ -------- 2222 cer c errr rrr tee 10 Pebbly yellow clay (Illinoian)_.......----.------------ +--+ +22222 e222 verre teres terres 30 Mucky gray clay (probably a Yarmouth soil) -----..-------------+-2+-----+ ee eee ccc c terete ne 7 Sandy and pebbly clay grading downward into sand (Xansam)) 222255522 5- -- ~-1--- -- <= == == 35 TRAAILGGNWN oos0es boosne Soosoe cabeds Hesees sebesp Cob eps eS0c50 DSe8s6cose5o CoS Go Soe Sadcdacse 82 On the plain northeast of this ridge, from the village of Burton east- ward to Liberty, the ravines expose a yellowish gummy clay, containing few pebbles to a depth of 50 feet, which is referred to the Hlinoian. There do not appear to be large pebbles or bowlders in such number as usually occur in the typical till. ; Farther south, in the vicinity of Plainville and eastward from that village, the ravines expose a large amount of cherty gravel and cobble in the lower part of the drift, but the upper part, to a depth of 20 feet or more, is usually a clay containing but few pebbles. his phase of the drift, as noted below, extends across Pike County and characterizes the extreme border of the Illinoian sheet. It is probable that the chert is a residual product from the cherty limestones of that locality. 60 THE ILLINOIS GLACIAL LOBE. Along the divide between the Illinois and Mississippi rivers, from the southeast corner of the county northwestward to the vicinity of Liberty, there is a ridge made up in part of till and in part of sand and eravel. In the vicinity of Kingston (Fairweather post-office) wells along the crest of the ridge have reached a depth of 90 feet without entermg rock. The ravines near this village expose an ash-gray soil (Sangamon) below the loess, and beneath this a brown gummy clay, slightly pebbly, with occa- sional bowlders, which is probably of Hlinoian age. This clay is seldom more than 15 feet in depth, and is underlain by sand containing few pebbles. In the vicinity of Beverly the sand is absent and a blue till appears below the brown gummy clay. A well at J. Sykes’s, about a half mile east of Beverly, is thought to have entered preglacial sand in its lower part. The well is an excavated one, 6 feet in diameter, and several wagon loads of the sand were thrown out on the dump, where excellent opportunity for comparing it with the glacial deposits was afforded. An examination of these deposits, supplemented by information furnished by Mr. Sykes, enables the writer to present the following section: Section in well of J. Sykes, a half mile east of Beverly, Adams County, Illinois. Feet Loess and gummy brown clay with few pebbles......--.---.----------------------------------+--- 35 (Cnnehy GRMN 056 sean S465 doene5 HSaSen ee cebes case soso ccosas Goon nead BS eSgosas Cece anSe Fone Sdasen saec 3 Blue till, very stony, with large bowlders and fragments of wood -.-.-...-----------------.------ 27 (Grayssandrandsonavel cal Cane Ouse ia atte ata alee aa tee ae tela ee el eel 5 Orange-colored quartz sand, noncaleareous..-.---------------------------------------------+----- 14 MOE) GIN, nos sas sachooeea sens sons osobSES SeoSaene Hoes SeubEeooSS SSaaes CneSdONSESSe ore siseee 84 This well is located in an elevated part of the county, about 350 feet above the Mississippi River. A similar deposit of sand was found in a well in the village of Beverly at a depth of 55 to 75 feet, or very nearly the same elevation above tide as the well at Mr. Sykes’s, the well mouth being on ground 15 or 20 feet lower than the Sykes well. The numerous ravines leading eastward from this ridge toward McKees Creek may afford expo- sures of the sand, but none were noted by the writer. Along the portion of the IHlinois-Mississippi divide between Liberty and Fowler the drift is very thick and its lower part is of peculiar constitution. Well drillers and several of the residents report that after a depth of about 30 feet is reached a blue-black clay, with sand partings and with much wood, is entered, which extends down nearly or quite to the limestone underlying STRUCTURE OF THE DRIFT BORDER. 61 that region. The writer had opportunity to examine the material thrown out of a well at the residence of James Loveless, in sec. 34, T.18., R. 7 W., and found it to be a blue-black silt, very calcareous, and containing only minute pebbles and sand grains. Several specimens of wood from this silt which were inspected by the writer also carried a coating of similar silts. Above the silt there is ordinary till, except a thin coating of loess at the surface and pockets or thin beds of sand or gravel or silty clay in the till. In Mr. Loveless’s well the following section appears: Section in well of James Loveless, between Liberty and Fowler, Adams County, Illinois. Feet. Mell owasiltions] Ossie. eens acecke see ei neimos cleo atemiciee asec eretinstetiee cele cceinsicic siete eicieaiavcitare lee .e,2 i5,- 6 Ashy soil and subsoil containing a few small pebbles... --. .---..---.---- 22-2 122-222. 2 ece teen eee 12 Callcarncons 3 GON? WHY coocosesds sobbed nobdS5 caSbod chen GooodscunS Cones bHads GaHeen tadcudiaesee nese Hee Graysoummiyzclayecesemblineysoil,moncal careous-ssstana-)ee sea -fre isos oe eel ee le eee ee 2 Callearaoms yell Wes ccscs oSeebe bases coanod coo SEopHUSOS RSS onb con EbSD Domne ecoo haooecsEDSooHeS 18 IBIMEHOCS Suki, WON, CHIKCEAOUS > cond 0525 chon ones bandos Sade oasnbe Sede coee asus Hocus o eoEScouLoSed 2 Rotalidepthyssss-e2 eee ee Sodcs cact oss Spee coca bene po uence boc cobaSE SEbUeoDEoSuEO GEES 62 At the county infirmary, in see. 11 of the same township (T. 1 S., R. 7 W.), a well struck rock at a depth of 165 feet. The lower 100 feet of the drift is a blue silt apparently similar to that in Mr. Loveless’s well. A shallower well at the infirmary obtained water in sand and gravel at a depth of 40 to 58 feet. A well on the farm of Mr. Henry, in see. 3, within a mile of the infirmary, has a section similar to that of the deep infirmary well and entered rock at 160 feet. Several of the wells in the village of Liberty penetrate a similar blue- black silt, entermg it at about 60 feet and continuing in one case to a depth of 90 feet without entering rock. In the vicinity of this village, however, rock is occasionally entered at a depth of 50 feet or less, and only 2 miles east of the village and at a slightly higher elevation rock is struck at only 25 feet. There is a low ridge leading from the village of Coatsburg eastward 5 or 6 miles on which the wells occasionally enter a blue-black silt similar to that found on the district just described. A well at the mill in Coatsburg is reported to be mainly through pebbly clay to a depth of 65 feet, beneath which there is a blue clay with sand partings and wood embedded, which was penetrated 30 feet without entering rock. A boring for coal a mile east of Coatsburg is discussed in the Geology of Illinois because of the oceur- rence of this blue-black material in the lower portion of the drift, which is . 62 THE ILLINOIS GLACIAL LOBE. there considered a “post-Tertiary soil” older than the drift proper, and formed under very different conditions. The following is the section there published: Section in a boring for coal, a mile east of Coatsburg, Adams County, Illinois. Feet Soulkandnyel lowe) ayeene see eee eae la ate ele a aa lol 6 Bluish-colored clay and gravel.......--.-------.----------- ------ +----- -----+ ---- -------- -=---- 45 Clay with large bowlders....---.------------------------ ------ +--+ ++ +--+ - +++ 2225 ------------ 40 EVES cial a IS ae eer ea oS Aamo Ame accent neato oo See 24 Clay (stratified) ....-...----.----------------- -------------- +--+ +5 ree rs cere ee eee eee 6 Very tough blue clay...-..-.--..---------- ---- +--+ +--+ 2222 22-22 eee nee ee re eee eee 20 eae GNIDGUL Gi faa] dab ban eros SsuSscos Use bees Obes bona oe SSon.c aside ssod sods eosessecsogsouses sase 119 It seems not improbable that the silt under the till of central Adams County is attributable to ponded waters held in front of the Keewatin ice sheet in the Kansan stage, for that ice sheet apparently crossed the Missis- sippi into Ilnois near Hannibal, Missouri, and covered the lower courses of its eastern tributaries. 4 In Pike County typical till has been seen at but few points. The several drift ridges which traverse the county are composed largely of clay and sand in which only a few small pebbles occur. ‘There is, however, on the borders of Hadley Creek, in the northern part of the county and the adjacent portion of Adams County, considerable waterworn chert in the base of the drift. This chert is apparently a residuary product from the decay of cherty limestone in that region, but it was worked over to some extent by the ice sheet and its associated waters, and this has resulted in the introduction into the chert of occasional bowlders and smaller stones of distant derivation, as well as the wearing and rounding of the chert frag- ments. These chert beds are in places 10 or 15 feet thick. They usually present the appearance of gravel beds, there being very little clay present. Exposures were found, however, east and southeast of Baylis, on the west side of Bay Creek, in which a large amount of clay is mingled with the chert and other stony material. In the southwest part of the county, which appears to have been but slightly glaciated, if at all, the chert. beds remain intact at the surface of the limestone. Quarries along the east bluff of the Mississippi afford good exposures. A few well sections and hillside sections obtained in the vicinity of the drift border are here given to illustrate and make clearer the above state- ments. STRUCTURE OF THE DRIFT BORDER. 63 Hillside exposures on the line of Pike and Adams counties, in R.5 W., have a bed of cherty gravel with occasional Canadian rocks resting on the surtace of the limestone, and covering it to a depth of 5 to 15 feet. Above this gravel there is usually 40 or 50 feet of clay containing very few pebbles. The deeper exposures show it to be of a gray color, but the surface portion is yellow. Capping this clay is a thin deposit of loess, separated in places from the clay by a gray or ashy (Sangamon) soil. At the residence of A. Hill, 2 miles north of Baylis, on the crest of the main drift ridge, a freshly excavated w ell was found to have the follow- ing section: Section in well of A. Hill, 2 miles north of Baylis, Pike County, Illinois. Feet BOE Clay YAWN Thi HOWE sashes cosnod bab cos bob ooueldesoun cnouebeadeece CpsboubEEBSHeuessaoeer 25 (Gymy SMG dL. ose pb dosoosocoossedo copceoEduoES Uaeocoo sd odop coneno HboenO Seeded dEseuoouEaLUSeSHeE ss 10 Grayrelayameanrlyatreestrom\ypebbleswaem ect jmietse ease tetalciniciciatefevsleleiaeicteie oie ee siete clelel ate ee eleteie eer lepsera 33 TON GDN oo occkeossS5e0 5a cbs suo co cSdocbingds son bab sostog soonce spouse oasoses Conon neeebose 68 At Baylis an experimental boring for water reached a depth of 90 feet without entering rock or penetrating coarse material of any kind. The upper 30 feet consisted of yellow clay and the remainder of fine sand. This well is located on the crest of the main ridge, at an altitude about 400 feet above the Mississippi River. East and south from Baylis numerous exposures are found in which a pebbly brown clay underlies the loess at a depth of 8 or 10 feet. In the northeast part of the county, im the vicinity of New Salem and Griggsville, and thence north to the county line, the wells and natural exposures reveal only a small amount of stony clay, the greater part of the drift being nearly pebbleless. Rock is often entered at 30 or 40 feet, or even jess depth. In the vicinity of Time the ravines expose a pebbleless clay, probably a phase of the loess, to a depth of 20 feet or more, beneath which there is a slightly pebbly brown clay. The village well at Time reached the bottom of this brown clay at a depth of 50 feet, and then penetrated 20 feet of blue clay resembling putty, and terminated at a depth of 70 feet without entering rock. At J. E. Dinsmore’s farm, south of Time (sec. 26, T. 6 8., R. 3 W.), a well 60 feet in depth is largely through typical till, exposures of which are to be seen in neighboring ravines. Mr. Dinsmore made a well in sec. 23, in a ravine 30 or 40 feet below the level of the upland plain, which 64 THE ILLINOIS GLACIAL LOBE. penetrated 46 feet of nearly pebbleless brown clay, beneath which there is a black muck 5 or 6 feet in depth which rests upon a red clay, apparently a residuary product from the decay of limestone. East of Bay Creek, in T. 6 8., R. 2 W., wells along the outer drift ridge frequently reach a depth of 50 feet, and occasionally 80 feet, without entering rock. From descriptions of the material, it is probable that ordinary till is penetrated, but no exposures were found. The loess in that locality is about 20 feet in depth. From Pike County the drift border passes to the east side of the Illinois. A typical till constitutes the greater part of the drift exposed in ravines along that side of the river in Scott, Greene, and Jersey counties. The loess on the river bluff is usually 20 or 30 feet in depth, but within 8 or 10 miles east of the river it decreases to 10 feet or less. The drift forms a deposit probably 50 feet in average depth at the east border of the Illinois Valley, but immediately west of the Illinois, in southern Pike and in Calhoun County, there is scarcely a trace of drift. There are several knolls and ridges of drift a few miles back from the drift border in Greene and Jersey counties, but no accurate well sections or other exposures of their structure were obtained. The descriptions given by residents, however, indicate that they are composed largely of clay. In Madison County typical till is found along the east bluff of the Mississippi throughout the entire width of the county, as well as at points farther east. At the immediate border of the valley there is a deposit of loess 30 to 50 feet in depth, but within 10 miles back from the bluff the thickness decreases to 10 feet or less. The till is usually 25 to 50 feet in ~ depth, and where thickest is of a blue color near the bottom. Opposite Madison County, in St. Louis County, Missouri, north from the city of St. Louis, deposits of waterworn material of glacial derivation underlie the loess for a few miles back from the bluff of the river. These deposits contain a few bowlders, 1 to 2 feet in diameter, as well as cobble and eravel. The rock constituents appear to be different from those of the drift in Madison County, Illinois, there bemg present considerable material appar- ently brought down from the exposures of the sandstone and limestone of Silurian age on the borders of the Mississippi in Calhoun County, Illinois, and Lincoln County, Missouri. The presence of this material suggests water rather than ice transportation, and it remains an open question whether STRUCTURE OF THE DRIFT BORDER. 65 the ice sheet reached into northern St. Louis County from the Ilinois side of the river. On the east bluff of the Mississippi below East St. Louis only a small amount of glacial drift has been found beneath the loess deposits, which there cap the bluff to a depth of 30 to 50 feet or more. The drift usually consists of a thin bed of stony material, but in some of the recesses of the bluffs and in ravines exposures of nearly pebbleless clay are occasionally seen. Some of these exposures near Columbia, in Monroe County, reach a depth of 40 to 50 feet. An occasional bowlder ‘a foot or more in diameter is found in these deposits, but stones are very rare compared with their number in the typical till, such as is exposed in the east bluff of the Missis- sippi above East St. Louis. It is probable that the ice sheet extended as far west as the east bluff of the Mississippi in St. Clair, Monroe, and Ran- dolph counties, but the deposits there are very much thinner than in drift ridges, discussed later, which traverse the eastern portion of these counties, and which perhaps mark an ice margin at a somewhat later period than that of the maximum extension. The portion of the drift border in southern Illinois, on the slopes of the elevated rock ridge in Jackson, Williamson, and Saline counties, con- tains typical till, but the deposit is seldom more than 20 or 25 feet in depth. In one instance, however, a well in the southwest township of Williamson County was found to have reached a depth of 70 feet without entering rock. The distance to rock is also great in the vicinity of Murphysboro, in J ack- son County. The wells and borings for coal often reach a depth of 100 feet, and occasionally 130 feet, before entering rock. The drift is reported to be largely sandy material, but the upper portion, exposed to a depth of 50 feet by Big Muddy River, is mainly clay containing but few pebbles. On the borders of the Ohio Valley, in Gallatin County, Illinois, there is a belt of sandy material several miles in width which is not referred with certainty to glacial deposition. Back of this a typical till sets in, which is exposed in ravines beneath 8 or 10 feet of loess. Wells usually reach the bottom of the drift at 20 or 30 feet, but one 2 miles north of Ridgway reached a depth of 98 feet without entering rock, and another 3 miles west of Ridgway a depth of 75 feet. In the Ohio Valley at Shawneetown a boring for gas and oil penetrated 112 feet of alluvial and other deposits MON XXXVIII——5 66 THE ILLINOIS GLACIAL LOBE. before entering rock This appears to be outside the glacial boundary, but the material penetrated is probably derived from glacial deposits brought down the valley. In southwestern Indiana the drift in the vicinity of the glacial bound- ary frequently reaches a depth of more than 100 feet in the valleys; but on the uplands it rarely exceeds 40 feet, and is usually but 10 or 20 feet. As a rule, a deposit of till several feet in depth appears along the drift border, but in places there are only scattermg pebbles for a mile or more back from it. The latter feature is most frequently found in the hilly parts of the border. The till in the portion of southwestern Indiana south of East White River contains a remarkably small number of bowlders and coarse frag- ments of rock. In places search is necessary to discover a pebble, though in a neighboring exposure a large bowlder may be found. In a few locali- ties sand is present instead of clay, but, like the clay, it carries very few pebbles. It is thought that these peculiar phases of the drift may be due in part to the character of the underlying rocks (there being a prepon- derence of friable strata which might easily be reduced to clay or sand) and in part to imperfection of drainage conditions, by which the very fine material was all retained in the till instead of being allowed to escape down the valleys, as in regions to the west, where drainage conditions were better. In connection with the first of these causes, it may be remarked that the local rocks throughout the entire region covered by this glacial lobe usually form so large a proportion of the coarse constituents of till that its character is found to vary in a pronounced degree in accordance with changes in the underlying rocks. The imperfection of drainage in southwestern Indiana attending the ice invasion was such that several lakes were formed in valleys which lie outside the drift border and whose streams had discharged westward before the ice invaded the territory covered by the ice sheet. These glacial lakes are discussed at some’ length on later pages, as are also the changes of drainage which resulted from the ice invasion. North from East White River the till usually carries a moderate number of pebbles, and differs but little from the typical till of the interior portion of the district covered by the Ilmois lobe. The coarse rock frag- ments are composed largely of sandstone from formations which outerop in the immediate vicinity of the drift border. Canadian rocks, however, STRUCTURE OF THE DRIFT BORDER. 67 are well represented, and bowlders 4 feet in diameter are occasionally found on the immediate drift border. Reference will be made to a few of the wells showing thick drift and to characteristic exposures, beginning in Posey County and passing northeastward. The thickest drift noted in Posey County is in an abandoned valley which connects the head waters of Big Creek with Black River. One well in this valley, on the farm of Joseph Nesbit, about a mile west of Cynthiana, penetrated 127 feet of drift, and entered sandstone at that depth. The well mouth is only about 420 feet above tide and 80 feet above the neighboring portion of the Wabash River. The driller, T. F. O’Herron, of Haubstadt, reports that the entire depth is a stiff clay, of which the upper 36 feet has a brown or yellow color, and the remainder a blue color. On a neighbor- ing farm, owned by Joseph Cale, a well reached a depth of 114 teet without entering rock. In this well two thin beds of fine gravel were passed through. Aside from these the drift is a stiff clay, of which the upper 40 feet is yellowish brown and the remainder a blue color. On the head waters of Big Creek, in northwestern Vanderburg County, several wells 40 to 60 feet in depth do not reach rock. This valley appears to have been silted up to a depth of 50 feet or more in the portion imme- diately outside the glacial boundary. Wells there are reported to pass through “clay and quicksand.” In the vicinity of Haubstadt, within a mile north of the glacial bound- ary, there is a plain in which several wells have penetrated 40 to 70 feet of drift before entering rock. The upper 20 or 30 feet is yellowish-brown clay and the remainder blue clay. Oceasionally the clay maintains a yel- low color to a depth of 40 feet or more. The loess in that region, both outside and inside the glacial boundary, is about 12 feet in thickness and is similar in color to the oxidized portion of the underlying glacial drift. In the ridged belt near Fort Branch there are several hillside exposures showing a few feet of till with considerable stony material just below the loess, and beneath this a fine sand. The wells along the ridge enter a soft blue clay, called “blue mud,” at a depth of 30 or 40 feet. Only one well was found which entered rock. This is located at the residence of Lawrence Byers, near the east base of the ridge, and reached rock at a depth of 97 feet. Several wells along the crest of the ridge, 50 to 100 feet in depth, 68 THE ILLINOIS GLACIAL LOBE. do not enter rock. East of this ridge, along Sandy Fork of Pigeon Creek, wells are usually obtained at a depth of 25 feet or less. In some instances they penetrate alternations of blue clay and sand beneath the loess, while in other instances nothing but sand is found. In some of the ravines lead- ing into Sandy Fork, a gray gummy clay carrying a few small pebbles immediately underlies the loess. It appears to be stained with humus, and probably represents the Sangamon interglacial stage. A creek exposure in the southwest part of sec. 23, T. 2 8. R.10 W., shows a red, weather- stained, sandy gravel below the loess. West of the drift ridge along Muddy Fork of Pigeon Creek, wells usually enter blue clay at about 30 feet, and in several instances have been sunk to a depth of about 100 feet without reaching rock. One well 3 miles west of Fort Branch, on the farm of Henry Lehring, struck rock at a depth of 114 feet. Two miles farther west, on more elevated ground, rock is struck at 12 to 20 feet. In western Pike County, Indiana, in secs. 13, 23, 24, and 26, T.15., R. 9 W., several roadside exposures of till having a thickness of 5 to 10 feet were found apparently at the extreme limits of glaciation. For several miles east from these sections the thickness of the drift on the uplands seldom exceeds 10 feet, and the loess here is reduced to a thickness of but 5 or 6 feet. In a lowland tract along Flat Creek, in eastern Pike County, which lies near the glacial boundary, the drift has a thickness of 75 to 120 feet or more. At the village of Otwell, which stands in this lowland, Dr. W. M. De Motte made a boring which reached a depth of 119 feet without strik- ing rock, though the well mouth is only 485 feet above tide, and scarcely 85 feet above the neighboring portion of Kast White River. A boring made by William Bell near the head waters of Mud Creek and Flat Creek, 6 miles west of Otwell, reached rock at a depth of 78 feet, and several other wells within 2 miles north and east are reported by Mr. Bell to have reached rock at 75 to 80 feet. The drift in this lowland is reported to be largely a blue mud. There is, however, considerable sand just below the loess, exposures of which may be seen along the ravines and at roadsides. This lowland, as indicated on a later page, was apparently the line of discharge for a part of the Patoka drainage basin into White River, which it entered near the junction of the two forks east of Petersburg. On the uplands bordering this lowland on the north and east, rock is usually entered at 35 feet or less, while on the STRUCTURE OF THE DRIFT BORDER. 69 uplands to the south it is found at 6 to 10 feet, there being little, if any, drift present. As already noted, in northwestern Dubois County there is a low plain covering about 50 square miles in which the loess is underlain by sand. The sand appears to have been deposited in the glacial lake Patoka, formed by the obstruction of the Patoka River by the ice sheet, the preglacial course of the river having been northwestward across this plain into East White River. The plain was built up to a level of about 480 feet above tide, which has been increased to 485 to 490 feet by the subsequent loess deposit. The surface of the sand at the base of the loess is deeply weather- stained, showing that it long antedated the loess in deposition. On the borders of this plain, about 3 miles north of Jasper, in sec. 15, T. 1 S., R. 5 W., an exposure of black soil was found immediately below the loess, which was apparently formed in the Sangamon interglacial stage. The clay below it contains a few glacial pebbles. In southeastern Daviess County, as noted above, the drift for a mile or two back from the glacial boundary is reduced to a few scattering pebbles. A heavy sheet of till there sets in, which fills the country to a nearly uniform level and produces plains known as ‘the flats,” on which the drift ranges from 20 to 80 feet or more in depth. The plane surface extends nearly to the glacial boundary in the vicinity of Whitfield, Mount Pleasant, and Loogootee, in Martin County. There are, however, scattering pebbles on the hills along the east border of the plain. On a tributary of Boggs Creek, 2 miles north of Loogootee, exposures of till occur 30 feet or more in height, in one of which a granite bowlder 4 feet in diameter was noted. Along much of the boundary from Loogootee to Scotland the drift is very thin, though it apparently forms a nearly continuous sheet. There are low hills along the east border of Daviess County which for several miles inside the glacial boundary show only a thin coating of drift. But the lowlands in that region have apparently been filled to considerable depth. At Scotland and along ravines northeastward there are exposures of sandy till 10 to 20 feet in depth at points within a mile of the apparent limits of glaciation. The hills in that region, however, carry very little drift. In the lowland tract north of Plummer’s Creek there are heavy depos- its of sand, which in places are capped by a few feet of fine gravel, apparently a glacial deposit. The fillmg amounts to 75 or 100 feet, and seems excess- 70 THE ILLINOIS GLACIAL LOBE. ive when compared with the amount of drift on neighboring hills. On some of the hills between Rockwood and Park post-office, there is scarcely a trace of drift, though they are surrounded by the lowlands in which heavy deposits of drift occur. The drift continues thin on uplands as far north as Richland Creek, and the boundary is located with some difficulty. From the narrows of Richland Creek, in sees. 8 and 9, T. 7 N., R. 4 W., northeastward to Newark, there is an exceptionally large amount of drift in the vicinity of the glacial boundary, both on uplands and on lowlands. Several exposures were found 200 feet above the creek, in which there is not less than 50 feet of drift. The old course of Richland Creek, through a lowland tract east of Newark, has been filled up to a height of nearly 100 feet above the creek with deposits of sandy clay, carrying a liberal admix- ture of coarse rock material and an occasional bowlder. Siebenthal reports that in southeastern Owen County the drift is heavy in the valleys, but comparatively thin on the hills, and this feature is char- acteristic of the boundary in Monroe County and southern Morgan County, as noted both by Siebenthal and by the writer. Small bowlders are present in moderate number in the vicinity of the glacial boundary in all these counties. ® CHARACTER OF THE OUTWASH. There appears to have been very little material carried out by water beyond the edge of this ice sheet except along the valleys. While the outer border plains and the small valleys heading in this drift margin ocea- sionally bear thin deposits of sand and fine gravel which seem to be an outwash from the ice margin, there is nothing comparable to what is dis- played along some moraines of the Wisconsin stage described below. The best exposure of such an outwash yet noted is found near West Point, in Lee County, lowa. About a mile northwest of the village, imme- diately outside the Ilinoian drift border, the following series of deposits is exposed in the gradings along an east-west road : Section near West Point, Iowa, showing gravel outwash. Feet 1. Brown silt, apparently to be classed with the Iowan loess...-............---.------------ 7 2. Fine gravel, considered an outwash from the Illinoian drift .. -...................-------- lto 2 3. Ash-colored soil, representing the Yarmouth interglacial stage .................---.------ Ij to 2 4, Kansan till, brown at top, becoming a yellowish gray at bottom, exposed.....-.--.....-.. 15 to 20 The full extent of the gravelly outwash at this place is not known, because of the silt cover, but it seems to be restricted to a strip extending RIDGED DRIFT OF KASKASKIA BASIN. Vall scarcely one-half mile out from the margin of the Ilinoian drift. The presence of the soil beneath this gravel makes it evident that there was but little erosion accompanying the deposition of the gravel. It also shows that the gravel is not a residue of coarse material formed in the process of ero- sion of the Kansan till sheet, either before or after the Illinoian glaciation. The principal valley affording a line of drainage for the ice sheet was the Mississippi, only short sections of the eastern tributaries being outside the Illinoian drift margin. This valley was covered by the ice sheet, as already indicated, from’ near the south end of the Driftless Area down to the vicinity of Fort Madison, Iowa. Possibly also it was encroached upon for a few miles in the vicinity of St. Louis, Missouri. The blockade in the portion bordering eastern Iowa was so complete as to cause the opening of a temporary line of drainage across eastern Iowa outside the ice margin, as indicated below; but there appears to have been at most only a partial blockade near St. Louis. An examination into the character of the deposits in the Mississippi Valley, between Fort Madison and St. Louis, has brought to light nothing to indicate vigorous drainage at the Illinoian stage of glaci- ation. Indeed, the valley seems to have become filled to some extent by sand and finer material at places where, previous to this glaciation, erosion had been in progress. This is markedly the case just below the lower rapids. The filling there is mainly silt and fine sand, though a fine gravel appears in places where the current was strongest. This matter is discussed more fully below (pp. 94-96). In the section of the Mississippi also between St. Louis and Cairo only sand and silt are found along the valley, a feature that apparently indicates a drainage no more vigorous than at the present day. Yet it seems probable that at times the volume of water greatly exceeded that now discharged through the valley. Much remains to be learned concerning the drainage conditions attend- ing this and later stages of glaciation, but from what is now known the drainage at the Illinoian stage appears to have been very sluggish not only on the Mississippi, but on all the valleys leading away from the ice sheet. THE RIDGED DRIFT OF THE KASKASKIA BASIN. The position of the principal ridges in this system may be seen by reference to the glacial map (Pl. VI). It will be observed that there is one belt lying near the Kaskaskia River and found chiefly on its west border. 72 THE ILLINOIS GLACIAL LOBE. Another belt a few miles to the west runs nearly parallel to the river from Tower Hill, in Shelby County, southwestward to Belleville, in St. Clair County. Still farther west there is a system, less definitely developed, leading from northern Montgomery County southward into northeastern Madison County. South from Belleville the ridges are reduced to a single chain which follows the west border of the Kaskaskia from Lementon, in St. Clair County, southward across eastern Monroe into northern Randolph County. he ridge there crosses to the east side of the river and passes southeastward near Sparta to Steelville. There is a slight ridging as far southeast as central Jackson County, beyond which the drift appears not to be definitely ridged. There are, however, occasional low ridges and swells in the vicinity of the glacial boundary in Williamson, Saline, and Gallatin counties, which may mark the continuation of the belt. Of the three systems developed northeast of Belleville the middle one is the best defined and most nearly continuous. It is interrupted only by a few narrow gaps, usually less than 2 miles in width, throughout the entire distance from Tower Hill to Belleville, nearly 100 miles. There are places, as in northeastern Montgomery and in southeastern Madison County, where a continuous ridge is maintained for a distance of at least 15 miles. The belt bordering the Kaskaskia River is maintained for several miles as a continuous ridge in the vicinity of Vandalia, but elsewhere is represented only by fragmentary ridges, seldom more than 3 miles in length, between which there may be gaps of even greater length. The western of the three belts is even more fragmentary, and is maintained for only 20 or 25 miles. These ridges are usually rather sharp and narrow, but in places assume a billowy topography. In still other places they have a vague irregularity of form and arrangement. The more sharply ridged type, however, pre- vails over the others, and may be said to characterize the system. The sharpest ridge noted is that in the vicinity of Cool Spring post-office, in Shelby County, where a ridge scarcely a mile in width has a height of 130 feet. A long ridge leading from Pocahontas, in Bond County, westward into Madison County, and thence southward to the village of Highland, is about 50 feet in average height and scarcely a half mile in average width. Knolls 75 or 100 feet in height are not rare, and occur in nearly every county traversed by this system of ridges. These knolls, as well as the RIDGED DRIFT OF KASKASKIA BASIN. {(33 ridges, often rise abruptly from very flat tracts, and seldom shade into the bordering plain, a feature which distinguishes them from the moraines of the Wisconsin series, which usually grade into plane tracts on their inner border. The ridge leading southeastward from the Kaskaskia across north- eastern Randolph and western Jackson counties is not so sharp as the majority of ridges west of the Kaskaskia, and has a gently undulating sur- face, similar to that of the ridges formed on the drift border in western Illinois and southeastern Iowa. It seems, however, to be definitely con- nected with the system of ridges following the west side of the Kaskaskia, and can scarcely be included with the ridges which characterize the drift border. The entire system of ridges is composed largely of typical till, blue till being present in the lower portions and brown till near the surface. In a few cases gravel and sand have been found, but such material is so rare that railways have not found it expedient to obtain ballast from these ridges. The origin or mode of formation of these ridges is problematical. Their trend is nearly in line with the ice movement, as shown by strize in the neighborhood of Alton, in Madison County, and is about at right angles with the course of the boundary of the Ilinoian drift sheet. Several working hypotheses were employed during the field investigations, among which may be mentioned the following: (1) That the ridges are similar in origin to drumlins. (2) That the ridges constitute an interlobate morainic system formed in a reentrant between a supposable lobe which covered western Illinois and one which covered southern [linois and southwestern Indiana. (3) That the ridges mark the western border of a lobe which persisted in southern Illinois after the ice had retreated from western Illinois. (4) That the ridges are dependent in some way upon obstructing rock hills - which constitute their nuclei. (5) That the ridges are a remnant of a sheet of drift which once filled that region to the height of their crests. In the study of these ridges it was found that in a few instances they bear resemblance to drumlins in their form, but the great majority bear little or no likeness to that class of ridges. The hypothesis of an origin similar to drumlins is therefore held somewhat lightly, but is not rejected. The hypothesis that these ridges were formed as an interlobate belt 74 THE ILLINOIS GLACIAL LOBE. lacks support because of the absence of a system of ridges leading up from the west. It is perhaps opposed by the direction of the neighboring strize at Alton, which is southwestward, parallel with the ridges, instead of south- eastward toward them. This hypothesis, therefore, is held lightly, but is not rejected. The hypothesis that this system of ridges marks the western border of a lobe which persisted in southern Illinois after the withdrawal of the ice from western Illinois is apparently supported by the distribution of the ridges. his is especially true of the southeastward extension of the belt across Randolph and Jackson counties which, in a measure, encircles the supposed lobe. This hypothesis apparently is the best-supported one of the group. The hypothesis that rock hills may constitute nuclei for the ridges was suggested by the occurrence of such hills in western Shelby County, in the midst of the system of ridges, but no evidence was found elsewhere along the belt which would support this view. Indeed, the majority of ridges have such abruptness that they can scarcely be supposed to carry an equally abrupt ridge of rock. The formations in that region are largely shale or shaly sandstone which, in all probability, would be preserved only in low hills and ridges with gentle slope. The hypothesis that the ridges are remnants of a sheet of drift which once covered this region to the height of their crests is presented in the Illinois Geological Reports as an explanation for their occurrence. This hypothesis involves such a vast amount of erosion as to be entirely unsup- ported by the features of the region, and is therefore no longer considered applicable. BUFFALO HART MORAINE. The Buffalo Hart moraine is well defined for a distance of about 15 miles in eastern Sangamon and southwestern Logan counties, passing from the Sangamon River near Mount Auburn northwestward past Buffalo and Buffalo Hart to Elkhart. It consists of knolls of considerable prominence, somewhat closely aggregated, many of which are 30 or 40 feet and a few 75 or 80 feet or more in height. Among the knolls there are sloughs and shallow basins, giving the surface a subdued type of knob-and-basin topog- BUFFALO HART MORAINE. (5) raphy. This belt has an average width of nearly 2 miles. East from it there are scattering knolls of considerable prominence, one at the town of Mount Pulaski being nearly 30 feet in height. The connections of this belt with other moraines are rather vague. There is, however, toward the southeast, a series of mounds and short ridges occupying the interval between the southern end of this moraine and the northern end of the ridged drift of the Kaskaskia Basin. In case those ridges prove to have been formed by an ice sheet occupying the district east of them, the Buffalo Hart moraine would seem to be a natural northward continuation of the belt. The northern terminus of the Buffalo Hart moraine is in the form of a very prominent mound, rising 150 feet above the bordering country, or about twice as high as any of the other knolls in the moraine. It is known as Elkhart Mound, being situated about a mile east of the village of Elkhart, and has been a landmark from the early days of settlement. It commands a view for 20 miles or more in all directions. From this mound a low ridge leads off westward about 3 miles, where it merges into the general upland plain. There are two lines of possible continuation for this moraine. The eastern line would lead northward through western Logan and eastern Mason counties and embrace a series of knolls scattered over that region. The western line would follow the low ridge westward and cross the Illinois River near the mouth of Sangamon River and there connect with the small drift ridge mentioned above which occupies southern and western Fulton County. The features are too vague to make a satisfactory correlation along either line. It seems preferable, therefore, to leave the belt without an attempt at definite correlations. The drift in this moraine, like that in the bordering plain, consists mainly of till. Even the very prominent Elkhart Mound has till exposed where the road crosses its northern slope. There are, however, local devel- opments of gravelly material in some of the knolls and ridges, as in the Kaskaskia system of ridges. The moraine is covered with loess, usually to a depth of 12 or 15 feet, and this obscures greatly the underlying drift and renders it difficult to discover places where gravel may be obtained. The knolls scattered over southern and western Logan County have been found in some cases to contain considerable sand, but they also, like the knolls of the moraine, appear to be composed principally of till. 76 THE ILLINOIS GLACIAL LOBE. The low drift ridge of southern and western Fulton County consists of till in its smoothest portions, but there are a few knolls in the northwest part of Fulton County which are of gravelly constitution. In this con- nection it may be remarked that the sections of wells made on knolls in western Illinois so far as obtained exhibit as a rule much more till than sand or gravel. In short, it may be said that the ridged drift and knolls of the Illmoian sheet are generally composed mainly of till and differ but little from the drift of the plane tracts which border them. But in north- western Illinois the ridges of the sheet tentatively referred to the Illinoian are largely of gravelly structure and some are of esker type. ESKERS OR GRAVELLY RIDGES OF NORTHWESTERN ILLINOIS. Leaf River or Adeline esker— The largest and best-defined esker found in north- western Illinois stands in the valley of Leaf River in northern Ogle County, and is discussed by Hon. James Shaw in the report on Ogle County." It has been discussed more recently by Mr. Oscar Hershey, who has applied to it the name Adeline, from the village of Adeline, situated near its eastern end.’ As Judge Shaw’s report was prepared before the distinguishing char- acteristics of eskers were fully known, the name moraine was very naturally applied to the ridge. This reference of the ridge to glacial action is of interest, since Shaw had, prior to the examination of it, followed the State geologist, Professor Worthen, in the support of the iceberg hypothesis as an adequate explanation for the drift phenomena of northwestern Illinois. Chamberlin was apparently the first to recognize this ridge as an esker, on a visit made to it about 1881, in his studies preparatory to the writing of the paper in the Third Annual Report.’ The writer’s examinations were made in the spring of 1886. The esker, as may be seen by reference to Pl. XII, is a practically con- tinuous ridge about 12 miles in length, extending from a point 1 mile east of Adeline westward to sec. 14, T. 25, R. 7 E., about 5 miles northwest from Forreston. The only notable gap occurs where a branch of Leaf River ‘Geol. of Illinois, Vol. V, 1873, pp. 108-109. Am. Geol., Vol. XIX, 1897, pp. 200, 201. 3 Preliminary paper on the terminal moraine of the second Glacial epoch, by T. C. Chamberlin: Third Ann. Rept. U.S. Geol. Survey, 1883, pp. 291-402. ESKERS OF NORTHWESTERN ILLINOIS. Wel breaks through the ridge, 2 miles west of Adeline. The crest line is very uneven and the height of the ridge varies greatly. The highest points slightly exceed 100 feet above the plain bordering Leaf River, but their elevation is no greater than that of the uplands on either side of Leaf River Valley. The lowest points are scarcely 20 feet in height. The esker con- sists usually of but a single ridge, ranging in breadth from 100 feet or less to probably 1,000 feet. At its eastern end, in the vicinity of Adeline, there is a series of nearly parallel ridges and hillocks covering a breadth of per- haps one-half mile and almost filling the valley. At the western end of the ridge there is no delta, or fan-shaped gravel deposit, such as sometimes occurs at the terminus of an esker. There are a few small gravel knolls within a mile north from its terminus, but they do not appear to be definitely connected with it. Several extensive excavations have been made in the esker, some of which expose its structure from top to bottom. It is made up largely of coarse gravel well rounded, but contains also beds of fine gravel and sand. The coarser material is most abundant in the upper portion and it is not rare to find bowlderets, and even moderate-sized . bowlders, embedded in it. The lower portion displays much cross bedding. The direction of flow of the stream which formed this esker is clearly shown to be toward the west, or the reverse of the present drainage of the Leaf River Valley. As the esker now stands, its western end is nearly 100 feet higher than its eastern. In case the esker was formed under the ice in the valley which it occupies, considerable hydrostatic pressure would have been required to force the water, with its burden of gravel, up this slope. It does not, however, seem necessary to restrict the formation of the esker to the under surface of the ice sheet, since it is found that nearly stagnant ice is traversed by tunnels at some distance above its base." The greater part of the gravel is composed of limestone such as occurs in the neighboring ledges, but there is also a liberal admixture of rocks of distant derivation. In order to compare the rock constituents of the esker with those of the till of the adjacent districts, pebbles were taken, without attempt at selection, from the esker and from a dump at the mouth of a well at Forreston, which 1See I. C. Russell, Jour. Geol., April-May, 1893, Vol. I, No. 3, pp. 240-242. See also Hershey’s discussion in Am. Geologist, April, 1897, pp. 238-239. 18 THE ILLINOIS GLACIAL LOBE. had just been excavated in till. Upon classifying the rocks the following results were obtained: Pebbles classified from an esker and the till near Forreston, Illinois. Esker. | Till. | | (GRMN. coqebseoa Sotede coScOn DNeShS Ce SeE cnecos cond SeesoeSe taSctomapecoos | 6 | 4 Mark-COLOLEGUDASICLOLUPULVCS sess te ee inte ee aete tele etot el aie tial | 6 5 Red quartz-porphyry -.----------- aqoStes SoeRes nesosb obese teoasecuoses sa05 i 0 QW EIMVAUIO)- ssocan noosdie cs onotoo peeceonogeas becobotnssas cosees LesesSunscoe aes 1 0 @iIENA Subs baoued boadee Hopeac nace spaus ten Cdomus caacee Dobos ane bas sseece crop ib) 2 Siliceous shale and thin-bedded sandstone.-...-..-....---..---.------------- 0 6 BROW AN ONG ie ocees sack cones CoS Sot spec osScnSesssebe cboscaS sos aceedoseuc 8 3 TRANG) ONG A ms ch50 soba ceoode Hoe cab obas Sese mon eoSo ccoke poccodsessoécEe oonaoE 21 21 Yellow limestone, largely Galena......---..---.---.------------------------ 86 | 76 Blue and gray limestone (Lockport and Trenton). -..-.-----..----.-----.---- 56 | 59 IOUBE cosnios 6s sdson sdek nacbds sacebe Dose) coscaonaee Sonoesdédccn ueae 180 | 176 Several fossils were found in pebbles of Lockport limestone, and also characteristic fossils of the Trenton and Galena, both by the writer and by other persons who have discussed this ridge. As the latter formations have an outcrop for only 40 or 50 miles to the east, the material may confidently be considered of local or semilocal derivation. Hazelhurst eske-—A short esker is found near Hazelhurst, at the borders of Ogle and Carroll counties. (See Pl. XII.) The esker proper is a sharp ridge about 14 miles in length, rising just west of Hazelhurst to a height of fully 100 feet above the station and maintaining a height of 60 to 75 feet for a distance of nearly a mile. Its eastern end is about a half a mile east of the village, and the western end about a mile northwest. The ridge is practically continuous, but has a slight deflection in its middle portion, one ridge terminating and another beginning a short distance south and immedi- ately opposite the end of the former. The general trend of the esker is east to west, but the western end points northwest. There is no delta-shaped deposit of gravel at the western end. On the contrary, the ridge contains considerable till at that terminus. Several gravel pits have been made in the ridge near its eastern end, which show it to be composed, like that of the esker in Leaf River Vallev, of very coarse material at the top and finer material in the basal portion. The pebbles are mainly limestone of local or semilocal derivation, as in the esker just discussed. ESKERS OF NORTHWESTERN ILLINOIS. 79 This esker is situated at the- eastern edge of a basin formed in the Hudson River shales, which is drained by Elkhorn Creek and is known as the Elkhorn Basin. The neighboring districts on the northeast reach an eleva- tion nearly as high as the crest of the esker. A well made on the slope of the esker a short distance west of Hazelhurst shows that the drift at that point extends nearly 100 feet below the base of the ridge and is composed entirely of sand and gravel, but at the village of Hazelhurst rock is reported to be struck in wells at a depth of only 20 feet. There are several prominent gravel knolls in the immediate vicinity of the Hazelhurst esker, two of which reach a height of about 100 feet, the others being 20 to 40 feet high. They are situated immediately south of the esker, and are scattered over a width of a mile or more and a length from east to west of more than 2 miles. These knolls are slightly elongated in an east-west direction in several cases, but the two prominent ones are ‘nearly conical. It seems probable that they were formed by agencies simi- lar to those which produced the esker—i. e., by glacial drainage—and they are referred to the same esker system. Garden Plain esker—In western Whiteside County there is a small esker set- ting in immediately west of the village of Garden Plain, and passing thence westward through the north part of secs. 22 and 21, and terminating on the Mississippi bluff in sec. 20, Garden Plain township. It hes along the south side of the wagon road which leads west from Garden Plain, and in its entire length of 24 miles does not vary 20 rods from a direct east-west line. The ridge has usually a height of but 5 or 10 feet and a breadth of 20 rods or less. Its structure is exposed only at one place, at a gravel pit in the west part of sec. 22. The beds here bear clear evidence of a westward- flowing stream. . The gravel has remarkably fresh appearance, being stained but little more than the usual stain of the Wisconsin eskers, and much less than the stain presented by the gravels in the Hazelhurst and Leaf River eskers. It is barely possible that it was formed at the Iowan stage of gla- ciation, though, as shown below, evidence of the presence of the Iowan ice sheet in this region is far from decisive. The direction of flow of the stream which formed the esker being westward, the ridge can scarcely be referred to a movement of the waters from the lobe of Iowan ice which covered the district to the west of the Mississippi, even if that ice lobe crossed into Ili- nois. It would seem, therefore, that the esker must be referred either to the 80 THE ILLINOIS GLACIAL LOBE. Illinoian invasion or to an extension of the lowan ice westward from the Rock River Basin. Pecatonica esker system.—In Stephenson County there are several gravelly belts which have been studied in considerable detail by Mr. Oscar Hershey and are discussed by him in a recent paper in the American Geologist.t These gravelly belts bear less resemblance to typical eskers than the Adeline and Hazelhurst ridges. They are marked by frequent interruptions and display a series of branches or spurs which give them greater complexity than the ridges just discussed. The main belt follows the Pecatonica Valley from eastern Stephenson County westward to the mouth of Yellow Creek, about 3 miles east of Freeport; thence it passes up the south side of Yellow Creek to the village of Bolton. The length of this belt is nearly 20 miles, and the ridges are in places scattered over a width of 2 or 3 miles. Their distribution may be seen on Pl. XII. It will be noted that there are usually two, and in places several, parallel ridges traceable for a few miles; they then either diverge to form branch belts or die out altogether. Hershey has called attention to points of special development in these belts where the ageregate bulk of the ridges is increased to several times the usual amount. One of these points of special development occurs opposite the mouth of Yellow Creek, another 3 or 4 miles farther west, and a third at the western end of the belt at Bolton. These are interpreted by Hershey to have been formed successively from west to east, and to mark each the position of the ice margin at the time it was forming. The ingenious hypothesis which Hershey has presented may perhaps satisfactorily account for the develop- ment of these belts, but the question can scarcely be decided in the present state of knowledge of such phenomena. At the western end of this gravelly belt the ridges culminate in an accumulation of greater strength than is displayed at any other point along the belt. An area of more than a square mile is occupied by sharp ridges, the highest of which rise 75 or 100 feet above the adjoiming plain. The plain immediately west of this system of ridges, though imperfectly exposed to view, is apparently underlain extensively by sand, and is referred to by Hershey as a sand plain. It bears only slight resemblance to the deltas formed at the terminus of eskers in other localities, for the ridges do not merge into the sandy plain. As suggested by Hershey, there was probably ‘Am. Geologist, Vol. XIX, 1897, pp. 197-209, 237-253. ESKERS OF NORTHWESTERN ILLINOIS. 81 a lake in the portion of the Pecatonica Basin west from the ice margin, for this basin is open only to the east, and in all probability a lake would occupy it outside the edge of the ice sheet and become expanded eastward with the retreat of the ice. So far as examined, nothing was found either by Hershey or by the writer to indicate that the structure of this belt of ridges differs from that commonly displayed by eskers. In several of the ridges the upper portion is found to consist of a coarse gravel and cobble, but there are other ridges composed largely of sand and fine gravel. The pebbles are chiefly lime- stone, and are largely of local derivation. Hershey maintains that they are derived by direct wear from the neighboring ledges rather than as a residue from the till, but the writer is inclined to question this interpretation, since the structure of the till and of the eskers is, so far as he has examined in this district as well as elsewhere, quite similar in the kind of coarse rock ingredients. Cedarvinle belt —Hershey has traced two other lines of gravelly drift for several miles in an east-west course in the portion of Stephenson County north of the belt just discussed. To these he has given the names Cedar- ville and Orangeville. The former belt he considers to have its beginning in the valley of Rock Run, about 1$ miles east of Rock City, but it can not be definitely traced until it reaches the valley of Cedar Creek, about 2: miles above Cedarville. It is prominently developed southeast of Cedar- ville, where it rises into sharp knolls 80 or 90 feet in height, which have so obstructed the old valley of Cedar Creek as to compel the stream to cut a gorge on the north side of the village. The belt is again prominent near the junction of Cedar and Richland creeks, 2 miles west of Cedarville. It is again prominent at the village of Damascus. The belt extends about 3 miles farther in a northwestward course, as a line of sharp knolls, the ter- minus being about 3 miles northeast of the village of Lena. The well- defined.portion of this belt is about 12 miles in length, but if we consider its beginning to be at Rock Run, its length is nearly 20 miles. Orangeville belt —The Orangeville belt has been only partially mapped by Hershey, and is found to be best developed south of the village of Orange- ville, and again just north of Winslow. At the latter point it rises into a very prominent knoll with a number of associated ridges. MON XXX VIII——6 82 THE ILLINOIS GLACIAL LOBE. General observations — he following observations concerning the belts in Stephenson and Ogle counties are made by Hershey, in the paper above cited: (1) They are not confined to any level, but cross ridges of any height, in several cases 150 feet or more above the present bottom of adjoining valleys. However, they are best developed at lower levels and the most prominent knolls and ridges stand in the center of valleys. (2) They will not bend from a direct course upon encountering a low ridge, but are readily compelled to change direction upon meeting one of the high ridges, which constitute the remains of the peneplain. (3) When in a narrow valley there is usually but a single ridge and only few secondary belts, but in such a wide basin as that of the Pecatonica River and Yellow Creek, there are a number of parallel ridges. ! The system of eskers of northwestern Illinois indicate that the drain- age from the ice sheet was somewhat vigorous, though the combined bulk of the gravelly material contained in them is but a small portion of the drift of that region. It is probable that they were formed during the gen- eral recession of a nearly stagnant sheet of ice. The trend of the main ridges is about in line with the supposed direction of the ice movement, which is usually nearly at right angles with the ice margin. Some of the ridges, especially the Cedarville belt and the Hazelhurst esker, curve toward the boundary in the western portions, changing from a westward to a north- westward course. Whether the ice movement was characterized by a cor- responding curve can scarcely be determined, though it seems a_ not improbable movement. TRANSPORTED ROCK LEDGES. In northwestern Illinois there are several remarkable instances of transportation of limestone ledges which have been discovered by Her- shey,” the most of which are indicated on Pl. XII. These ledges in some instances occupy an area of several acres. They have been moved west- ward from the crest of rock ridges without completely destroying their stratification. In most cases they have been deposited at levels lower than the ridges from which they are derived and rest upon glacial deposits on the slopes or bottom of neighboring valleys, but in some instances such ledges have been transported to points as high as their original position. It ‘Am. Geologist, Vol. XIX, 1897, pp. 197-209, 237-253. *Loe. cit., pp. 245 253. TRANSPORTED ROCK LEDGES. 83 seems necessary to call in the action of the ice sheet to account for these transportations, for they can not, as a rule, be the result of landslides or of a slow creeping down the slope. Hershey refers them to the closing stage of the ice movement, for the reason that if transportation had occurred in the midst of the invasion the ledges would, in all probability, have been more thoroughly intermingled with the drift. Except in a very few instances no drift pebbles have been found in the body of these deposits. There are often bowlders and smaller drift pebbles scattered over their surface. Hershey has also discovered places where the ledges have been pressed into slight folds without suffering transportation. In these folds the strata show dips of 10 to 30 degrees, while the greatest dips of the strata due to orographic bending, so far as he has discovered, do not exceed 2 degrees The reference of this disturbance to ice action appears well sustained. If the folding of the strata is not due to this agency it seems necessary to refer it to a remarkable local disturbance, since the strata in the surround- ing districts are practically horizontal. The transported and disturbed rock masses are especially numerous in the township of Dakota, in Stephenson County. Within 4 miles west and southwest of the village of Dakota, Hershey has found at least thirty distinct deposits of this class. They are generally conical or dome-shaped masses a few rods in diameter, which appear as though embossed on the top and slope of high rock ridges. When the internal structure is revealed by excavations, the incoherent portions are found to alternate, both horizon- tally and vertically, with other portions in which the original bedding planes have been but little disturbed. Hershey cites two instances of the occur- rence of transported ledges in the midst of valleys 2 or 3 miles west of Dakota, in which burrowing animals have brought out waterworn gravel and sand from under the limestone. The largest ridge is about 75 feet high and nearly obstructs the valley in which it stands. The smaller one is about 30 feet high and is composed of Galena limestone, not much broken, but with the strata dipping steeply in every direction from the center and top of the mound. These masses are scattered widely over Stephenson County east of the meridian of Freeport. Hershey has noted a tendency to greater development of this peculiar class of rock transportation along lines leading north and south from the 84 THE {ILLINOIS GLACIAL LOBE. strongly developed portions of the Pecatonica esker belt, and this has led him to suggest that along the lines where these deposits are heavily devel- oped there is the culminating limit of some stage of glacial readvance—a suggestion which implies that the ice had not reached an entirely stagnant condition at the time the eskers were forming. The reader will find in Hershey’s discussion of these ridges a detailed account of the several instances of transported rock ledges which he has examined, together with a discus- sion of their probable mode of origin. So far as known to the writer, such remarkable transportation of rock ledges has not been reported in other localities. Possibly the ‘disturbed beds which pass horizontally mto and rest upon undisturbed beds, have been wrinkled in post-glacial time in the manner suggested by Gilbert for the somewhat similar phenomena in New York, and which find illustration also in northeastern Ohio. GLACIAL STRLA. Striz have been found not only in the interior portion of the district covered by the Illinois lobe but also in several instances near the extreme borders. The latter usually bear directly toward the drift border. Thus in western Illinois the bearing is westward, in southwestern Illinois south- westward, in southern Illinois southward, and in western Indiana southeast- ward, as appears on the glacial map, Pl. VI. The strize in southeastern Iowa present an apparent exception, there being several eastward and but one westward bearing observed. But it should be remembered that that district was coyered prior to the Illinoian invasion by another ice lobe which deployed eastward across southeastern Iowa, and it is to that ice lobe that the eastward-bearing strize are referred. There are wide areas in this region where strize have not been discov- ered. ‘The absence of observations does not imply that the ledges are not striated, for too little attention has been given the rock surfaces to insure a complete mapping. It is probable that many more instances will be reported as detailed investigations are carried on. There are, however, extensive areas in which no rock exposures occur, and other areas in which the surface rocks are of such character as to break down quickly upon exposure, so that striae can scarcely be preserved. This condition is found ‘Proc. Am, Assoc. Adv. Sci., Vol. XXXYV, 1886, p. 227. Also Vol. XL, 1891, pp. 249, 250. (See also Bull. Geol. Soc. Amer., Vol. X, 1899, pp. 131-134.) GLACIAL STRIA. 85 not only in the sandy shales of the Coal Measures but also in a large part of the area immediately underlain by limestone. The Galena limestone, for example, has scarcely ever afforded exposures of striation in its exten- sive outcrops in Stephenson, Jo Daviess, Ogle, and Carroll counties, for its surface is usually so rotten, even under the deepest deposits of till, that strie would not be preserved. In not a few instances the ice sheet is found to have failed to remove the residuary clays which overlie the bed rock, and in such instances striz, of course, were never formed. How extensively the surface ledges escaped striation is not known, but the present knowledge of rock exposures within the glaciated portion of the Mississippi Basin leads the writer to think that a large percentage of the rock surface never was striated. A few of the strize on the border of the lobe merit special notice. At the city of Burlington, Iowa, striz formed both by the Illinois glacial lobe and by the southern extension of the Keewatin ice sheet are present. Only one instance, however, has been found in which the strize on the Iowa side are certainly referable to the Ilinoian ice sheet. This exposure occurs at the northeast corner of the intersection of Court and Prospect streets, in the north part of Burlington, and was the joint discovery of Mr. F. M. Fultz and the writer. The bearing is 8. 72° W., and satisfactory evidence is found, from prominences on the striated ledge, that the movement was westward and not eastward. Strie were discovered by the writer on the east bluff of the Mississippi, opposite Burlington, which have a nearly due east-west bearing. In this exposure the evidence concerning the direction of movement, whether eastward or westward, is not decisive, there being no prominences on the ledge which would throw light on the direction of movement. The bearing harmonizes more easily with a westward moye- ment than an eastward movement, and the balance of probabilities seem in favor of westward movement. The striz due to the earlier or Keewatin ice lobe, both in Burlington and at other points north of the city reported by Mr. Fultz, have a bearing generally about 8. 65°-70° E., their direction being about the same as that of strie found by the writer near Washington, Iowa, and by Professor Calvin in the vicinity of Iowa City. One locality, however, was found in quarries one-half mile north of West Burlington, in which the bearing 36 THE ILLINOIS GLACIAL LOBE. (@ 6) ¢ is very nearly west to east. The prominences on the rock ledge appear to sustain the eastward rather than the westward direction of movement, but they are so slight that some distrust of this interpretation is felt. The harmony with the westward-bearing striz and lack of harmony with the eastward would be in favor of their classification with the former. It will be noted that two exposures north of Burlington are eccentric in showing bearings 8. only 15° and 383° E. All the strize ir. the vicinity of Burlington are found at elevations 100 feet or more above the level of the Mississippi, or at about the general level of the higher portions of the rock surface. The glacial origin of certain strize at Alton, Illinois, has been called in question by Prof. J. E. Todd.* The striz first seen at that city occur beneath a culvert on Piasa street, in a small valley near the round house of the Chicago and Alton Railway, at a level perhaps 30 feet lower than the higher part of the rock ledges of the immediate vicinity. Todd has expressed the view, in the paper just cited, that these striz were produced by a hori- zontal slipping of rock ledges, and that they are now exposed through the removal of ledges which once covered them. Numerous exposures of slick- ensides and slight faults appear in that vicinity, showing that it is a district where disturbances have occurred. He recognized, as has the writer, that the striee bear a strong resemblance to glacial strize, but as glacial striee and slickensides are both produced by the movement of rock upon rock, he urged that the resemblance to glacial striz does not forbid their being con- sidered slickensides. Since the appearance of Todd’s paper the writer has reexamined this ledge and found satisfactory evidence that the strize are not slickensides. he striation occurs on three different layers of surface rock. Now, if it was produced by rock ledge slipping upon rock ledge, we should expect the striation to occur between these layers as well as on their exposed surfaces, but an examination showed that the striation is confined to the exposed surfaces, and that the striating agency must have been such as could affect only the exposed surfaces. Furthermore, following the Chicago and Alton Railway track north- ward from this exposure, two other striated surfaces were found at levels 'Strize and slickensides at Alton, Illinois, by J. E. Todd: Proc. Am. Assoc. Ady. Sci., Vol. XL, 1891, pp. 204, 255. GLACIAL STRL#. 87 about as high as are reached by the limestone in that vicinity. These surfaces had been exposed by the removal of till in the railway cuttings and were overlain by several feet of unmodified till. The glacial origin of these strize seems supported, therefore, by the character of the striation, the position of the strize, and the character of the overlying beds. The striae observed by Prof. G. F. Wright in Jackson and Williamson counties, Illinois, are the southernmost ones yet found in the drift-covered region of eastern North America. Wright states that the glaciation is as heavy as is often found at points some distance within the glacial boundary. They are scarcely more than 5 miles from the extreme limit of glaciation, and bear directly toward the glacial boundary. Those noted by the writer a few miles northwest from Murphysboro are also very heavy glacial grooves and are situated equally near the glacial boundary. The strize in Greene and Owen counties, Indiana, are usually found on a firm sandstone. Those observed by the writer near Worthington are heavy grooves. The character of the glaciation at points reported by other observers appears from descriptions to be as vigorous as at the points just considered. The remarkable variation in bearing in Owen County is worthy of further investigation. The bearings of the striz in the vicinity of the Wabash Valley in Clark County, Illinois, and in Vigo and Sullivan counties, Indiana, give rise to some surprise, for the striae appear to show no disposition to radiate toward the neighboring portion of the glacial boundary on the southeast. Dr. J. T. Seovell, who made all these observations in the vicinity of the Wabash, reports that there is heavy glaciation at each exposure. In the list of striae given below four exposures are reported from northern Hlinois which are situated within the limits of the Iowan drift. It is not certain whether they were produced at the Iowan invasion or at the ‘Tilinoian. They appear to be in harmony with the general movement of the ice sheet at the Illinoian stage as well as at the Iowan. These exposures were in each ease first observed and reported by Mr. I. M. Buell, and are said to be very faint compared with the striz seen by him within the limits of the Wisconsin invasion. The list given below is restricted to the district outside the Wisconsin drift, the strie within the limits of the latter drift being included in a table presented later (pp. 412-414). 88 THE ILLINOIS GLACIAL LOBE. Table of strie outside the Shelbyville moraine. Location. | Bearing. Observer. Near Winnebago, IIl., at quarry in sec. 6, T. 26, R.11 E..-...-.--- SP TBE Ne SS45 | Buell. Bluff of Kents Creek near Rockford, Il., two exposures, sees. | 8. 75° W..---- Do. 28 and 29, T. 44, R.1E. Cutting on Chicago, Milwaukee and St. Paul Railroad, west | NaGD oh Whererise Do. of Fielding, Ill. | Cutting on Chicago, Milwaukee and St. Paul Railroad, east of | Sao Wieeeee Do. Fielding, Ill. | East bluff of Mississippi near Gladstone, Ill. .-.....--.-------- SS Wisteee Leverett. Court and Prospect streets, Burlington, lowa..-.-..-.--.------ Bb (2 Wheeoce | Leverett & Fultz. NonthwEnl eB onlin ton lowarpsee sass. eee eee eee eee | HHO) Coes ec | Leverett. Wiesteb unlinoton so walaq cereale alesis ee eee eieen eee Ce eee aeeee | We SI8i8 Soce Do. DOF See macars a skiecne sv clinicistelsaelese eve eee eee eee eeee | S.75°R ..-.. | Fultz. Flint Creek bluff, northwest of Burlington, Iowa .--.---.-----. S878 Cun} eee Do. One-eichthimilertromiprecedingsenqeesce ae eeee eee eee | S..330:B) = 2222 | Do. About 5 miles north of Burlington, Iowa .----.......--....---- isp ks}o0 Dees | C. A. White. Near Kingston, Des Moines County, Iowa. Main setof striw. | S.64°E.....) Fultz. (Seattering strive 8. 30° 15’ E., S. 60° 30’ E., S. 72° 15/ E,) One-hal fami eifromiprecedin ey asses eee eee eee eee eee ee SE70°ih, 23) Do. Five miles north of Hamilton, Ill., line of sees. 4 and 5, T.5, | S.65° BE ..... | Leverett. R.8 W. maze Wiestiot Havana, Ill); in/sec: 6, D3 Ne Ria Sibeeeeeceesseece see S. 103° W..- Do. Al ton sallle vo miMblasanstree bers cicrs seers ne aire eae ene aa S.40° W...-. Do. Cuttings on Chicago and Alton Railroad, north of Alton... ....) S.30°-40° W. Do. Six miles northwest of Murphysboro, sec. 10, T. 8, R. 3 W.-.-. Sy 30° Wieeer Do. One and one-half miles southwest of Carbondale, I] ..........) S50 Wiis 222 | G.F. Wright. Southwest corner of Williamson County, I].-.............-..- | §.10°-15° E _} Do. Two miles northeast of Marshall, Il].........-.....--.--+.---- $5209 We 2-2 Scovell. Two miles southeast of Farmersburg, Ind.................-... SOW oo osoce Do. Southeastern part of Linton township, Vigo County, Ind..-.... South. ...... Do. Northern part of Linton township (sec.3)..-..........-------- $2209 Wie---- Do. One mile northeast of Worthington, Ind......-......-....--.-. Sb 72918) so Soe Leverett. Diwommiles|sontbto tab uin am valle eee sees see em NSB ae Collett & Brown. NeCuOnMe TukvaoiWie Greene Countyeindess. 9). 5 -e eee SUigenia 2 Siebenthal. Romon ain does cee ee ste eter MEE TL aes iGO 5o6| Do. Three miles south-southwest of Vandalia, Ind.............___. Wiehe en | Wright. Hive miles/west from preceding, =--5- +222. -2-s2---. 02. 4ee- 2 22s) $e 409-50 Do. Near Bowling Green, Ind., sec. 19, T. 11, R.5 W._.........---. ie ae fee al ie -- (Collett. Sacks MeL eld MRO A Wiatee eee et tate Sete SH. ta Ween |{S. 26° 30'R -.| lS. 29° 30’ E ..| Seer Gael: wll Rav O RV past te set ine Mica aie ace PRE | §. 26° 30’E ..| Do. Sie HEME, OU INTos dite (8 \ hi Sagooco ancoes Beso Dosa so CosOSes sob beecas SuSdCn aes | Leverett. Do ---. 2+ 2-22 eon ee ee eee ce eee eee eee ee eee eee | S.36° 56’ E._| Collett. Three miles south-southwest of Bowling Green............._.. $.32° 10! B. Do. NeariCloverdalle wind pire epee eer aes e ieee eater au QOISs mira Renieine! THE ILLINOIAN DRIFT SHEET. Rg EFFECT OF THE ILLINOIAN ICE INVASION ON THE OUTER-BORDER DRAINAGE. A most important question connected with the Hlinoian invasion is its effect upon the drainage lines of the border districts. The slope of the region west of its western border in Lowa is directly toward that border, and the large streams had apparently opened channels to about the present line of the Mississippi prior to the invasion of this ice sheet. The ice nowhere extended more than 20 miles beyond the present valley of the Mississippi, but it covered that valley for a distance of over 100 miles. It apparently furnished an obstruction of such consequence that the question of a more or less complete displacement of the main artery of drainage naturally suggests itself. - On the southwest, below Keokuk, Iowa, the ice sheet failed to cover the Mississippi and the obstruction to the drainage disappears. At the south the terminus was near the crest of the elevated ridge that crosses southern Illinois, and no streams discharged toward the ice margin. On the south- east a part of the border touches an elevated tract, whose natural course of drainage appears to have been toward the ice margin. The amount of drain- age obstruction in that region becomes, therefore, an important question. TEMPORARY DISPLACEMENT OF THE MISSISSIPPI. That the Illinoian ice invasion did not permanently displace the portion of the Mississippi which it covered is certain, for a considerable section of the present course of the stream crosses the territory covered by the Ih- noian drift. Furthermore, this section of the river follows, in the main, the line of a preglacial valley which appears to have been the main artery of drainage for this region down to the time of the Ilinoian imvasion, except perhaps during the Kansan invasion. The rapids between Montrose and Keokuk, 12 miles in length, and the rapids and narrow portion of the Mississippi Valley between the mouth of the Wapsipinnicon and Muscatine, 40 miles in length, are the only departures made by the river from the line of broad preglacial valleys. The latter displacement is not such as to coincide with the border of the Ilinoian drift, and was apparently not determined by this invasion. There remains, then, but the stretch of 12 miles at the lower rapids, in which the present stream has opened a new course, that even approximately coincides with the Ilinoian drift border. 90 THE ILLINOIS GLACIAL LOBE. But turning from the question of a permanent displacement to that of a temporary one, the influence of the Ilinoian invasion becomes more appar- ent. Several years ago the writer found a large abandoned valley im Lee County, Iowa, shown in fig. 4 (p. 468), which leads southeastward across the county from Big Cedar Creek, a tributary of Skunk River, to the Mississippi River, which it jos about 6 miles below Fort Madison. This large valley is now occupied for a few miles by East Sugar Creek, a small tributary of the Mississippi. This abandoned valley was at first supposed to have been the former course of Big Cedar Creek, which now makes a singular deflec- tion to the north, near its mouth, and this interpretation was published in 1885.'_ A few years later (in 1894) the writer began systematic investiga- tions in southeastern Iowa and found evidence that the valley has a con- tinuation northward from Lee County along the north-flowing portion of Cedar Creek past Skunk River, the present valley of that stream being along it for a few miles above the village of Rome, in Henry County. The study that season did not develop evidence of the further continuation of the valley. But in 1896 the district between the Skunk and Jowa rivers was examined, to determine whether the upper Mississippi with its western tributaries did not utilize this abandoned valley during the Illinoian invasion. This study resulted in the discovery of an abandoned channel which leaves the Iowa River just north of Columbus Junction and passes southward imme- diately outside the limits of the Illinoian drift to the valley of Crooked Creek near Winfield, and thence westward to Skunk River along a double channel, the northern one being now occupied by Crooked Creek, while the southern is only partially occupied by a stream. It thus appears that the waters of the Iowa, with its main tributary, Cedar River, as well as of Skunk River and Big Cedar Creek, have followed this abandoned channel southward around the western edge of the Ilinoian drift. To complete the connection at the north and show that the Mississippi follows this channel it was only necessary to utilize results already obtained by W J McGee and J. A. Udden. Professor Udden three or four years previously conceived the idea that the Mississippi, either in preglacial or in interglacial time, had taken a south- westward course from the Wapsipimnicon to Cedar River, through a broad sag now drained in opposite directions by streams each of which is called ‘The deflection of Big Cedar Creek, by Frank Leverett: The Aurora, Iowa Agr College Monthly, November, 1885. TEMPORARY DISPLACEMENT OF THE MISSISSIPPI. 9] a Mud Creek.- The sag leaves the Wapsipinnicon a few miles east of Dixon and comes to the Cedar River at its bend near Moscow, passing just west of Durant and through Wilton. Its course may be seen by reference to the Durant and Wilton Junction sheets of this Survey. The north end of this portion of the valley was occupied by the Iowan ice sheet, which has in a measure concealed its erosion contours, though the valley may still be traced without difficulty. It is now thought to have been utilized by the Mississippi at the Illinoian stage of glaciation. The point at which the Mississippi was deflected into this old channel was probably at the mouth of the Maquoketa (see glacial map, Pl. V1), from which poimt it had southward course through the Goose Lake channel, brought to notice by McGee’, to the Wapsipmnicon, coming to that valley near. the mouth of the Wapsipinnicon, as may be seen by reference to the topographic map of that region, Pl. XVIII Gn pocket). Perhaps the Missis- sippi also occupied its present channel from the mouth of the Maquoketa to the mouth of the Wapsipinnicon. The only apparent objection to this view is the possibility that the Illmoian ice sheet obstructed the present course of the river. his being a region in which the Iowan invasion obliterated the marginal features of the Lllinoian drift it becomes a difficult matter, as already noted, to determine the precise position of the Ilinoian boundary. It probably encroached but a few miles at most on the Iowa side of the river above the mouth of the Wapsipinnicon. This abandoned course of the Mississippi can be studied to best ad- vantage in the portion south from the Iowa River, as the northern portion has been greatly modified by the Iowan ice invasion. The description, therefore, begins at the point where the old channel departs from the Iowa River. As above noted, the course of the channel is southward from just above Columbus Junction to the vicinity of Winfield, a distance of 12 miles, crossing Long Creek, a small tributary of the Iowa, about 6 miles south of Columbus Junction. The bed of the old channel is about 120 feet above the level of the Iowa River bottom at Columbus Junction, or very nearly 710 feet above tide. Itis cut to a depth of 25 to 35 feet below the bordering plain, and has a width of 14 to 1$ miles. Its depth and breadth are not much greater than that of the present Mississippi within its 'The drainage systems and loess of eastern Iowa, by W J McGee, private publication, 1884. Also the Pleistocene history of northeastern Iowa, by W J McGee, Eleventh Ann. Rept., U. S. Geol. Survey, 1891, pp. 227, 228. 92 THE ILLINOIS GLACIAL LOBE. banks, and it has the appearance of being a stream channel or bed rather than a valley proper, the only flood plain being the bordering uplands. A fine view of the valley may be obtained just west of Columbus. Before - reaching Winfield a channel branches off to the west from the main channel and joius it again just south of Wyman. This channel has a breadth of but one-eighth mile or less. It is more direct than the main channel, and has about the same depth. A short distance east of Winfield the main channel is entered from the east by the East Fork of Crooked Creek, and this stream meanders through the broad bottom of the main channel westward to its junction with the West Fork, and thence continues west and south to Skunk River Valley at Coppock. Another channel leads directly west from Winfield past Wayne to Coppock, a distance of 15 miles. The combined width of the two channels is but little greater than that of the portion of the channel north from Winfield, the channel along Crooked Creek being about three- fourths to 1 mile in width and the channel leading past Wayne one-fourth mile. The lower portion of Crooked Creek nearly occupies the full width of the north channel, but throughout the greater part of the course it is bordered by a broad terrace-like, plain, several times the breadth of the valley which it has excavated. The depth of about 25 to 35 feet continues, as in the portion north from Winfield. The portion along Skunk River from Coppock to Rome, a distance of 10 miles, is so completely occupied by the valley of that river that only occasional narrow remnants of the abandoned channel appear as terraces on its borders, the average breadth of that part of Skunk River Valley being fully 1 mile. The most extensive remnant of the abandoned channel is found in the double oxbow made by the river north and west from the village of Rome, which stands, where not broken down by subsequent erosion, about 670 to 675 feet above tide. From Rome the abandoned valley continues southward along the valley of Big Cedar Creek (reversed) and is preserved in terracelike rem- nants on each border of the valley which stand 30 feet or more below the level of the upland plain. The average breadth of the valley being not less than one-half mile the terrace remnants are narrow. From the bend of the Big Cedar, 8 miles south of Rome, the old valley, as noted above, leads southeastward across Lee County to the Mississippi Valley at Viele, 6 miles below Fort Madison, gradually deepening from 30 feet at the north to 50 TEMPORARY DISPLACEMENT OF THE MISSISSIPPI. 93 or 60 feet at the south. It is occupied for about 4 miles by Little Cedar Creek just south of the bend of Big Cedar. The remainder of its course is drained by Sugar Creek. The excavation along the channel from Columbus Junction to Viele is estimated to be one-half a cubic mile. The precise elevation of the bottom of this old channel has been deter- mined at only a few points in the portion south from Columbus Junction. The elevation at the border of the Lowa River 12 miles north of Winfield is apparently not more than 710 feet. At Winfield its elevation is about 10 feet below the railway station or 703 feet above tide. The altitude appears to fall but little in the 15 miles between Winfield and Skunk River. The aneroid determinations made at Coppock give the old channel an alti- tude of about 700 feet above tide. In the oxbow near Rome the altitude is about 675 feet. At the point where the Keokuk and Northern Railroad crosses the channel, near the line of Henry and Lee counties, the elevation is 657 feet. At St. Paul station on the Fort Madison and Des Moines Rail- road 5 miles southeast, the elevation is 645 feet, and at the point where the channel joins the Mississippi, 14 miles farther southeast, about 620 feet. The distance from the point where this channel leaves the Iowa River to its junction with the Mississippi is about 75 miles. The fall of 90 feet which it makes in this distance would therefore give an average of slightly more than 1 foot a mile. The fact if it be proved that the channel has no tall in the portion leading west from Winfield may bring support to the hypothgsis suggested by studies farther north that the surface has been sub- jected to a westward differential uplift in the later part of the Pleistocene. The measurements of altitude, however, are not sufficiently exact to justify the presentation of these data in support of the hypothesis. The writer has been unable to discover any notable amount of sand or gravel in the bed of this channel. It generally appears to be swept clean of such deposits. The valley is coated with a sheet of loess similar to that which occurs on the bordering uplands, but this deposit is apparently as late in deposition as the Iowan stage of glaciation, in which case it can not be considered as a deposit of the stream which formed this channel. In northwestern Lee County sand to a depth of 10 to 20 feet is found along the channel. Chamberlin has suggested that the ground in which this channel was excavated may have been frozen at the time of the Ilinoian glaciation, its situation being on the immediate border of the ice sheet, and 1See Chamberlin: Third Ann. Rept. U.S. Geol. Survey, p. 391. 94 THE ILLINOIS GLACIAL LOBE. the frozen condition of the ground may have prevented the stream from eroding more material than it could readily transport. In that case the material should be accumulated in portions of the Mississippi Valley to the south, where the gradient became too low to admit of its being swept along. In apparent support of this view there is found, immediately below the Des Moines or lower rapids of the Mississippi, a marked fillmg of the valley with deposits of sand and fine gravel. This filling may be seen to good advantage at and below the village of Warsaw, which stands on a terrace of aggradation antedating the loess in its formation and apparently sepa- rated from the Kansan glacial stage by an erosion interval of considerable length. The Warsaw exposures were examined by the writer in 1894 and reexamined by Professor Chamberlin, Dr. H. F. Bain, and the writer in the summer of 1896, when the relationships given above were worked out. The Kansan till has suffered erosion to a level but little above the present stream and a bowlder bed marks the junction of this till with the overlying sand and gravel. This bowlder bed is continued on the north side of the river in Keokuk, as pointed out by Prof. C. H. Gordon.t| The sand and gravel deposits are typical fluvial material and are built up to a height of about 80 feet above the river. At their top is an ashy silt resembling a soil but perhaps redeposited as flood-plain material, and above this a deposit of sand grading upward into loess, the sand and loess together being 20 to 25 feet in thickness. Opposite Warsaw near the mouth of the Des Moines River there is a somewhat different exposure of fluvial filling known as the ““Yellow banks.” This has been examined, both by the writer and by Pro- fessor Gordon, and the following section was published in the Geology of Towa in 1895 :* “ Vellow-banks” section, near Keokuk, Iowa. Ft. in Olay, yellow, pebbleless.... -----. ------ ---- 2. 22 = 22 = nnn en ne = ne ee enn 5 Silt, drab, pebbleless;--+------ 2. -5----.- 222.2 22-2. Tosbies ch Sek Seer cde one Seco eee eee eee 1 3 Earth, black, with a few small pebbles; apparently an old flood-plain deposit.--.---....--- 12 Clay, yellowish (local) --..---..-2--- ------+----- s-2 20+ -- ++ eee eee e+ 2222 2 eee eee eee eee 6 Sand, with a few small pebbles; layers of bowlders 1 foot thick at base.................--. 20-25 Earth, black, with yellow streaks; apparently an old flood: plain deposit. -2-- --2ss.-s-554-- a (9 Gravel, with some sand beds; pebbles 2 inches or less in diameter ..-....---.-.-..----.---- 20 Blue clay, till, exposed ....2. ---- 12-2 2222 cone eee nee eee ee cee nee eee ene ee eee 15 ARRAS A. aoo boo SooG OS Sa neo Sacd San C odo Roo COS sb toOdO Sate adocoussissedese Gogcdsdce 85 1 Towa Geol. Survey, Vol. III, 1895, pp. 252-254. 2 Op. cit., p. 243. PL. Vil MONOGRAPH XXXVIII U. S. GEOLOGICAL SURVEY =F BOWLDER BED AT KEOKUK, IOWA. TEMPORARY DISPLACEMENT OF THE MISSISSIPPI. 95 As the base of this exposure is 10 or 15 feet above the level of the river, the level of the top of the bank or bluff is about the same as at Warsaw. It differs from the Warsaw section chiefly in carrying two black earthy deposits resembling a soil, one being at a higher elevation and the other at a lower elevation than the soil exposed at the Warsaw section. The sand bed which immediately underlies the loess at Warsaw is not present at the ‘‘ Yellow banks.” The great thickness of the dark earth at the ‘Yellow banks” exposures seems to justify the interpretation that it is a flood-plain deposit, for a humus stain produced by vegetation rarely extends to such a depth (12 feet). There may, however, if it is a flood- plain deposit, have been a time interval of considerable length between the deposition of the upper bed of black earth and that of the loess which overlies it. It seems not improbable that the lower black earth constituted a flood plain, or perhaps a second bottom or terrace, prior to the main filling of the valley. In that case the portion of the section above the lower black earth may be the full equivalent of the fluvial material at the War- saw section. It seems not improbable that the difference in the sections is referable to their relation to the channel of the stream. The difference in level between the bed of a channel and the terraces or flood plains on its border may easily amount to as much as the differences displayed by these sections. ; A bowlder bed at Keokuk described by Gordon* merits notice in con- nection with these exposures at Warsaw and Yellow banks. Between the foot of Main street and the mouth of Soap Creek in Keokuk the rock bluff is but 50 to 60 feet above low water, and is capped by a bed of bowlders about 20 feet in thickness, a view of which is given in PI. VII. In the dis- cussion of this bed Gordon presents three interpretations: (1) That it was formed by river action alone—i. e., as an alluvial bar; (2) that it is due to the cutting down of a till sheet, the coarse material being left as a residue; (3) that it is an accumulation formed at the edge of the ice sheet at the Illinoian stage of glaciation. Of these interpretations the second seems to the present writer, as well as to Gordon, the most applicable, especially when the Warsaw bowlder bed and overlying deposits are taken into con- sideration. The Keokuk bowlder bed, like the Warsaw, is capped by ‘Geology of Iowa, Vol. IIT, 1893, pp. 252-255. For an earlier notice of this bed see paper by S.J. Wallace, Proc. Aim. Ass‘u Ady. Sci., Vol. XVII, 1869, p. 344. 96 THE ILLINOIS GLACIAL LOBE. deposits of sand and silt that seem referable to the valley filling at the Illinoian stage of glaciation and which antedate the loess by a long period, as shown by weathering. The surface of the sand presents a deep red stain to a depth of 3 or 4 feet below the base of the loess, and contrasts strongly in color and weathering with the sand at greater depth as well as with the overlying loess. The weathered zone here is apparently the cor- relative of the black earth found below the loess at the ‘ Yellow banks.” Excellent exposures of this weathered zone may be seen at the corner of Second and Timea streets in Keokuk. Examinations have been extended down the Mississippi on the Illinois side, and it is found that the altitude of the valley filling decreases more rapidly than the fall of the present stream. At a point opposite Hannibal, Missouri, where Hadley Creek enters the valley from the east, the filling reaches a level only 15 or 20 feet above the broad bottom of the Mississippi or scarcely 35 feet above the stream, and about 90 feet below its altitude at Warsaw, 45 miles up the valley. This rapid increase in the amount of filling apparently supports the view that material was SSrEDE into the valley and there deposited in delta-like fashion. Returning to the discussion of the abandoned channel, and taking up the portion northeastward from the Iowa River, it is found that it has slightly lower altitude than the portion in the district south from the Iowa River, much of it being below 700 feet above tide. “In explanation of this lower altitude it is suggested that the section to the north of the Wapsipin- icon River and possibly the portion between the Wapsipinicon and lowa rivers may have been occupied by the Mississippi for a considerable period after the southern portion had been abandoned. Possibly it persisted in the occupancy of its channel until the Iowan ice invasion forced it out. The broad valley of the southwestward flowing portion of the Cedar appears to have held a lake at the Illinoian stage of glaciation for which Udden has recently suggested the name ‘Lake Calvin.” The features of this old lake bed are discussed by Udden in a report on the geology of Muscatine County, Lowa.* The abandonment of the lower end of the channel from Columbus Junction southward probably occurred as soon as the ice sheet had with- drawn sufficiently to uncover the present line of the stream, for the altitude ‘Towa Geol, Survey, Vol. IX, 1899, pp. 350-357. Siam “LLGYSAdT MNVoeT Atl oSeurerp jeroe]s- oid ot) SULMOYsS VNVICNI NUCLLSHMHLAOS AO dVW — I WA Td INAXXXHAVYOONOW ASBAYNS IVWDIDOT0R9'S'N 4 : \ in y allpy filling ak the ess by } lonsperlod, resents ¢@-eep red stain \ iG. Wuesp, gai contras$s rreatel a7 th,as well Xs is hefte is % pp ently/the corse i) is. at the“ Mc v saris a b enat the/corner off so o co 7 the Nississip}< Sythe Yale valley\glling Grea Me NaN: SONS Opposi 2 I aT, cwilay frofl the east, the MHhaye hha £3 OAC both: Gof the MG ~UQ) feet Helow its 3 hh 5 ea a 1 a Anse: { 2 — Ae re DS rotei( er Pertion X [- aay) NS VARY i feet ne Mississippi fora, considerat ert Lx ncoue He Ossibly it persisted /f co o J * hg ‘ caer w_jiowan ice linvasion forced ik oni twanrd eowine pornen of ¥ } | /siage of Sinclatic sity Wd | ba e aké Calvin.’ thid old Miilae a! ye o Bs} qustudee \" AAD. Tw be ~ 1 ; id Wy 1 fel fram Jol@mBut ie s . Jmetion Sypyes nS ia se Lge. e sheet th age drajwn preset stream, for themabtitiided b BA us POMHMBe 2VOMs Me WYVb Ol < ie A < se x x 5 Bo} > x ro) ° = ° 2 ne CEOrOCICVF @NBAEA 8681 > F == == SATINST OL 9 S| s aTROS “LLIGYAAdT MNWU Ad MOVNIVACGC INASAdd UNV AUVCNNO@ TVIOVTS HHL ONIMOHS VNVIGNI NYULSHMHLOOS 0 dVW “CN Hit 09 8 N3I8 Sor 08 OT 08 oll ] 24 & vodysou fo ae BE SHOdTY TVIOVIO =p squms f//6 = KS ZL Uy Pe Y/7 YZ SAMVTTVIOVIO Yi _ | | IJ Yy (ureyd 77y pue pueydn) : : OSPR swe = ay Y NVIONITII aes = =2= = = = : G oo : Sy WYfG SSA TLIC (Tees you) TWIAQTTV GN43931 er EE St oll “WIA Td IHAXXX Hd VYOSONOW ‘ASAYNS 1V91I901039' SN CHANGES OF DRAINAGE IN SOUTHWESTERN INDIANA. 97 along the present Mississippi bluffs is a few feet lower than the bed of the abandoned channel. This lower altitude along the Mississippi is due to the incomplete filling of the preglacial channel by drift. CHANGES OF DRAINAGE IN SOUTHWESTERN INDIANA. The Illinoian invasion produced important drainage modifications in southwestern Indiana, only a part of which have as yet been fully worked out. The present discussion aims to deal chiefly with the changes which have received the most careful attention. The discussion begins with streams in the southwest corner of Indiana. By reference to the map, Pl. VIII, it will be seen that the greater part of Posey County and adjacent portions of Vanderburg and Gibson counties are now drained westward into the Wabash through Big Creek. The South Fork leads almost directly west from near Evansville in Vanderburg County to its junction with the North Fork in central Posey County. The North Fork leads northwest from northern Vanderbure across southwestern Gibson into Posey County, and there near the village of Cynthiana turns southwestward and maintains this course to the Wabash. It receives a tributary from the southeast near the crossing of the Peoria, Decatur and Evansville Railway, but no other tributary of importance enters above its junction with the East Fork. An examination of the head-water portion of the North Fork has brought to light decisive evidence that its preglacial line of discharge was westward into Black River and thence to the Wabash at a point 20 miles or more above the present mouth of the creek. A broad valley deeply filled with drift leads from Big Creek westward to Black River, passing just north of the village of Cynthiana. The aban- doned valley is nearly a mile in width, while the new passage is scarcely one-tenth of a mile in width. ‘The creek soon enters another old valley whose head water portion is occupied by the southeastern tributary referred to above, but whose lower course is abandoned. The Peoria, Decatur and Evansville Railway utilizes the abandoned valley between Big Creek and Poseyville. From Poseyville the valley passes northwest to Black River. In the narrow valley near Cynthiana the present stream thus cuts across a low ridge separating two streams, which formerly drained northwestward into Black River. Below the railway crossmg Big Creek soon enters a MON XXX VIJII——7 98 THE ILLINOIS GLACIAL LOBE. narrow valley and crosses the preglacial divide between Black River and the South Fork of Big Creek. Thus the latter drainage basin has been greatly enlarged at the expense of the former. The glacial boundary follows nearly the present course of the North Fork of Big Creek below Cynthiana, and the location of the new stream across the rock point near that village is evidently due to the presence of the ice sheet in the lowlands to the west, and the diversion across the divide between the preglacial drainage basins of Black River and Big Creek is due to occupancy of the former by the ice sheet. The Pigeon Creek drainage basin has also been enlarged at the expense of Black River. Muddy Fork of Pigeon Creek lies m a lowland which connects on the southwest with Black River, and this lowland appar- ently received the portion of the Pigeon Creek dramage m Gibson and northern Warrick counties. The location of the col was not definitely worked out, though it is in all probability east of Elberfeld, in T. 4 S., R.9 W. Upon referring the question of changes of drainage in the Pigeon Creek basin to Dr. George H. Ashley, of the Indiana survey, who has made an examination of the portion in Warrick County ouiside the limits of the writer’s own examinations, the following reply was received:? I think you are right in believing that the head waters of Pigeon Creek drained to the west in preglacial times, the divide running nearly east and west across the center of T. 4S. through Rs. 8,9, and 10 W. The present course of Pigeon Creek through Ts. 4 and 58., R. 9 W., while not so markedly a postglacial channel as many to be found, has nevertheless several of the characters of such a channel. In the first place the bottoms are narrow, averaging probably less than one-half mile in width from above Elberfeld to below Millersburg, or scarcely half the usual width of the west-flowing head-water portion. Secondly, the bluffs are more abrupt than is usual for streams of this size in that region. This is especially true north of east from Elberfeld, where the stream appears to have crossed an old divide. Thirdly, the short tributaries on each side of the streams in the vicinity of the supposed divide also sustain this view. Fourthly, reports suggest that rock is to be found within a dozen feet below the stream bed in this narrow portion, but this has not as yet been verified. The changes of drainage become still more important in passing north- eastward into Pike and Dubois counties. The streams which formerly had a northwestward discharge into the White River drainage have been turned westward just outside the glacial boundary to form the Patoka River, as 1 Letter written June 8, 1898. CHANGES OF DRAINAGE IN SOUTHWESTERN INDIANA. 99 may be seen by reference to the map, Pl. VIII. These perhaps may be discussed to best advantage by beginning at the east with the head waters of the Patoka. The portion of the Patoka above Jasper seems to be following a preglacial line, but at that town a deflection of the stream into another drainage basin has been effected. The preglacial valley is easily traced from the Patoka, in sec. 24, T. 1 8., R. 5 W., northwestward to Mill Creek Valley and thence into East White River. Its breadth is about 15 miles, and it has been filled with sand and loess-like silt to a height of 30 to 35 feet above the present level of Patoka River, in sec. 24, or to about 490 feet above tide. This filling was sufficient to turn the stream across a low divide in the east part of Jasper. In opening a passage across this divide the stream has accomplished a remarkably small amount of work. The narrow part of the valley which marks the position of the old divide is only about one-half mile in length, 600 to 800 feet in width, and 20 to 35 feet in depth. The stream is reported to be several feet in depth through this narrow portion, thus increasing the depth of erosion perhaps 10 feet. There is in part of the gorge a thick-bedded sandstone which has probably greatly resisted lateral erosion. Immediately south of Jasper the present Patoka River enters a valley fully 1 mile in width which constitutes the preglacial line of discharge for several southern tributaries entering in Dubois County. The valley is not occupied far by the present stream, but leads from Jasper in a course north of west into Pike County, passing south of Ireland and directly under the vil- lage of Otwell, its course for several miles being nearly coincident with Flat Creek, though in the reverse direction. Whether it joined the East White Valley near Highbanks or entered a few miles below, at the mouth of Mud Creek, is undetermined. There are shallow valley-like depressions connect- ing the abandoned valley with East White River along each course which are underlain by heavy deposits of drift, each of which apparently has a width sufficient to have accommodated the old stream. Probably, however, one of these lines will be found to be separated from the old valley by a concealed rock barrier. This old valley, as above noted, has a rock floor considerably below the present bed of the neighboring portion of East White River, a boring at Otwell having failed to reach rock at a level about 35 feet below the river. 100 THE ILLINOIS GLACIAL LOBE. The present Patoka River leads southward from Jasper for several niles, occupying the northern end of the broad valley of Hunleys Creek, a southern tributary of the abandoned valley just discussed. The river then takes a northwestward course, cutting across a narrow neck of upland and touching the border of the abandoned valley about 2 miles south of Ireland. In this passage across the neck of upland the width of the flood plain is nowhere less than one-fourth of a mile, or about double the width of the valley bottom in the gorge at Jasper. Whether this difference in size is referable to variations in the texture of the rock or is due to difference in date of deflection has not been determined. It seems, however, not improb- able that this narrow neck had been encroached upon ,by valleys on each side and severed from the main upland prior to the glacial invasion. After touching the old valley near Ireland, the Patoka turns to the southwest and near the line of Dubois and Pike counties enters a narrow valley 800 to 1,000 feet in width. The narrow portion extends from the county line southwest about 2 miles to the mouth of Rocky Creek, a south- ern tributary. It there expands to twice or three times the width of the narrow portion and from that pomt gradually increases in width down the stream, reaching nearly 2 miles in western Pike County. The narrow por- tion evidently marks the position of a preglacial divide. That this divide had been reduced to a low elevation is shown by neighboring cols, which, though low, were not utilized by this stream in selecting a new course. One of these cols at the village of Velpen stands only 510 feet above tide. It is probable that the blockaded stream had to rise no higher than 500 feet to cross the divide, or to a height of less than 75 feet above its present level; possibly the divide was not more than 475 feet at the col. The latter alti- tude is slightly lower than the sand and silt filling made by Lake Patoka which, as above noted, is found in the abandoned valleys to the north and east of this divide. This filling is conspicuous in the vicinity of the divide as well as above, and seems to pass down the present stream beyond the divide without appreciable decrease in altitude. The col was nearly if not quite covered by silt before the present channel was opened across it. The Patoka River apparently follows the line of a preglacial stream from the mouth of Rocky Creek, in eastern Pike County, westward into Gibson County to the bend about 6 miles above Patoka. It there is in a low tract which extends northward to White River. But instead of follow- CHANGES OF DRAINAGE IN SOUTHWESTERN INDIANA, 101 ing this lowland it continues westward and passes through a range of hills which leads northward from Princeton past Patoka to White River at Hazel- ton. This deflection lies within the glaciated region and calls for a some- what different explanation from those just considered. It is probable that 2 lower passage was afforded across a col near Patoka than the lowland to the north else the stream would not have suffered this deflection. In the pas- sage through this range of hills at Patoka the valley is reduced to a width of scarcely one-half mile or to about one-fourth the width of the preglacial valley which it occupies a few miles to the east. Upon passing this range the stream soon enters the broad valley of the Wabash and takes a some- what direct course into that river. Since Patoka River enters the glaciated region in its lower course the question arises whether it found discharge beneath the ice margin during the time when its lower course was covered by the ice sheet or found a line or lines of discharge southward through the unglaciated region into the Ohio. There is a col on the divide between Patoka and Ohio rivers crossed by the abandoned Wabash and Ohio Canal about 1 mile southwest of Francisco, which stands only 480 feet above tide, or about the altitude of the silt deposits along the Patoka in western Dubois and Pike counties. From this col there is an open line into the head waters of Pigeon Creek. But as noted above there may have been another col in northern Warrick County on the present line of Pigeon Creek to offer resistance to the discharge of water to the Ohio. It is doubtful, however, if that col stood any higher than the one near Francisco, and it may have been so low as to afford an easy passage for the stream. An examination of the col near Francisco failed to bring to light decisive evidence that a stream had crossed it. The sag crossing the divide is scarcely 100 rods in width and is not bordered by banks or well-defined erosion contours. The features seem to be no differ- ent from those of other sags at higher altitudes on the divide. ‘The canal euts through about 12 feet of loesslike yellowish-brown earth before strik- ing the rock surface, which is similar to the material found on border dis- tricts at all altitudes. It seems less probable that cols on the Patoka-Ohio divide farther east were utilized, for they stand considerably higher than the col under consideration; the lowest stand probably about 525 to 550 feet above tide. The col crossed by the railway near Ferdinand station, 7 miles south of Huntingburg, is probably as low as any, standing 530 feet 102 THE ILLINOIS GLACIAL LOBE. above tide. The sag leading across this divide, like that near Francisco, is too narrow to have suffered much erosion by a stream discharging across it. On the whole the evidence of southward discharge into the Ohio seems very weak, and the view that the water which accumulated along the ice margin in Dubois and Pike counties found its main discharge to the Wabash under the ice margin, appears more probable. At most the col near Francisco appears co have served only temporarily as a waste weir for the accumulated waters. Several interesting deflections of small streams have been noted in the vicinity of the glacial boundary in the district lying between East White and the main White River. These have been brought to light by the studies of Mr. C. E. Siebenthal, of the Indiana geological survey, with perhaps one exception, that of Furse Creek in northwestern Martin County. Siebenthal has kindly furnished notes on these changes of drainage in advance of the publication of his report. Since receiving his notes the writer has had opportunity to examine some of the deflections brought to light by Siebenthal, but for the detailed examination, as well as the discovery of these deflections, Siebenthal should receive credit. It is scarcely probable that all the deflections have been brought to light, for the valleys of some streams in Daviess County have not been given sufficient attention to warrant their discussion. The first deflection discussed is that of Furse Creek, after which the streams examined by Siebenthal are taken up in order from south to north. . Furse Creek as shown in PI. IX, strikes the glacial boundary about 2 miles east from the west line of Martin County. It there turns abruptly southward and enters a gorge in the southeast part of sec. 8, T. 5 N., R. 4 W., in which the creek bluffs border the stream closely on each side for a mile or more. The stream then enters an open valley formed by the small southern tributary which joins it in sec. 18. Whether it has suffered other deflections below this pomt has not been determined. From the point of deflection in sec. 8 a lowland tract heavily coated with drift leads north- westward to the valley of Doans Creek, near Scotland. This probably was the preglacial line of discharge for Furse Creek. Siebenthal has found that Richland Creek was deflected southward near the point where it strikes the glacial boundary 14 miles east of the village of Newark, its old course having been northwestward from that point. The position of the col on the old divide below the point of deflec- tion of the creek is clearly shown in a view from a hill southeast of Newark. \ Fy ys = LS y. / Was / 2 / { 4 | \ = = / | : (SS tse y / ee —— cae Ser1ist OL e eS es a[R9S alqronoeid oseureap ap jo UO}NR1OSIL BV AYU OF deur Sty] U0 UMOTS JOLNSTp au} jo syed ysea pue yrsou ayy ar sirsodep [emeys Aq Ppounosgo Afyeois 00) ST aseutesp elorys-old ou, ON Ta nt) S % ott — \ / J joni SS i \ > Le so (Nes AY S ny N Ze ears ~ Col S I e fi AG. & \ \ S x > / a x =. Si a \ : e Fy = ‘ = IX v4 \ =] re J { ( ‘868I “DLAMAAAT MNV UT AL VNVIGNITIVEINGD BLNOS WO HOVNIVAC TVIOV TO ad J ae Id IIAXXX Hd VYDONOW ‘ASAYNS 1V91901039 SN r Teomcltinge aecavnss this divide, like that near - Francisco, is is am ly erosion by a stream eee across i awe Ww bite, Gatenibiae J along ee mire i eel ite main aenaege re ta the ‘Wa sh — ial, of the nian x yse C peek) ny nk je Ss Cowetyhave not bce given gia vat thely disvuss ai Che (irst deflection. discuss . ite wiach the stidants éxin ined by Siebenthal to worth. ‘ wn Ry PEAX, stevkés | ths glacial eee bos at Hue ‘of Reatns Sot. It there tures “¥ § gored iyAh¢ sduthpagt part of sec. 8, Léy bhatt border the stream closely on we / then enters an open valley formelt hich joind ein set. DE. io it has fe oink assy 7 ce heya traX hosviy e pare > Doar 8 ON ek, mez “i cot near fre wht /Miere it strikes ries mat ‘al Gases 14 mnileel east of vi) , its old couse wire ee mort eebrige enw ‘WILLS NS ssa Lama (Te1I9e]3 10U) TWIANTIV (qytp Soe) NISNOOSIM = (sureyd 119) NISNOOSIM. Le (AoTreA) AYIONITH (urejd}g sopueydn) NVIONITII ‘AUN HLI1'00 9 N3IG Sn nar SAIINST OL VNVICNI a6sl a = Ss aTeoS “LLAYHAYT MNY Yt TIVUINGAD HLNO0S te) AC HO dV 'TIVIOV'TO | sre Uy WY, WS SSS “ASAYNS TWOID01039 SN CHANGES OF DRAINAGE IN SOUTHWESTERN INDIANA. 105 The bluffs close in on either side of the creek near the center of sec. 19, sloping gradually to the border of the stream. The stream has cut a notch nearly 100 feet in depth across the col. It soon enters a small preglacial valley, but appears to follow the course of that valley for only a short dis- tance. Its course for about 8 miles is mainly across rock points and low divides and lies just outside the glacial boundary. At its junction with Beech Creek a preglacial valley is found, but the stream turns out of this valley in sec. 9, T. 7, R. 4 W., and takes a direct course westward through a gorge, thus cutting off a rock point on the south side of the preglacial Beech Creek Valley. It reenters the old valley near the corners of sees. 7, 8, 17, and 18, after traversing a gorge for about 14 miles, and is reported by Siebenthal to continue in a preglacial valley to its mouth. The stream les within the glaciated region throughout the portion below the mouth of Beech Creek, but is only about 5 miles by direct line inside the glacial boundary at its entrance into White River. It seems probable that the stream discharged through the low glaciated districts bordering White River, even at the maximum extension of the ice, for no line of dis- charge is found across the elevated districts outside the glacial boundary. In the head-water portion of Richland Creek, above the point of deflec- tion from its preglacial valley, there appears to have been a glacial lake for which Siebenthal has proposed the name Lake Richland. The presence of the lake is shown by terraces and deposits of silt and sand which filled the valley up to a definite level. They stand nearly 100 feet above the creek at the point of deflection, but in passing up the valley they gradually approach the creek level, being but 30 or 40 feet above the stream in the vicinity of Whitehall. Whether they are perfectly horizontal has not been determined. The lake apparently extended up the creek a short distance into Monroe County. About 4 miles south from the point where Richland Creek turns west- ward into the glaciated district the glacial boundary comes to the west end of another glacial lake whose site is now known as the ‘‘ American bottom.” It extends eastward about 5 miles from the glacial boundary and has an average width of nearly 1 mile. This old lake bottom now has subterra- nean drainage southwestward through sand deposits to a tributary of Clifty Creek, where it appears in the form of springs. Because of the subterranean drainage the plain is preserved in nearly the condition left by the lake. 104 THE ILLINOIS GLACIAL LOBE. Passing northward into Owen County there is found a slight deflection in Raccoon Creek, just inside the glacial boundary. Instead of following its old course the creek passes across a rock point on the south, occupying a gorge for about a mile. The head-water tributaries of Raccoon Creek outside the glacial boundary carry terraces of silt and sand which are inter- preted by Siebenthal to be the accumulations made in small glacial lakes held in front of the ice sheet. The ‘Flat Woods” of eastern Owen and western Monroe counties cover an area of several square miles of elevated land, immediately inside the glacial boundary. The flats in this area are interrupted by hilly tracts, and the entire area is above the general level of border tracts. These features are thought to indicate that no large stream occupied the “Flat Woods” in preglacial times. It is suggested by Siebenthal that the region had a system of subterranean drainage prior to the glacial invasion, but that glacial accumulations have caused a change to surface drainage.' The flats are now drained chiefly to the north through McCormack’s Creek. The western portion drains westward through Ellison’s Branch into White River. On McCormack’s Creek there is a fall about a mile from its mouth, above which there is only a shallow, poorly drained valley. The main work of the stream since the Glacial period has been given to the excava- tion of the gorge below the fall, but no accurate estimate was made of the work accomplished in cutting back to the fall. The effect of the ice invasion upon the course of White River has been even greater than on the small eastern tributaries which enter it from the unglaciated region. The preglacial drainage is so greatly concealed above the north line of Greene County that it seems impracticable to determine even the course of the main drainage line. The stream is now occupying a preglacial valley for a few miles in southwestern Morgan County, and is also in a preglacial valley throughout much of its course below Owen County. But in its passage across Owen County it is opening a new val- ley. It has been suggested that this stream had a subterranean passage across the sink-hole region of Owen County, in which case no well-defined surface channel may have been opened prior to the glacial invasion. The available data seem insufficient to test the applicability of this interpretation. 1 Twenty-first Ann. Rept. Indiana Geol. Suryey, 1896, pp. 301, 302. RELATIONS OF THE ILLINOIAN DRIFT SHEET, 105 PLEISTOCENE DEPOSITS BENEATH THE ILLINOIAN TILL SHEET. Although the Ilinoian till sheet throughout much of the region under discussion may rest immediately on the rock, there are, in places, deposits separating it from the rock formations. The deposits are principally of two classes—namely, the Kansan till, with perhaps a somewhat distinct pre- Illinoian till, and valley silts or sands. KANSAN TILL. Attention has been called to the till of southeastern Iowa and western Illinois, which underlies the Hlinoian drift and which is referred to the Kansan. The full extent of this sheet of till in western linois is not determined. Its eastern border comes to the Mississippi Valley from the south near Hannibal, Missouri, and it probably continues northward into Illinois across Adams and Hancock counties. It probably also extends into counties east of the Mississippi farther north, although this has not been so clearly determined. That it extended into western Adams and Hancock counties is shown by at least two lines of evidence. he first line of evidence is that furnished by striation, An exposure of a striated ledge with a bearing 8. 65° E. appears on the south side of Wagner's Creek, about 4 miles above Hamilton, Hlinois, and 2 miles east of the Mississippi. This, so far as known, is the only instance yet discovered of striation produced by the Keewatin ice field east of the Mississippi and south of the Wisconsin Driftless Area. The strie reported above in the vicinity of Burlington, Towa, are in some cases situated on the brow of the west bluff of the ‘Mississippi, showing that the eastward movement extended at least to the Mississippi Valley. The second line of evidence of the extension of the Keewatin ice sheet into western Illinois is furnished by till deposits separated from the over- lying Ilinoian by a soil and carrying other evidences of greater age than the Illinoian. In the discussion of the border of the Hlinoian drift in Han- cock and Adams counties, Illinois, attention was called to the occurrence of a heavy sheet of blue till similar in structure to that found beneath the Illinoian west of the Mississippi, and to a few exposures near the line of Hancock and Adams counties of a black soil separating the till from the overlying Hlinoian. In these exposures it was found that the till under the 106 THE ILLINOIS GLACIAL LOBE. soil had been leached to a depth of several feet, a feature which testifies to the lapse of a considerable period between the deposition of the two till sheets. This black soil between the tills is also penetrated in wells in western Hancock County. A possible third line of evidence of the extension of the Keewatin ice sheet into western Illinois is found in the presence of laminated clays in a buried preglacial valley in central Adams County. These clays are con- jectured to be due to an obstruction of the lower course of the valley in western Adams County by the Keewatin ice sheet. The obstruction might have formed a lake in which these deposits were laid down contempora- neously with Kansan till. The lapse of a long interval between the deposition of the Kansan till and the Illinoian is clearly shown in southeastern Iowa, not only by the presence of a soil and leached subsoil between two sheets, but by the markedly greater erosion of the Kansan than of the Hlmoian sheet. This erosion is manifest to the trained observer on passing from one sheet to the other. In the district occupied by the Kansan the erosion is so great that only narrow remnants of the original drift plain are preserved along the water partings. But in the district occupied by the Illinoian more than half the original drift plain is preserved, and that, too, on the immediate borders of the Mississippi, where conditions for erosion are more favorable than in the area to the west which is occupied by the eroded Kansan sheet. The great contrast in amount of erosion supports strongly the view that a longer interval elapsed between the Kansan and Hlinoian glaciations than between the Ilinoian and the present time. Attention is called, in the discussion of the Ilinoian drift border, to an instance of its fillmg a valley in Des Moines County, Lowa, that had been cut in the Kansan drift. This valley apparently had a depth of 50 feet below the bordering plains, but no data are available concerning its width. It appears from a study of the terraces on valleys cut in the Kansan drift of southeastern Iowa, that the erosion in the interval between the Kansan and Illinoian stages of glaciation was such as to form broad shallow valleys rather than narrow deep ones. The large valleys appear to have been cut to adepth of but 50 or 60 feet, though they had a width of one or two miles. : PLEISTOCENE DEPOSITS BENEATH TILL SHEET. 107 PRE-ILLINOIAN (?) TILL AND ASSOCIATED DEPOSITS. As yet the evidence poiting toward the occurrence of drift of greater age than the Ilinoian in the districts to the east, which lie beyond the limits of the Keewatin ice sheet, has not sufficient strength to make it. seem advisable to advocate a pre-Illinoian till. There are occasional well sections reported to have passed through a bed of wood or of soil in the midst of the till in central Hlinois. Thus at Pana a section reported by Worthen is as follows: Section of well at Pana, Illinois. Feet Soil and clay...-.--------+----+-----7 777-77 eoundaee yy aubboo ceSoos Geaded ubnS BocubeuDeEEeccocs 11 THING GER? saasad pees boos batc cane eons cob bes cbases anea ge ara pooR a cdon ey eR Ber E Er ces ae 4 Rival eRnGlEnENO)l oudeacndoscb ade ated 52e0 S8ees Uoce Pon casrier ES 290 sad GQHORD Ske SSeS GS vs 12 Hard red GER? wiccigs sevieas Sede auguecieeh ue aus Se ehn ere encodane: aden ode subeos cdboEs osomSoseDooeS 18 TURE Wal suse cose donoee abecos pss cng es pouomdeacoseno eescap cecncs seeerocneaod S908 aOR SaaS 34 Tin GeN7 Sub asdasaese Sacusesdne cena ceooIseds Han oreo ebm oabeodcaceneded secon oF Sate oe Tegel 57 THIRVE EG@iill Ge RONCHI WEL qaaHaqbecoe padee9 osc een ngd > Heecis CARD ECB pIEGE aS RRO GARD ene ee un 24 Fane Glen? Usk kod daues sdb eee anrcos csed paige oUBcbb Iau aero cen pL bre camcHyanGe cos eon a jaiiae 19 AHL oon coud aaee sade Sooobacecheucoobes seeucbedcaagch SS0Nbaee oSESsoS9s CoSo ERO Sue 127 This section is based upon specimens preserved from a test boring with diamond drill. The specimens were recently examined by the writer and some light obtained concerning the interpretation to be put upon this sec- tion. The upper 15 feet consists of a pebbleless material to be classified with the loess. The upper forest bed proves to be simply fragments of wood embedded in ordinary till. The till was found to be very calcareous at the horizon of this wood and to show no evidence of atmospheric expo- sure subsequent to its deposition. ‘The wood appears, therefore, to be simply material deposited in the till by the ice sheet and has no more sienifi- cance in determining a time interval than the presence of a Paleozoic fossil embedded in the drift. The lower forest bed consists of a humus-stained elay in which fragments of wood occur; it is apparently a soil. Under it is a greenish clay subsoil, such as occurs beneath swamps. This, as well as the soil, is pebbleless. At the bottom of the clay, resting on the limestone rock, there is a thin bed of ferrugimous conglomerate, in which angular chert is mingled with waterworn pebbles. No Canadian rocks or specimens which can be referred to glacial action were found. This raises the question whether the conglomerate is not of preglacial age. The soil 1 Geol. Illinois, Vol. VII, pp. 22-23; also Vol. VIII, p. 15. 108 THE ILLINOIS GLACIAL LOBE. at the base of the drift, together with the underlying subsoil, appears to be connected but remotely at least with glacial agencies. The deposit appar- ently antedated the deposition of the overlying till by a considerable interval. The writer is inclined to refer to the [linoian invasion the series of clays setting in at 27 feet and extending to 106 feet. Worthen reports a section at Virginia, Illmois, in which a black soil appears between tills at a depth of 67 to 70 feet? On making inquiry of Dr. J. F. Snyder, of Virginia, concerning this section, it is found that the record of the coal shaft on which Worthen based his section of the drift was not kept with a sufficient degree of accuracy to insure its correctness. Dr. Snyder is of opinion that the distance to rock is about 70 feet greater than shown by this record. It would certainly be hazardous to base an important time interval on the reported occurrence of soil in the shaft at Virginia. The section of a coal shaft at Bloomington reported by Dr. H. M. Banister” represents the occurrence of two buried soils. The section as reported by Dr. Banister is as follows: Section of coal shaft at Bloomington, Illinois. Feet Surface sollvandybrownl clay es cc ecco ceo a= mses oe Stememe os ee Bee CEE Ree ene eee 10 Blue rCla years sec ale aise aaa claws anes = aioe lease eye eee eyte cer aiee fe Saye rete Ree te ee ee 40 Gravelly am dip atemretsctatesatece seta aoa ssiatcte aia = cicine ine ree ahaa eee eee ne er 60 Black moldswith ple cesvOfawOod are. sactsow sce ee cee ae nel Mee aN See ee Oe Ee eee ASSy 1s emalae Ra ThE) osbo cog 2 aa5 Ke SeK GA SOEOMHAY oaRARe nae Bmace Guedes bdor cant Saud pseeeds dads ssoede 89.0 * IB acksmOla sete! soars ate ots mein are SS a Slee we eee core oe eS ee oe ee 6 IB Merch ayaa oee seein cise oe Ste Stes eee eo ee See ye Sie et eee tae 34 Quicksand, buff and drab in color, and containing fossil shells --.......-..----..--.-------..----- 2 ANCA EOD GRO i ee SE ce ie rs ee SE te Seale Rem eceyS Hee Mitty sr Se RGAE Mee SSCs 254 In this section the upper 110 feet may be referred with considerable confidence to the Wisconsin drift. The upper ‘‘black mold” at 110 to 123 feet was apparently post-Illinoian. It is probable that the Hlinoian sheet is represented in the “hardpan and clay” at 123 to 212 feet. The remainder of the section would be therefore pre-Ilinoian. Whether the blue clay below the lower “black mold” is a glacial deposit is not clearly shown. It may prove to be a water deposit. In view of this uncertainty it seems unsafe to use this section as evidence for the occurrence of a pre- Illinoian drift sheet in central [linois. ‘Op. cit., Vol. VIII, p. 16. 2 Op. cit., Vol. IV, 1870, p.178. Also Vol. VIII, p. 14. PRE-ILLINOIAN (7?) TILL AND ASSOCIATED DEPOSITS. 109 In this connection attention is called again to the section of a shaft at Coatsburg, in Adams County, in which a laminated clay of considerable depth underlies the till, but which is not a strictly glacial deposit. The Bloomington section may be of similar character in its lower portion. The sections above discussed comprise the most puzzling ones reported in the geology of Hlinois. The buried soils there reported are usually found, when in the district outside the Wisconsin drift, either at the base of the loess, which is a post-Ilinoian interval (Sangamon), or at the bottom of the glacial deposits, where only silt or sand occurs between the soil and the underlying rock. Prof. R. D. Salisbury has reported the occurrence of two sheets of drift in southeastern Hlimois and southwestern Indiana. He considers them representatives of two episodes of a single glacial epoch. The upper sheet is thought to extend fully as far as the lower, if not beyond it. As the features referred to by Salisbury have never been investigated by the writer, some hesitancy is felt in offering an interpretation. It is, however, suggested that the invasion limited on the southwest by the ridged drift of the Kaskaskia Basin may have formed the upper sheet, while the invasion, which in southwestern Illinois was the more extensive one, may have formed the lower sheet. Possibly the interval will prove to be too long to support this interpretation. In that case the lower sheet would be referable to a pre-Hlinoian invasion. In northern Illinois there are certain deposits which need consideration in this connection. The studies of Mr. Ira M. Buell in eastern Winnebago County led to the discovery of several exposures of glacial conglomerate which appear along the east bluff of Rock River. Bowlder-like masses of this conglomerate have been incorporated in the till of that region, a good illustration being found in the cuttings of the Illinois Central Railroad, immediately southeast of Rockford. The firm cementation, and also a deep orange-colored stain presented by the conglomerate from which these bowlders are derived, seems to have been produced prior to the deposition of the sheet of till in which they are embedded. This till is probably of Iowan age. It therefore remains to be determined whether the conglom- erate is of Illinoian age or of still earlier date. There are other deposits in this region, noted by Buell, which favor the view that there were not 1 See Arkansas Geol. Survey, Crowleys Ridge, Report for 1889, Vol. II, p. 229. 110 THE ILLINOIS GLACIAL LOBE. less than two ice invasions prior to the lowan. Reference is made to the evidence found in the occurrence or distribution of bowlders of Waterloo quartzite, a subject which has been investigated in considerable detail by Buell and discussed in a recent paper published in the Transactions of the Wisconsin Academy of Sciences.’ The earliest movement affecting the ledges of Waterloo quartzite, which has been recognized by Buell, is interpreted by him to have been westward. This movement is indicated by the westward transportation of bowlders from the quartzite ledges, and farther south by the occurrence in the marginal portion of the drift of Devonian and Upper Silurian rocks, which could only have been derived from the east. Following the westward movement, he thinks there is evidence of a southward movement, through which quartzite bowlders were carried into northern Illinois. He considers the western margin of the ice lobe which transported this material to be indicated by a “belt of thickened stony till and kame-like gravel deposits, the former appearing on the ridge surfaces and the latter spreading over the lower level.” This supposed line of marginal deposit has been traced by Buell from the pomt where it emerges from beneath the Kettle moraine, near the line of Dane and Greene counties, Wisconsin, southward through eastern Greene County, Wisconsin, into northeastern Stephenson County, Illinois. Quartzite bowlders have been discovered in this belt and over the country to the east to points slightly beyond Rock River, but none were found by Buell west of this belt. They are readily found as far south as the latitude of Freeport and Rocktord, but farther south they are very rare, and apparently represented only by small fragments. Buell thinks it probable that the southward movement extended but little beyond a line connecting these cities, the scattering pebbles to the south being transported perhaps by water. The southward movement is thought to haye been followed by a southwestward one im southern Wisconsin, with perhaps westward movement in southern Ilinois, by which quartzite bowlders were carried southwest from the ledges slightly beyond the limits of the Kettle moraine. This invasion is referred to the Iowan stage of glaciation by Buell, and is correlated by him with the main loess deposition. He limits its western extension to the east border of the loess. The interpretation made by Buell would reter the earliest or westward ‘Bowlder trains from the outcrop of the Waterloo quartzite area, by Ira M. Buell: Trans. Wis- consin Acad. Sci., Vol. X, 1894-95, pp. 405-509. : SILVERIA (?) FORMATION AND OTHER SILT DEPOSITS. Wall movement to the [linoian stage, while the southward movement is interpo- lated between the Hlinoian and Iowan. If, therefore, this interpretation be correct, it affords no evidence of a pre-Ilinoian invasion. The subject of bowlder transportation has been studied so little as yet that it may be unsafe to take the interpretation given by Buell as final, although it appears well sustained. On this question, as well as on that of the age of the con- glomerate found on the borders of Rock River, further light is desirable. Hershey has recently discussed certain silts in northwestern Illinois, which underlie the Illioian drift, as probable representatives of a stage of glaciation preceding the Illmoian.t | He does not, however, refer the silt deposition to a time much earlier than the Illinoian.” There is evidence of erosion of this silt prior to the ice invasion which deposited the Mlinoian drift. It is possible that these silts may be correlated with the ferruginous glacial conglomerate along the east side of Rock River, the conglomerate being deposited by a stream and the silts by a temporary lake, though there is as yet no adequate basis for such a correlation. SILVERIA (?) FORMATION AND OTHER SILT DEPOSITS. In the course of the discussion of the [linoian drift and of the Kansan till sheet, which it overlaps on the west, frequent reference has been made to the occurrence of deposits of silt beneath the Hlmoian. These deposits are known to be distributed very widely beneath the Ilinoian drift, but it is not known how large a combined area they cover. They appear to be present in conspicuous amount beneath many streams of northwestern IIli- nois, but are not often exposed to view because of their position beneath the level of the streams. They appear to be less extensively developed in western and southern Illinois, though not rare in either district. Their best development, so far as known, is along the lme of valleys which were favorably situated for the development of lakes in front of the ice, valleys whose lower courses were entered by the ice sheet, while their upper courses remained for some time uncovered by the ice. Hershey has proposed -the name Silveria for deposits of this class in northwestern Illinois.’ The necessity for a name for such deposits will 1Am. Jour. Sci., 4th ser., 1896, Vol. II, pp. 324-330. * As Hershey uses the word Kansan for the sheet which we are diseussing as the Illinoian, the reader may find it somewhat confusing to interpret his language. Hershey, however, is not at fault in the use of this term, since his paper was prepared before the name Illinoian had been introduced. He naturally inferred, in the absence of knowledge to the contrary, that the same name should be applied to the sheet outside the Iowan in northwestern Illinois as has been applied in southern Iowa. 11 THE ILLINOIS GLACIAL LOBE. depend upon the bearing they may have upon glacial history and their relation to each other. Should it be found that any of them bear evidence of a distinct stage of glaciation to which no name has yet been applied, or to any part of geological time not assigned a name, it would seem proper to introduce a name. But if they simply mark the deposits of small lakes of temporary character formed during an ice advance to which a name has already been applied, it would seem better to extend the name of the ice invasion to the silts. Thus we might speak of buried silts of Kansan age or of Illinoian age. The relation to the glacial deposits would then be more clearly seen than if a separate name were applied to the silts. In the vase of the silts which Hershey has named Silveria there appears to be evidence that they do not connect definitely with the advancing Ilinois ice lobe, for, as noted above, they seem to have suffered some erosion prior to the Ilinoian ice invasion. It therefore may be necessary to retain the a, Present soil. 6, Loess. ¢, Old soil. d, Till (Mlinoian). e, Chert, etc, J, Extra-glacial silt. g, Brown sand, h, Blue laminated silt. Fic. 1.—Section showing the ‘‘Silveria formation ’’ near Freeport, Illinois; prepared by Oscar H. Hershey. g and h com- bined are the ‘‘ Silveria.” : name Silveria, but to restrict it to deposits which are clearly of similar age to those examined by Hershey. If, on examining the silts of valleys in other parts of the region covered by the Illinois lobe, it is found that a similar interval of erosion separates their deposition from that of the Illi- noian drift, the name may be extended perhaps to such deposits. But if it is found that valleys contain silt deposits which immediately precede the Tllinoian till sheet in date of deposition, it seems advisable to withhold the name Silveria and refer to them as the silts of the Ilinoian stage. It is probable that many if not all the valleys in which the Hlinoian till sheet blocked the lower course and formed the temporary lakes contain deposits of this latter class. It is likely, therefore, to be more extensive than the Silveria formation. Hershey recognized this restricted application of the name, and gives the extraglacial silts a separate place (see fig. 1). In western Illinois, as was indicated above, there are silts which appear SILVERIA (?) FORMATION AND OTHER SILT DEPOSITS. eles to nave been formed at the Kansan stage of glaciation by the blocking of valleys which had westward discharge to the Mississippi. If this be the correct interpretation, these silts can not properly be termed Silveria, for they may be much older than that formation and their relation to the Glacial series would be more clear if they were termed Kansan silts. The Silveria formation discussed by Hershey ‘is a thick bed of strati- fied silt of a nearly uniformly dark bluish-gray color with bands often several feet in thickness which are a. lighter tint.” But one surface exposure has been found, and is located in a small ravine 15 miles south of the city of Freeport, yet wells have shown its occurrence in the valleys of nearly all the streams in the Pecatonica drainage basin. At the surface exposure “the upper portion is a false-bedded, calcareous and ferruginous, light- brown fine sand and silt, and appears to represent the shore deposits of an ancient lake in which this formation was apparently laid down.” Its calcareousness strongly supports the view that it is a glacial silt. Several species of small shells and also fragments of partially decayed wood have been collected by Mr. Hershey. Specimens of the shells, submitted to Dr. W. H. Dall, of the United States Geological Survey, are found to represent three different species, with fragments of still other species. These species are present in about the following proportionate numbers: Succinea avara 50, Pupa blandi 5, Pyramidula striatella 2. Hershey refers the occurrence of this terrestrial fauna in a deposit of lacustrine character, to the position near the shore of the lake. This deposit appears to have considerable bulk in the valleys of Stephenson County. In a well 3 miles southwest of Freeport, in the old valley of Yellow Creek, it was penetrated to a depth of 150 feet without reaching the bottom. Hershey estimates that if spread out over the entire surface of Stephenson County, this deposit would make a uniform layer at least 14 feet in depth. He estimates the total depth of the superficial deposits of Stephenson County to be 324 feet. It forms therefore nearly half the bulk of these deposits. Above the silt which Hershey has called the Silveria formation there is another silt deposit separated from it by an erosion unconformity and a slightly developed soil. This he considers an extraglacial lake deposit formed during the advance of the ice sheet which formed the overlying till. This deposit he estimates to have an average thickness, if spread over the MON XXXVIII——8 114 THE ILLINOIS GLACIAL LOBE. entire surface of Stephenson County, of but 1 foot, or only one-fourteenth the bulk of the Silveria formation. In the vicinity of Rock Island several exposures of silt have been found by Prof. J. A. Udden beneath the lowest deposit of till, and through his kindness the writer has been conducted to them. Whether these deposits are all of similar age, and whether they are earlier or later than the Kansan, has not been determined. They appear to be at least as old as the maximum extension of the Illinoian sheet. One of the best exposures is that made by a well at the base of the Mississippi bluff, near Thirty-sixth street, in Rock Island. The bluff back of the well carries about 40 feet of loess and several feet of till above the level of the well mouth. The "exposures are not adequate to show the age of the till, though it is probably Illinoian. ‘The section of the well, which was observed while in process of excavation both by Professor Udden and by the writer, is as follows: Section of well near Thirty-sixth street, Rock Island, Illinois. Feet Yellow till (probably Illinoian) -.....----.-------------+------- +2. ++ +--+ ++ 2-22 eee eee ee eee 5 Black muck (Yarmouth?)...-.-..--..------ -----+ 2-2-2 2 222 ne ee nee een eee ene neon nee eee it Browmstilly(leached 2/orr3) feet) hsv = etaia ofan ema ee aaa lola note oleae ellie alam ale fermi lane alot vi Blue till (probably Kansan) ....--..----------.------------------ ---- +++ --- +--+ 02-222 +--+ +--+ -- 4 Black calcareous silt, with gasteropod fossils ....-.-.--.----.------ ------ -- 20+ enn enone wan e- 8 Dk wile 3 so seé ge decbebseeosdbobos boSoudocodoN DeScae bsondp boedos cogone counSoSse Sod DaSSbbingonSs 4 Greenmmuck with atew local pebbles =o. ccs sects a aimee ela nta alae ale mista data ale) ote la lw tmledelatelare —geraterarae 5 Coal Measures shale. MINI. adeno boebbe caieoo ogguue coosep Spoon saneco oases Senads SaoaKE boeSedessocoosESSE Geese 34 Within a mile east from this exposure, in the city of Moline, a well observed by Udden reached a fossiliferous loess-like silt beneath a pebbly clay at a depth of 30 feet. The well is on the Mississippi River bottom, corner of Seventh avenue and Fifth street, Moline, at an altitude about 30 feet above the low-water mark of the river. A ravine on the range line between sec. 7, 'T. 17 N., R. 1 W., and see. 12, T. 17 N., R. 2 W., exposes the following section: Section of ravine on range line between sec. 7, T. 17 N., R. 1 W., and sec. 12, T. 17 N., Bie 2) Wre Feet: DBT tele aS Eon e hae tap ee ees EHSE cS ebe CBAs R ECoD culnca SHO CR ESO CODOS A nEeRAr camasanac ac acoroge ies BIOORG Ae eee) Soooe beets cooone peepcoeo cose asbgee coos odess sos Fours cEceso omosses SoS tesa sadond 2 Nigel aedowll Gocces Hea ser oeecor MaScce os00 SomacinboGese paDene Sans Cesebasd caahooochhoeceoseo 12 oessslikkersilt; Contain ino LOSS is fe oe ere ep epete tee ole malate tatelnlelainl tere elm ialal = ole |= sie) olmla le reitel=isle| aie / lie alma several feet Coal Measures sandstone. SILVERIA (?) FORMATION AND OTHER SILT DEPOSITS. 115 Another exposure occurs in the east bluff of the Mississippi near the line of Rock Island and Mercer counties and has the following section: Section of ravine near the line of Rock Island and Mercer counties, Illinois. Feet ILE KAS JER HOB Bol bead cone adag SRS ASAS ED CABSGOn OE Ise Oe iieteieeeects och eT lm Res Ot ee 25 Bac kAso ilies mee mecrete eee eters ietats 2 appa esicicte ye psy ehs eae etal ete a Se onoase cnos sapcud Dabo SuosSs naaH 2-3 Hills ainihyfopabliwWencolovese sats sec yrse cers shee eke = eat ee crete eee ac boc. Bel So Ahacece. 90 ILA SSMS) RWlis, MOA TRIS OT OME) coo codes, coe0 RUOR SE eoau sone bnoeed dome BroGae Sendo saeou casas SEEae 12 AO Galler eters cums aire eleen =e tlenetee es aatoc iat eis sais aie Seteie mies ce SER cee Sete ae dincc ees eC biclbeamccw che 130 The bottom of the lower loess was not reached by this ravine. This deposit differs from the surface loess in containing a large number of nodules and tubes of partially solidified material. These have a yellowish color and are largely due to the presence of iron oxide. Specimens of fossils have been collected by Udden from these buried loess-like silts in Rock Island County as well as from surface loess and submitted to Dr. W. H. Dall and his assistant, Mr. C. T. Simpson, for examination. The buried silt deposits are found to contain a larger pro- portion of Helicina occulta than the surface loess and a smaller proportion of Succinea avara. ‘These two species are the most abundant ones in all the deposits, whether surface loess or buried silt. With the exception of the exposure of the east bluff of the Mississippi, the only additional fossils found in the buried silt are Pyramidula striatella and Pupa alticola. The latter species is now confined to the Rocky Mountain region. The speci- mens collected from the ravine in the east bluff of the Mississippi, near the line of Rock Island and Mercer counties, contain a greater variety, as follows: Helicina oceulta Say; very abundant. Helicodiscus lineatus Say. Limnea humilis Say (variety). Pyramidula perspectiva Say. Pyramidula striatella Anth. Pupa armifera Say. Strobilops labyrinthica Say. Succinea avara Say; less abundant than in surface loess. Succinea luteola Gould. Vitrea arborea Say? The origin and relations of the buried loess-like silts of Rock Island County remain to be determined. Whether they are the deposit of an 116 - THE ILLINOIS GLACIAL LOBE. extraglacial lake formed in valleys in front of the advancing ice sheet, or, like the surface loess, have a wider distribution less clearly connected with the ice invasion, is not at present known. They may be widely distributed beneath the Ilinoian sheet in western Illinois. In texture and general appearance these deposits are very similar to the surface loess. They are apparently not so compact as the laminated silts of northwestern Illinois, described by Hershey under the name Silveria formation. The deposits of laminated clay with sand partings, found beneath the till in central Adams County, Ilinois, have already been discussed as prob- able products of an obstruction of an eastern tributary of the Mississippi by the Kansan invasion of the Keewatin ice sheet. It is probable that similar deposits fill the valleys of other eastern tributaries of the Mississippi in western Illinois, though as yet none have been observed. The date of these laminated clays, compared with that of the buried silt of Rock Island County, or of the Silveria formation of Stephenson County, is not known. The silt beneath the till at Pana, noted above, is so much older than the overlying till that it can scarcely be considered an extraglacial lacustrine deposit formed during the ice advance which deposited the till. Its origin and date are not determined. In the reports of the geology of Illinois there appear several instances of the occurrence of a plastic blue clay, or ‘‘blue mud,” below the till in the vicinity of the glacial boundary in southern Illinois. This blue material , appears to be a silt deposit stained by humus. It often contains much wood and other organic matter. The writer has not been successful in finding an exposure and can not pass an opinion upon the character or the origin of the deposit. It is probable that valleys in that region which were obstructed by the advancing ice sheet were filled to some extent by silt, but since the deposit in question contains wood and other vegetal material it apparently antedated the till by a considerable interval, though it is possible that the accumulation of wood and organic matter is due to the introduction of this material by currents of water during the silt deposition, and not by the growth of vegetation on the silt after the completion of the deposition. A detailed section of the material penetrated by the Isabella Thompson ‘Geol. Illinois, Vol. I, pp. 299, 300, 316; Vol. III, pp. 75, 86, 87, 103. SILVERIA (?) FORMATION AND OTHER SILT DEPOSITS. 17 coal shaft near Sparta in eastern Randolph County, has been published by Prof. J. M. Nickles.t The Pleistocene deposits are as follows: Section of Pleistocene beds penetrated by the Isabella Thompson coal shaft near Sparta, Tllinois. Feet Soil and clay .---- 2 Sodaoo.coSGou seees SoDESS Stas: GHodas baDDSO ¢soRObo Sane Sooo ay poRESE Seeeodsdcees 3 VGHONY GER aécc codcos sroong sadobe coseQobasnodmadansbaaEEEnodsco n Hodes aap oUS Heer aSESrn TES eeTeaes 17 IIDO.CIE Nr so dasecconde adaddaoansta tobeod aSwond Conse modoase arenas Peto. Sea tee sane Cero er mren Reeeee 3 Quicksandieeeesse=-ee besos canoes sosede = = aavgdeDdod Sodess CoODDS BooRod cos sao ns0EsE SodSaoRSs donede 4 SL eee eater aie eicre eee petate Teele late winters eis See helaisietntonsic ete seeps cists eer Mal miso aeinemred see aendees hoes oe. 2 (CREPRUOILS SES oOHRGA BanSo ao Omnis CHa caGsus a det aSS tO GOSette sce De sae) see tc reese ie nee iets tae ea a 4 RS soe goco cots ccbu coos cobg ondd adoH CDOS S965 50 obbd BOGad coESdobonD coms oUSn conemOoceRe qocass asbeoe 34 Sevag) emnel emeNG coocosoceso sessed esoone coqced bdoobs cop osasodesy asosE4 aonb be ssunES Bonece sd ceeabe 64 1DED OF THOTEO0) Oneal Gh) Socg=b6 c0cG0s saacad Soames ooE dea saobos bboSSdessaus scoode daeder so sacaee 11 Concrevevorsh andi ames evs errs aye tele eset elas cin tS Sara Tatelat SENN alec oO tran ee te I a 4 ING) Area Ol o coce dons sob eosoESeson ponnee ducSos BSH onOo Emo sernoed S6uone se Saco eseeSbuSEeaess 6 Sandeanduclayamixedasernecesrr cence (seeker aisle eters setae Jarre ee eae aan eieeieeiaeais cee ame 64 Silli cy obo hacuon Bago pons bog EES Neon ESTOS SOaO CacSeSueroSHoUsseS aoecise ese ieee aseeeese sac 24 Bowl derkel ayaeanem acces oe eats wee eee a eile ioral Se meee eels ayers en etnies ese ete eicecnesicteentcisisiee 64 Hines eravelle ses seisee ere ecicmasmereeauceciassissieresine cinerea sodesceocquseo pdadoooccbos HéaupoodauS 4 Bowl derzcl ayaa acy tars serosal ste eerste inteve te as eieie Sans eae a ele resins seataay alae eee ata eisie Sie encom meetetay eevee eos 1¢ aminatediclayeecontainin cawo00dber ei eemess sneer stern tceeeceae seine e reer eerie cee 5 PRO talk clrrttlesce oso aa ee ee eve ister dea en oe aterseeaven ia oe ate, fictclne rs micron wee ctslaee ears tel acee 90 In this section there appears to have been an alternation of glacial and lacustrine deposition without distinct evidence of long interruption. The laminated clay at the base of the series contains a large amount of wood, specimens of which have been sent to the writer by Professor Nickles, but which await specific identification. Borings for coal and water in the Big Muddy Valley in the vicinity of Murphysboro usually penetrate a large amount of sand. As this valley does not appear to have been obstructed by the ice invasion the sand can not be referred with any certainty to lacustrine conditions. It seems more probable that it is an indicator of the weakness of the currents of the stream. The tributaries of the Wabash in southeastern Illinois are usually filled with sand or silt, and these open southward in such manner as to avoid obstruction by the advancing ice sheet. The filling probably may be taken as an index of the weakness of the currents of the stream just before the ice invasion. It may be remarked in this connection that the filling of the valleys of southern Illinois apparently opposes the somewhat popular hypothesis that there was a period of high elevation and vigorous ' Final report Illinois Board World’s Fair Commissioners, 1893, pp. 200, 201. 118 THE ILLINOIS GLACIAL LOBE. stream action in this part of the Mississippi Basin just before the first ice invasion. The character of the deposits beneath the till in the valleys of south- western Indiana has not received attention, for that region has been given only a hasty reconnaissance. The Wabash Valley is filled to considerable depth with sand and fine gravel, but this may be in large part derived from the Wisconsin glacial drainage. Its rock floor stands 75 to 100 feet below the present stream at the points where tested by borings. The tributaries show a correspondingly low rock floor, but their filling in the district outside the Wisconsin drift is not so coarse as that along the Wabash. @HVAGP MEE Raave THE YARMOUTH SOIL AND WEATHERED ZONE. The occurrence of a definite soil and weathered zone between the over- lapping portions of the Illinoian and Kansan till sheets has been so fully set forth in the discussion of the Illinoian drift border that but few further remarks seem necessary. The name Yarmouth, as above indicated, is from the village in Des Moines County, Iowa, where the evidence of a prolonged interval between the till sheets, now known as Kansan and Mlinoian, was first recognized. It remains to be determined whether the occasional instances of soil reported to occur between sheets of till in portions of the Illinoian area east of the limits of the Keewatin ice sheet are to be referred to the Yarmouth interglacial stage. Further light is also necessary to determine whether all instances of buried soils within the region of overlap of Hlinoian upon Kansan till are to be referred to the Yarmouth stage. For example, the buried soil in the gas belt west of Letts may prove to be of earlier date than the Yarmouth, though it seems quite probable, as above noted, that it is found in a valley which had been cut in the Kansan drift prior to the Ilinoian invasion. WEATHERING OF THE BURIED KANSAN DRIFT. Among the several evidences of a long interval between the Kansan and Ilinoian invasion, that of weathering is the most common and perhaps the most decisive. As shown in the sections given above, there is found to have been a general leaching of the sheet of calcareous Kansan till to a depth of 4 to 6 feet prior to the deposition of the Ilinoian sheet of drift. Accompanying the leaching the upper portion of the Kansan drift was weathered to a brown and in places reddish-brown color. The brown color extends much below the limits of the leaching, there being not a few instances in which it extends to a depth of 25 or 30 feet, and it is rarely less than 12 to 15 feet. The reddish-brown stain usually extends only to a depth of 2 119 120 THE ILLINOIS GLACIAL LOBE. or 3 feet from the surface. The Kansan till, as noted above, is commonly characterized by vertical fissures and shows a tendency to fracture in rec- tangular blocks. Along the lines of the fissures the brown stain often extends some distance into the blue or unoxidized portion of the sheet, thus extending the limits of oxidation still lower than the general zone of oxida- tion. As previously stated, the amount of leaching and oxidation at the Yarmouth stage appears to be about as great as in all post-Illinoian time. There are, as above noted, places where the Ilinoian till rests directly upon an unleached Kansan, but in such places the oxidation and vertical fissuring are present to testify to the changes effected in the Kansan sheet. The absence of a leached zone at the top of the Kansan in such places is readily accounted for through removal by the Ilinoian ice sheet. It is perhaps more remarkable that the leached zone is so well preserved than that it should have been occasionally removed by the Ilinoian ice imvasion. BURIED SOIL, PEAT, ETC. The accumulation of beds of peat at the surface of the Kansan drift, prior to the Illinoian ice invasion, constitutes as impressive an evidence of a prolonged interval as the leached and reddened surface. In the Yarmouth section the peat has a depth of 15 feet while underlying beds of sandy clay, and sand carrying bits of wood, probably also to be classified as inter- glacial, extend the depth of the Yarmouth deposits to 43 feet. Buried soil of black color and beds of peat have attracted the attention of well diggers in nearly every township of the region of overlap in southeastern Iowa, and specimens of the peat obtained from wells are preserved at many of the farm houses. Along the border of the Hlinoian the soil is usually found at about the general level of the upland portion of the Kansan drift surface and may be referred with confidence to the Yarmouth stage, but occa- sionally it occurs below that level. In such instances, so far as the writer is aware, no soil has been noted at a level corresponding to the upland sur- face of the Kansan. The presumption is that the soil occurs in interglacial valleys which had been cut into the Kansan prior to the Ilmoian invasion, and that the entire till deposit above the soil is Illinoian. The erosion thus indicated commonly shows a depth of less than 50 feet and harmonizes with the depth of pre-Ilinoian valley erosion of the drift outside the limits of the Illinoian drift. There is, however, an occasional example of the occurrence EROSION OF THE KANSAN DRIFT SHEET, 12a of a buried soil in the district west of the limits of the Ilinoian, either under- neath or within the Kansan drift. This feature makes it necessary to leave open the question of the age of buried soils within’ the Ilinoian area which occur at a level below the general elevation of the outlying Kansan drift. EROSION OF THE KANSAN DRIFT SHEET. The pre-Illinoian erosion of the Kansan till sheet is a third evidence of the great length of the Yarmouth interglacial stage. Such erosion, as just noted, is suggested within the limits of the Illimoian by the occurrence of a buried soil below the general level of the Kansan drift surface. But evidence may be found in the portion of the Kansan drift lying outside the limits of the Illinoian which is not at all open to question. The evidence first to attract notice was that of the relative degrees of erosion displayed by the [linoian and Kansan drift sheets. Prior to the discovery of the extension of the Illinois lobe into southeastern Iowa it had been noted by Chamberlin, as well as by the writer, that southern Iowa presents a more eroded appearance than western Illinois and the southeastern counties of Iowa, and the matter was discussed as a remarkable feature. In the district outside the limits of the Hlinoian the original drift plain is preserved only in narrow strips along divides, estimated to comprise scarcely one-fourth of the surface, while in the district covered by the Ilinoian drift the remnants are far more extensive, comprising apparently more than half the surface. The branching of drainage lines is also carried to markedly greater maturity in the Kansan than in the [linoian drift. Definite means for determining the amount of pre-Illinoian erosion of the Kansan is afforded by a study of the valleys in Kansan drift which connect with the abandoned valley of the Mississippi, which was occupied at the Ilinoian invasion. These embrace the valleys of West Crooked Creek, Skunk River, and Big Cedar Creek. Valleys farther north have generally been greatly modified by the Iowan invasion, and hence do not furnish good illustrations. It is found that the three valleys just noted have been cut at their points of connection with the abandoned valley to a depth of about 50 feet below neighboring uplands and to widths of about three- fourths of a mile, 14 miles, and 1 mile, respectively, at the time the Missis- sippl was occupying this abandoned channel, i. e., at the Illinoian stage of glaciation. This width is two or three times that of the inner valleys, which 122 THE ILLINOIS GLACIAL LOBE. are now cut far below the level of the pre-Illinoian valleys, but repre- sents nearly as much removal of material, and the removal was probably effected at a lower gradient, i. e., under less favorable conditions than are now attorded. In this connection it should be noted that no evidence has been found that the gradient of the streams was increased until after the Iowan stage of glaciation. The inner valleys represent, therefore, post- Iowan rather than post-Illinoian excavation. But this fact does not appar- ently set aside the estimate given above, for if the pre-Illmoian valley excavation had not reached the level of the channel opened by the Missis- sippi at the Illinoian stage of glaciation, that valley would have furnished a more direct and presumably more favorable line of discharge for all these streams than their present line. The features along the present line of dis- charge for the three streams under consideration (eastward through Skunk River) strongly support the view that a pre-Illinoian valley was formed in the lower course of Skunk River. A broad terrace borders the portion of the valley below the point where Skunk River crosses the abandoned valley at Rome, which stands sufficiently low to have afforded a line of discharge for the portion of the valley west of the abandoned channel. This would have been blocked at the Illinoian ice invasion, but not necessarily con- cealed or greatly filled by Hlinoian drift. Upon the withdrawal of the ice, if it chanced to stand slightly lower than the Ilinoian course of drainage, it would receive the post-Ilinoian drainage and become the line of a reestab- lished stream. There is near the mouth of Skunk River an exceptionally clear illustra- tion of the work of that stream in the Yarmouth interglacial stage. By reference to fig. 4 it will be seen that a valley or depression turns away from Skunk River at Augusta and leads southward to Lost Creek. This valley is more than a mile in width and 30 feet or more in depth, and is excavated in the Kansan till. Evidently it was opened by Skunk River after the Kansan stage of glaciation and before the Ilimoian stage. Whether it carried the whole or only a part of the stream is not yet known. The northern end has received only a thin coating of Lllinoian drift. The southern end received a sufficiently heavy deposit of that drift to prevent its subsequent use as a drainage line. Since the Ilinoian stage of glacia- tion the entire drainage of the river has been directly eastward into the Mississippi. Low swells of Illioian drift occupy the south end of the ORGANIC REMAINS. 123 valley and show clearly that there has been no valley excavation there since they were formed. The valley of Lost Creek in Lee County, Iowa (see fig. 4), though lying wholly within the limits of the Hlinoian drift, bears evidence of having been occupied and largely excavated by a pre-IIlinoian stream. It presents a shallow trough cut in Kansan drift, which is covered, but not greatly concealed, by Ilinoian drift. Low swells of till formed at the Ilinoian invasion occur on its slopes and bottom, thus proving its pre-[linoian exca- vation. This valley is about one-half mile in width and 80 to 50 feet in depth, and holds this size nearly up to the head, which is found in the marginal ridge of Illinoian drift. It seems probable that prior to the Ili- noian invasion its drainage basin was much more extensive than at present. This affords an illustration of a partially reestablished stream. This valley and that of the lower course of Skunk River ‘are exceptional, for as a rule the pre-Ilinoian tributaries of the Mississippi were so completely filled at the Illinoian invasion that the post-Illinoian drainage was opened along new lines. It is probable that the portion of the Mississippi between Mus- catine and Fort Madison, Iowa, is reestablished along a pre-Illinoian and also pre-Glacial line. ORGANIC REMAINS. As yet no specific identifications of the wood and smaller plants found at the Yarmouth horizon have been made, unless some of those reported by McGee from northeastern Iowa have this horizon. The wood appears on a superficial examination to be coniferous and largely red cedar. It is planned to have careful examinations made in the near future to ascertain the bearing the plants may have on the climate at the Yarmouth intergla- cial stage. It should be considered, however, that the plants found in the peat were presumably living just before the culmination of the Ilinoian imvasion, and may not afford a true index of the interglacial stage; for a general lowering of temperature probably preceded as well as accompanied the culmination of the ice sheet. Possibly a deposit will yet be found in which plant remains occur which were buried in the middle part of the interglacial period. The specimens of wood noted in the clay beneath the bed of peat at Yarmouth may have been buried at a sufficiently early date to be unaffected by the Ilinoian glaciation. Unfortunately no specimens of that wood are now available. 124 THE ILLINOIS GLACIAL LOBE. The animal remains (rabbit and skunk, .see p. 42) found in the peat at Yarmouth show a remarkable state of preservation, the marrow of the bones being still preserved, as noted in the examination by Dr. F. W. True. This is perhaps no more remarkable than the state of preservation of some speci- mens of the wood from the same horizon. Several of the wood specimens have been found to take fire as readily as the wood from our living forests. In not a few cases within the writer’s notice leaves of grasses or sedges have been found in a fair state of preservation. Instances of the occur- rence of leaves of oak or other deciduous trees have been reported to the writer from the Yarmouth horizon, but none have come under his personal observation. The character of the life of this interglacial stage is a field promising much of interest, but which as yet is scarcely at all developed. (dab Seles (Pa) 1s WIE THE SANGAMON SOIL AND WEATHERED ZONE. Between the disappearance of the Illimoian ice sheet and the deposi- tion of the Iowan till and loess there occurred an interval of deglaciation about as marked as that between the Kansan and Illinoian stages of ola- ciation, a period marked by leaching and oxidation of the Ilinoian drift, of peat and soil accumulation, and of erosion. This interval was long since brought to notice by Prof. A. H. Worthen in his report on Sangamon County, Illinois. For this reason, and because of the conspicuous development in the Sangamon drainage basin, it seems appropriate to name it the Sangamon interglacial stage. This name was suggested by the writer in a paper pre- sented before the Lowa Academy of Sciences in December, 1897. The following section, published by Worthen, was furnished him by a well digger, Joseph Mitchell, who had dug many wells in the northwest part of Sangamon County and in the adjoining portion of Menard County:° Generalized section of wells northwest of Springfield, Illinois. Feet SOs coSsd seobee bodabaded dean bsan Sates Goosde DAOENS GES EbdOneo Ha CORE EEEO pens KUED RMORe ET Seema 1-2 UG ON, Gy ssuceh 656 bakes Sa5SS soadn bosoecdsoce bees Booed GacH SoS badd SSeS ROR Aos Uuaaee Bed aeaeeses 3 Wihitishy(orayat)pomtediclay, swithtshelllstaessaseecnleeetecee ee esee eee ciseeicies-eieeceace een D- SO Blacksmuckawatheira coments) Ofmw OO deerse renee eat emae eae a sce ee mim ase e-eiacietoncle ial 3- 8 IBhawisy GolaneG! WOME Oley Gasca 4585 co65e0 g600 GubSduise gene Sedo SooupEes bedeledo Edseos.sc6e Gssene 8-10 (Ghiny nena} oan (\7oay NEEL) Coc oteades tess aode coup neoose cosoeo see Ese nadond cuBsee Eye etaieds Net carats 2 SOs Mines Gleay, WALTON IMAGENS ca65 ssoqcecobess ode5 o654 cnos casa cede besu Sone HHOD BAS aea econo see 20-40 This section represents the formations beneath the upland plain near the western edge of the Sangamon watershed at an altitude 200 feet or more above the level of the mouth of the Sangamon. Worthen remarks ' Geol. of Illinois, Vol. V, 1873, yp. 306-319. 2Op. cit., p. 307. 125 126 THE ILLINOIS GLACIAL LOBE. that the fossiliferous clay of the section is undoubtedly loess. He calls attention also to the prevalence of conditions suitable for the growth of an arboreal vegetation prior to the deposition of the loess. In the section just given, the black soil appears to be the representative of the Sangamon interglacial stage. But this interglacial stage, like the Yarmouth stage, is often represented by a leached and slightly reddened till surface, unaccompanied by black muck. These two phases seem to be mutually exclusive, there being but slight reddening of the till surface where the black muck is present, or but slight accumulations of black muck where the reddening of the till is pronounced. The black muck is developed in portions of the uplands where the surface is very level and conditions for drainage are defective, while the reddened soil is developed on the more undulatory tracts, where a fair condition of drainage probably existed. The black muck phase is common in the Sangamon Basin, and also in the northern part of the white clay district of southern Ilinois, and southwestern Indiana just outside the limits of the Shelbyville drift sheet. In western Illinois and southeastern Iowa it has a more restricted develop- ment, for the surface there is generally more elevated and better situated for the development of drainage lines than in the districts first mentioned. In southern Illinois and southwestern Indiana and throughout much of western and northwestern Illinois, the reddened till surface is a conspicuous feature. In certain areas an alternation of sand with peaty beds has been found between the Iowan loess and the Ilinoian till. This phase is apparently restricted to the borders of valleys where stream action has probably been influential but with intermittent activity, the sand being deposited by the streams, while the peat was accumulated at times when the streams failed to cover the land. The accompanying views, Pl. X, 4 and B, taken in cuttings along the Santa Fe Railway in eastern Knox County, Illinois, show a dark soil (b) at the junction of the loess (a) and Illinoian till (¢). In the exposures seen in these views, acid tests show the till to have been leached to a depth of about 4 feet below the dark-colored soil. The overlying loess is calcareous at base. The leaching, therefore, took place prior to the loess deposition in connection with the development of the soil. The depth of leaching noted U. S, GEOLOGICAL SURVEY MONOGRAPH XXXVIII|_ PL. X A. NEAR VIEW OF SANGAMON SOIL IN KNOX COUNTY, ILLINOIS. (a) Loess, partly eroded, 4 feet; (/)) Sangamon soil, 1 foot; (c) Illinoian drift, 4 feet. LB. MORE DISTANT VIEW OF SANGAMON SOIL IN KNOX COUNTY, ILLINOIS. (a) Loess, 12 feet; (b) Sangamon soil, 2 feet; (c) IIlinoian drift, 40 feet. THE SANGAMON SOIL AND WEATHERED ZONE. 127 in this railway cutting represents about the average depth found in the interior portions of the district covered by the Ilinoian drift. Along the borders of the drift, as previously noted, the Illinoian till is, in places, noncaleare- ous throughout its entire depth, and seems to be made up largely of the leached portion of the Kansan drift which it had overridden. Some care must be exercised, therefore, in deciding upon the amount of leaching which has taken place since the Ilinoian ice sheet disappeared. In northern Cumberland County, Illinois, a short distance north of Greenup, Professor Chamberlin and the writer examined exposures of the Sangamon soil in which branching root-like extensions of the soil penetrate several inches into the underlying subsoil. These are thought to mark the former presence of forests on that soil. In a few places peat beds of considerable depth have been found at this soil horizon. Some of the best instances occur a short distance west of the region in which the section reported by Worthen is found. The coal shaft at Ashland, Illinois, near the line of Sangamon and Cass counties, shows the following series of drift beds: Section of the drift beds in a coal shaft at Ashland, Illinois. Feet. IMGs ONES oo Aclnan sas coSeae cases Gods HaScb py MGE OPE SUR bd eH beSenia Hea Nao ucud seedon CEC oEomeRaaS 1+ UGE OH sO? COKOR SSG she boon soos eos ous cats Sen esonaEneodeSs sodO su shad cddbds Banoo sone eaenSe Nae 9 HE OESSFOLDITEYCO] OTA ee venalste eee ete reece pale Seth Ce si ya elena pat Ag Prep eD RAD eS 2 Peatrandublackssandysslus epee srniscs t-te vaens et py ae erie eas See see ete RS Bee ee eens SDD IDlor A awh; CEA Ssood oSéd nes vp odbads sodGbe secp Sous eneneeuedE Sadties DooGicaae todaop GUeOnBISSosIaebe 20 Wallon; Wl) sdacebe saonoouseclcudd coun Suns bebe nd opbpmaoeS EU sod bapaGancrnecd CaceanutEHasecueBeaueeae 30 JROUEY| Git s Soho seopsurnhoEssassd sene SeboubgE NaHS choose con bos soadbdoaeooesgecosed H CEN aasEe 85 At the air shaft sand was found beneath the peat in the place of the blue gummy clay. At Virginia, Illinois, a well made by Mr. Oldridge entered a bed of peat at the base of the loess at about 15 feet and continued in it to a depth of 28 feet, beneath which a blue clay was entered. An instance of the occurrence of animal remains in the basal portion of the loess, immediately above a deposit of peat, probably Sangamon, was long since brought to notice by Mr. Pratt, of Davenport! In a railway cutting made by the Chicago, Rock Island and Pacifie Company, in the ‘Proc. Davenport Acad. Sci., 1876, p. 96, Pl. XXXII. See also Geol. of Iowa, by C. A. White, Vol. I, 1870, p. 119. 128 THE ILLINOIS GLACIAL LOBE. west part of Davenport, Iowa, the following beds are exposed, as reported by Mr. Pratt, who examined the exposure while the excavation was fresh: Section in railway cutting near Davenport, Towa. 1, Ordinary prairie soil, altitude 167 feet above Mississippi River .----.------------------------ 1 . Loess, iron stained and distinctly laminated with lamine curved and in places interbedded with thin layers of sand; the deposit also contains small calcareous nodules and shells of the genera Succinea, Helicina, and Pupa.--...-.----------------+++---- -+++-----+---------- 20 3. Bluish-gray clay, containing a few shells like those of No.2; a tusk, several teeth, and other portions of Blephas primigenius (?) were found just at the junction between Nos. 2 and 3... 3-5 4. Bed of brown peat in which the peat moss, Hyprum aduncum, was sufficiently well preserved to be identified; quantities of much decomposed coniferous wood were also distributed through this bed .....-----.-----. ----++ ---- +--+ 22+ ++ - 2+ eee eee een ee een eee eee eee eee 1 5. Dark-brown soil, resembling the peat, but more decomposed. .-..-...----..----.-------------- 2 6. Blue clay, very tenacious, containing sand, gravel, and small bowlders, many of them distinctly glacier scratched, extending beneath base of cutting. bo The peat bed, with its associated soil and silts, is reported to have been exposed for a distance of 30 or 40 rods. Concerning it Dr. C. A. White remarks:” ‘This deposit is quite remarkable in many respects; in none more so perhaps than in the fact that the bed of peat rests upon a bed of clayey silt and is in turn covered by a similar but much deeper one, these varying conditions evidently having been produced by the shiftings of the adjacent and then sluggish river in that very early period of its postglacial history.” The Sangamon soil has been exposed by some of the streams within the limits of the Wisconsin drift, notably on the Embarras and Kaskaskia rivers and tributaries of the Illinois. It is found below loess or white clay, which in turn lies beneath the till of the Wisconsin drift. Two excellent exposures on Farm Creek, east of Peoria, Illinois, are shown in Pl. XI, figs. d and B. In the first (A) the soil is not shown, but there is a deeply leached and weathered zone at the top of the Illinoian. In the second (B) there is a bed of peat resting upon silt which bears some resemblance to the overlying Iowan loess in texture, but is not so calcareous and is of a deeper brown color. Whether it is similar in origin to the loess can scarcely be decided. The writer also is inclined to question whether the silt below peat in the Davenport section just described should be referred to the Iowan loess. Beneath the silt which underlies the peat shown in fig. B there is Illinoian till, and this is leached to a depth of 3 to 4 feet. This section 2 Op. cit., p. 120, U. S. GEOLOGICAL SURVEY MONOGRAPH XXXVIII A. EXPOSURE ON FARM CREEK, 7 MILES EAST OF PEORIA, ILLINOIS. (a) Bloomington gravel terrace, 8 feet; (b) Shelbyville till sheet, 14 feet; (c) lowan loess, 10 feet; (d) Illinoian till, 30 feet. (View taken by Dr, Samuel Calvin, May, 1898.) B. EXPOSURE IN A RAILWAY CUTTING ON THE TOLEDO, PEORIA AND WESTERN RAILWAY, 7 MILES EAST OF PEORIA, ILLINOIS. (a) Bloomington gravel and cobble on slope, 6 feet; (b) Shelbyville tilksheet, 8 feet; (c) lowan loess, 6 feet; (d) Sargamon peat bed, 3 to 5 feet; (e) Silt below peat, 2 to 5 feet. Below the silt there is Illinoian till leached and weathered at top, 4 fect, beneatn which it is calcareous. (View taken by Dr. Samuel Calvin, May, 1898.) THE SANGAMON SOIL AND WEATHERED ZONE. 129 seems to indicate that for a time after the Hlinoian sheet was exposed to atmospheric action the drainage conditions were good, but that subse- quently they became imperfect and the peat was formed. The possible relationship between the lower silt and the gumbo of the Mississippi Basin is discussed in connection with the latter deposit (p. 32). The wood found in association with the Sangamon soil and peat, like that of the Yarmouth, appears to be largely coniferous. Wherever identi- fications have been attempted such woods have been found to oceur, and specimens not critically examined have the aspect of the coniferous rather than the deciduous varieties of wood. The aspect of the flora is decidedly boreal. However, as noted in connection with the discussion of the vege- tation found in the Yarmouth soil, it is necessary to guard against the inference that the vegetal remains preserved in the peat and mucky portions of the soil furnish an index of the climatic conditions throughout the entire interglacial stage. They pertain only to the close of that stage when gla- cial conditions were being inaugurated, and may have an aspect very dif- ferent from that of plants which grew in the midst of an interglacial stage. Slight exposures of the Sangamon soil and weathered zone are to be seen on nearly every hillside within the limits of the Ilinoian drift where erosion has opened a fresh exposure low enough to reach the base of the loess. A few exposures have been found within the limits of the Iowan till, but such exposures are far less common than beneath the Iowan loess. Several excellent exposures of the Sangamon soil have been made by railway companies at points where the overlying loess has been stripped off to obtain a filling for the railway track. For example, along the Van- dalia Railway, a few miles west of Marshall, in Clark County, Illinois, an area of more than an acre has been stripped of the loess, leaving the black mucky Sangamon soil at the base. A similar exposure, though less exten- sive, is found at West Point, Iowa. The presence of the black muck here seems somewhat remarkable, inasmuch as it occupies the crest of the marginal ridge of the Illinoian drift. The upper 6 or 8 inches is a deep- black color, beneath which there is a deposit of gray gumbo 2 or 3 feet in thickness, capping the Tlinoian till. Extensive exposures of black muck below the loess have been made by the Chicago, Burlington and Northern Railway at the crossing of Johnson Creek, about 4 miles south of Mount MON XXX VIII——9 130 THE ILLINOIS GLACIAL LOBE. Carroll, Hlinois. At this place the loess has a thickness of nearly 20 feet. The till beneath this buried soil has been leached as far down as exposures extend, 3 to 4 feet. Still another extensive exposure of the soil is found in the pit of the Brick and Tile Works at Galva, Illinois. The loess, to a depth of 15 feet, is used in the manufacture of the brick and tile, beneath which is a black mucky soil about 1 foot in depth, which caps the Hlinoian till sheet. In this soil a log about 1 foot in diameter and several feet in length was found embedded. The conditions for erosion during the Sangamon interglacial stage seem to have been decidedly less favorable than in the Yarmouth stage. The streams apparently were so broad and sluggish as to cut only shallow val- leys, and these are seldom sharply outlined. The general absence of well-defined valleys beneath the Iowan loess on the area occupied by the Illinoian drift sheet, when taken in connection with their conspicuousness in the Kansan drift, is liable to give the impression that only a brief inter- val separates the Illinoian from the Iowan glacial stage. But if interpreta- tions are made from the leaching, and depth of peat and muck accumulation during the Sangamon interglacial stage, there are found indications of a period which compares favorably in length with the Yarmouth interglacial stage. The depth and degree of oxidation of the Illinoian, when compared with the Iowan, are also impressive evidence in favor of a wide separation in the dates of deposition of the two deposits. The amount of erosion, therefore, appears to be a poor index of the length of the interglacial period, though if low altitude and slack drainage be assumed it easily harmonizes with the evidence of a long interval denoted by the other features of the drift. In discussing this matter with the several glacialists who are familiar with the deposits representative of each glacial stage the writer finds them unanimous in considering the Ilinoian drift a much older deposit than the lowan. There is some difference of opinion as to whether the Sangamon or the Yarmouth is the longer interglacial interval. The writer inclines to the opinion that the Yarmouth is the longer interval. face { Ja Vv oat is = SaTIWST “J pueg ye A[qeqoud pue-9:g;y 1eS[O9 Sassodd OAT yooy Juosoid ayy, payeeouod are SAB]PeA SB ]JOMSe SOplalp oy} 1OoJ ‘Ternqoofuoo aie UTseq JaATY UddLO, OY} SSOJOe Soul] oseuteIp yo sosanod oy deur SIy} UO UMOYS 19LN}SIp ayy Jo aed Usoyos ain ut poinosgo Ajayajdutoo st aSeureip jetor[s -od ayy, :a}0N ‘868I “LLSMYAT MNVUA AT SIONITIL NYULS AMALYON 40 HOVNIVEC WIOVTO Aud WX Id IIAXXXHAIVYHYSONOW AAAYNS 1V91901039'S'N (y i perl | Trou, 4 t Ty tiny 2 npaves favorablwe © HE I sr OI a od “Py a y hi we wa thickes Coes 2() feet. . Mig /. «esd OR Hes VXposures enties : Thin ie | | eE. Ea ; mod aevree ot oxidation af 1 1 : ; : ; i 1] ‘ > evidenee in favor osition of the twoxdeposits. The amount de eraslOR, z he mate! Ww . ; . ‘ aa »pe poor index @& Sha BPeth Or th > 1HteE relacial peridl ; ee MOISE eoaies a » 5 : ~~ 2 oa ABS - tude and sldek eet eh sumed it easily harmonizes 5 — ras Se ; i of a i Mterval abs a & by th: ar iegGires of the : Uy Bui@ise iret Cae a 2) het ecg ay this 7 rwith Stisesdal clacialists whceQre Igy tar Leos So as ; entatyee of eagh page gil stage the writer fing them vy. + 2 Be Os & : Fay: Sn ering Dlinoias SSR a much older dgperit tlgn the ; Ons 220 : Ie ee 1 at @ O1 URE As to Wh ther She Paleyamon - = th ‘3 ~~ ; } q Fh 7 H Bo ee ) if. 4 inte rege Bsery 1 Overs Bebo s to S 2a Sau = = 7 i the SDSS zit } = % = 3 Seyas52 BES | x <& § Soy anaes is gbuess ee ae Se isl .- e2e8 = 2 BO Og 2 SS Yow: Ly Vp olan, fee comorred eparatwin 7 b of a wide Ee oo 2) < wa << a ae fj Pea ei Ore om Ne oO # = CYP @ABAEA 4a n'2-ceoroel 868l + = =—— =r Tory SUTINST OL s 2TB0S “DLAYSAAT UNV A SIONTTIL NHALSAMHLYON 40 dVW TWIOVTD AN H1I1'09 B NSIS Samar i. : ree S - QM, y y Fin y Y ok TSQI MAN > JIN NING O di) i YY GE Gel 3 hs == SO Sunbosnyy STVNVO NS SeSSeUl YOOL poyzodsuevsy, 1} —— © ja0duaxeq KIS Pewryy Jeplog IJlIp wemoy eu 10 U0 sasplt Ssooy pue pueg JJlIP weLourT]] wo segpla ATToxway MO]JIOAO 0} YOolqus SoM Iddississyy pure stoutl|{ JO Suroy0q'Mo'T WLP UISUODSTM YIM poyoaUUOD SooBLlo] pus sureyd ekers pue pues ase uisuoosi Ajree Jo sured qr, ase UISUODSIM AyIV9 Jo SaUTe1OW Japiog IJlip WeMo] Uo pues pue ssaoy pospry ylap wemoy | W/, ssapyud | — eenbnang NX 1d WIAXXX Hd VHOONOW AAAYRNS 1VOIDO1039°S'N CHE ASE Rk Vain: THE IOWAN DRIFT SHEET AND ASSOCIATED DEPOSITS. THE IOWAN SHEET OF THE ILLINOIS LOBE. The sheet of drift to which the name Iowan is here applied is referred to the Iowan stage of glaciation, not because of direct connection with the Towan drift of eastern Iowa, but because of an apparent similarity with the Towan drift of eastern Iowa in its connection with the great sheet of loess in the Mississippi Basin. As shown below, the loess overlaps this drift sheet only a short distance, and was deposited apparently while the ice sheet was melting away, there being no clear evidence of an exposure of its till to protracted atmospheric action prior to the deposition of the loess. DISTRIBUTION. The Iowan sheet of the Ilinois lobe was formed by a southwestward ice movement over northern Illinois. Its western border has been traced in some detail by Mr. Oscar Hershey, through Winnebago, Ogle, Lee, and Whiteside counties. The writer had previously noted the occurrence of this drift in Winnebago, Ogle, and Lee counties, but had not attempted a precise mapping of its western border. The border is found to enter Illinois from Wisconsin at the valley of Sugar River, about 12 miles west of Beloit. It follows this valley south- ward to the Pecatonica Valley and thence, as shown in PI. XII, passes up the Pecatonica about to the line of Winnebago and Stephenson counties, where it crosses to the south side of the river and returns eastward to the city of Rockford, thus forming a narrow lobe at the Pecatonica Basin, hav- ing a protrusion of about 12 miles and a width no greater than its length. This lobe is called the Pecatonica lobe, since it occupies a low district or basin drained by the Pecatonica River. 131 132 THE ILLINOIS GLACIAL LOBE. Below Rockford the border is found to follow nearly the course of Rock River to the vicinity of Oregon. Here Hershey makes a division of the drift margin. The outer margin passes westward to Polo. The inner margin passes southward along or near Rock River to the vicinity of Dixon. It there crosses the river in a westward course and follows the north border of a lowland tract which extends a few miles back from Rock River. North of Sterling it joms the outer margin. Hershey’s tracing of the outer margin was carried no farther than Polo, but the writer has examined the district south and west from Polo, and also the portion of this margin from Polo eastward to Rock River. Eastward from Polo there is a definite border, characterized by low swells of till, among which are saucer-like depressions, giving the surface a much fresher appearance than that of the older sheet which occupies the district to the north and west. At Polo the margin appears to swing south- ward and follow the east border of the Elkhorn Creek Basin into Whiteside County. The border is not so definite here, however, as east of Polo, there being only a few till swells and occasional basins in the outer part of the drift sheet. This line connects in eastern Whiteside County, about 5 miles northeast of Sterling, with the inner margin traced by Hershey. Hershey’s chief criterion in mapping the inner border is a change in the character of the till, such as characterizes the margin farther north, that to the east of it being more sandy than that to the west and displaying a pink tint not noted to the west. The portion between the inner and outer margins has a more compact texture than the remainder of the Iowan drift sheet. The cause for this difference is not yet apparent. The margin lies north of Rock River at least as far west as Rock Island Junction. There is a small area on the north side of Rock River, west from Rock Island Junction, in which a sheet of drift with fresher aspect than the Illinoian is found. It is apparently confined to a lowland tract whose north border is followed approximately by the Chicago and Northwestern Rail- road from Round Grove to Morrison, and whose west border lies along Rock Creek from Morrison south to the valley of Rock River. To the north and west of this lowland there is a heavy deposit of loess which largely con- ceals the underlying deposits, but the lowland has only a thin coating of loess except in a few ridges resembling the paha of eastern Lowa. Such an extension of the lobe as would be necessary to carry it to Morrison seems THE IOWAN DRIFT SHEET. 133 rather questionable, especially since it calls for a movement north of west. It is, however, not so narrow a tongue as appears to have been thrust west- ward into the Pecatonica Basin, and projects but 4 or 5 miles beyond a regu- lar border in line with that in eastern Whiteside County. The difficulties seem scarcely as great as would be involved in an invasion of ice from eastern Iowa into this district at the Iowan stage of glaciation. There are, however, in northwestern Whiteside and southwestern Carroll counties features which raise the suspicion that ice from the Iowa side may have crossed into that district in the Iowan stage of glaciation and extended as far east as the meridian of Morrison. It becomes necessary, therefore, to consider the question of an extension of the Iowan ice sheet from Iowa southeastward into this tract. This question is considered later (p. 144).: It is difficult to determine the position of the border of this ice sheet south from Rock River, since there is a broad area occupying the interval between Rock and Green rivers, in which heavy deposits of sand occur. Exposures of fresh-looking till north of Spring Hill seem to be of Iowan age. South from the Green River sand deposits there is a narrow tract of low country extending eastward from Geneseo to the vicinity of Sheffield, in which there is very little sand, and also very little loess compared with the covering on the higher districts to the south, and which may prove to have been occupied by the Illinois lobe of the Iowan ice sheet during the loess deposition. Its south border is within 2 or 3 miles south of the Chi- cago, Rock Island and Pacific Railway throughout the interval between Geneseo and Sheftield, and is marked by a bluff-like rise of 40 to 60 feet to a belt of heavy loess. Immediately east of Sheffield the outer moraine of the Wisconsin drift sets in, and no drift attributable to the Iowan invasion has been recognized outside its limits in districts to the south. There appears, therefore, to be striking similarity between this lobe of Iowan age and that which occupied eastern Iowa. They each show at the north remarkable pro- trusions, extending in both cases nearly to the borders of the Driftless Area. Their margins also are strikingly different in outline from those of preceding and succeeding sheets in the same districts. The east lowan sheet has been found to extend only about to the latitude of Rock Island and Muscatine, and possibly the lobe which we are considering extended no farther south. There are, however, till deposits in eastern Illinois, as far south as Iroquois County, which are suspected to be of Iowan age, as indicated below. 134 THE ILLINOIS GLACIAL LOBE. TOPOGRAPHIC EXPRESSION. At several places along the border of this drift sheet in Winnebago, Ogle, and Whiteside counties low swells and ridges appear, but they are seldom more than 10 or 15 feet in height. These serve, however, to give definite- ness to the margin, although they are very inconspicuous features. In most cases the low swells are plainly independent of drainage erosion, there being instances in which they pass across a valley which had been formed in the earlier drift, dotting its slopes and bottoms and passing onward over the bordering uplands in utter disregard of the drainage lines. Such knolls may be seen near the mouth of Leaf River in Ogle County, and also on the borders of the Pecatonica in Winnebago County. Along portions of the border the separation of the erosion features from the drift aggregations produced by this ice invasion is somewhat difficult. Such is the case on the borders of the lowland tract north and west from Sterling, where the undu- lations are probably in part due to drainage erosion. A similar difficulty is experienced in the narrow belt of lowland east from Geneseo. There are present, however, in both these districts knolls and ridges of drift which appear to be independent of drainage erosion and referable to the inequali- ties of deposition of the ice. No paha have been found in Ilinois except in western Whiteside and northwestern Henry counties in the districts in which some uncertainty is felt concerning the occupancy by ice at this stage of glaciation. The paha are scattered over the portion of Whiteside County north of Rock River from Round Grove westward to the borders of the Mississippi, but are best developed on the lowland tract south and east from Morrison and on the till tract between Rock and Green rivers, which leads from Spring Hill south- westward to the mouth of Green River. They are straight ridges, usually a mile or less in length, but occasionally reaching 2 miles. They are often sharp crested, with a width of scarcely 50 feet at top, and present abrupt slopes. Occasionally they reach a width of 40 or 50 rods, including slopes. In height they range from 10 feet or less up to about 50 feet. The trend is quite uniformly about WNW.—-ESE. Several of them may be seen in the Clinton topographic sheet, Pl. XVIII (in pocket). The longest paha noted is found about 4 miles south of Morrison, and leads from the center of sec. 4 west-northwest to the north line of sec. 6, T. 20, R.5 E., a distance of about THE IOWAN DRIFT SHEET. 135 2 miles. It is interrupted by a narrow break in the west part of see. 4, through which a small stream passes. This paha is 30 to 45 feet in height and 40 or 50 rods wide, including slopes. It presents the unusual feature of carrying basins on its slopes. One near the line of sees. 4 and 5 contains a pond with an area of about one-half acre. Another prominent ridge, appar- ently a paha, is found at Round Grove, that village being situated near its western end. The ridge is about 14 miles long, 30 to 40 rods wide, and 20 to 40 feet high. It is separated by only a narrow sag, scarcely wider than the ridge, from an upland tract on the north which stands as high as its crest, and it may possibly be only a detached portion of that upland. It seems difficult, however, to account for a stream capable of causing its separation from the upland, and that interpretation would not be thought of if it stood like the paha last mentioned, some 8 miles from the upland. Just north of the village of Spring Hill there is a paha nearly a mile in length which rises about 20 feet above the general level of border districts and has a width of only 20 to 30 rods, including slopes. Several paha ridges appear on the low upland north of Green River in northwestern Henry County. The most prominent ones noted are a group of three nearly parallel ridges crossed by the Geneseo and Sharon wagon road 3 or 4 miles north of Geneseo, in sec. 34, T. 18, R. 3 HE. Their highest points rise 40 to 45 feet above the bordering uplands, and they are each nearly a mile in length. Shorter ridges of about the same height occur in sees. 31 and 32 of the same township and in see. 4, T. 17, R. 2 E. There are in eastern Winnebago and Boone counties till ridges elongated in an ENE—WSW. direction, apparently the direction of ice movement, which are drumlinoid in form. These ridges have been exam- ined by Mr. I. M. Buell, in connection with his study of the drumlins of eastern Wisconsin, and he considers them a phase of drumlin development, though less perfect in form than the typical drumlin. These ridges usually have a length of a mile or less and a breadth scarcely half as great as their length. The higher ones rise 40 or 50 feet above border districts, but the majority are 30 feet or less in height. With these drumlinoid ridges there are associated knolls of nearly conical form, giving the surface a semi- morainic aspect. No definite morainic belts, however, have been traced across the district occupied by this ice sheet. The knolls appear in isolated clusters surrounded by plane-surfaced tracts of greater extent. 136 THE ILLINOIS GLACIAL LOBE, In the southeastern part of Winnebago County and in the portion of Ogle County between the outer moraine of the Wisconsin series and the present valley of Rock River, and also in southwestern Boone County, gravel knolls of considerable prominence are found. These in most cases appear to be a product of the Iowan invasion, for the gravel has a freshness corresponding to that of the Iowan till. In one instance (near King’s Station, in Ogle County) a gravel knoll, opened for railway ballast, shows what appears to be a more aged gravelly deposit at the base than that constituting the body of the knoll. It had a height of 45 feet before the excavation was made, and several others in that vicinity are equally large, though the majority are 20 feet or less. A chain of sharp gravel knolls in southwestern Boone County, near Irene, trends north to south and has a length of over a mile. At the north it merges into a till ridge with gentle slope and with a smoother contour than the gravelly belt. This ridge, with the gravelly knolls, is probably a marginal deposit formed at a slight halt made by the ice. The knolls are only 20 to 30 feet high, but rise promptly from the bordering upland plain. Near Stillman Valley a few esker-like ridges of gravel are developed which trend northeast to southwest. These are closely associated with gravelly knolls, and the longest are only a mile or less in length. An esker-like ridge was also observed by Hershey near Sterling, Ilinois. The greater part of the surface of this sheet of drift, like that of the Illinoian sheet, is plane or but very gently undulating and devoid of notable topographic features. The principal ridges and knolls associated with the drift sheet are represented on Pl. XII, a reference to which will serve to show the small percentage of the area occupied by them. THICKNESS OF THE DRIFT. In eastern Winnebago and northern Boone counties, where the drum- linoid drift ridges and associated knolls abound, the drift of Iowan age is known to have considerable thickness, possibly an average of 40 feet or more. Aside from this small district, the drift referable to the Iowan invasion appears to form generally only a thin and somewhat patchy deposit. In the vicinity of the border the drift is often confined to the small knolls, 10 or 15 feet in height, the low ground among the knolls THE IOWAN DRIFT SHEET. 137 being immediately underlain by an older sheet of drift. On hillside expo- sures also, some distance within the border, it has been found that in places a thin deposit of Iowan drift occurs at the tops of hills, while the greater part of the slope exposes [linoian drift. In not a few places in the midst of the Iowan drift area only the Illmoian drift is found at the tops of the hills, though the hills were apparently covered by the Iowan ice sheet. There is apparently a smaller amount of loess associated with this ice lobe than with the Iowan of eastern Iowa. The districts immediately outside its border have only a thin coating, 5 or 10 feet, while the thickness of the loess within its borders is even smaller in amount. It would seem a liberal estimate to allow an average of 10 feet of both till and loess as the product of the Iowan invasion in Illinois. It is therefore sufficient to modify but little the features of the country which it occupies. STRUCTURE OF THE DRIFT. The drift of the Iowan invasion has generally a more sandy constitu- tion than that of the Hlinoian which underlies it. Along the wagon roads and in other situations where it has been exposed to the action of slight wash, it frequently presents the appearance of fine sand, where the Ilinoian drift would present the appearance of clay. Not infrequently the matrix appears to be nearly free from clayey material. There are other places, however, where the till has a stiff clayey matrix, but is readily distinguish- able from the Ilinoian by its fresher surface Associated as this till sheet is with the loess, the latter being apparently a derivation from the former, a sandy till is a natural product, the fine material being carried into the loess. This difference in the two tills greatly affects the character of the soils. Where the Iowan drift is present a dark soil is usually developed, while in the outlying districts of northwestern Illinois the soil is of a yellow or brown color. In places the Iowan till is covered to a depth of several feet by loess, but in the Pecatonica Basin and much of the country east of Rock River the loess amounts to scarcely more than a skim coating 1 or 2 feet in depth, a coating such as may have been deposited by wind action since the final withdrawal of the ice sheet or have accompanied the melting of the ice. The portions best protected by loess present a till scarcely at all stained or 138 THE ILLINOIS GLACIAL LOBE. leached by atmospheric action, a feature which seems to indicate that the deposition of the loess closely followed the withdrawal of the ice. Within the limits of the Pecatonica lobe there is a very sandy till liberally set with small fragments of limestone and usually leached to a depth of 2 to 4 feet. East from Rock River, m Winnebago and Boone counties, the till is, on the whole, less sandy than west of that stream. Several exposures were noted in railway cuttings between Roscoe and Caledonia in which the till becomes calcareous at a depth of but 14 to 2 feet, but there is usually leaching to a depth of 3 feet or more. Exposures of Iowan till were noted by the writer on the south and east borders of the city of Dixon. One on Second street and Dumont ave- nue shows a thin sandy capping, beneath which is fresh-looking calcareous till. Farther east the sand disappears, yet the till is found to have suffered leaching only to a depth of 3 or 4 feet and is markedly fresher than the Illinoian. In the south part of Dixon, along the Chicago and Northwestern Railway, the first cutting east of the crossing of the Illinois Central Rail- road shows a calcareous sand, apparently Iowan, resting on a leached till in which no effervescence with acid could be obtained within 5 or 6 feet of top. In exposures farther east a thin capping of loess rests directly on the Illinoian till. There appears, therefore, to be only a patchy deposit of Iowan drift in the vicinity of this city. Hershey has noted several expo- sures of the Iowan between Dixon and Sterling, and west from there to Rock Island Junction. The common phase is a very sandy till, in places becoming clear sand. Inrailway cuttings east from Polo low knolls belonging to the Iowan drift have been well exposed. They are capped by about 4 feet of loess- like silt, beneath which the till is found to be calcareous from top to bottom. It is more clayey than in exposures near Dixon and Sterling. In this locality the Iowan drift appears to be restricted mainly to the knolls, for exposures of the Ulinoian drift appear in ditches made by the railway in crossing the low tracts among the knolls. . At the village of Stratford, 5 miles east of Polo, the railway exposes a bed of fossiliferous silt at the base of the Iowan drift, resting on an old land surface formed on the Illinoian. The fossils appear to be entirely of one species (Succinea avara). In two other localities fossiliferous silts have been found at the base of the Iowan, one being in the railway cuttings on the Ilimois Central immediately west of Irene, in southwestern Boone County, and another in the railway THE IOWAN DRIFT SHEET. 139 cuttings on the Chicago and Northwestern, 1 mile east of Belvidere. Here, as at Stratford, the fossils are mainly of one species (Succinea avara). The pebbles and smaller rock constituents of the till appear to be largely limestone whose native ledges are distant but a few miles to the east and north. In this respect it conforms to the structure of the underlying Illinoian sheet, and it seems not improbable that it has obtained much of the material from the Ilinoian. There is not found between the Iowan and Illinoian till sheets of the Illinois lobe such a striking contrast in rock constituents as is reported by McGee and by Calvin to be found in the Towan and Kansan of northeastern lowa. The lowanis reported by Calvin to carry scarcely any pebbles or large rock fragments of local derivation, while the underlying Kansan is thickly set with them. g The paha ridges of western Whiteside and northeastern Henry coun- ties usually contain a peculiar phase of loess. The basal portion is a fine sand, rather than loess, in which many of the individual grains may be seen by the naked eye, though with some difficulty. The great majority of grains of ordinary loess are much too fine to be seen with the naked eye. From Round Grove the fine sand at the base of the paha ridge has been shipped to Chicago foundries for use as a molding sand. In some cases the upper portion of the paha assumes a sandy consti- tution. As a rule, however, it consists of a loess similar to the bluff loess of the main waterways, and its banks will stand in vertical walls for years. Like the bluff loess, it is fossiliferous, but as yet, so far as the writer is aware, no determination of the species of fossils represented has been made. Before leaving this subject a few sections are presented from the debatable district in central and southern Whiteside County, which serve to show the freshness of the till and the occurrence of more than one drift sheet. A well made for Mrs. Seeley on the slope of the Round Grove Ridge, at a level about 10 feet from the base, is reported by the driller to have penetrated the following beds: Section of well of Mrs. Seeley at Round Grove, Illinois. Feet Denny Goul aval QUO SoG b668 Soa0l6bon base Hacbee cone boDO nobeca oEBE peObES CoSDsueaaS DOSE beHuEae Iie elllon? GAMNGls cursso cseqHssooeNs cooonS coos dese Kea cate Gee Seo tdobos HaeooS Cone easce SeOSSORSeeErS 5 Nellowgelayenoypebbicspnoue deere er eeee ye eee eh hee eimeicciom soc sisaretincine Seeeroeneiscioercs 5 Sottbluempebblyaclaya(pronabliyslow ancl) sere seem ielaee mi eae isle pees eae me efecto oe 8 Black dirt with wood embedded (probably Sangamon)...-.-.--.--...--.---.----.----------------- 2 Dill’mainl yore blue-cray,color (probably Vi) imolam))) == -eccjer oaeiscie a= aeelo eine ew l= ol = = winless onl 2 = = 17 Limestone. 140 THE ILLINOIS GLACIAL LOBE. The reference of the soft blue clay of this section to the Iowan is apparently supported by an exposure a short distance west of Round Grove, where the excavations at the side of the railway show a soft till which, though yellow at top, assumes a blue color within 3 or 4 feet of the surface. It has an appearance as fresh as any exposure of Iowan till noted im districts to the east. The exposure is not sufficiently deep, however, to show the depth of this till or to enable one to determine whether an older sheet underlies it. Directly east of Round Grove about 14 miles, the loess is found to rest upon a till having leached and reddened surface, evidently as old as the Illinoian. These features indicate either that the Iowan ice failed to cover the district immediately east of Round Grove or that it did not form a continuous sheet of till. The first interpretation seemed to the writer at one time the more probable, but further reflection and considera- tion of the fact that this drift sheet is somewhat patchy m the districts to the northeast has led to a more favorable view of the second interpretation. If the fresh-looking drift found west of Round Grove is of Iowan age, the district to the east of that village was probably covered by that ice lobe. West and south of Morrison, on the borders of Rock Creek and east- ward from its valley, sandy till of fresher appearance than the Hlinoian was noted at several points. In some cases it is found to be calcareous within 3 feet of the surface. At the point where the wagon road ascends from Rock River Valley toward Spring Hill an exposure was found in which the loess rests directly upon an unleached surface. It seems scarcely probable that there had been erosion of the till prior to the loess deposition, for the till surface there rises to its usual elevation in that locality. In the cases above noted also no evidence was found of any removal of the surface por- tion of the till. Exposures of till are rare in this region, partly because of the shallow depth of valleys and partly because of concealment by loess. The few above noted comprise all that were observed by the writer in central and southern Whiteside County. STRIZ. A few exposures of striae have been found in Winnebago and Ogle counties which fall within the limits of the lowan drift sheet, but which are not referred positively to that ice invasion, since they may be referable to IOWAN DRIFT SHEET AND ASSOCIATED DEPOSITS. 141 the Illinoian. These have all been observed by Buell, who has kindly furnished a list of the localities and bearings for publication. They appear in the list on page 88. PROBABLE EXTENT OF IOWAN DRIFT SHEET BENEATH THE WISCONSIN. The extent of the Iowan drift beneath the Wisconsin can be deter- mined only approximately, and chiefly by inferential reasoning. An infer- ential determination may be based upon the occurrence of a series of drift sheets sufficiently full to include the Iowan. For example, if there is but one older sheet of drift near the southern or western border of the Wiscon- sin, and if upon passing back beneath the Wisconsin two distinct sheets of older drift are found, it may be inferred that the additional sheet is either the Iowan or is a sheet still older than the Hlinoian. A series of well sections have made it evident that there are three well-defined drift sheets in the northern portion of eastern Illinois, two of which are older than the Wis- consin. It may be difficult to determine whether the additional sheet is of Iowan or pre-Illinoian age, since the data are based almost entirely upon well sections, and the material thus obtained is scarcely adequate for a satisfactory determination. The complicated series extends as far south as southern Iroquois County, and may possibly extend into Vermilion and Champaign counties, though the sections obtained in those counties do not furnish such decisive evidence of the triple series as is found in Iroquois County. The Wisconsin drift may usually be readily separated from the older sheets which underlie it. Its uniform blue color and the ease with which it may be penetrated by auger or spade enables the well drillers to distinguish it readily from the underlying deposits, which are of brown or gray color and more difficult to penetrate. There is also in many places a black soil at the junction of this sheet with the underlying drift which furnishes addi- tional evidence of the passage from the Wisconsin to an older drift. The well records obtained in the flowing well district of southern Iroquois County have brought to light the occurrence of a second soil at a horizon 25 to 50 feet or more lower than the base of the Wisconsin drift. There is often considerable peat at this lower soil horizon, and with it a large amount of water-bearing sand from which the flowing wells are obtained. 142 THE ILLINOIS GLACIAL LOBE. The peat in one instance is found to have a thickness of 30 feet Gn a well on Dr. Ludden’s farm, 5 miles south of Clayton), and not infrequently has a thickness of 5 or 10 feet. Few wells have been sunk below this lower soil horizon, but these indicate that the drift may extend in places to a con- siderable depth. In several cases, however, the bottom of the drift was reached within 20 or 30 feet below the lower soil. Both sheets of drift beneath the Wisconsin are described to be of a brown or brownish-gray color, and the writer was unable to learn of any distinguishing character- istics. They are each described to be harder to penetrate than the overly- ing Wisconsin drift. In its: surface exposures the Iowan is usually more easily penetrated by a spade or auger than the Ilinoian, and this fact may seem to favor the view that the two sheets beneath the Wisconsin in Iro- quois County are Ilinoian and pre-Ilinoian rather than Iowan and Ilinoian. However, the information is so meager and the character of the observa- tions so imperfect that it can scarcely be decided from these records whether the middle sheet is Iowan or Illinoian. The following data con- cerning the three sheets in Iroquois County will serve to set forth their relative thickness: Clayton and vicinity. Feet. Upper or Wisconsin drift sheet....--....-.-.------ Se edse SoSOSeSOCSSD SSSR OSENSS oo 000805 60 or 70 MGS GA AEC S36 Sone ooo seeecoe seo sossbo ca05 Hose aos occo ees see e SaUSadUSoN sed osesee 30 or 35 LOW? CLOT SINCR cosh56 s590cs s5SRS0 SISSSe Seeods Sos ossss eck eS SsEeescSos o5e8 sang ochs2n55 45-+- Ash Grove timber belt. Feet. KU PETROL AVVAS CONS UCT TL tere ce ere eee ee eee 55 or 60 NMG GhmM i INEE cccdooascs co5 566 daoeas HSSoma somone sodoc0 s5b0 dons coNSES Dodo dasSSanSSsea55s 30 or 40 ILO Ter Ghai GINGA s So 556 so25 Goh S505 55525 sdsaot sossck Seance cosoeS Sabcro Soop bose Scosso secs 50+ Crescent City and vicinity Feet. WipperiormWwascOnsINCGrittiS Mee bert tle a mee tee ene eel a eel eee yea ee 60 Middle drift sheet..--...----..---- Possess uo osedoscouses Sescas HoShdonsoscoe EE seceSe sons 15 or 20 Lower drift sheet .,....-----..----..-.- oodecious otioSaa dolce HS55 boon SoSdcood Sosdlscgses ses= 70+ Onarga and vicinity. : Feet. Oso Ox Waecontsin Chobiy SG Sok 64 conse toss Hone geno casos coos oauo tors Dato cons sseices 50 or 60 Mid@lerdniftishee ter aatesnelpecte aie icve sete iata aie ee oleae epee alae alata eee 30 or more TGOKIED CHM INGEN sasads caoa dsbeod done oseo Coa een Gods sess esbors DsebE Sand cosasan csecibone 1754 Gilman and vicinity. Feet. Up pemoreWisconsinvdritgshe@tesses sme eee sees ene ase eme a aaiaee sie enisemeceneetaieeera a 75 Middle and lower drift sheets .............----.---------- aD OCoo DoccoO pout boSdEacadSSeEs c0so6 120+ IOWAN DRIFT SHEET AND ASSOCIATED DEPOSITS. 143 Milford and vicinity. Feet. Uppernorawasconsingdriftis lee tie emcee see tee me ciae tepenieis se ceteteeieteel ee ie ere sis orice ee nner 50-4 Mid dlerdriftisheetiesamemacerc css sinc ere ae ish sisiat ra evseis et cereteiacins f tales cyeylecpentstaia(aicie eaves ote 40 or 50 onveraritt sheet pees ree merse ter is eeat a aie weet te lene a eeigainieie e Sleinleaie sjsictsjetaibiewecis wikacie 25 Donovan and vicinity. Feet (Up periorawAsconsinednintishee tie m-meecmene eter crac ne eee a eecieeie ect an miosieccisesstes ac 100 WUTC NKG GhstaP ANGE 8b SoneSaon sHeSiooudss Keds OODA.< Sabon Bode Hone ConauSH a Reda nHay oseacBooeeSeosoE 40 ILONIG! Chaba SINCE cone coco loade boonoe oss caod Goon cHnD apes node ceco Ddos Sbby asco.nocO osoN ASSO mCaaES 30 In counties farther north a series is found similar to that displayed in Iroquois County. It is best shown in localities where the drift is very thick, as is the case in much of Kane, Dekalb, and McHenry counties. As these counties are adjacent to the exposed portion of the Iowan drift sheet and equally far to the north, there is scarcely a doubt that the middle sheet should be referred to the Iowan. Numerous sections of wells in these counties are presented in the portion of this report dealing with the wells of Illinois (Chapter XIV), together with a discussion of the probable age of the sheets, where more than one was penetrated. From these it may be seen that the Middle or Iowan drift, as in the exposed portion, is much thinner than the Wisconsin and has a depth about the same as the middle sheet in Iroquois County. These points of resemblance, although not demonstrative of contemporaneity, at least suggest the possibility that the Towan drift extends into Iroquois County. A loess-like silt, as shown below, covers the Ilinoian drift of southern Illinois outside the limits of the Wisconsin and is traceable northward several miles beneath the Wisconsin. This appears to be a deposit of Iowan age like the loess of western Illinois, and, like the loess, it may be derived from the ice sheet. Its presence in southeastern [linois and also in districts farther east, for it is found as far east as central Ohio, is thought to bring strong support to the view that the ice sheet, at the Iowan stage, did not fall short many miles of reaching the line occupied at a later date by the Wisconsin ice invasion. This silty outwash is of sufficient volume to mantle the region, as far south as the Ohio River, with a deposit having an average depth of probably 5 feet. The volume of this deposit would seem to indicate that the southern limits of the ice sheet from which it was derived were at least within 100 miles, and possibly much nearer, the south- ern limits of the Wisconsin drift sheet, not only in Illinois, but in Indiana and Ohio. ! 144 THE ILLINOIS GLACIAL LOBE. PROBABLE EXTENT OF THE IOWA PORTION OF TOWAN DRIFT. i Inasmuch as there is some evidence suggesting a slight extension of ice from Towa into northwestern Illinois at the Iowan stage, the question of the extent of that ice sheet is here considered. The “upper till” of northeastern Iowa now classed largely as Iowan drift is represented by McGee to have its eastern border near the western edge of the Driftless Area from the Minnesota-Iowa State line southeastward to the southern point of the Driftless Area near Sabula, lowa.’ Generally it falls short a few miles of reaching the Driftless Area, but in southern Jackson and in Clinton County, Lowa, it is represented to extend beyond the earlier sheet and to constitute the border of the Driftless Area. It is represented to extend to the Mississippi Valley from northern Clinton County southward to Scott County, and to fall short but a few miles of reaching that valley in Scott and Muscatine counties. A tectonic map” represents the ice sheet to have extended across the Mississippi and rested on the east bluff for < few miles below Clinton. From Muscatine County westward the limits are not definitely given. The upper till, however, is represented to. extend to the limits of the district reported upon. The investigations carried on by the Iowa survey have supported the mapping and results of McGee in a general way, but not in all details. Very little disagreement as to the boundary is found from the Minnesota- Iowa State line southward to Delaware County, Iowa. But from that county southward to eastern Jones County Professor Calvin, of the Lowa survey, places the limit of Iowan drift a few miles inside McGee's limit. There are certain extramarginal phenomena recognized in the disputed ter- ritory which he considers closely related to the Iowan invasion, but not requiring the presence of Iowan ice, chief among which are heavy accumu- lations of loess and a tendency to ridging of the loess in lines trending from WNW. to ESE., as in the undoubted Iowan area. From northern Jones County eastward to the Mississippi the border has not yet been investigated by the lowa survey, but the writer made some examinations in this district in 1894 while engaged in tracing the west border of the TIllinoian drift. The examinations were begun in Clinton County and carried westward. On the uplands northwest of Clinton a belt ‘Eleventh Ann. Rept., U.S. Geol. Survey, Pl. XLIV. 2 Op. cit., Pl. LVI. EXTENT OF IOWA PORTION OF IOWAN DRIFT. 145 of thick drift was discovered along which rock is seldom encountered at less than 80 feet, and in places the drift reaches a thickness of 200 feet or more. This thick belt of drift has a breadth of 3 or 4 miles and at first was conjectured to be the marginal ridge of the Illinoian drift, though it is somewhat broader than the general width of that ridge in southeastern Iowa. It carries a thick capping of loess 20 to 30 feet or more) which greatly obscures the glacial deposits. A few exposures were found, however, which showed a surface reddening and leaching of the till such as is displayed in the Hlinoian or Kansan sheets of drift. Such reddening has not been found in loess-covered portions of the Lowan drift in northwestern Illinois, nor, so far as the writer is aware, has it been noted in the Iowan drift of north- eastern Iowa. These observations were made in the district where only the upper till is represented on MecGee’s map. The writer, therefore, inferred that the upper till here should be considered Illinoian and proceeded west» ward, expecting to find the belt of thick drift swing southward to connect with the margin of the Illnoian already traced to western Scott County. It was found that the “Goose Lake Channel,” described by MeGee as an old course of the Mississippi, cuts through this belt immediately south of the village of Goose Lake (see Pl. XVIII). From the west side of this broad valley the belt continues nearly due west across northern Washington and Welton townships, occupying its usual width of 3 or 4 miles and constituting the divide between the Maquoketa and Wapsipinicon rivers. It there takes a course north of west, passing between Elwood and Lost Nation and still constituting the water parting between the two drainage systems. Slight incursions into the district north of this belt showed only thin deposits of drift resting on or mingled with residuary clays. The thick drift was traced to the vicinity of Onslow in Jones County, and there the examination was dis- continued, for it had become evident that this belt of drift could not connect with the Illinoian margin in Scott County. In returning eastward it was found that the thick drift, with its heavy coating of loess, lies along the north edge of a plain of [owan till, strewn with the immense bowlders characteristic of that deposit and presenting only thin or patchy develop- ments of the loess. At Dewitt Prof. J. A. Udden joined the writer for a couple of days’ study, and a trip was made together from Dewitt to Sabula. The large MON XXXVIII——10 146 THE ILLINOIS GLACIAL LOBE. Jowan bowlders were found east as well as west of Goose Lake Channel, as far north as the south edge of the belt of thick drift, but were not observed farther north. The first night was spent at Bryant, near the north edge of the belt of thick drift, and in the vicinity of this village a few exposures of the drift were found at the base of the loess, all of which showed a leached and reddened surface. Continuing northward from Bryant to Miles the loess was found to remain nearly as heavy as on the belt of thick drift, but the glacial deposits were very much thinner and seemed to be restricted to small bowlders and pebbles of crystalline pre- Cambrian rocks. These were usually found embedded in a slightly dis- turbed residuary clay of a deep reddish-brown color which can scarcely be called till, the commingling of pebbles with residuary material being so imperfect. Between Miles and Sterling the surface is ridged in a peculiar manner, though somewhat similar to the paha of the neighboring county on the west (Jones County) in trend and form, the trend bemg WNW. to ESE. and the form somewhat similar to an inverted canoe. The wells made on these ridges were reported to have penetrated “clay and quicksand,” and in some cases have reached a depth of 40 feet without entering solid rock. As no exposures were found, the precise nature of the deposits remain unde- termined. A few granitic and greenstone pebbles were found in ravines between Sterling and Sabula, showing that the glacial deposits occur a few miles outside the limit mapped by McGee. Reviewing the above observations, it appears that nothing to suggest the occurrence of Iowan drift was found along or north of the belt of thickened drift except the paha-like ridges near Miles, and there the resemblance is not known to carry with it the interpretation that they are of similar origin or date to the paha of the clearly recognized Iowan drift. At best the paha are still an enigma from which as yet nothing can be proved. In view of the very thin and somewhat patchy development of the Iowan drift near the terminus of the lobe in Ogle and Lee counties, Illinois, some hesitancy is felt in declaring the Iowan drift to be absent from northern Clinton and southern Jackson counties, Iowa. For in the latter counties the heavy deposits of loess greatly interfere with the determination of its extent. The occurrence of a sheet of drift markedly older than the Jowan in the district mapped by McGee as occupied only by wpper till is abundantly evident. The thickened belt of this older drift merits further EXTENT OF IOWA PORTION OF IOWAN DRIFT. 147 investigation, especially since in some of its features it suggests a terminal moraine. During the past season (1897) the’ writer, together with Mr. Oscar Hershey, made further observations in eastern Clinton County, Iowa, as well as in Henry, Whiteside, and Carroll counties, Illinois. At Clinton the glacial deposits on the bluff of the Mississippi are found to be very thin, amounting usually to but 5 or 10 feet. These deposits, however, appear to be capable of separation into two distinct till sheets. One is reddened and leached at the junction with the overlying loess and apparently is much older, while the other is scarcely at all leached or stained at the junction with the loess and in one locality appears to graduate upward into loess. The former deposit is probably of Kansan age while the latter appears to be Iowan. The best exposure noted is found a short distance northwest of the Clinton Brewery in see. 1, Clinton Township. The loess here has a thickness of 20 to 25 feet. At its base, near the east end of the exposure, is a fresh-looking calcareous till, about 4 feet thick, resting upon a bed of rotten, deeply stained gravel which there caps the older till. A few rods west the older till comes up to the base of the loess and farther west there are several exposures in which the loess rests directly upon the older till. Had the exposure of fresh till not been observed, there would have been nothing to indicate the presence of an Iowan drift at this locality. Such being the case here, where exposures are extensive, it can scarcely be affirmed that the Iowan drift is not present in the district immediately north and west, where only slight exposures can be found beneath the heavy covering of loess. The exposure just mentioned was visited in November, 1897, by Messrs. Calvin, Udden, Bain, and the writer, and the interpreta- tion given above was assented to without reserve. Hershey and the writer noted two exposures in the bluff in the north part of North Clinton (formerly Lyons) in which a few feet of fresh-looking till rests directly upon the residuary clay of the underlying limestone, a till which seems referable to the lowan rather than Kansan. Southwest of Clinton along the Burlington, Cedar Rapids and Northern Railroad bowlders were noted by Messrs. Cal- vin, Udden, Bain, and the writer near the east bank of the Mississippi. They are of the large angular type recognized by Calvin as characteristic of the Iowan, and they occur on a gently undulatory plain, such as is also characteristic of the lowan. Similar bowlders were observed by the same 148 THE ILLINOIS GLACIAL LOBE. party of geologists near Long Grove in northern Scott County, and are reported to occur for several miles farther east. Here also they occur on a plain referred with some confidence to the Iowan stage of glaciation. Hay- ing traced undoubted Towan deposits to the border of the Mississippi, it becomes a matter of interest to determine whether the Iowan ice crossed into Illinois. The examination made by Mr. Hershey and the writer in Whiteside and Carroll counties, directly east from the district just discussed, brought to light several features of a puzzling nature, some of which may have direct bearing upon this question. These features fall into five classes, (L) fresh till; (2) a tract free from loess; (3) a sand border east of the fresh till; (4) a loess apron outside the sand border; (5) ridges of loess with similar trend to the paha of the Iowan drift area. Certain other features found in southern Whiteside and northwestern Henry counties are considered in con- nection with the probable extension of the Illinois lobe at the Iowan stage. The features here considered lie outside the probable limits of that lobe. Deposits of fresh-looking till occur on the elevated upland about 10 miles due east of the north part of Clinton, near the south line of sec. 13, Ustick Township, and near the west end of the line of sees. 18 and 19, Clyde Township, Whiteside County. The till has a yellowish-gray color similar to that of the lowan near Polo, in Ogle County, and effervesces at a depth of less than 2 feet from the surface of the ground. As the exposures occur in the midst of a tract nearly free from loess, there is nothing to protect the till from leaching. It is in marked contrast to numerous other till exposures in the immediate neighborhood, which show decidedly stronger surface stain and are leached to a depth of 5 or 6 feet. These exposures of fresh-looking till were visited by Calvin, Udden, Bain, and the writer in November, 1897, and by all were recognized to present a much fresher appearance than the surrounding exposures. It was alse recognized that advantages for erosion here seem no greater than at points where a stained and deeply leached surface is presented. Although several different lines have been traversed by Hershey and the writer in Carroll and western Whiteside counties, no other exposures of such fresh till have been noted outside of the possible limits of the Iowan sheet formed by the Ilinois lobe. These exposures, it will be observed, occur within the limits of a single square mile. ‘Taken by themselves they seem a weak, though perhaps not EXTENT OF IOWA PORTION OF IOWAN DRIFT. 149 uncertain, prop to support the hypothesis of an extension of ice from Lowa into Ilinois at the Iowan stage of glaciation. The elevated tract just noted stands near the south end of a strip which is nearly free from loess. The strip extends northward several miles into Carroll County and has a general width of only about 2 miles. It is in decided contrast with the thick belt of loess on the west which follows the east bluff of the Mississippi and probably averages not less than 30 feet in average depth. It is also in contrast with the district on the east which for a distance of several miles back is covered to a depth of 12 to 15 feet with loess. On the south also there is heavy loess separating this tract from a similar tract south and east of Morrison. The tract with scanty loess is in an exposed situation, but apparently no more so than the bluff of the Mis- sissippi both to the west and south. It, therefore, seems difficult to account for its scant deposition by the force of the wind. It stands like the fresh till as a feature out of harmony with the general features of the region. It seems, however, to have a parallel in the region of Iowan drift to the west, where similar areas free from loess are bordered by loess-covered tracts. In this connection it may be remarked that the belt of loess along the Mississippi bluff leads down the river from far to the north and may be somewhat later than the loess to the east, and possibly subsequent to the occupancy of eastern Iowa by the lowan ice sheet. Kast of this tract characterized by thin loess is a narrow sandy belt in which dunes are common. This belt is best developed in Clyde Township, Whiteside County, where it has a breadth of fully 1 mile. Its southern end is found at Rock Creek Valley about 5 miles above Morrison, as indi- eated on Pl. XH. From this point it bears slightly west of north into Carroll County, lying mainly east of the valley of Little Creek. Its general altitude is slightly lower than the tract on the west, but it has about the average elevation of the region, being not less than 200 to 250 feet above the Mississippi River. It is so far removed from the river as to be outside the range of the aeolian deposits which in places accumulate on the east bluff. The best developed portion, as may be seen by reference to Pl. XI, stands 6 to 10 miles back from the river bluff and is separated from it by the still more elevated tract just discussed. On the south, east, and north borders of the sandy belt there is a blanket of loess 12 to 15 feet thick near the margin of the sand, but decreasing 150 THE ILLINOIS GLACIAL LOBE. in thickness to scarcely half that depth within a few miles east or north, beyond which for many miles it continues thin. The distribution and general relations of this loess in reference to the district west of it present some points of similarity to the loess borders of the Iowan drift in north- eastern Iowa where the loess is considered an outwash or overwash apron from the ice sheet, formed while it occupied the neighboring tracts of Iowan drift, which are nearly free from loess. The thinning out of the loess upon passing a few miles back from the hypothetical ice margin, as well as the abrupt border next the ice margin, may here find illustration just as in Johnson County, Lowa." The remaining feature bearing upon the question of the lowa invasion into northwestern Illinois is that of canoe-shaped ridges of loess, with parallel shallow troughs, having a WNW.—ESE. trend. Such ridges and troughs are best developed in a belt of thick loess lying between the strip of thin drift just considered and the valley of Rock Creek in western Whiteside County (see Pl. XVIII). There are other well-defined ridges, as already noted, south and east of Morrison, in the lowland tract nearly destitute of loess, and a few have been found south of Rock River in northwestern Henry County. There is a faint development of this class of ridging in northern Rock Island County, Illinois, and in southern Scott and eastern Muscatine | counties, Iowa. It is, perhaps, significant that they are, best developed in the district lying between the well-defined phases of the Iowan drift of the two ice lobes. While the origin of this class of ridges like that of the loess sheet is in all probability attributable to a combination of aqueous and xolian agencies the precise mode of action and relation of the two agencies have as yet received no adequate explanation. These ridges and bordering troughs were apparently developed before the present drainage lines had been opened in that region, if not while the ice occupied the neighboring drift plains on which the loess is a scanty deposit. The length of the ridges ranges from a fraction of a mile to two or three miles, but the width seldom reaches one-eighth of a mile. In height they range from 5 feet or less up to about 50 feet. While usually made up of typical loess they occasionally include fine sand, as noted above (p. 139.) Aside from the canoe-shaped ridges of loess there are found other forms of loess and sand aggregation in the region under discussion. On the east ! See Calvin, Iowa Geol. Survey, Vol. VII, 1897, pp. 86-90; also map of Johnson County, p. 92. RELATION OF ILLINOIS AND IOWA ICE LOBES. 151 bluff of the Mississippi Valley, opposite the broad sandy bottoms, such as occur in southwestern Carroll and northwestern Whiteside counties, sandy knolls and ridges are found which are evidently due to wind action. Some of them are in process of drifting even to-day, for the sand is too barren to nourish an adequate protective cover of vegetation. These ridges are irregular in form and trend and seldom bear a resemblance to the canoe- shaped ridges of loess. A few sandy ridges are found on the strip of drift in southwestern Carroll County, above noted, where the loess is scanty, which like thé canoe-shaped ridges of loess have a general WNW.-ESE. trend. They are, however, more irregular in form and are usually broader than the loess ridges. Possibly they should be classed with the dunes. If all the features of the region just discussed be considered, it appears that positive evidence of the invasion of the Iowa ice into northwestern Illinois at the Lowan stage of glaciation is at best very weak. The features, however, appear to favor rather than to antagonize the hypothesis of such an invasion. The debatable ground is restricted to a belt but 10 or 15 miles wide on the north and east borders of unquestioned Iowan drift. It embraces northern Clinton and southern Jackson counties, Lowa, and south- western Carroll, western Whiteside, and possibly neighboring portions of Rock Island County, Illinois. Were this belt low, like the tracts occupied by the Iowan drift in Clinton and Scott counties, Iowa, the extension might be granted, even with a very limited occurrence of fresh-looking drift. But the fact that the debatable region, both on the north and east, stands 100 to 300 feet above the low plain of Iowan drift, necessitates a very careful study of the evidence in the light of all applicable hypotheses. Having set, forth the available data, the question is left open with the hope that either by the light of further data or by more mature reflection a satisfactory solution may be reached. RELATION OF THE ILLINOIS AND IOWA ICE LOBES. In concluding this discussion a few remarks seem necessary concerning the probable relation of the Hlinois and Iowa ice lobes at the Lowan stage of glaciation. In his paper on northeastern Iowa, above quoted, McGee considers it probable that at the invasion now called Iowan the ice from the Iowa side culminated earlier than that on the Illinois side, and caused a displacement of the drainage of the Mississippi near Clinton, southeastward 152 THE ILLINOIS GLACIAL LOBE. to Rock River.!. He has represented the Illinois lobe to have subsequently extended to the border of the Mississippi Valley in Whiteside and Rock Island counties, and to have led to the flooding of the Driftless Area, forming what is termed Lake Hennepin.’ It would appear from McGee's discussion that the dates of culmination of the two lobes were separated by only a brief interval, an interval which in no wise compares in length with that which has been found to have occurred between the Kansan invasion of the Iowa lobe and the Ilinoian invasion of the Hlinois lobe, and that one lobe held nearly its maximum extent until the other culmmated. The rela- tions of the two lobes of the Iowan invasion appears to have been largely a matter of conjecture, for it is now found that the Illinois lobe fell far short of reaching the limits assigned to it by McGee. It is doubtful if evidence has yet been collected by which it will be possible to demonstrate clearly either the space or the time relations of the two ice lobes. The space relations as well as time relations of the two lobes being still unsettled, the influence upon drainage is at best a matter of conjecture. The Iowa ice lobe appears to have reached as far east as the Mississippi River in southern Clinton and northern Scott counties. Possibly it reached a few miles beyond the river in southwestern Carroll, western Whiteside, and northern Rock Island counties, Illinois, though such an extension is, as already noted, but weakly supported. The Illinois ice lobe certainly extended a few miles beyond Sterling on the north border of Rock River Valley and probably extended about to Geneseo, on the south border of that valley. The debatable tract east and south of Morrison, in central and southern Whiteside County, was apparently covered at the Iowan stage, either by the Illinois or by the Iowa ice lobe. If the latter is found not to have extended beyond the Mississippi Valley, it would follow that this district was occupied by the Ilinois lobe. The question of a coalescence of the two lobes, or the overlapping of their fields, depends, therefore, upon the determination of the extent of the Iowa lobe. If that lobe did not extend beyond the Mississippi, there would remain a strip about 8 miles in width along the east border of the Missis- sippi Valley which remained uncovered by ice throughout the Iowan invasion. By including the valley its width would be increased to 10 or i Eleventh Ann. Rept., U. 8. Geol. Survey, p. 570. 2Op. cit., Pl. LVIII; also pp. 570-577. 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Several chemical analyses of the loess have been made which repre- sent its structure at widely different points. The first four analyses in the table below were made by R. B. Riggs, of the U. S. Geological Survey, in connection with Chamberlin and Salisbury’s study of the loess bordering the Driftless Area, and were published in their paper in the Sixth Annual Report of this Survey. No.1 was taken from the summit of a ridge in the suburbs of Dubuque, Iowa, at a point about 300 feet above the Mississippi River. No.2 represents a 7-foot stratum of loess lying over brown residu- ary clay near Galena, Illinois, at about 350 feet above the Mississippi River. No. 3, from Kansas City, Missouri, was chosen as a representative of the most pronounced loessial characters at that locality. No. 4 was taken from near the center of Vicksburg, Mississippi, about 200 feet above the Missis- sippi River, and probably fairly represents the upper half of the stratum there, but not the lower portion, which seemed heterogeneous. The remain- ing two analyses were made by Prof. W. A. Noyes for Dr. J. T. Scovell, and are published in the Twenty-first Annual Report of the Indiana Geo- logical Survey. They are designed to illustrate the constitution of the white clay east of the Wabash River, near Terre Haute, Indiana. No. 5 represents the subsoil, the sample being from a depth of about 22 inches. No. 6 represents a sample from a depth of only 10 inches. The samples analyzed by Mr. Riggs were dried at 100° C.; those analyzed by Professor Noyes at 135°. Table of analyses of loess. r = No. 3.— NOB Yo. 6.— | “mms | ES Fa Tonos Neat tree Neat Tone | (eiore item cu na uah emia 7o GS 64. 61 74. 46 60. 69 72. 87 719.77 INTRO Sans He a ae WE ONS 10. 64 12.26 7.95 11.25 9. 95 Ot Os ete coeneie cen Uae a Pang NGIN| eases 2.61 65 3.39 RaO sce meet) kee aaa ANE OG 51 WA MRR Y Mallee ee ek THOMA ie eee AL e yd 72 .40 2a 2 595) | mnTO TEA OF Pose exs ee ee eed 23 .06 .09 Published in Proc. Davenport Acad. Sci., 1876, pp. 96-99; also in Eleventh Ann. Rept. U.S. Geol. Survey, 1890, p. 471. c Published in Proc. Iowa Acad. Sci., 1880, p. 16; also in Eleventh Ann. Rept. U.S. Geol. Survey, 1890, p. 471. dSee footnote a on next page. Pyramidula striatella (Anth.) leeeils: Pyramidula strigosa iowensis lee bass | Succinea avara Say. | Sueeinea obliqua Say. Succinea avara Say. | Succinea obliqua Say. Helicina occulta Say. Leuchocheila fallax (Say) Try. Pyramidula striatelfa (Anth.) | Pils. Succinea avara Say. Succinea luteola Gld. Succinea grosvenorii Lea. Cochlicopa lubrica (Mii l].) P.& J. Pyramidula striatella (Anth.) Pils. Helicodiscus lineatus (Say) Morse. Helicina occulta Say. Sphyradium edentulum alticola (Inger.) P. & J. Pyramidula striatella (Anth.) Pils. Conulus fulvus (Drap.) Miill. Vallonia pulchella(Miill.) Binn.d Helicodiseus lineatus (Say) Morse. Pyramidula strigosa iowensis Pils. Bifidaria pentodon (Say) Sterki. Bifidaria corticaria (Say) Sterki. Pupa muscorum L. Sphyradium edentulum alticola (Inger.) P. & J. Suecinea avara Say. LOESS FOSSILS. 169 Lists of loess fossils—Continued. Names heretofore commonly used. Names in Pilsbry and Johnson’s check list of terrestrial mollusks for 1898. List IV. From Muscatine, lowa. (Identified by F. M. Witter; revised by B. Shimek. )—Con- tinued. List V. From Burlington, Iowa. (Collected by Frank Leverett; identified by C. T. Simpson.) List VI. From near Freeport, Illinois. (Collected by Oscar Hershey ; identified by W. H. Dall.) b. 1. Terrestrial species. Succinea obliqua Say..-....-..... Helicina occulta Say -......-..... Limnaea humilis Say ..--.....-... Unio ebenus Lea Unio ligamentinus Lea . .. (Uniolrectuss ames eeee seo eeee es Campeloma subsolidum (Anth.) Call; also Melantho subsolida. Margaritana confragosa Say. Succinea obliqua Say Succinea lineata W.G.B Helicina occulta Say Patula strigosa cooperi W.G. B.; also Pyramidula strigosa. | Pyramidula striatella Anth.; also Patula striatella (Anth.) Morse. Pyramidula perspectiva (Say) Binn. Vallonia costata Miill. ; also Vallo- nia pulchella var. costata. Vallonia perspectiva Sterki..._... Zonitoides arboreus Say; also) Zonites arboreus (Say) Binn. Zonites radiatulus Ald; also Hya- | lina radiatula Ald. Zonites minusculus Binn; also Hyalina minuscula Binn. Zonites indentatus (Say) Binn; also Hyalina indentata Say. Patula alternata (Say) Binn; also | Pyramidula alternata Say. Patula striatella (Anth.) Morse; also Pyramidula striatella (Anth.) Morse. Helicodiscus lineatus (Say) Morse- Stenotrema hirsutum (Say) Try.; also Polygyra hirsuta Say. Succinea obliqua Say. Helicina occulta Say. Succinea obliqua Say. Succinea grosvenorii Lea. Helicina occulta Say. Pyramidula strigosa iowensis Pils. Pyramidula striatella (Anth.) Pils. Pyramidula perspectiva (Say) Pils, Vallonia costata Miill. a Vallonia perspectiva Sterki. Zonitoides arboreus (Say) P.& J. Vitrea hammonis (Strém.) P. & J. Zonitoides minusculus (Binn.) P.& J. Vitrea indentata (Say) P. & J. Pyramidula alternata (Say) Pils. Pyramidula striatella (Anth.) Pils. Helicodiscus lineatus (Say) Morse. Polygyra hirsuta (Say) Pils. aIt is now difficult to ascertain the correctness of the earlier identifications of the species of Vallonia. The species were all formerly referred to V. pulchella or to V. pulchella var. costata, but Dr. Sterki’s investigations have brought to light a greater number of species than was at first recognized. Most of the forms formerly called V. pulchella from the loess west of the Mississippi are V. gracilicosta, and those called V. pulchella var. costata are at least in part V. parvula Sterki. This difficulty in making the identifications does notin any manner affect the general discussion, as all the species are strictly terrestrial in habit. (Shimek.) 6 Published in Am. Jour. Sci., 4th series, Vol. IV, 1897. 170 THE ILLINOIS GLACIAL LOBE. Lists of loess fossils—Continued. | | Names heretofore commonly used. Names in Pilsbry and Johnson’s check list of terrestrial mollusks for 1898. | List VI. From near Freeport, | Strobilops virgo Pils..---.-------- | Strobilops virgo Pils. Illinois. (Collected by Oscar Pupa contracta Say-..-------.---- | Bifidaria contracta (Say) Sterki. Hershey, identified by W. H. | Pupa corticaria Say ...--.-------- Bifidaria corticaria (Say ) Sterki. Dall.) 1. Terrestrial species— | Pupa armifera Say ..---..------- Bifidaria armifera (Say) Sterki. Continued. Pupa holzingeri Sterki -...-.....- Bifidaria holzingeri (Sterki) Sterki. Vertigo tridentata Wolf -.-...--.-- Vertigo tridentata Wolf. Succinea avara Say.---.---------- Succinea avara Say. | Carychium exiguum (Say) Gld -... Carychinm exiguum (Say) Gld. | Carychium exile (?) Pils-.-..---- Carychium exile Pils. 2. Fluviatile species (gill-bear- | Pleurocera subulare (Lea) Try. --- ing univalves). | Campeloma decisa (Say) Call ....- | Bythinella tenuipes (Coop.) Binn., Amnicola cincinnatiensis Anth ---| Amnicola porata (Say) Hald ----.- | Somatogyrus depressus (Try.) Gill. Valvata tricarinata Say--.--------. 3. Fluviatile bivalves (some o¢- | pj.igium compressum Prime ..---- casionally in ponds). Pisidium cruciatum Sterki--....--- Pisidium fallax Sterki-..---....---. | Pisidium punctatum Sterki-.-.--. | Pisidium variabile Prime .....--.- Pisidium virginicum Gmel.-....--. Pisidium walkeri Sterki--....----. Spherium stamineum (Con.) Prime | Sphzrium striatinum(Lam.) Prime Spheerium simile Say -...--.. secce Spherium solidulum Prime - ..----. 4, Pond species air-breathing | Planorbis parvus Say....--.-.---- (some fluviatile). | Planorbis bicarinatus Say -...---- | Physa heterostropha Say .-..-.-.-. Segmentina armigera (Say) Ad--.- Limnaea humilis Say --.-.--..---- | Ancylus tardus Say... ----------- | Ancylus rivularis Say. ....-....--- | | Ancylus parallelus Hald -.--...... | f List VII. From Moline, Illinois. Suceinea avara SEMe secs cosedsccee | Suecinea avara Say. (Collected by J. A. Udden;) Succinea luteola Gld ...-..-....-- Succinea luteola Gld. identified by C.T. Simpson.) | Succinea obliqua Say---...-.-..--- Succinea obliqua Say. | Helicina occulta Say --..-....---- Helicina occulta Say. Patula striatella (Anth.) Morse; | Pyramidula striatella (Anth.) also Pyramidula striatella. Pils. i a LOESS FOSSILS. 17] Lists of loess fossils—Continued. Names heretofore commonly used. | Names in Pilsbry and Johnson's check list of terrestrial mollusks for 1898. List VII. From Moline, Illinois. (Collected by J. A. Udden; identified by C.'T. Simpson. )— Continued. List VIII. From Virginia, Illi- nois. (Collected and identi- fied by J. F. Snyder.) Pupa alticola Inger.......---.---- PUpA ANUS COLUM LER eeyese eee ae Pupa pentodon (Say) Gld--.....-.- | Vallonia pulchella (Miill.) Binn-. - Patula striatella (Anth.) Morse; also Helix striatella. Helix orbiculata? Perhaps Heli- cina orbiculata or Helicina oc- culta Say. Macrocyclis concava (Say) Morse; also Helix concava. Mesodon clausa (Say) Try.; also Helix clausa. Helix solitaria? Perhaps Pyra- midula strigosa iowensis Pils. Stenotrema monodon (Rack.) Morse; also Helix monodon. Mesodon multilineata (Say) Try; also Helix multilineata. Mesodon pennsylvanica (Green) Try; also Helix pennsylvanica. Patula alternata (Say) Binn. ; also Helix alternata. Ariontaexarata Pfeiff. ; also Helix exarata. Succinea obliqua Say. .-----.---.. Limnaea humilis Say. Bulinus dealbatus; probably Buli- nus hypnorum or Bulimus deal- batus. Sphyradium edentulum alticola (Inger.) P. & J. Pupa muscorum L. Bifidaria pentodon (Say) St. Vallonia pulchella (Miill.) Binn. Pyramidula striatella (Anth.) Pils. Circinaria concava (Say) P. & J. Polygyra clausa (Say) Pils. Polygyra monodon (Rack.) Pils. Polygyra multilineata (Say) Pils. Polygyra pennsylvanica (Green) Pils. Pyramidula alternata (Say) Pils. Epiphragmophora exarata (Pfeiff.) P. & J. Succinea obliqua Say. Bulimulus dealbatus ?. Professor Shimek has furnished the following notes in reference to the fossils given in the foregoing lists. Of the foregoing lists I, I, II, IV (except the last five species), V, and VII contain typical loess fossils and may be considered together. The species mentioned are the following : 1. Conulus fulvus (Drap.) Miill. 2. Helicodiscus lineatus (Say) Morse. 3. Pyramidula striatella (Anth.) Pils. 4, Pyramidula strigosa iowensis Pils. 1) THE ILLINOIS GLACIAL LOBE. 5. Pyramidula perspectiva (Say) Pils. 6. Vallonia pulchella (Miill.) Binn.! 7. Cochlicopa lubrica (Miill.) P. & J. 8. Leuchochila fallax (Say) Try. 9. Pupa muscorum L. 10. Bifidaria corticaria (Say) St. 11. Bifidaria armifera (Say) St. 12. Bifidaria pentodon (Say) St. 13. Sphyradium edentulum alticola (Inger.) P. & J. 14, Suecinea avara Say. 15. Succinea obliqua Say. 16. Succinea Iuteola Gld. 17. Suecinea grosvenorii Lea. 18. Helicina occulta Say. 19. Limnaea humilis Say. Of these species all but the last one are strictly terrestrial in habit. One species, No. 5, rare in northern loess, is very common in the loess of Mississippi. The last species, No. 19, is an aquatic pulmonate, occurring in pockets or restricted parts of the loess as though deposited at the edge of a pool or pond.” As for the last five species in List IV this may be said: They are strictly fluviatile. There are reasons for believing, however, that they did not come from unmodified loess,* and morever they and their relatives have thus tar not been found in any other locality except in what is clearly modified loess. There still remain lists VI and VIII which will be discussed separately. The fossils of List VI are in all probability from alluvium, and not from the loess, for two reasons—one positive, the other negative: 1. The list very closely resembles lists of species found in alluvium along several streams, notably along Rock River near its mouth, along the Cedar River at Cedar Rapids and near Mount Vernon, and along the Iowa near Iowa City.* It will be observed that the species in this list are grouped according to habit. The first section or group contains the terres- trial forms, nearly all of which also occur in the loess. All row live on alluvial bottom lands or the adjacent hills, and their shells are often washed down for short distances. 2. The list in its entirety is unlike any undoubted loess fauna which has been reported by trustworthy observers. ' See footnote a on p. 169. 2 See discussion of Limniea by Shimek, in Proc. lowa Acad. Sci., Vol. V, 1898, pp. 34, 35. 3 Professor Shimek reached this conclusion after a conversation with Professor Witter. 4The Rock River list was published in Iowa University Bulletin, Vol. II, pp. 170 and 171. LOESS FOSSILS. eves The shells in List VIII are for the most part terrestrial, and most of them occur in ordinary loess more or less commonly. The list is striking because of the number of large Helices and the absence of small forms, ‘in this respect being more like the southern loess. It is probable that the “Helix solitaria” of the list is our Pyramidula strigosa iowensis, a frequent loess fossil. Helix orbiculata may really be Helicina orbiculata, a species much like our Helicina occulta, to which the specimens may possibly belong. Helicina orbiculata, however, is common in the loess of Natchez. Helix exarata, of this list, is a west coast species, and if the determination is correct it must have been transported a great distance overland. It is out of place. As for the remaining species, all the species of ‘“ Helix” are strictly terrestrial. Succinea obliqua and Limnaea humilis have already been discussed. Bulinus dealbatus should be either Bulimus dealbatus, a southern terres- trial species, or it is Bulinus hypnorum, a pond snail like Limnzea and Physa in habit. Valvata tricarinata and Vivipara intertexta are fluviatile, or may be found in ponds. It will be of interest to ascertain their relation to the other fauna as to abundance and distribution. On the whole the shells are unlike those of our northern loess, but differ still more from the southern loess fauna, which, so far as I have been able to determine, is absolutelv without aquatic forms. “To these lists,” writes Professor Shimek, ‘‘I can add but few names. From Davenport I have specimens of Limnea humilis; from Muscatine Zonitoides minusculus (Binn.) P. & J.; from Moline Limnea humilis Say, and Polygyra clausa Say.” Since the foregoing statement was written Professor Shimek has received several collections of fossils from Prof. J. A. Udden, and reports upon them as follows: , From Division street, Davenport, Iowa, near base of loess. Collected by Prof. J. A. Udden: Helicina occulta Say. Succinea avara Say. Sphyradium edentulum alticola (Inger.) P. & J. Pyramidula striatella (Anth.) Pils. Bifidaria pentodon (Say) Sterki. Limnea palustris Miill. (fragment.) Limnea caperata Say. Spherium—fragment of a valve. 174 THE ILLINOIS GLACIAL LOBE. The last three species in this list are pond species. “From loess in blutt above Hershey avenue, Muscatine, Iowa.” (Prof. J. A. Udden’s note.) Helicina occulta Say. Polygyra multilineata (Say) Pils. (Probably this species; specimen young.) Polygyra monodon (Rack.) Pils. Strebilops virgo Pils. Bifidaria pentodon (Say) St. Pupa muscorum L. Cochlicopa lubrica (Miill.) P. & J. Pyramidula alternata (Say) Pils. Pyramidula perspectiva (Say) Pils. Pyramidula striatella (Anth.) Pils. Succinea obliqua Say. Succinea avara Say. Succinea ovalis Gld. Limniea caperata Say. Valvata sincera Say. Succinea ovalis, of which one specimen was submitted, lives on mud flats, ete.; Limnea caperata and Valvata sincera are pond species—the latter now for the first time reported from the loess; all the others are terrestrial From base of loess in bluff of Mill Creek, about 5 miles south of Milan, Illinois, collected by Prof. J. A. Udden: Succinea avara Say. Limna stagnalis L. A fragment, probably this species. Limnea reflexa Say. Planorbis albus Miill. Not heretofore reported. Planorbis parvus Say. Valvata tricarinata Say. Valvata sincera Say. Pisidium . Five fragments of valves, probably belonging to two species. . With the exception of the first, all of these are pond species. These lists, remarks Shimek, are of special interest because of the comparatively large number of pond species which they contain. The presence of these forms, however, does not strengthen the aqueous theory of loess formation. Both the distribution of these aquatic forms in the loess and their habits in life indicate this. They do not represent the average loess-fauna even of the Mississippi River, but occur in restricted areas and seem to have been collected chiefly from the lower part of the loess. In habits these forms are pond-inhabiting, air or water breathers, which do not require or favor large bodies of water, but which flourish in smaller ponds. LOESS FOSSILS. ERD Their presence rather only serves to emphasize my contention that the fauna of the loess is in all cases very similar to the fauna of the surface in the same region. Pond species are more abundant and of greater variety in eastern Iowa and Illinois, especially along river courses, than they are westward. Probably during the deposition of the loess the same conditions existed, and the agency chiefly concerned in the work of deposition, whether wind or water, buried more of these aquatic species in the eastern loess, simply because there were more of them, proportionately, upon the surface. The following quotation’ bears upon this point: No distinction can be made between the origin of eastern and western loess. The finer quality and lesser thickness of the former rather suggest that there had been more moisture (i. e., a shorter dry period during each year) and hence less dust; that the winds were less violent, and that there were greater areas completely covered with vegetation, this resulting in the necessity of transporting dust much greater distances, which would therefore be finer. It should be borne in mind that the above noted differences between the regions in question actually exist to-day. There is more rain—there are larger areas closely covered with vegetation, and less violent winds prevail in eastern Iowa and eastward— and considering the position of mountain chains and seas, the same differences must have existed for a long time. That they did exist, during the deposition of the loess, is also indicated by the proportionately somewhat larger number of species in the eastern loess which prefer or require moist habitats. But the fauna of the eastern or Mississippi River loess is essentially a terrestrial fauna. The great fluviatile groups, now everywhere common in the streams of eastern Iowa, are wanting in the loess, and the few fossil aquatic species are such as to-day prefer ponds, and are often found even in those which dry up during the summer. In addition to these notes furnished by Professor Shimek, a few remarks are taken from his discussion of the loess in a recent paper published in Proceedings of the Iowa Academy of Sciences:° The majority of the geologists who have given attention to the loess of the Mississippi Valley have ascribed its deposition to water in lakes or sluggish streams Some have also contended that this occurred in a glacial climate, or at least in a climate much colder than that of to-day in the same region. That fresh water has been regarded as the agent of deposition is due in no small degree to the belief that a very considerable portion of the species and individuals found in the deposit consist of aquatic or semiaquatic forms, although the fact has long been recognized that terrestrial species prevail. There is, however, absolutely nothing in the loess fauna to indicate that the loess land surfaces were more moist, or to any extent more widely or more deeply covered with waters, than are the surfaces ‘Shimek: Proc. Ia. Acad. Sci., vol. vi, 1898, p. 110. *Proc. Iowa Acad. Sci. for 1897, Vol. V, 1898, pp. 32-45. 176 TAR ILLINOIS GLACIAL LOBE. ot Iowa and Nebraska to-day—the evidence, if it suggests any difference, indicating rather less moisture than is found in eastern Iowa at the present time. This state- ment, which can not be too strongly emphasized, is based upon the study of the modern mollusks of Iowa and Nebraska and their fossil prototypes, extending over a period of nearly twenty years. * * * Moreover the molluscan loess-fauna of any region is on the whole like the modern fauna of the same region. For example, Binney reports a number of specics from the ‘“ post-pliocene” (evidently the loess) of the lower Mississippi Valley, of which eleven are southerly species, and all now live in the same region. Call reports! fifteen species from the loess of Arkansas, three of them included in the southerly list, and all belong to the modern molluscan fauna of that State. The same is true of the faunas of Iowa and Nebraska, as has been stated. This does not indicate transportation from a distance. It is interesting and noticeable that for the most part the species of the loess are common over the same region now. There are some exceptions, for there have been changes no doubt, but these changes, as indicated by the distribution of the shells, are no greater than may now be observed in any limited region in the course of a few years. Species are sometimes disposed to appear, disappear, and reappear in a surprising manner in a given locality, and if we may judge from the vertical distribution of the fossil shells, the same was true during the deposition of the loess. The horizontal distribution of the fossils is likewise such that it suggests at once that they are deposited in situ. | As there are surface areas to-day which have no mollusks, lying in close proximity to those on which mollusks are abundant, so there are deposits of loess without fossi's adjacent to those which are fossiliferous. As the lands, high or low, lying adja- cent to larger streams have greater numbers of mollusks to-day than the outlying prairies, so the loess bordering these streams is usually much more fossiliferous than that which covers more remote areas, but the distribution of the fossils is not in bands, as if drifted, but is similar to that of the modern specimens at the surface.” Summing up the evidence of the fossils, we may assert that it points to conditions not unlike those which exist to-day, and that geologists in seeking for the cause and manner of the deposition of the loess must give up the assumption of widely submerged areas over which fossiliferous loess now occurs, and of a cold climate. MODE OF DEPOSITION. The mode of deposition of the loess still remains one of the most puzzling problems of Pleistocene geology. Both the zolian and aqueous hypothesis have strong adherents among the students of the Mississippi Valley portion as well as of other portions of this formation. The students of the Mississippi Valley portion, however, all grant that the influence of wind has been important, and probably all would concede that water has 1 Geol. Survey Ark., Vol. II, pp. 49, 165, and 166. 2In a recent paper Shimek has discussed more fully the distribution of loess fossils: Jour. Geol. Vol. VII, 1899, pp. 122-140. Also Proc. Iowa Acad. Sci., Vol. VI, 1898, pp. 98-113. MODE OF DEPOSITION OF THE LOESS. Ile e¢ been influential. The division of opinion, therefore, is concerned with the relative importance of wind and water in the distribution of the loess. The question of the influence of the atmosphere as an agent of erosion, trans- portation, and sedimentation has been very carefully examined by Udden, with the result of showing that a large part of the loess may have been deposited through this agency.! In a recent paper? Chamberlin has dis- cussed the peculiarities of distribution and considered the difficulties attending the application of either hypothesis to the entire deposit. The distribution of the thickest and coarsest loess along the main valleys, with its great extent down the Mississippi, creates a strong conviction “that the deposition of the loess was in some vital way connected with the great streams of the region.” The abrupt border of the loess at the edge of the Iowan drift sheet both in Hlinois and Towa gives it a “more or less direct genetic relationship with the ice.” The graduation of loess into glacial clays ‘further tends to confirm the association of the loess with glacial action.” The influence of glacial action is also shown in the presence of silicates which are decom- posable under prolonged weathering and of calcium and magnesian car- bonates, none of which can be supposed to come from the residuary clays. An illustration from the Lower Mississippi Valley is given which strengthens this inference: Above the Lafayette gravels and below the loess there is a stratum of silt which does not habitually contain the characteristic silicate particles of the loess. This Stratuin has been by most observers associated with the loess, but it is separated from it by a soil horizon, as abundantly affirmed by the observations of Salisbury and the writer. On the other hand, it graduates more or less freely into the Lafayette sands and gravels. ‘The stratum is, as we interpret it, the last deposit of the Lafayette Stage. It is a typical finishing deposit succeeding a fluvial sand and gravel. Now this has special significance in this relationship in that it shows that in the stage closely preceding the loess deposition the Mississippi did not lay down silts of the Same constitution as the loess. The inference, therefore, is that the loess is not simply a fluvial silt brought down from the surface of the river basin, nor common wind drift borne into it, but that it had a special origin connected with the glacial action which was competent to supply precisely the kind of silt of which the loess was made. ‘The main results of Udden’s studies are presented in the following papers: ‘Erosion, trans- portation, and sedimentation performed by the atmosphere”: Jour. Geol., Vol. II, 1894, pp. 318-331. ‘Loess as a land deposit”: Bull. Geol. Soc. Amer., Vol. IX, 1897, pp.6-9. ‘‘ The mechanical composition of wind deposits,” Augustana Library Publications, No. 1, 1898. Lutheran Augustana Book Concern, Rock Island, Illinois. *Supplementary hypothesis respecting the origin of the loess of the Mississippi Valley, by T. C. Chamberlin: Journ. Geol., Vol. V, 1897, pp. 795-802. MON XXXVIIL 12 178 THE ILLINOIS GLACIAL LOBE. The leading difficulties cited by Chamberlin as attending the hypoth- esis that the loess is simply an outwash of glacial grindings distributed by elacio-fluvial waters, are its vertical distribution and the presence of shells of land mollusks. ‘The extreme vertical range is not far from 1,000 feet. The range within a score of miles is frequently from 500 to 700 feet.” In its interfluvial phase it mantles an undulatory surface and apparently reaches a greater elevation on the east than on the west side of the main valleys. It is difficult to bring its border into strict accord with a horizontal plain as required by the lacustrine and marine phases of the hypothesis, or even into a consistent gradient as required Sy the fluvial phase, without an arbitrary warping of the surface. It seems also extremely difficult to conceive how a great flood which had the ice sheet for its northern border could have been peopled so widely with land mollusks. In view of these difficulties, Chamberlin proposes to divide the influence of wind and water as follows. He adopts the glacio-fluvial hypothesis as the funda- mental explanation, assuming, (@) the presence of the Iowan ice at the chief stage of deposition; (b) a very low slope of the land and consequent wide wandering of the glacial waters; (c) the development of extensive flats over which the glacial silts were spread; (d) great periodic extension of glacial waters caused by (1) periods of warm weather in the melting season, and (2) by warm rains. He considers it probable that the periodic extensions of the floods were not always destructive to vegetation over the flat region, and that land mollusks and other animals dependent upon the vegetation may have found temporary retreat from the flood on the taller vegetation. Upon the retreat of the waters, extensive silt-covered flats would become exposed to the sweeping influence of the wind, and when dried the silt would be borne in great quantities over the adjoining uplands. This hypothesis demands an accommodation between the breadth of the fluvial deposits. and the extent and massiveness of the zolian deposits, for a restriction of the glacial floods to narrow channels would render the sweeping ground for the winds too limited in area to supply material for the great mantle of silt found on the uplands. In proportion as the river work is narrowed the wind work is expanded. It follows that the eolian factor will cut away its own ground if pushed too far. It is further urged that the eeolian deposits are measured not by the quantity of silt borne by the winds and lodged on the surface, but by the difference between such MODE OF DEPOSITION OF THE LOESS. 179 lodgment and the erosion of the surface. ‘‘ Erosion is ordinarily more than a match for the dust accumulations. The conditions must have been extraordinary which would give a dust deposition sufficient to supply erosion and still leave such a large residuum as the loess mantle implies. The unleached and unweathered nature of the body of the loess is specially in point here. These considerations warn us of the theoretical danger of too greatly circumscribing the fluvial action.”! An undue extension of the fluvial hypothesis is thought to be antago- nistic to the existence of molluscan life and also encounters the topograph- ical and physical difficulties previously urged. In conclusion Chamberlin calls attention to the efforts made by himself and colleagues to find criteria of discrimination between aqueous and zeolian loess, and remarks that “while individual types of both deposits are not difficult to find, a crite- rion or series of criteria of general applicability which shall distinguish the two and assign to each its appropriate part are wanting.” Turning now to the region under discussion in order to test the appli- cability of the hypothesis suggested by Chamberlin, it is found that the variations in level are sufficiently great to put the hypothesis of fluvial deposition to severe tests, though they are not so conspicuous as in border- ing districts on the east or west. The district covered by the Tllinois glacial lobe is largely embraced between the levels of contours lying 800 and 500 feet above tide, the general elevation in the northern portion of the district being about 800 feet and the southern portion about 500 feet. This descent of 300 feet in passing from the northern to the southern portion of the State is about the same as the fall of the Mississippi River along its western borders. The Mississippi Valley, however, is cut to an average depth of about 200 feet below the bordering uplands. A small portion of northern Ilinois slightly exceeds 1,000 feet and portions of southeastern Ilinois and southwestern Indiana fall below 400 feet, thus giving a range of fully 600 feet within the limits of the State, aside from the deepening of valleys since the loess deposition. The most conspicuous abrupt variation in elevation of loess- covered districts is found in the southern end of the State, where, as above noted, a ridge rises 300 feet or more above border tracts. A few conspicu- ous reliefs occur along the border of the Mississippi in northwestern Illinois and in the portion south from Quincy. ' For a partial dissent from Chamberlin’s views see Udden: Bull. Geol, Soc. Amer., Vol. IX, 1897, pp. 7-8; also Shimek: Proc. Iowa Acad. Sci., Vol. VI, pp. 109-110, and Jour. Geol., Vol. VII, 1899, p. 135, 180 THE ILLINOIS GLACIAL LOBE. The streams of southern Illinois are flowing in broad shallow troughs in which a rise of 380 or 40 feet would cause an expansion of the stream to a width of several miles. Such is notably the case in the valleys of the Kaskaskia, Big Muddy, Saline, Little Wabash, Bon Pas, and Embarras rivers. ‘The same is true of the lower course of the Wabash and of a por- tion of White River below Worthington and of the lower course of East White River. The valleys of western Illinois and southeastern Iowa were apparently, at the time of the loess deposition, cut down only to a level 50 to 100 feet above the present level of the streams, as is shown by the level of the lowest loess-capped terraces. This, however, is 50 to 100 feet below neighboring uplands. A rise similar to that which would cause extensive flooding in southern Illinois would not carry them beyond the limits of their present valley bottoms. Unless, therefore, a rise much greater than 30 or 40 feet be assumed, the glacial waters would have been confined to the immediate channels of the larger streams, and, as urged by Chamberlin, the sweeping ground of silt for the winds to work upon would have been too restricted to supply the great mantle of silt covering the neighboring uplands. The problem here puts both the fluvial and eolian hypotheses to severe test. It seems necessary to grant a rise of water sufficient to overspread the neighboring uplands in order to afford a sufficient sweeping ground to supply material for the portion of the loess mantle found along the divides. In southeastern Iowa and neighboring portions of lmois and Missouri a rise of 100 to 150 feet would be necessary to cause a wide expansion of the glacial streams. However, with the assumed low altitude of the loess-covered region, and resulting low gradient of the streams, a depth of 100 feet of water over the main valleys may be within the limits of probability. A rise of this amount in the southern Illinois district would carry the waters over the greater part of the interfluvial districts. The evidence relied upon to demonstrate the agency of water in con- nection with the deposition of the loess and associated silts is the presence of material too coarse to have been transported by wind, and the occur- rence of water-laid beds of sand, silt, or coarser material. Such evidence must be weighed very carefully to guard against including redeposited material, in which the loess and the coarser material have been brought down from higher ground. It may not in all cases be possible to decide whether there has been a redeposition. But the present writer feels MODE OF DEPOSITION OF THE LOESS. 181 confident that he has seen not a few places where the basal portion of unmodified loess carries sand and coarser material. It is found that on the borders of the Mississippi Valley in southeastern Iowa, and also for some distance back from the stream, pebbles are of frequent occurrence in the lower portion of the silts, which there cap the Sangamon soil or rest upon the slightly eroded surface of the Ilnoian till. Well-defined bedding planes also appear, especially in the basal portion of the silt, in which thin sand partings alternate with clay, giving an appearance similar to that found in the fine deposits of alluvium on the bottoms bordering the large streams. These pebbles and bedding planes have been found in Lee and Des Moines counties, Iowa, at an elevation of slightly more than 700 feet above tide, or fully 200 feet above the present level of the Mississippi River, and about 130 feet above the level of the lowest known deposits of loess in that region. The breadth of the glacial waters along the Mississippi Valley must have been 25 to 50 miles if the deposits just noted mark the highest level; possibly a still higher level was reached. Whether there was clear evidence of the spreading of glacial waters over the entire divide between the watersheds of the Mississippi and Illinois, can not be stated. But the known extent of the glacial waters seems adequate to have furnished material for mantling the higher portions of this divide by eolian agencies. Exami- nations in southern Illinois have brought to light the general prevalence of small pebbles in the silt which covers that district. There seems little ques- tion that from the base of the elevated ridge in southern Ilinois northward, as far as these silts are exposed, outside the Wisconsin drift, the aqueous agencies have been influential and were probably the chief agencies of deposition. To what extent the elevated ridge in southern Hlinois was covered by glacial waters has not been determined. Possibly a portion of the silt which caps this ridge was deposited while the Illinoian ice rested upon its northern slope, though no positive evidence of such deposition has been noted. The extent of the glacial waters on the borders of the Mississippi in northwestern Illinois and northeastern Lowa is also undetermined. Mr. Oscar Hershey has found water-bedded silt along the Pecatonica River and Yel- low Creek valleys, in Stephenson County, Mlinois, which he thinks imme- diately preceded the loess in deposition. This silt is confined to low levels along the valleys rising scarcely above the present water level. The full extent of water action in this basin has not been determined. It seems 182 THE ILLINOIS GLACIAL LOBE. probable that the loess on the immediate borders of the Pecatonica lobe is water-bedded, even at levels 800 feet or more above tide. Possibly this lobe held a body of water in the Pecatonica Basin at a level nearly as high as the bordering uplands (900 feet above tide). The relation of the bluff loess to the upland loess is a question of prime importance. It has been commonly assumed that deposition was completed at nearly the same date on the uplands and on the valley borders, and that the difference in porosity is due to a greater strength of the current along the line of the main valleys. It is probably true that the main valleys were the line of strongest current during the deposition of the upland loess, and possibly the deposition of the bluff loess was completed at a date nearly as early as that of the water-laid deposits on the bordering uplands. There is thought, however, to be evidence pointing to a continuance of loess depo- sition along the main valleys after deposition had practically ceased on the uplands. The evidence referred to consists of an excessive filling by loess of the valley recesses and lower courses of tributaries, such as seem explain- able as a result of transportation down the valley after the flooding of the uplands had ceased. Accumulations of this class are especially noticeable on the lower course of the Wabash and Ohio rivers, and they are found to some extent along the Illinois and Mississippi. Mr. H. F. Bain also reports that the same feature is noticeable along the borders of the Missouri River in western Iowa.’ It is found that the blocking is most conspicuous on the east side of the valleys, a feature which suggests that wind action has been effective in causing the blocking of the mouths of tributaries, for the pre- vailing winds are from the west. Upon the retirement of the glacial waters to the limits of the main valleys or to their immediate borders the material available for transportation would be chiefly loess, and the loess would have had little opportunity to become leached. We may suppose, therefore, that a deposition of unleached loess continued until the glacial waters had retired completely and the streams were fed only by the rainfall of the region. This may have been maintained for some time after the disappearance of the Iowan ice sheet, though it appears not to have continued sufficiently long to have overlapped to any marked degree the valley excavation which followed the loess deposition. As noted aboye, the fossils of the loess are confined largely to the 1 Discussion at Twelfth Annual Meeting Iowa Acad. Sci., Dec., 1897. MODE OF DEPOSITION OF THE LOESS. 183 immediate borders of the valleys, i. e., to the portion of the loess which may have been deposited after the retirement of the foods from the uplands. The most notable exceptions are their occurrence in the paha ridges ana in the heavy loess bordering the lobes of Iowan ice in eastern Iowa and west- ern Illinois. It seems difficult to refer the latter deposits to a much later date than the culmination of the glacial flood, though it is possible that the filling was continued along the immediate borders of the ice lobes to a time considerably later than the culminating stage of the flood and even to a time when vegetation had obtained a foothold on the neighboring: silt- covered tracts. If the deposition of the portion of the loess containing fossils can be shown to have continued down to a time when the floods had retired to the limits of the main valleys, objections drawn from the char- acter of the fossils against the aqueous deposition of loess on the bordering uplands would be fully met. It becomes, therefore, a matter of much importance to settle definitely the age of the fossil-bearing deposits with reference to the culminating stage of the glacial water. Before leaving this subject a few remarks seem in place concerning the deposits of loess which are evidently zeolian. The first eeolian loess to attract the writer’s attention, as such, is found along the east border of the Missis- sippi Valley opposite Burlington, Iowa. The loess there has accumulated in dunes which give it a relief of 25 to 75 feet above the neighboring uplands on the east. When viewed from the uplands it appears as a bil- lowy ridge fringing the river bluff. This loess is found to be fossiliferous and calcareous, and were it not for its topography and for a slight admix- ture of sand recently drifted to it from the broad bottoms of the Mississippi River it would present no essential difference from the flat-surfaced portions of the loess along the borders of the river elsewhere. A similar relief of the loess on the brow of the bluff, above uplands to the east, has been since noted just below Alton, Hlinois. It also occurs to a slight degree on the east border of the Mississippi above Burlington. It is now known that the general thickness of the loess on the east side of the Mississippi Valley, from the Driftless Area southward through the entire length of the State of Ili- nois, is markedly greater than on the west side of the valley in Iowa and Missouri, probably twice as great. Fane ChE SOS EOS Seo sS5 Soe boSSSS nto Saticse cbeses ese 25 Sand and water, flow of 400 gallons per minute..--.....-.....-........-.----.----- ---.--------- 30 IBNe Gay sosess deus edeeeoe aco Aboocsonce soseeu Oscrod GaccEe S50 cos ease nooe scene Esc ssoseeosdces 4 Di eMs! AGl sol oes os baseds SoneS aSbase Sondss cHSOkS S1b5S6 Ha SoSe oa nqucasbdenseaodaco sSeaee 2 (GiRAGIN SING 535 aS5 cds sean eScond Goh Soca cceend sodensboc0scs spaces SucU cose Sasa DedSds SSedtsreecose 4 (Cigihy GRIN oe So abo son5 Beda nono Good deco Hebece Sosccee recon caus ends coSsRecpagSO3 CoSbs0 Gacqnscs 6 Sete! Thin Obs -cde Seas e056 Scan bobes9 0000 bes oseede SHbads SH6 otn6 Ges8 cost ntdb ods] sess dese ososes 9 Sand and gravel, fine strata -.....- 2. ---- 2. eos oon a nnn nn nn wore wwe nn === 37 TEN Ch OEM ose cao gee tebeoe CHaS comb OSHS p52 GooSdesaes acon ooboce Goce cane aso boss onosad pasSedosce s36 23 Ao Ghai = Sins6 co scee coou seatoade seco Sodeos caso bse sods= HosbecrosoneeeaStood sss sce s2a59 140 The bed of driftwood and soil was struck at about the level of the sur- face of the older drift sheet outside the moraine; it may be either Peorian or Sangamon. In the coal shaft two soils are reported, of which the lower one appears to be in the midst of the older drift; at least it is placed below a gravelly hardpan, such as is commonly reported when the older drift is struck. The following is the section as published in the Geology of Ilinois: Section of drift in a coal shaft at Decatur, Illinois. Ft. in Stoll ayndl GPR jeescnc Sh cone Soeoposned esos ses case eosey cass 0SSSe0 dSaso= Sass Sots oasesoseooseeocs 31 0 Spyaal ata ie Glen Waa 66 se Gbse 5466 Sone cood sesso coca bee pea coders bosesc Sheaen conecegecoS Wil (Qi SEINE! oo os enc pon esbode coos teas oo Ss ado bed ones aso cbon sete Reaead Seco sSsaeesecsessescse 2 6 Tough) clay, --2--- ---- <= ---- whoSch GooSem Heciese sonnds Seco caso boseod segs beso dsosbs Essbccisoses 4 0 THOS SOM S546 pate Hoes oo0has 5465 Hote eceocesoes Saceene occd one soca dosocseSes seeb casoeaco esos 2 6 Spindle ssccocesS shsessoseetossdocscsas Ssaabe bons osaadeSedesesesdes caso msdsSa66 sas0 bss Ssasbe 2 0 (CHEN conoss sotade Soto Gacy dotebs Sees Rad Sse SSeS BEES PB EasE CSosao SEES DSOHSS SSO Cnc Kebsenss ssee 3 0 (Giese s Fen ee ssoSendse oscocacecedenses tenes: Esso eRSaSoeass Hbaoeg ceSosocosenssssescoos 6 0 (Greasy MERTEN Coe6 Soo Sse Seo cas setts Sas aesepeedddcends Cosson mess ceca medo sosorSsassoesasos 11 0 WEOK ROM cssotontassnaccos soesesocewd Sons sess SaeenaesSsaosesqesse Seca sess56 bets Fae See eee 2 0 Quicksand .-.--.-- 2-2. 52-22 < oo ane nnn rn = a = nm oa = wn wn an Se ww is en wn 4 0 Gravelly clay --..---- ------ ---- ---- 2+ 022-2 ee nn ins wens rae ne ns enn Sen ee en = 24 0 Quicksand .---.. ---- -------2--- + --25 22 23 one nn nnn nn ne 2 een eee nen en enn ane 6 6 MeL GNF Sono cose Hoos we doe SAROSO Ob eSoe See ceHlbocobeSooods cboESO doce seot cade oSeees 109 6 Many wells in the vicinity of Decatur are sunk to a depth of about 80 feet before obtaining a strong supply of water. ‘The till is apparent-y a nearly unbroken sheet. On the moraine west of Decatur, in the vicinity of Harristown, wells are often sunk through blue till to a depth of 100 or 125 feet. It is thought that they obtain their supply of water at or near the base of the Shelbyville sheet. North from Decatur, in the vicinity of Maroa, about 60 feet of blue till is penetrated before water-bearing sand or THE SHELBYVILLE MORAINE. 205 gravel is reached. The waterworks wells at Maroa have a depth of about 100 feet and terminate in gravel. At Clinton the drift is found to have the remarkable thickness of 352 feet, making the altitude of the rock surface there but 380 feet above tide. In the record published by Worthen’ twenty-seven changes in drift structure are reported. The lower 140 feet of the drift is entirely sand and gravel, while in the remaining 212 feet there are thin beds of sand and gravel whose combined thickness amounts to but 47 feet, the bulk of the deposit being of clayey constitution. Another boring about one-half mile north of the one recorded is reported to have penetrated only 270 feet of drift. In the vicinity of Hallsville, 6 miles west of Clinton, several gas wells have been obtained in beds of gravel below blue till at depths ranging from 96 feet to about 140 feet. Some of these wells furnished a sufficient amount of eas to supply fuel for one or more stoves, but at last accounts (1897) the supply was decreasing. The section’ of one of these gas wells on James Barnett’s farm shows an interesting series of drift sheets separated by buried soils, as follows: Section of a gas well in drift near Clinton, Illinois. Feet iL, Sahl endl syoHl G7 @lenyceksde spose socdos KoUsaS 4G 55Ry OsHEco Auab eEnbacebus Sante SoHOsS Sasm cease 15 Bo ARIM@ ClO cabo cece sosess dbo sos neetoe 656000 cauaou Huou BueneD poDGas oasuedad esoane becouse SaH5 30 Sepblackssolleawibhywoo aes oerse ire we atest oe nine cine pear asleep a mada Tr ot Se ual ee liver cheese 3 dle IORI) GAS) cose se sopacs oao5 secnS8 a cdoa60 sseSe0 sSocce anes Sobeto DBaodd GeaSeanoos Soub Cans edaasS 8 By BIRO mm Gamal. GhabiinrOOdl2 2s Sees Seneces anes ssoscconnop Hens Cons oEse Hood easaeeUEEeuneoecus 8 GleWrab=colorediclaneeniselseeae he once oes. Teele ese Sepsicicie clean ate ae eeisicibaee es ogists ee cs 20 Tad Dee ti cKOeXe WG GR Ace Cetera aaa o OnE med HaHa re a Seine SAO IMAC CIA SE eters eH ES Se maby chen eo leas 2 Som rab=COLOLE nC Divanerys ces mate sete se ean ie cretcas eter aes SONA pe eal al aaa sarees ep alaie phan A Fee ere 21 Oy TERWUN IY aed A Sei Sak CUSs Cone ae HES Bac eooaAae ae Dene ad Us Sree Oeeces Re hae SerIac eer een a seeeetenan boy LOND rab-coloredycl aysccee cere ris ease a= = inreeee eC ee resi iernn Sc lotace ee mmeeinje aoa eis Serine L 1bl, Guerin Obi ccao hese seGmesaccoe see apeduinsbe! SSa56- CONO SORCICe ROE SENSE CSc oR ee Sela mnrRteioe 10 1G SENG) GUO! (eS Sbate pe SAR BO ASE OBE e eNOS He BOSSE CoH ies, oe ONC eynes ne eae el ees cere rear 5 IOUS mame dao SOS aO ORM ana e CO COC OE EA DC OU GEO a SSSR See eae nee CSE eee geeear ges ae ae 137 In this section it is probable that only 1 and 2 are to be included in the Shelbyville drift. Number 3 appears to be the Peorian soil which caps the loess in the region outside the moraine, while 4 probably represents the loess and 5 the Sangamon soil between the loess and Illinoian drift. In the vicinity of Atlanta the drift has a known thickness of over 200 feet. Records of several wells were obtained which range from 125 to 210 1 Geology of Illinois, Vol. VIII, p. 34. 1Published in the Geology of Illinois, Vol. VIII, pp. 58,59; also p. 13. 206 THE ILLINOIS GLACIAL LOBE. feet in depth, and none of them reached the rock. They penetrate about 100 feet of soft till of blue color, probably referable to the Shelbyville sheet, beneath which a harder, brownish-blue till is entered, which seems referable to the Hlinoian drift. The village of Atlanta obtains its water- works supply from two 8-inch wells 151 feet im depth. The following detailed record of the drift beds penetrated was furnished by J. 5. Bevan, mayor of Atlanta: Section of a well at the waterworks at Atlanta, Illinois. Feet. BACK Moll = o5d553 sescse coones bedace Hoc0 Sooes6 sho5es Hoesed aesd SooDSabaanns omSSnS ceo ceo Comshe secs 3 MONON? CEN Shgee5 coseso Sones secon sl odenSs Hane BosdsoSEa paps ac beeoakocos Dee SdS cmb ess eooShe gecone 15 IBJLOK Wlby? ae sabe nese HH js obeben edosee dace Sa sees npaRts ca seebiedincesbasees soEbcusocetrsees ssc055 35 10 Gray sand and gravel -----. --- 2. 225 228 ne a nnn ne ns na ane 10 TBI) WANA Soomccascass cseca Soe asa0 Seas eases anermooa as dsas Bopeennadcnuooausc oS ssSose saad oecooeoe 2 Sand and gravel. .-----..----. ---- +--+ 2+ --- 22 22 een = one er ee sen 2 eee 9 Vangie) Clay andl eepeGl oo 56556 Ghee Sons conn Se con oo0 ono sso sages sso se Snsneors Sass soSSso sconces 7 Bluo clay with gas -- <= -2- san no a nlm am mw nin i a sooetics 3 Vane sal andl faehyOll . 55 Skene soos cio sadece aaee same cemees capaac os55 S665 Scns copeRdcadoceace 10 Sills soosocesoe sosaao Sosa Sebo asus bd5bEs conde0 doseha=sHces srBacaosdas- ssapsosensco seas oSsacs d26 6 Dry sand and gravel with gas. ..---.------ .--.------+----- ------------ ------ ++ +--+ +--+ +--+ ------ 13 IBIS OES, segedes coos see ord Bee nsd CJoaoe eoesee seca onSonS conser ous Babee san eLeecy csckianco peebas £ Clay, sand, gravel, and gas.-..-..-..---.-------------------------+-------------------- RUE Sie ss 18 IE ehh) sone see sees oes Socb Gen eee See eso esao Ceenes Scar Sec an escahs sooo s SS c059 bose b econ bons Sade 9 IIs beauty Gnaolbmibhy IeorMan ISO) s565 sesend Cooked ocoslcuce edapaaec qege eoboomennsssoscasncnsese 3 6 White clay (probably Wowan\silt)-—--: == - =o. (a sai m= aia = ea 2 Greenkelay (prob aby@lonvamys lh pees ea ee ea lee ae eee ee ete 4 Hardpan (probably, Tlimoian till) - oe eee ne eae ocean eee ce ieee 10 (Greavdell Guatll WW ooasc Gaston sSeh ae Sad See e se oo dso bees ceecas acooos sSbo scrose Saabs Sees a0sRcsne 12 INL, eoocooet eden gosmce eae Sane eases Gaoe CeNebo Hoos UopaneE Scone bosd. snes sgoss5 oposSsoceses 151 The black drift noted in this well section has about the level of the plain outside the Shelbyville drift sheet, and is probably a soil formed above the Iowan silt. In the vicinity of Delavan the drift over an area of several square miles may exceed 300 feet m depth, for the Shelbyville sheet -here encroaches on a preglacial valley; the thickness in one well is 313 feet. The city waterworks well is 240 feet in depth and has the following section, furnished by J. D. Mount, city marshal: Section of the well at waterworks in Delavan, IUinois. weet. Vellonvsbowlderelayal(Shellbyavalle@e sh Cet) eget ete se te aint allele eee ee 15 Bltreowlderelay.(shelbyvilll GSN Cet) me ate eet at ele ate ele ate 60 Black=mucels withiwoods (probably eorinnesoil)) yee =e se = ee ne ee eal lee 6 Soft ereen clay (probably Iowan silt). ..---- .------.------.----. ------ ---- -++= ---- -=------------ 8 Hard gray bowlder clay (probably Ilinoian till) ..-.-.. .----.-----.-.----------------------------- 30 Gray sand containing water .-..-.-.---.---------------- -------- +--+--- +--+ 2222-2 5+ + -- 2-2 --e- 122 BI a eonn cobdee beecse Gan eod SSSSa0 commas SoScosscetadsosc Sasooe Sasaccesds 66 casa anseSecasa 240 THE SHELBYVILLE MORAINE. 207 The black muck penetrated in this well is at the base of the Shelby- ville drift sheet. Mr. Mount reports that several wells in the vicinity of Delavan have encountered a similar bed of muck at this horizon. : Attention was called above to exposures along the Toledo, Peoria and Western Railway east of Peoria, and also on the east bluff of the Ilinois opposite that city, where the Shelbyville sheet is underlain by a bed of fossiliferous loess similar in texture and in age to that found on the surface of the Hlinoian drift outside the limits of the Shelbyville drift sheet. The loess is 8 to 12 feet in thickness, or about the same as on the uplands outside the Shelbyville sheet. It occurs at a corresponding elevation of about 200 feet above the Illinois River. Beneath it there is exposed fully 100 feet of the older drift sheet. The thickness of the Shelbyville drift sheet above this loess varies greatly, being in places but 20 feet, while elsewhere it is 75 or 100 feet. ‘The variation is due in part to erosion and in part to original inequalities of thickness. As previously noted, these exposures afford excellent opportunity for contrasting the Shelbyville sheet with the older drift and for studying soils formed on the surface of the older drift. In the portion of the Shelbyville moraine west of the Illinois River there are several wells 150 feet or more in depth which penetrate a blue till until the level of the base of this drift sheet is reached. In places its depth is more than 100 feet, and seldom does it fall below 70 feet. A large well was dug by William Dickison on the crest of the moraine 24 miles west of Alta. The well entered blue till at less than 10 feet, which continued to a depth of 117 feet. Here a very bowldery bed 4 feet in thickness was passed through, under which a bed of loess was found, specimens of which were examined by the writer. Beneath the loess there is a hard pebbly clay, apparently Illinoian till, alternating with sand beds. Gravel con- taining water was struck at a depth of 156 feet. A well made by John Holmes, jr., one-half mile west of Alta obtained an abundance of water at 125 feet in gravel below till. But a boring made for John Holmes, sr., 1 mile east of Alta failed to obtain water, though it reached a depth of 370 feet. It apparently did not strike rock, but terminated in a fine sand. A bed of muck with wood and leaves was found at the remarkable depth of 245 to 247 feet. The sand below the muck is perhaps an alluvial deposit of pre-Illinoian age. In the vicinity of Dunlap the best supply of water is obtained at 100 to 112 feet, in gravel and sand associated with the older drift. In the 208 THE ILLINOIS GLACIAL LOBE. village the base of the Shelbyville drift sheet is reached at 65 or 70 feet, and afew wells are obtained at this depth. A well at Harrison Harlan’s, 2 miles south of Dunlap, at a level about 40 feet lower than the village, has a depth of 117 feet. It is mainly through the older drift, which is largely till, and water is obtained in sand and gravel at the bottom. CHARACTER OF THE OUTWASH, Considerable attention has been given the deposits and valley terraces immediately outside this drift sheet amd on its outer slope in order to ascer- tain the character of the outwash. It is found that silt deposits, as well as sand and gravel, cap the surface of the outer face of the moraine and extend out onto the border plain. The silt deposits are loess like and fos- siliferous, and suggest a feeble drainage. The sand and gravel deposits are very limited in their extent, and, on the whole, favor the view of feeble drainage. The amount of coarse outwash is very much less than is found to characterize the Bloomington morainic system, as is shown farther on. In some portions of the border the close association of silt and gravelly out- wash renders the interpretation somewhat puzzling. The features can per- haps best be set forth by giving attention to each valley in turn which leads away from the Shelbyville sheet into the outer-border district, beginning with the Wabash Valley and proceeding westward. In the vicinity of the Wabash Valley the Shelbyville drift sheet is found to be generally coated to a depth of several feet with a yellowish loess-like silt. This is especially well shown on the west side of the valley in the vicinity of St. Mary’s, Indiana. This silt is better developed on the border of the river than at points a few miles back, there being scarcely enough silt in the latter situation to conceal the bowlders which cap the till. The distribution of the silt seems such as would be expected if drainage conditions were inadequate to carry off the water from the melting ice. There are, however, other features which seem to indicate good drainage conditions. At the point where the moraine crosses the river, near Ather- ton, a gravel plain is built up to a height of about 75 feet above the present stream, whose surface carries basins such as occur on gravel plains or ter- races leading away from a moraine, and are found only near the moraine. There is at least a suggestion that this gravel plain is to be correlated with the Shelbyville moraine. This view is strengthened by the fact that the THE SHELBYVILLE MORAINE. 209 material is very coarse at this point compared with that above or below, there being many bowlders, as well as cobblestones, embedded in the gravel. Were there no basins, the coarse material found in this portion of the terrace might be explained as a product of subsequent streams working upon the portion of the Shelbyville moraine which had been laid down within the valley, but the basins favor the view that this portion of the terrace is the product of the headwaters of a glacial stream. The removal of fme material from this terrace seems to indicate that there was good drainage at the time it was forming, a view which does not readily har- monize with the silt deposition along the valley. Passing west to the Embarras Valle y, which leaves the Shelbyville drift near the line of Coles and Cumberland counties, one finds evidence of a moderate discharge of water down the valley. The outer face of the moraine contains knolls of gravelly constitution in the immediate vicinity of the Embarras River, and among these knolls there are plane-surfaced tracts of gravelly material having the appearance of being the deposit of streams issuing from the ice margin. On the immediate borders of the Embarras Valley there is still better evidence of glacial outwash. Gravel deposits form a sheet which caps the till to a depth of several feet and which declines rapidly from the crest of the main ridge southward to the plain outside the moraine, occupying a very shallow valley in the passage down the slope of the moraine. Remnants of this gravel, preserved along the brow of the bluffs, stand 90 feet above river level at the northernmost point noted (2 miles north of the county line), and but 70 feet opposite the ford at the county line, and 45 feet at the south edge of the moraine about 2 miles farther south, and 35 feet above the river at the oxbow curve a mile farther south. The rate of descent is, therefore, about 10 feet to the mile more rapid than that of the present stream. At the north the gravel over- wash stands 35 feet above the level of the base of the Shelbyville drift sheet, whose limits are here well defined by a white clay such as caps the older drift outside the Shelbyville sheet. At the south border of the Shel- byville drift the surface of the gravel stands 25 feet below the level of the white clay; it therefore cuts right down across the plane of the white clay. The valley of the Embarras above the south edge of the Shelbyville sheet has probably been excavated entirely since the Shelbyville drift was MON XXXVIII——14. 210 THE ILLINOIS GLACIAL LOBE. deposited. The depth of the gravel deposits on the outer face of the Shel- byville moraine is but a few feet, seldom so much as 15 feet, and the gravelly belt, including the knolls as well as plane-surfaced tracts, has a width of scarcely more than 2 miles. The gravel has been carried but a few miles south of the limits of the moraine, there being only sand from the vicinity of Greenup southward in the terrace remnants found along the valley. These terrace remnants stand 20 to 40 feet below the border uplands and have apparently been built up at least from the level of the stream, 25 feet or more. The moderate transportation of gravel seems to indicate that the discharge was not vigorous and that drainage conditions were rather imperfect, except on the slope of the moraine. Passing westward to the Kaskaskia Valley, which leaves the Shelby- ville drift at the city of Shelbyville, one finds that the valley below the border of the moraine contains scarcely any deposits coarser than sand in the terraces built up during the Shelbyville or later stages. Light deposits of gravel were found on small tributaries at the pomts where they leave the Shelbyville drift sheet, but these are only a few feet in depth and are not, as a rule, continued down to the river valley. Within the limits of the moraine immediately above Shelbyville there is a terrace standing about 25 feet above the river which contains gravel and cobble. In places the gravel and cobble are found to rest upon till and to have a depth of but 8 or 10 feet. In other places the gravel apparently extends to the underlying shale, which, as shown by the bridge piers east of Shelbyville, sets in at 15 or 20 feet below low water. It is not entirely clear that this gravel and cobble was formed as an outwash from the ice sheet at the Shelbyville stage. On the contrary, it seems quite as probable that it is a residue resulting from the cutting down of the valley since the Shelbyville stage. In the process of cutting down, the coarse material would become concentrated while the fine material would be transported down the valley. In harmony with this view it is found that the surface of the terrace is somewhat below the level of the Shelbyville drift sheet and occupies a valley cut in that and the older drift sheet. The evidence from this valley, therefore, indicates a feeble outwash from the ice sheet at the Shelbyville stage. The next valley of importance-leading away from the Shelbyville drift sheet is that of the Sangamon River. Along this valley from the edge of THE SHELBYVILLE MORAINE. PALL the Shelbyville sheet down as far as Springfield the terraces are composed of a gravelly sand with a few large pebbles. It is not certain, however, that these terraces should be correlated with the Shelbyville drift sheet, for they seem to be quite as well developed above the point where the river leaves the moraine as they do below that point. As indicated farther on, these deposits may be correlated with the Cerro Gordo moraine. At the point where the river crosses the Shelbyville moraine, south of Decatur, and also south of Harristown, the terrace remnants are found to lie in a valley cut to considerable depth into the Shelbyville sheet, and no over- wash gravels were found at higher levels. It should be stated, however, that, owing to the absence of wagon roads following along the valley and the inclemency of the weather at the time the writer was there, the valley was examined only at the two road crossings south of Decatur and south of Harristown. Further study at intermediate points or below Harristown may bring to light gravels which can be correlated definitely with the Shelbyville moraine. Along the valley of Salt Creek, the first stream of importance issuing from the Shelbyville moraine north of the Sangamon River, a light deposit of gravel was found immediately outside the moraine on the road between Kenney and Hallsville, but the main deposits of the terraces along the valley are sand. This stream, like the Kaskaskia and Embarras, seems, therefore, to have carried only a weak discharge at the time the Shelbyville moraine was forming. ; Two tributaries of Salt Creek—Kickapoo Creek and Sugar Creek— which cross the Shelbyville moraine farther north than the main creek, have their sources in the Bloomington morainic system and carry terraces whose head is found in that moraine. The valleys were not given sufficient study to enable the writer to determine whether they also have terraces which may be connected with the Shelbyville moraine. If such terraces are present, they are far less conspicuous than those which head in the Bloomington moraine. On the Mackinaw River a terrace has been traced into connection with the Bloomington drift sheet, but none has been found which ean be corre- lated with the Shelbyville. A deposit of loess several feet thick caps the Shelbyville moraine in the interval between the Mackinaw and Illinois Pie THE ILLINOIS GLACIAL LOBE. rivers, and also farther north and south, which, as above noted, seems to have been derived from the Shelbyville drift rather than brought by wind from the plain of Iowan loess on the west. On Farm Creek, which enters the Illinois River opposite Peoria, and on small western tributaries. of the Illinois just north of Peoria, as well as on the borders of the Illinois Valley in the vicinity of that city, there are gravel deposits which it is thought are derived in the main from the Bloom- ington moraine, though some of the deposits west of the river may prove to be connected with the Shelbyville. Those along Farm Creek may be traced with but slight interruption eastward into connection with the Bloom- ington moraine. These gravel deposits have a remarkably high altitude above the Illinois Valley, their elevation being about 175 feet above that stream on each side of the Illinois Valley at Peoria. It would seem, there- fore, that the Illinois and its tributaries have been cut down this great amount at the point where the Shelbyville moraine crosses the river, since the Shelbyville stage, and probably since the Bloomington. However, the valley was apparently filled here to a greater height than at points above and below. A view of the gravel at Peoria is given in Pl. XIII. It is of medium coarseness, and in this respect harmonizes with that usually found in terraces that head in the Bloomington morainic system. It is coarser than is commonly displayed by the terraces that head in the Shelbyville drift sheet. Kickapoo Creek and its tributaries, which lead away from the Shelby- villé moraine in northern Peoria County, have terraces of sandy gravel which are doubtfully referred to the Shelbyville stage. They may prove to be simply incidents in the cutting down of the valleys through the some- what sandy drift deposits outside the Shelbyville moraine. There appears to be no gravel terrace along Kickapoo Creek that can be correlated with the Bloomington moraine, though the stream heads in that moraine. In view of the evidence just cited concerning the character of the out- wash, it appears that in general it was weak, and it is doubtful if a vigorous outwash at any point can be proved. THE SHELBYVILLE MORAINIC SYSTEM, PV INNER-BORDER TRACT. TOPOGRAPHY. The topography for some distance north and east from the border of the Shelbyville drift is of a gently undulating type, not markedly different from that of the thickened border. North and west from the Sangamon River there is a triangular tract included between the Shelbyville and Bloomington moraines in which swells 10 to 30 feet high are not uncom- mon, but no well-defined morainic belt has been found. East from the Sangamon River there are several small drift ridges lying between the Shel- byville and Bloomington moraines, but the greater part of the surface is plane. Aside from the ridges, the surface is less undulating than in the tract west of the Sangamon, just mentioned. These ridges are discussed individually and in some detail farther on. THICKNESS OF DRIFT. ~The Shelbyville till sheet covers this inner-border tract to a depth gen- erally of 50 or 75 feet, and in places 100 feet or more. The depth seldom falls below 50 feet. It is usually not difficult to ascertain the thickness of the Shelbyville sheet, for well drillers report that it is much easier to pene- trate than the underlying older drift. In the detailed discussion which follows, these differences are set. forth. STRUCTURE OF DRIFT. In the district west of the Illinois River the Shelbyville moraine is separated from the Bloomington moraine by a narrow lowland, nowhere more than 8 miles in width, and running to a point in northern Peoria County and also at the border of the Illinois Valley. Apparently the drift beneath this lowland is mainly till and has considerable depth, one well having gone down 218 feet without entering rock. The well referred to is located on the farm of John Miller, 4 miles north of Dunlap. The well driller reports that the upper 69 feet was a soft till, mainly of blue color, and probably to be referred to the Shelbyville drift sheet. The remainder was a hard, brownish-gray till, apparently Hlinoian. 214 THE ILLINOIS GLACIAL LOBE. Passing to the east side of the Illinois, we find the Shelbyville and Bloomington moraines closely associated at the east bluff of the river, but becoming separated within a few miles southeast to a distance of 10 or 12 miles. An interval of this width separates them from the Mackinaw River southeastward to Kickapoo Creek, near the meridian of Bloomington. The Shelbyville moraine there turns south and the Bloomington moraine turns east, thus leaving a wider interval between the two morainic systems. In the remaining 75 miles from the meridian of Bloomington eastward to the Indiana line the interval between these morainic systems is 40 to 60 miles. This interval, however, as stated above, is not entirely occupied by a plain, but is crossed by several drift ridges, which form the Champaign morainic system and the Cerro Gordo moraine, and these ridges are found mainly east of the Sangamon River. A wide tract west of that stream has a generally plane surface, with only occasional swells, and these but 10 to 30 feet or less in height. This tract included between the Shelbyville moraine on the west, the Bloomington moraine on the north, and the Sangamon River Valley on the east, is underlain by a very thick deposit of drift. Records of several wells which penetrate more than 200 feet were obtained, and it is probable that the average thickness of drift exceeds 200 feet throughout the entire tract. The following represent the deepest wells of which records were obtained. At the village of Morton the waterworks well terminates in sand at a depth of 230 feet, and three other wells within 2 miles northwest have about the same depth, and none reach the rock. The engineer at the waterworks states that for about 100 feet the drift is soft and easily penetrated, and is mainly of blue color. This, presumably, is the depth of the Shelbyville drift sheet. The next 100 feet is mostly a hard, gray till, though a bed of sand 20 feet in depth is included. The lower 30 feet is white sand. At Hopedale, 12 miles south of Morton, near the inner border of the Shelbyville moraine, a well made by the railway company reached a depth of 195 feet. It was mainly till, except the lower 35 feet, which was a fine ° sand. A bed of black muck was passed through between till sheets, but the precise depth at which it occurred could not be ascertained. ; In southwestern McLean County a few wells have reached a depth of 200 feet without entering rock, but the majority of tubular wells are 75 feet or less in depth. The Shelbyville drift sheet apparently has at least “this THE SHELBYVILLE MORAINIC SYSTEM. 215 depth (75 feet), for the wells are entirely through soft till to the water- bearing gravel near the bottom. In the vicinity of Heyworth inflammable gas is found in sand at depths ranging from 155 to 214 feet. The strongest well is located on the farm of J. C. Wakefield, three-fourths of a mile southeast of the village, and has the following section, reported by the driller, Mr. Gault: Section of Wakefield’s gas well near Heyworth, Illinois. Feet EME (Shelbyvillelsheet)perseneeersarecmae saan cece ee ae eee ae nen eee noe 33 Grayeland san dagpropablygsnellbyville)ieeeeeneeeeseeees tees eee eee eee ee eee nn nal 69 Hardiclayanduhin ospe bb] estore rittesssssrer eee neste erence eet eee ae ee nt 36 SENG Siso doch nodece eoDHoS.doodaS De bees SORE Ab OROHEe qHoRGH Bere ScGds uscoao SSE ECE eee Eee 15 Ha rdeblu exe] ayz cme rastartaey eis lee cpa sents ee Scie Soe eae oa oc see Reo ee Pe oo ee 35 Har dtclayawithen Oj ori time sn sores ce tery ke vee e aine acon ine mrs eae eaemeen ee eC envi) hs ere Ls 11 IRIE CATO S SaGdan asccboosede sehee BAG GUE BOA 4 bouU Sen BBe6s BSS BE ons aloe koe Soe alah tc rays eae aes 2 isteneal pam Cleny \WilNON Fr oobo cbeAa6 sododo beaten Guu bobooU leanne soaadecagdae cobeneedosde choco: 13 Sand and gravel with gas. Rotalidepthyereeeesccseceeeee ses Sbon Code teiceas socded posclodebae uaSeaRtodecSBebLaSs Basueaae 214 When the gas was struck, sand and gravel were blown out of the mouth of the well, and the well now has a pressure of 22 pounds to the square inch from a 2-inch pipe, and supplied fuel for 200 stoves during the winter of 1896-97. At Wapella, a village 6 miles south of Heyworth, the deep tubular wells penetrate about 80 feet of soft blue till referable to the Shelbyville drift sheet. Beneath the blue till is a bed of black muck, probably Peorian, with a green clay, apparently a swamp subsoil, underlying it. This is perhaps an Iowan silt. Beneath the green clay is a hard bowlder clay, referred to the Illinoian. Many of the wells are obtained at the base of the Shelbyville sheet at 65 to 80 feet. Those which reach a ereater .depth obtain their supply from sand associated with the older till, and the sand not infrequently yields a considerable amount of gas. At Leroy, in southern McLean County, the waterworks supply is from a well 110 feet deep, which obtains its water from sand below the till of the Shelbyville sheet. Wells are occasionally sunk in that vicinity to a depth of nearly 200 feet and penetrate a large amount of sand in the lower portion. At Farmer City the waterworks supply is from a well 176 feet in depth which does not reach the rock. It is mainly through till, but there are 216 THE ILLINOIS GLACIAL LOBE. several beds of sand and gravel associated with it. A prospect boring for coal made at this city penetrated 189 feet of drift, as follows: Section of boring for coal at Farmer City, [Uinois, Feet. AGL EO lc cos GooaeduesS sobose Sadooe sbeeed sopoes padeSho0C 0c Ser neb me GRomos Sens AoIDaGC 0500 Sosa 2 Slit WOU Ge oem ease pode cedaeso oeeseb ob oae) gaSebo C0 beso Od sp SO0080 BORmDrno HOO ACSCOC A OOOC DOO 9 TMG nll boo 5 eye eco Spbeas cocolS Cone Goce ban Goce ChES CSCO Onto ts SSE ODOSROBanMinnoCoT etiSco 55005 36 Spinal Atal Wd) Pigg aeog OonCnd Boos sooo ee ouasau Dodds CoS US Ocnn0S 90 GU RS GEES Bemmon HoBecoccag o0o 5507 2 TOO AHW oes Boo eseGse seocoerboS Secomuldaniaae crite Sodd napSbe pdonep Sea oE DSCC oodobS beaencsacicg 21 Sand and gravel ---..-.- -22- 222-0522 o-oo cane eens wenn wen enn oon meni oe eee 40 IBN Cle hy) Gasees ducaes beebab sSeba> b9eSa5 040005580050 0000 CSE SE DDO oO COS SES EGO DECC Eo chan bonGono5 6 Sand and gravels. 22. 2222-2 2 nene one ne en nin ee nn nn ene Se nici nin cin no nine anal nicinim 8 Senha MAN) Gl Ey feseooeueeeeo pobeon beaeec Seca SS pec OS 000 COO Cde FURR Se hee S006 0 OEg OSE b SOO CosoGOrp 40 Sand and gravel.----. .--- 2-2. e222 2 cee ee ee en cee cee ee een ene non ee ere re er nc cons 23 Inllnt) eh) coeese saceioo eseous codec osecdes Secacd oocoms b4ose SopeSr acesr pec aned aches Coens S500 0500 2 Gla LGhsb in gone SoseSb boos Coneou bedode code Sooo bb Gera Gucaao Eecere cscoc 556005 saan a4cc 189 Several interesting well sections and bluff exposures are found along the west side of the Sangamon River below Mahomet. About 13 miles _ southwest of this village, in sec. 16, T. 20, R. 7 E., the river exposes in its northwest bluff a bed of peat under the Shelbyville till sheet: The expo- sure is several rods in length and the section is as follows: Exposure in bluff of Sangamon River near Mahomet, Illinois. Feet Yellow till with gravelly places near base, where springs issue...--------------------+--------- 10-12 Gray till with yellowish tinge......--.----.------ -----+ ----+- ---+++---+ 22-22 222222 ce rere eee 20 Peat, earthy except 3 to 6 inches at top. .----.----------- ------------------------------------- 2 Gray earthy subsoil, exposed .....---..---. ---- ---- -- ---- +--+ -- ++ --- + 2-22 222 eee cere ee 2-3 Total, to river bed.-.. ..-..----------- ------ ---- 2-3-2 oe ne nn wn en nn wn eee 36 It is probable that the Shelbyville sheet is reduced at this place to a thickness of only 30 to 32 feet, as the altitude near the river is slightly lower than the general level of the border plains. Wells between this exposure and Mahomet pass through a black muck or peat at about the same level as that exposed along the river. One on the farm of James Lester strikes it at 36 feet, and one at the residence of D. McArthur at 42 feet. Mr. MceArthur’s well was continued to a depth of 100 feet and pene- trated a harder till below the black muck than that which overlies it. There are places between this exposure and Mahomet where the entire bluff is composed of gravel. It is principally on the farm of Mr. Lester, and he has tested its extent by means of borings and found that it underlies only 60 acres. Around the gravel on all sides except at the southeast, where it fronts the river, there is till. Its depth is found to reach 50 or 60 feet in THE SHELBYVILLE MORAINIC SYSTEM. PALA places. Its surface has about the same altitude as the bordering till plain, 35 feet above the Sangamon River. At Dalton City, located about 12 miles southeast of Decatur, the bot- tom of the Shelbyville drift sheet is found at 65 feet, and wells have been sunk to a depth of 150 feet without reaching rock. The majority of wells are about 70 feet. It is not uncommon to find beds of black muck below the Shelbyville drift in the vicinity of this village. At Bethany, 5 miles southeast of Dalton City, the Shelbyville sheet is apparently only 40 feet in depth. At this depth a greenish clay, associated in places with a black mucky soil, is usually entered. This clay is but a few feet in depth, and is probably an Iowan silt. It is underlain by a hard eray till, called hardpan, which seems to be [llinoian. The tubular wells in that vicinity range in depth from 70 to 140 feet without striking rock. At Sullivan the drift, as shown by records published in the Geology of Illinois, has a depth of about 200 feet. The public water supply is from wells 100 to 125 feet in depth. The mayor reports that the upper 50 feet is a soft blue till, beneath which considerable sand is penetrated. This is underlain by a hard till which is penetrated 40 feet or more before the water- bearing gravel is reached. In northern Coles County, between Humboldt and Fair Grange, wells are 60 to 120 feet in depth without reaching rock. In some wells a hard gray till is struck at about 50 or 60 feet. The overlying till is soft and probably is referable to the Shelbyville sheet. At Oakland, in northeast- ern Coles County, rock is entered at about 50 feet. At Kansas, in western Edgar County, rock is entered at 80 feet or less. In a few cases wells have struck a black soil at about 30 feet, which is probably just below the Shelbyville drift sheet. A well midway between Kansas and Isabel entered rock at only 40 feet, but others in that vicinity 50 feet or more in depth do not strike rock. In the eastern part of Edgar County, on Clay’s Prairie, rock is occasionally struck at only 20 or 25 feet, and is extensively exposed along Bruillett’s Creek, in eastern Edgar County, Illinois, and southern Vermilion County, Indiana. The general thickness of the drift in that region can scarcely exceed 40 feet. The Indiana district, immediately north from the Shelbyville moraine, has generally a comparatively thin sheet of drift on the uplands, rock often being struck at 50 feet or less, but in the preglacial valleys the drift may 218 THE ILLINOIS GLACIAL LOBE. exceed 150 feet in thickness. As there are several moraines crossing this district the discussion of its features is taken up in connection with them on later pages. CERRO GORDG MORAINE. DISTRIBUTION, The Cerro Gordo moraine emerges from beneath the Champaign moraine opposite the village cf Mahomet, in Champaign County, and fol- lows the east border of the Sangamon River Valley, at a distance of 1 to 3 miles from the stream, from Mahomet southward to Cerro Gordo, a village 10 miles east of Decatur. It there swings away from the river, and is dis- tinctly traceable only to Laplace, 6 miles south of Cerro Gordo, there being for a few miles no definite continuation. A distinct ridge, however, appears near Humboldt, in northern Coles County, which is supposed to be its continuation. This ridge is traceable in a general eastward course, but with slight windings, through southeastern Douglas and central Edgar counties. The interval between the Cerro Gordo and Shelbyville moraines varies greatly in width. Near the city of Paris they are closely associated; at Humboldt they are separated by a space of 10 or 12 miles, and a similar interval is found opposite Cerro Gordo. From Cerro Gordo northward the ridges pursue divergent courses, so that opposite Mahomet they are separated by a space of 25 or 30 miles. TOPOGRAPHIC EXPRESSION, The portion of the moraine between Mahomet and Laplace consists of an irrecular aggregation of drift swells and short ridges, occupying a belt about 2 miles in average width. The knolls are so closely aggregated that very little plane surface is found among them. The usual height is 10 to 20 feet, but a few are 30 feet or more above bordering low ground. The belt is sharply in contrast with the level tract to the east, and has on the whole a stronger expression than the Shelbyville moraine. The portion leading eastward from Humboldt presents more variation in topography than the portion just mentioned. In northern Coles and southeastern Douglas counties, and for several miles in western Edgar County, it consists of a smooth till ridge one-half mile to a mile in width, with a relief of 20 to 30 feet. In places it is but 60 to 80 rods wide, and THE CERRO GORDO MORAINE. 219 stands only 10 to 15 feet above the border plain. The ridge is nearly continuous except at the Embarras River, which cuts through it opposite Dora Station. In Edgar County the belt has, on the whole, a stronger expression, though there is not so continuous a ridge as in Douglas and Coles counties. There are several small ridges, one-fourth mile or less in width and 10 to 20 feet in height, which form a disjointed chain leading southeastward from Brocton to Paris. Associated with these there are knolls of considerable prominence. A cluster in secs. 15, 16, and 17, T. 14, R. 12 W., known as the Blue Mounds, rise 50 or 60 feet above the border plains. An isolated knoll in sec. 32, T.15, R. 138 W., is about 50 feet in height and occupies perhaps 20 acres. North and northwest from this knoll, in secs. 29 and 30, several knolls rise abruptly to a height of 20 or 30 feet, and one to a height of 40 feet. In the northeast part of Paris there is a ridge leading from Sugar Creek southwestward about 15 miles, which is 30 to 50 feet in height and has a billowy surface. Its width is 40 to 60 rods. Probably this ridge belongs in the belt under discussion, though it is slightly out of line with the belt and is separated from it by a plane tract about 2 miles in width. Toward the northeast there are occasional knolls as far as the State line, but no definite ridge or chain of knolls appears. The well-defined belt terminates at the Blue Mounds. STRUCTURE OF THE DRIFT. Some of the sharpez knolls of the moraine contain gravel and sand, especially along the border of the Sangamon River and in Edgar County. There is, as a rule, considerable till associated with the gravel and sand, and the knolls are usually underlain by a sheet of till The gentle swells and the smooth ridges are composed more largely of till than those of sharper contour. The majority of wells along this belt obtain their supply at a level little, if any, below the base of the knolls and ridges and within the limits of the early Wisconsin drift sheets. A few pass into the older drift. Very rarely a well reaches the rock. The drift, as in the tract outside the moraine, is very thick in Illinois except in the vicinity of the State line, but is thin in Indiana. The following are the deepest wells of which records were obtained: On H. H. Hollis’s farm, in sec. 30, T. 20, R. 7 E., a well is 215 feet -in 220 THE ILLINOIS GLACIAL LOBE. depth, and on B. F. Hollis’s farm, in sec. 31, two wells are 190 feet in depth, without reaching rock. The drift is largely a blue till and but a small part is thought to belong to the early Wisconsin. It is described to be mainly hard till below a depth of 40 feet. F.G. Seymour has a well in sec. 6, T. 19, R. 7 E., 215 feet in depth, which is similar to the wells on the Hollis farms. At Monticello the city water supply is from two wells 212 and 303 feet in depth, neither of which enters rock. The early Wisconsin drift here is apparently but 20 feet thick, the wells being on low ground near the San- gamon River. The following is the record of the deeper well as published in the Piatt Independent soon after the completion of the well in 1891: Section of a waterworks well at Monticello, Illinois. Feet. IO IAN. S55 Sboecme soooes bot Sesno Sos oaed sp oesees cebete ebeoacto race shee cn boredocsosedscoses 3 WOU? DER S26 bene Gesetses ctsesce's Sd 5 nobess cea eee esebosb eso ced nss Sopeas cc sbeciseSriotsedeasens 10 Blue clay (gravelly) -.----..----- BSB SSSR OSES AR ROne Se RoE RO SUES HESS Asoc occ asso oseaeds eS ones ase 7 IBrowenepest yal OAM (CORT RI)® ) ete eet eel eee elle le Cae ee le 7 Sandjandoravelim ~~ --—aie— sb sess conosh SSS Soe Sbe Sasseo SoSobercad SSeS ces sens oe55 2 IOS CLAN? Goseta bons aS S86 Ses ese Sse co doco esSaqqs seus cass dacs Sasa sseshe boseso osasnsss seco scon sé 11 SENG, REG EIGER 5 565 Seto casos cee Ses Sse ese ces aoe SdSon Sosees ocoSas osecassaskacoesc 5 SME ona ondeeceets HeSo ed ho sods Sesocs pa sade dan Sedoses Sek SoSH Seas SoecosooseSsesopasesecuoseses 12 Sind any Glh GG) Was seoce be oe co soe seco oes Ses Soe Sees SSeS ects croc cosocceSascecceacess, OE iHandipluerclay(pebblya hardpan) ceeeecscss sins soe sale ee oe es ese emia seee fs ie eee 494 QGREGIG) oS SRS coS SSeS rs atins Coca SE cies Grands Saceeb seer Da Sse cdSs SosSso bested ceSssesecess 754 Shing] engl ene yal eee s sh oss scone oSoSes SSesen Base pes aes osu SSS bess osooss HSS SooScen cesest G4 (COREG) GRP GM eosen Soe Ssd edicindia sass ssose sense ce cess eee Cee SSS Sec de Sedea sass ceeseolsscensscens 2 INDE Ssh - se Se cco cose sh snes coo SH SSeS Sh SoS eo SSeS ese ss OhSSSs MSSSdS choe soe edé oases stad 303 In the veins of water above the “hardpan” the water is less suitable for culinary and laundry purposes than in those below, because of greater hardness. Both wells are, therefore, sunk to a coarse gravel in the lower water bed. At Bement a well in the business part of town struck rock at 222 feet and is 225 feet in depth. Wells at the waterworks, the railway station, and the mill obtain a good supply of water at 140 to 150 feet, after penetrating a large amount of blue till. It is not certain that the Wisconsin drift has so great a depth as 150 feet at this point, the records of wells being imper- fect. At the cemetery, 2 miles north of Bement, near the crest of the Cerro Gordo moraine, a well 221 feetin depth is mainly through blue till and does not reach rock. At Cerro Gordo there is a nearly solid bed of blue till to a depth of 150 feet, and strong wells are seldom obtained at less depth. That the THE CERRO GORDO MORAINE, OO iT Wisconsin drift has a depth of 150 feet at this point is supported by the fact that the moraine there reaches an altitude nearly 150 feet above the level of the buried soil along the Sangamon Valley at Monticello and near Mahomet. Along the ridge from Humboldt eastward into Douglas County wells apparently reach the base of the Wisconsin drift at 65 to 75 feet, and farther east at 50 feet or less. The sharp ridge situated in the northeast part of Paris has been opened extensively for gravel. ‘There is at the surface a brownish yellow till 5 to 15 feet thick, and beneath this are beds of calcareous sand several feet in depth. Beneath the sand there is a sandy gravel. Both the sand and the gravel show considerable cross-bedded structure, The beds are also arched, and appear to have been crumpled somewhat as if by a disturb- ance by the ice sheet. In order to ascertain the proportion of the various kinds of rock in this gravel, a small space was marked off in the gravel pit and the pebbles therein were classified, with the following result: Classification of pebbles in a gravel pit at Paris, Tllinois. ChEithie pdécsoadse sa pEsaacod cnabes Beso Cason poSaacas Bead coon ase Be pHSEedaune baasoe sccaee cee 6 Othericrystallineyrock ety t= cvscee pare tae onsen seieacty teers Sete ema eee arn eee eee eee 8 Quartz. .... NO SoU IPeoo nO Ddco.oseS cobd CoussG done Sues DomdoO DeSHed saeces cone Buon copa Goo6 SEcH OnE ool 3 Cinging oi Ibysiny COP. caseosccsoxadase nog500 ado SoHo bna500 G4da5— SadSAD SobEsS desu SeoOSS Rubs SooabeoE 13 IBROR WAT CONG is Cdiseree eae eB Aare a5 NERS See SSUES PC ICIS es eI M eS aot ast ly a et 1 Carboniferous sandstones (local) mee srarest ete ere eee rs ree eats Se ee pat re a a 11 Grayalimestone) (probably locall)) meer s-isytanes ee ree eee eae eee eee ae eee 45 Magn esianplimes tone penetra eitaierinsisscioce ieee rete eee ee eee eee en ee ees 48 JRO ass co cB ciocrtocObG5 DOuOE SEO SAO BD ABSA oEESeac GaSe iE SEO SET SG AE es SU SERN tae Siete Mu tes 135 A few of the gray limestone pebbles are striated. These pebbles show less rounding by water action than other classes. It is probable that some of them are from the Carboniferous limestone exposed near Baldwinsville, north of Paris. CHARACTER OF THE OUTWASH. The character of the outwash from the Cerro Gordo moraine has received very little attention. It has been noted, however, that the valleys leading away from the moraine, with the exception of the Sangamon, are small and are usually cut in till. There can not, therefore, be very heavy sand or gravel outwash. Along the Sangamon River for a few miles below Mahomet this morainic belt is bordered on the west by a gravelly plain, whose origin and 222 THE ILLINOIS GLACIAL LOBE. relationships are not fully determined. It may be due largely to the cutting down of gravelly portions of the Shelbyville sheet, such as that near Mahomet just noted. It stands about 20 feet above the Sangamon River, or about halfway from the level of the river up to the level of the till plain on the west. In places the morainic knolls east of the river extend down to the level of this gravelly plain, and seem to be merged with it so intimately that there is a strong suggestion of similarity in age. However, it is not fully established that even in such places the gravel is an outwash from the moraine. As shown below, there is a light gravelly outwash near Mahomet from the Champaign moraine over the till plain that borders it on the south. It is possible that the gravel plain along the valley was built up in part at that time, though the lightness of the deposit at Mahomet scarcely warrants the reference of a large part of the filling to this source. INNER BORDER TRACT. Between the Cerro Gordo moraine and the outer ridge of the Champaign morainic system there is a plain whose width nowhere exceeds 25 miles and usually is about 12 or 15 miles. ‘This plain has a very level surface, there being few swells or knolls and but little variation in altitude. It is under- lain by thick deposits of drift, except for a few miles near the State line. Wells indicate that it may average nearly 200 feet, of which probably more than one-half is older than the Shelbyville sheet. Since the majority of wells obtain water without reaching the base of the Shelbyville sheet, few data concerning the older drift are available from this region, but inferences may be drawn to some extent from neighboring districts on either side, where the data concerning thickness of the drift are more full. Wells in the vicinity of Arcola are reported to have passed from the soft till of the Shelbyville sheet into a harder till, presumably of the older drift, at a depth of only 45 or 50 feet. In the vicinity of Tuscola the wells usually pass from the soft till of the Shelbyville sheet to a harder till, termed hardpan, at a depth of 35 to 40 feet. A prospect boring for coal at Tuscola penetrated 186 feet of drift. It is probable that the thick- ness of the Wisconsin drift is somewhat greater on the portion of the plain to the west of these towns, as shown by records outside the Cerro Gordo moraine already given. The thickness to the east of these villages is prob- ably less rather than greater than in their vicinity, there being a general decrease in thickness in that direction. THE EARLY WISCONSIN DRIFT SHEETS. 223 SECTION II. CHAMPAIGN MORAINIC SYSTEM. Under this head is discussed a group of closely associated ridges which interlock to some extent, but usually consist of two or three distinct mem- bers. The system receives its name from the city of Champaign, Illinois, the site of the State University. The ridges, which are more or less dis- tinct east from this city, become united in a single ridge from this city westward. The discussion begins at the westernmost point at which the system has been recognized, and proceeds eastward to the point of disap- pearance beneath a morainic system of late Wisconsin age. In the com- plex portion separate names have been applied to the several members, viz, Outer or West Ridge, Middle Ridge, and Inner Ridge DISTRIBUTION. The westernmost prominent development of the Champaign morainic system is found in “ Blue Ridge,” which sets in near the village of Blue Ridge, in northern Piatt County, and leads southeastward into Champaign County. There is, however, a narrow belt, with rather more undulation | than is common on till plains, which leads westward from near the north end of Blue Ridge past Leroy to the Bloomington moraine at Downs, and which is doubtfully referred to the Champaign morainic system. This undulatory belt stands 20 to 30 feet or more above the general level of the plain on the south, but the rise is so gradual that the relief is scarcely perceptible. The portion known as Blue Ridge comes to the Sangamon River just above Mahomet. With a gap scarcely one-half mile wide the moraine reappears on the east bluff, and leads southeastward to Champaign, crossing the Cleveland, Cincinnati, Chicago and St. Louis Railway west of the city. The width from Blue Ridge to Champaign averages about 2 miles. A short distance west of Champaign the Outer or West Ridge sepa- rates from the main belt and passes southward through Savoy and Tolono to West Ridge village, in Douglas County, near which it swings rapidly eastward and joins the middle member of the series in southwestern Ver- milion County. This ridge has an average breadth of scarcely one-half mile in its north-south portion, but in the west-east portion it increases to a width of nearly 2 miles and becomes the principal ridge of the series. 224 THE ILLINOIS GLACIAL LOBE. From Champaign a ridge nearly as bulky as the combined belt leads southeastward through Philo. A short distance southeast of this village it separates into two quite distinct ridges. One continues the southeast course past Broadland and joins the outer ridge in southwestern Vermilion County. The inner ridge passes eastward into Vermilion County along a line nearly parallel with, and about 2 miles south of, the Wabash Railway until it reaches the meridian of Fairmount, where it turns southeastward. It comes to Little Vermilion River east of Georgetown and follows the north side of that stream to the Wabash Valley. East of the Wabash its course is north- eastward to Veedersburg, and thence eastward into western Montgomery County, where it is overridden by a late Wisconsin moraine and its further course lost to view. This ridge throughout its entire length is narrow and low, seldom exceeding one-half mile in width, and rising but a few feet above border plains. It is also scarcely so continuous as the other mem- bers of the series. From Veedersburg another weak drift ridge leads northward past Rob Roy to the Wabash Valley near Attica, beyond which it can not be traced, because of concealment beneath later moraines. Returning to southwestern Vermilion County, where the Middle and Outer ridges become united, and tracing their further course, one finds a ridge about 2 miles wide and 50 to 100 feet high passing eastward near the line of Vermilion and Edgar counties into Indiana. In places it has a double crest, but in other places it is a thoroughly combined belt. For a few miles on the west side of the Wabash River it is not well defined, but it is easily located on the east bluff just below the mouth of Sugar Creek. Its course for about 8 miles is south of east. It there curves, near the village of Bloomingdale, and takes a nearly northeast course, crossing Sugar Creek at a narrow gorge known as “The Shades of Death” near the line of Parke and Montgomery counties. In western Montgomery County near the village of Alamo, which stands on its crest, the course is again changed toward the north, and it trends nearly due north to where it is overridden by a moraine of the late Wisconsin series, near Wesley, Indiana. The course of the members of the Champaign system is such that the Inner Ridge is separated from the combined Middle and Outer belt by a space 15 to 20 miles in width in the district immediately east of the Wabash, while west from that valley the space is 10 miles or less. The THE CHAMPAIGN MORAINIC SYSTEM. 295 Outer Ridge at its widest separation from the Middle one is distant but 8 or 9 miles. It is separated from the Middle Ridge for only about 30 miles of the 100 or more miles in which they are exposed to view. The Inmer Ridge is distinct from the others for a much longer distance, being combined with them for only about 30 miles of the 100 which the belt occupies. It will be observed that the moraines are looped across the Wabash Basin after the fashion of the looping of the late Wisconsin moraines about the basins and large valleys, as brought to notice by Chamberlin in the Third Annual Report of this Survey. The axis of the Wabash Basin is depressed only 150 to 200 feet (aside from the immediate valley of the river) below the borders of its watershed where crossed by this morainic system. This slight amount of depression seems scarcely adequate to be the sole cause for the protrusion of the ice sheet into the valley, though it no doubt had some influence. RELIEF. The relief of the combined belt between Blue Ridge and Champaign reaches about 90 feet above the outer-border plain at several points, though it usually is about 60 to 75 feet. The outer-border plain declines from 750 feet at Blue Ridge to about 710 or 720 feet east of the Sangamon. The crest of the moraine reaches 820 feet in northern Piatt County, and 800 to 810 feet near Rising in Champaign County, but averages only about 775 feet above tide. The imner-border plain lying north of this portion of the moraine stands about 730 feet above tide. The outer ridge has a measured relief of 45 feet on the outer border and 40 feet on the inner border at the crossing of the Wabash Railway at Tolono, but at the crossing of the Chicago and Eastern Illinois at West Ridge it scarcely exceeds 35 feet on either border. Farther east, near its junction with the Middle Ridge, the relief inéreases to 70 feet, and one point near Palermo, used by the United States Lake Survey as a site for a geodetic station, stands 90 feet above the general level of the outer border plain. The Middle Ridge has a relief of 25 or 30 feet on its outer border throughout the interval in which it is distinct from the Outer Ridge. On its inner border the relief is about 20 feet. At Philo, where the Inner and Middle ridges are combined, the outer-border relief, as shown by the MON XXXVIII 15 226 THE ILLINOIS GLACIAL LOBE. Wabash Railway survey, is 30 or 35 feet, while the inner-border relief is about 50 feet. The relief of the Inner Ridge throughout its entire course in Illinois and Indiana is but 15 to 20 feet, except where knolls rise above the general level of the crest. In such cases a relief of 40 or 50 feet may be found. The combined Middle and Outer ridge has a general relief in eastern Illinois of about 40 feet above the outer-border plain and about the same relief above the inner border. Where there is a double crest, the sag between the crests is 15 to 25 feet in depth. In the Indiana portion the relief seldom reaches 40 feet, and the aver- age is probably 30 feet above the plains on the outer and inner border. It appears from the data just given that the outer and imner border reliefs in this morainic system are not markedly different. There is not such a filling on the inner border and transition from the moraine into the plain as in the Shelbyville or Cerro Gordo moraines. As seen in profile, the ridges of the Champaign system rise with nearly as rapid slope on the inner as on the outer border, a feature which distinguishes them from nearly all of the moraines of the Wisconsin series, it being the habit of the Wisconsin moraines to present a long inner slope and a somewhat abrupt outer slope. RANGE IN ALTITUDE. As indieated above, the moraine, near the western end, attains an alti- tude of 820 feet above tide, while the border plains are about 750 feet. The altitude of the plains decreases to about 700 feet in southern Champaign County and to 660 feet in the vicinity of the Embarras River, in northern Douglas County. From this point eastward to the borders of the Wabash the plains stand 650 to 675 feet along the border of the combined Middle and Outer ridge. The altitude is less uniform along the line of the Inner Ridge, there being a range of about 75 feet in the Illinois portion. The highest part of the plain near Sandusky is fully 720 feet above tide, while in the western part of the county it scarcely reaches 675 feet, and in the eastern it falls to about 650 feet. On the borders of the Wabash in western Indiana the altitude of the upland plain declines to about 600 feet. There is a gradual rise from the valley eastward to 775 or 800 feet in western Montgomery County, where the moraines of this system pass beneath a moraine of the late Wisconsin series. THE CHAMPAIGN MORAINIC SYSTEM. bo G a | SURFACE CONTOURS. On the whole the ridges of this system are of a type which may best be designated the smooth-ridge type, the surface undulations being very gentle, while the crest is usually well defined. A detailed examination, however, brings to light considerable variation in the features. The portion west of the Sangamon River, known as Blue Ridge, has a well-defined crest, along which undulations of 10 to 20 feet occur. On its slopes also there are gentle swells 5 to 15 feet in height. In the vicinity of the Sangamon River a few knolls of greater prominence appear, though the highest scarcely rise more than 40 feet above bordering low ground. Between the Sangamon River and Champaign the moraine presents a well- defined crest and undulatory slopes. The undulations commonly fall below 20 feet, both along the crest and on the slopes. The outer face is more abrupt than the inner, there being places where a rise of 50 feet is made within a mile from the border of the plain outside the moraine. The Outer Ridge from the city of Champaign around to northeastern Douglas County has a very smooth surface, in which undulations seldom exceed 10 feet. The relief of 20 to 40 feet, however, makes the ridge a noticeable feature. In passing eastward through northern Douglas County the ridge becomes much larger, but maintains a nearly smooth surface. A short distance west of its junction with the Middle Ridge it presents a double crest, but each ridge is very smooth. The belt leading southeast from the city of Champaign presents swells 15 feet or more in height, but the crest is ill defined between the city of Champaign and sec. 33, Urbana Township. From this section southeast- ward, through Philo Township, and thence eastward to sec. 4, Raymond Township, the crest is well developed. It has oscillations of from 10 to 25 feet, and the slopes are characterized by knolls of similar elevation. In the vicinity of Lynn Grove geodetic station knolls and sharp winding ridges 30 or 40 feet in height occur, and the moraine maintains this strength of expression for about 3 miles east from the geodetic station. It there loses strength, and in northeastern Raymond and South townships, Champaign County, and in Sidell Township, Vermilion County, it consists of a smooth ridge scarcely 20 feet higher than the plain south of it. North of this 228 THE ILLINOIS GLACIAL LOBE. ridge there are scattering knolls surrounded by very level tracts. One knoll near the line of sees. 1 and 2, Raymond Township, covers not less than 10 acres and has a height of probably 30-feet. Other knolls 10 to 25 feet in height were observed. The Middle Ridge does not connect closely with the Outer Ridge in southeastern Champaign and southwestern Ver- milion counties, but is separated from it by a sag or depressed tract a halt mile or less in width. This depression connects on the east with the Little Vermilion River and on the west with the Nile, a tributary of Embarras River. For about 5 miles eastward from the Palermo geodetic station a single broad ridge, 14 to 2 miles wide, constitutes the equivalent or continuation of the two ridges found farther west. It does not long continue the sole representative, however, for another ridge sets in just north of the head- waters of Bruillett’s Creek, in sec. 4, T. 16, R. 12 W. From this section eastward nearly to the State line there is a double ridge, the members of which are nowhere separated more than one-half mile. Mortimer stands on the outer and Ridge Farm village on the inner of these ridges. A few basins occur along the ridges in southeastern Vermilion County, the deepest of which are depressed 8 or 10 feet below bordering land and are occupied by peat bogs. The ridges have gentle undulations of 10 to 20 feet, both along the crest and on the slopes. The Outer Ridge has mterruptions or gaps which attord a passage for waters which fall between the two ridges south- ward to the outer-border plain. The gap through which Bruillett’s Creek passes is nearly 75 feet in depth and less than one-half mile in width. Sey- eral other gaps of less depth occur, all of which are quite narrow. They appear to have been deepened considerably by the streams which pass through them. The two ridges become coalesced at Pilot Grove, a promi- nent point in sec. 33, T. 17, R. 11 W. From this grove eastward to the State line, knolls and ridges rise from the crest and slope somewhat abruptly to heights of 15 or 20 feet, and give the moraine a sharper expression than is usually displayed. From the State line eastward to the Wabash River the bulk as well as the expression, decreases, the crest becomes poorly defined, and the undulations are scarcely 10 feet in height. For a few miles east of the Wabash River the moraine is represented by knolls only, there being no well-defined ridge or crest me. The most prominent knolls observed are in sec. 17, Reserve Township, Parke County. THE CHAMPAIGN MORAINIC SYSTEM. 229 They are somewhat elongated in a NW.-SE. direction, and rise abruptly to a height of 20 or 30 feet. Farther east, in the vicinity of Bloomingdale, the knolls are in some cases 30 feet or more in height. In secs. 24 and 19, 25 and 30, 'T. 16, Rs. 7 and 8 W., the moraine consists of a ridge 80 rods to a mile or more in width, on whose slopes and crest knolls 10 to 25 feet in height are numerous. Outside the main ridge there is, in sec. 29, a chain of knolls 15 to 20 feet high, rising abruptly above the bordering plane tract. In eastern Parke County the moraine for a distance of about 10 miles constitutes the water parting between Little Raccoon and Sugar creeks, and there is scarcely a mile of this portion on which knolls 15 to 25 feet high do not occur, while in some sections they reach heights of 30 or 40 feet These knolls stand upon a basement ridge whose relief, independent of the knolls, is 30 or 40 feet. In this part of the moraine the knolls are arranged in chains trending parallel with the crest. In southwestern Mont- gomery County, on the south side of Sugar Creek, there are numerous sharp knolls in the moraine, but not a distinct ridging or well-defined crest. North of Sugar Creek the moraine assumes a ridged form near the south line of see. 34, T. 18, R. 6 W., from which point the ridge leads NNE. through Alamo. Its general height is about 30 feet above the plain west of it, and still more above the bluff of Sugar Creek Valley on the east. Near Alamo, in secs. 23 and 26, several basins occur, the deepest of which are 15 or 20 feet below their bordering rims. The basins usually have outlets through narrow breaks in the rim. West of the main belt for several miles the surface is very flat, but east of it there are ridges and knolls extending to the valley of Sugar Creek. The knolls are nearly as prominent as those in the main belt, but are less closely aggregated. They are separated by nearly plane tracts. The northeast fourth of Ripley Township, comprising a tract 3 or 4 miles wide, is sharply undulatory, with many knolls and ridges 20 to 40 feet high. The moraine here is over- ridden by a late Wisconsin moraine. The latter trends NNW.—SSE., intersecting the Champaign moraine at an angle of about 45 degrees. The Inner Ridge of the Champaign morainie system is well defined from its point of separation from the Middle Ridge, near Philo, Illinois, eastward to the Fairmount geodetic station. It is about one-half mile in width and 20 feet in height, and presents a gently undulating surface. South and east from the geodetic station there is a series of knolls and 230 THE ILLINOIS GLACIAL LOBE. short, rather, sharp, ridges. The most prominent ridge traverses secs. 25, 26, and 36, T. 18, R. 13 W., and its highest points stand fully 50 feet above the bordering plain, yet its width, including slopes, is scarcely one- half mile. A lower ridge passes north-south through secs. 16 and 21. In secs. 9 and 10 also there is a low ridge which trends WNW.-ESE., and stands perhaps 20 feet above the bordering plain. Blue Mound, a sharp knoll in sec. 11, stands 55 feet, by, aneroid, above the border plain and covers about 30 acres. In sees. 10 and 15, T. 18, R. 12 W., a well-defined undu- latory ridge occurs which carries shallow basins on its crest and slopes. There are several knolls 10 or 15 feet high in secs. 7 and 18 of this town- ship, which should probably be referred to this morainic belt. From Blue Mound, in sec. 11, T. 18, R. 13 W., to sec. 27, T. 18, R. 11 W., a distance of 10 miles, only occasional low ridges and knolls are to be seen, the highest of which rise scarcely more than 15 feet above the bordering plain. But from sec. 27 southeastward to the Wabash River bluff near Eugene, Indiana, a distance of 7 to 8 miles, there is a well-defined ridge, about a half mile in width, whose highest points rise 40 feet or more above the bordering plain, while its lower points seldom fall below 20 feet. It carries winding ridges and sharp knolls on its surface, among which shallow basins are inclosed. East from the Wabash River this moraine has, as a rule, a gentle swell-and-sag topography, with undulations of 10 feet or less and a relief of scarcely 20 feet. In the vicinity of Rynear, however, in sees. 2 and 3, T. 19, R.7 W., there is a chain of knolls standing 20 to 40 feet higher than the plain on the north, and occupying a belt about a half mile in width. The Cleveland, Cincinnati, Chicago and St. Louis Railway passes over a spur from this ridge just east of Rynear, while west of the village it passes through a gap in the ridge. In sec. 9 the ridge takes a NE. to SW. trend and is dis- tinctly traceable to the southwest part of the section. The remainder of this belt consists of knolls more or less closely aggregated but seldom exceeding 19 feet in height. The weak belt leading northward from Veedersburg to Rob Roy has no prominent knolls except in the northern portion. The slight undula- tions which it presents, however, are in decided contrast to the very flat surface of the plain on the west. Although the moraine has but feeble expression its relief is sufficient to cause the southward deflection of Coal THE CHAMPAIGN MORAINIC SYSTEM. ill Creek. The slope of the country is such that the creek would have con- tinued directly westward to the Wabash and reached that river in about 6 miles from the point where it encounters the drift ridge, but the deflection occasioned by the drift ridge makes it necessary for it to flow not less than 25 miles before reaching the Wabash. At the northern end of the ridge, near Rob Roy, knolls 20 to 30 feet high occur, and points in sec. 25, T. 21, R. 8 W., stand 50 or 60 feet above the bordering plain. 'To give added morainic expression these prominent points are thickly strewn with bowlders. THICKNESS AND STRUOTURE OF THE DRIFT. The thickness of drift in this morainic system is to be measured by the relief of its ridges rather than by the distance to rock, for beneath the level of the base of the ridges older sheets of drift occur. The relief, as shown above, nowhere reaches 100 feet and seldom exceeds 50 feet. ‘The distance to rock, on the other hand, rarely falls below 50 feet along the line of the ridges, and in places is known to be 300 feet. In the Indiana portion and in eastern Illinois, for some 20 miles west of the State line, rock is usually entered at 100 feet or less, and there are numerous rock exposures along the principal streams. Farther west the rock surface lies lower, and the few borings which reach the rock indicate that the average thickness of the drift in Champaign, Piatt, and McLean counties is not less than 200 feet, while the maximum thickness is fully 300 feet. These morainic ridges are composed in the main of till, Gravel and sand beds are occasionally found in the knolls and near the level of the base of the ridges, but even in these situations they are of comparatively limited extent. Along this morainic system in Indiana there is sufficient gravel in the knolls to supply material for improving the roads in their vicinity, but in Illinois road material is generally difficult to obtain. Gravelly knolls were observed east of Ridge Farm village and on the inner slope of the moraine near Champaign and Urbana. Along the sharply ridged portion of the inner ridge in the vicinity of the State line, and also in the sharp knolls near Fairmount, there is considerable gravel associated with the till. It is possible that many knolls contain gravel which has not yet been discovered. On the whole, water-bearing beds are more extensive in the Indiana portion of these morainic ridges than in the Hlinois portion. In the latter district wells are often sunk to a level below the base of these Dove THE ILLINOIS GLACIAL LOBE. drift ridges before water can be obtained, while in Indiana, water-bearing beds are usually found before reaching the base of the ridges. This morainic system is characterized by a limited number of surface bowlders, and a moderate number are incorporated with the till. The majority of the surface bowlders are crystalline rocks of Canadian deriva- tion. They are usually subangular and seldom show striated faces. As in the drift sheets of this region generally, the bowlders incorporated in the till appear to be much more frequently glaciated than those on the surface. There is also apparently a larger proportion of limestone rocks of local or semilocal derivation embedded in the till than are found on the surface.’ Several large blocks of limestone, however, were found on the surface in Champaign County, Illinois. At George Stewart’s, a few miles southeast of Philo, on a prominent portion of the ridge in see. 4, T. 17, R.10 W., two large limestone blocks were examined by the writer. They are of gray color and contain Pentamerus shells, apparently of Niagara age. Mr. Stewart has dug to a depth of about 4 feet at the side of one of the rocks without reaching its base, and it has a surface exposure nearly 10 feet square. The other block has been uncovered for a space of about a square rod and extends some distance beneath the ground. ‘The nearest known outcrop of this rock formation toward the north (the direction from which the ice came) is in northern Troquois County, some 60 miles distant. In Indiana the district traversed by these moraines and the morainic ridges themselves are characterized by few surface bowlders, except in north- western Montgomery and northeastern Fountain counties. They there abound on the plains as well as on the ridges. It seems probable, however, that these bowlders are to be connected with the late Wisconsin ice invasion, though their position is such as to throw them outside a regular border of the ice sheet. The bowlders apparently connect on the north with well- defined bowlder belts of late Wisconsin age which lead northward from the Wabash River near Williamsport. Whether the bowlders on the group of knolls near Rob Roy referred to above were deposited by this‘ later invasion is uncertain. It is also not entirely certain that these knolls are independ- ent of the later invasion. The surface of the ridges of the Champaign morainic system, as well as the plains between them, is commonly covered with a pebbleless clay 1 For discussion of these features see Chamberlin: Jour. Geol., Vol. I, 1893, pp. 47-60. THE OHAMPAIGN MORAINIC SYSTEM. Doo loam 2 to 4 feet in thickness, and this has probably concealed many bowlders which would otherwise have been exposed on the surface of the till. The number of bowlders on the surface is less than on the plains between this morainic system and the Cerro Gordo moraine. The sheet of loam is apparently distinet in origin from the sheet of till which underlies it, but no evidence was discovered that it was separated from it by a wide time interval. This silt is distinct from the main loess deposit of western and southern [linois, since the latter preceded the Shelbyville moraine in its date of deposition. The origin of surface silts of this class, like that of the great loess deposits, is problematical. . A buried soil is frequently found beneath the ridges of this morainic system, but it appears to be at a lower horizon than the base of the drift deposited in connection with these moraines. Its horizon is probably at the junction of the Shelbyville drift sheet with the underlying older drift. Professor Rolfe, of the Illinois State University, has collected records of many wells in southern Champaign County, between Urbana and Tolono, in which a buried soil is found at a depth of 60 to 100 feet. These records have not as yet been published by him. When found beneath the plains the depth to the soil is less than when beneath the drift ridges. On the ridge in the vicinity of Tolono it is struck at about 100 feet and it is found at nearly as great depth on the ridge near Urbana, while on intervening plains the depth is but 60 to 75 feet. Instances of buried muck reported from Vermilion County, Indiana, by F. H. Bradley’ occur beneath the gravel of the Wabash terraces. Wells were sunk through about 60 feet of alluvial sand, and then encountered 6 to 10 feet of soft, sticky bluish mud filled with leaves, twigs, and trunks of trees. In Fountain County, Indiana, between the main morainie belt and the Inner Ridge, there is a plain in which a black muck has been struck below the till at depths of 25 to 50 feet. Although the depth is much less than in Champaign County, Illinois, the soil is thought to be at the same horizon, namely, the junction of the Shelbyville drift sheet with the underlying older drift. The detailed discussion of well sections which follows begins at the west end of the morainic system in Piatt County and passes eastward, and serves to illustrate variations in the structure from point to point. ‘There are, unfortunately, but few reliable records obtained. : : E 1Geol. of Indiana, 1869, p. 140. 234 THE ILLINOIS GLACIAL LOBE. A well on the farm of Mrs. Robert Carson, in eastern Piatt County, near the south border of the moraine, reached a depth of 200 feet without encountering rock. It appears to have been mainly through a fine sand. On the north border of Blue Ridge Frank Delaney sunk a well to a depth of 280 feet without encountering rock. A well was sunk by George Frank- enburgher on the crest of the moraine, 2 miles east of Mahomet, to a depth of about 200 feet without ehcountermg rock. It was almost entirely through till. ! An experimental boring for gas, oil, etc., made at the city of Cham- paign in the winter of 1891-92, is reported by E. M. Burr, of Champaign, to have the following drift section: Section of boring at Champaign, Illinois. Feet. Blackisoiljandianpebblelessrelayisulbsolleee nso meise eee eee eee ieee rinse eee e eee 4 Wellowaandvoray pebblyclayierise soem ot ease eels acinar eee eee ee ees 44 Quicksand ee mae see ie saa sale neem led anneve nner e sriate a alsiae tee ene acne late raion erie ieee evens 12 (CROW an oso o Second ossesee sce ecds cose nban Bees DSSeSH cocsesho does cose oSaoseSE Sect setats econ scéntos 7 (Guphy WEN ohy Obyoseo dacs sScaseoscbies cobs ope sseS bse cose sé ce sobs senbco ees esds acca donsesedonsee 35 OQun@ keel pods Kosa nnessoco eSob Cosa Her E Bates Oop ee bere so boadco ds enemadenas coco mcebaSbs see 71 \WWAIGE CHEN ON Gli conan cose Sogo bese GE bo sabS coebSeces acon essacscons cons esue abba ceeSeagdeses 6 Terai onan (eC WTS WO NOEs) has Coos cece Seen Sone SeoSesbe seas coos ere scoscesnescocosetscsce = & (MONG S565 Sesnabsbowcaop dc Scud sebe sees isos cede sean cosobo Saco cosy cosa cesqusseseesccancccocs lil (CHI ell 65 SS so oscoedes csocce sees soesen nsdn bess ShebeseS code. nsos sooctiasas sods Sond seeSSseese sslsacs ii 1semGl, Wah, CEN 7s 506 wesc cue Seco se cee BESS EDH OOH conSso Doan Se Sod CUES Sees Hose sas6 coco Gobo SeseSe 51 Glay.containinoysmalllipiecesio fs Coal eases ate san ise eee eee ae ee ee aon al @uriokemmal onl reno cos tens case oeSese5edebuaeqo best osbesdcnes Hesg ses Sednas ctsc,.sces ther teinelee 21 Gray clay, containing pieces/of coal near bottom ---- ~~ 22222 se ne ee ee ne ee eee (jab KEE NNG! Soo oe 556 Gone conn aa He Sap Se S6e Cee esa baee Shon SSbo me ones = endeao seco eogcos sees asosemce anes 16 AMGEN GbR oA got cose Sob Soooes oo Beep rose Guo eeUA Sade cone Hoge eodsbs comerstg se oscesscsoss Sill) The following section of an attempted coal shaft sunk by John Faulds at Champaign appears in the Geology of Illinois (Vol. IV., p. 272): Section of coal shaft at Champaign, Illinois. Feet. Sill Gleay, chnGl mio Wen! o- Siosse sao G55 ceee copa sese cues Sans Choo cose eso csodesaoboscconessecto, IZ Ietatil ayaa HNO) Gb apoos s23 cons sSec ceca case secu seen pom goon ueacisane seadoneS beds Roce cses ceed coro Hces 73 TRE oao5 coed Sebo coro sone Goss ood same sadn doeosese senbes ns cseses BHaone sbooae oncaso hoseSS cao secwe 2 Quicksand, with tree 7 inches in diameter.---..----..---..--.-------..--.--- slosh so oeeenesee eae 9 minal, Chips sso ccos ccc) c05. 6555 Ses0 Deee sone cece Son AenSes sced doa6 sees choo Saeo soeocesecosest 9 SPH eee sooner aon oc ea cara odes csiesno BSSSEe bansco BHapcsbo se Seccom orcs Sass asecsecsse ass 9on8S 3 Yall Gay o22245 choses ocoe sb dere Sood bose 4005 468s Hood odes Sondosen sdcdigeds cada bees sion dotiowses 7 Sandvandie navel ace ere ayaa al aaliyah ineeeo e eeeeaa 59 ARO GOWN ..-Soccsec we asdesecHecoo beasts pondes Sonesdonatiag Oscsms Caoets Szeossecosseshoesc 179 The bottom of the drift was not reached in this place. The statement is made that an earlier boring near by, of which a complete record was not THE CHAMPAIGN MORAINIC SYSTEM. Dae accessible, is said to have reached a blue shale at 168 feet. This sup- posed shale may, however, prove to be hard blue till. A boring made in Urbana in 1884, about a half mile east of the roundhouse of the Cleveland, Cincinnati, Chicago and St. Louis Railway, has the following section, as reported by Prof. C. W. Rolfe: Section of boring at Urbana, Illinois. Feet Soil Seaaa Heco Son comG oR eG Hone Ae Se SHO HEON BREE Sect tees Cesena enn ce ees eee ee 1 Mellowsiclayxcontaimin cite wapebDlespae py meee eer e nt tanya eee ae ae nape en eet 12 ITS Gleyy COmuEmbAES Ni? OOS coke cade soda deds couse poog USaN SEsbecae eo dasaee cebb cosa bose ues 13 VWORy Gust Oly cadaoo baba ecco nnebos cube sem aaccuute done BaueeeeeMs cease. ees Nk sine Senn 32 Coarselsandian dior avellcamter seen see tee sneer eens see eee aie ey Neth ld vee 14 LT BNO Gt DS soda Sadute Mase OceiscH 6 loner RoRaSp Os Sane SI cS o SEC OS OEE ESS UE eee eine ny Cnn 2 Wiater-bearin oy ellowysan dat serene slcrnt es easels ce Ses See elem 16 LING Cl N7 SagcGdc aabnde don Beek Bhes Send Vea SC Rone ak emmEe arenas antes ely yale kei ase a iala 1 QUINT NSE ING Dab oats Chose a Sls Socinmd eh Hise BEAU BOCe Hea eee ree ee amen ate anata hirer UIE Sey TUNee UMN A: aed ee 4t JOO GIERY cSaseaaeas tacts ten See men ee Greats meee ya prinReEaen aa eRC nln uaa Gr SONOMA Me age 1 ULC L cg aur Ue Meee eet Was ileal Pe teagan Ma a LU Nal ia aU MUL Eo ey a Ueda ot 3) BB huegh ow d ork cleus ase ese ase ycrat sent ea epen Vee nears oat eae CR TC 0 AGM 16 (QAI RSET NGS oe GS b SSA aU Bars SBMS ys ae Score aa are eee i eS nS Ciaaus oie on aS ne Aman cat 35 Beg ON dense] ayes sees tence pare: owe eee sateen) ye 20M Le ay es aaah gtemb iene Ape Ws (Ul eel bu tyres 18 Sema) nll pre) see cree soon Goou nce cose DHaaeaad Cnaseace Bese SoeB LEM SU HG uci toes we DUN DEOae ke aay Qhinkel serial SoS aus td neeNeodasd Sos ose Hat ee eae eR MESES om Osa SEEM a iment lu dine manta ethene 69 Gmravellygsam dice clas sepa eee eee Se Scob Dagan Rb OO GSOU. CSO DHE GAUSS a UAUE DO OSES RE seooumanmee 9 UND IED Celis ese G So Eggo Ba Ces saAe BEC ASR NEE Se Se Clatise toe) nneeye AR Ie eaceaee NA Mya en Se 265 The altitude of the well mouths, both in the Champaign and in the Urbana borings, is about 750 feet above tide. Within 14 miles east of the court-house in Urbana, at a level but a little lower than the well just recorded, rock is struck within 100 feet of the surface. On a line eastward from that point to the Wabash Valley, in Indiana, the drift seldom exceeds 100 feet in thickness. S A well at Thomas Goody’s, in Philo, on the crest of the moraine, attained a depth of 171 feet without reaching rock, and penetrated the following drift beds: Section of well at Philo, IWinois. Feet. ebblygclayichanginestromybrowny toy luc saseee meee ene een tale ar kel ee AUR ail 20 Reb bly b le iela yeas cases ete ees intern oi Wace em n yu yeC TEN a eee Vad yailn, aMeh si Mat 75 Pebbly blue clay, interbedded with dry sand in thin beds..._................................. 30-35 Sandyiclaycalledthardpaner tener -eeins= ca saaen tee eee ee tee i LE Uh 4 Hinoryellowsand water Doarin gerade. <2. mutters nice es Oat oc 36 BLO tapes. cect an mete Meera eee mses adoons oboSco' Shon Seas Soar edd eed DOQUE A GoeSss HeBESE 171 A well on the moraine 2 miles south of Philo, in process of boring at the time of my visit, penetrated 110 feet of till, mainly of blue color, and 236 THE ILLINOIS GLACIAL LOBE. apparently referable to the Shelbyville and later sheets. Beneath this depth alternating beds of sand and clay of blue color continued 46 feet to the bottom of the well. Several other wells have been made along the moraine in this county whose depths exceed 100 feet. As a rule they pass through a thick bed of till before striking water-bearing sand or gravel. A similar sheet of till is passed through on the plain between the middle and outer ridges in southern Champaign County and-on the inner ridge and bordering plains in eastern Champaign County. A boring at Sidney on a plain north of the inner ridge, made in 1884 by the Sidney Mineral Company, penetrated but 95 feet of drift, as follows:’ Section of drift in a boring at Sidney, Illinois. Feet Wellowiclay-containinptennpebblesi tees ac fama cj oes eet e ee oan eee eee eae 17 Blneyclaycontainin oie wpe D les sam iecea = stenial setae = earl = aa eames See alee ee eee eee eee eee 18 REDD Lyle Clays sac e sae epee a may vee sae a ree ee a 3 secre nme sie le ale eee ee 5 LEG NS KAI AGEN ee cn eS eSee Bete Ae Roe BAU See Ree eee nese cancers PER DARE OCGOCH Sana coeae esses 15 Sand and gravel.....-.--- BOCAS GEO B OBOE RE ebee HOSS oS DRESS boSand Sognsochecesoescce cossca a saness 5 Rebblyel iy iis os cas cccs ena doc oes wees s- wad Sonige oe paleo ceive we sclae eee e ee Mee eee ee ee 35 Noro Ghat oe ae ode an BSeoen ose seo Gonos soseasn HeSeoo esc conascnwadSsdalsesernsasdsad Hades 95 In northeast Douglas County, and thence eastward along the moraine, wells are usually but 30 to 40 feet in depth and very rarely reach a depth of 100 feet. They are mainly through till, except in southeastern Vermilion County, where in some cases considerable gravel is penetrated. A well on the north face of the Inner Ridge, a short distance east of the State line, at the residence of Mr. Malone, did not reach the bottom of the drift at a depth of 241 feet, and failed to obtain water. The well mouth has an altitude about 625 feet above tide, or 160 feet above the Wabash River. The following section was furnished by Mr. Malone: Section of Malone’s well near Eugene, Indiana. Feet Pebbly yellow) clay. 2-22 = 222s ose ena ons ow nolan os acct oe eee ee eee ees aE ee ne eee eee 15 Rabblycblueiclayne= = sete = co See ee el hae cca soe ee eee tea eae See ee Cea eee eee 35 Dry sandanderavel oo oe 2c. oe ce cae ec weeeismn oe sae esas ai a eee Sa eee 10 Hard wpebblycray clay: (probably ldlinolan) o=o- sess s<))ceeide sees ee eee eee eee eine 55 Alternations of clay with sand and gravel in thin beds... -....-.- ---=-----2--2+ -2--0--2-------e 125 NG GENIN soos sco oes SssocestoS cies prea Sees cosS ceSb osodes cece oe Soap csesnsheassssted cee 240 F. H. Bradley has published the following section of drift exposed on a branch of Johnson’s Creek, near Newport, Indiana:* 1For this section Iam indebted to Prof. C. W. Rolfe. >Geolory of Indiana, 1869, p. 141. THE CHAMPAIGN MORAINIC SYSTEM, 937 Section of drift near Newport, Indiana, Feet. In Bowlder clay, with pebbles of Silurian limestone and trap.-.--.--------------------------- 30 0 Yellow clay, with fragments of coal, shale, sandstone, etc..---. .-------------+------------- 0 4 Bowlder clay, with pebbles of Silurian limestone ..---.---.-------------------------------- 25 0 Ferruginous sand. -...-.-----.----------. ------ -----------+ +--+ 2-2 2+ eee nee re eee eee Streak. Bowlder clay, from the northwest, with pebbles of various metamorphic rocks and ine. and nuggets of native copper ..---------------- ------ ------ --- +--+ 0-22 erent ene rr eee 50 0 ROE rq scaccaocoopasces pensds ececdp esbo Beene seo=o> Se ocar eaecos Sead e ea baUeeE 105 4 East of the Wabash, in Parke County, wells along the outer or main belt and on the plain north of it are seldom more than 30 feet in depth. They pass through about 15 feet of yellow till, beneath which some of them enter blue till, while others enter gravel. Thin beds of sand or gravel are often found associated with the yellow as well as the blue till. Wells in western Montgomery County are in some cases sunk to a depth of 50 or 75 feet, mainly through blue till. On the plain in Fountain County, and also on the inner morainic ridge, wells seldom reach a depth of 50 feet, and usually obtain water without entering rock, there being beds of water-bearing sand or gravel associated with the till sheet. CHARACTER OF OUTWASH. As a rule the plains outside the ridges of this morainic system show scarcely any sand or gravel outwash from the moraine, and there appears to have been only a gentle movement of waters from the ice margin south- ward down the valleys. At the point where the Sangamon River emerges from the moraine in the village of Mahomet there is a gravelly outwash having a depth of 6 or 7 feet, which caps the till plain on the immediate border of the valley. Expo- sures are to be seen east of the railway station and also at several points in the village. The exposures east of the railway station show a bed of loess- like silt about 3 feet in thickness immediately below the gravel, and beneath this a brownish-yellow till. The loess-like silt is similar to that which covers the plains quite extensively in this region. The gravel overwash is of very limited extent, reaching out scarcely a half mile from the south border of the moraine. It merges into low gravelly knolls on the border of the moraine. These features seem to leave no question of the gravel being derived from the ice sheet during the formation of the moraine. Attention has already been called to a gravelly tract along the Sangamon - 238 THE ILLINOIS GLACIAL LOBE. River below this point. The small amount of outwash shown at the border of the moraine seems to make it doubtful if the gravel belt along the river was chiefly formed as morainic outwash. The gravel may be largely a residue from the cutting down of the sheet of drift outside the moraine. Kaskaskia and Embarras valleys have, as a rule, either silt or till banks where they border the ridges of this morainic system. It is probable that the ice sheet had feeble outwash at these valleys, as they are favorably situated for receiving any outwash which may have been contributed from the moraine, the course of the Kaskaskia being for several miles but a short distance outside the Outer Ridge and the course of the Embarras being for an even greater distance just outside the Middle Ridge. Near the head of Bruillett’s Creek, in northern Edgar County, the plain outside the moraine has an area of several square miles which is underlain by gravel. Tributaries of Bruillett’s Creek lead down from the moraine into this plain and lose their waters in its gravel. In some cases these streams do not maintain a channel in this plain. It is not entirely certain that this gravel is an outwash from the moraine, since the moraine itself is of a stiff clayey constitution on the immediate borders of the gravelly plain. If the moraine had a gravelly constitution on this border, as it does at Mahomet, the case would seem more certain. Along the Wabash River Valley extensive gravel terraces occur both above and below the points where the ridges of this morainic system cross. Possibly a portion of the gravel connects with this morainic system, but by far the larger part connects with moraines of later date which cross farther up the valley. Near Bloomingdale, Indiana, a gravel-filled valley not now occupied by a stream leads southward from the moraine across Leatherwood Creek to the valley of Rocky Run, a distance of 2 miles, and thence continues down Rocky Run to the Wabash Valley. The portion not occupied by a stream is bordered by bluffs 30 to 50 feet in height, and has a width of from one- third to one-half mile. The relation of this valley to the Champaign morainic system is not definitely settled. It is perhaps an interglacial val- ley, whose upper course has been overridden and concealed by the Cham- paign drift sheet. The gravel fillmg in its bottom may prove to be an outwash from the moraine, though this is not entirely certain. It is not evident why Leatherwood Creek chose a passage westward instead of turn- THE CHAMPAIGN MORAINIC SYSTEM. 939 ing down this valley. Its flood plain is now only about 20 feet below the level of the bottom of the abandoned valley at the point where it crosses it, and the difficulties of opening a westward passage seem greater than would be necessary to have adopted the course of the abandoned valley. On the outer border of the Inner Ridge in Shawnee Township, Fountain County, Indiana, just north of the point where Coal Creek is deflected southward by the morainic ridge, there is a small plain underlain with gravel which is perhaps an overwash from the moraine. There is also considerable gravel along Coal Creek below the bend, preserved in terrace-like remnants standing 35 to 50 feet above the present stream. It is not determined, however, whether this gravel is an outwash from the drift ridge or is merely a residue formed in the cutting of the valley. Against the latter view it may be said that the present stream seems scarcely adequate to transport gravel deposits of such coarseness as are here displayed. Sugar Creek Valley carries gravel terraces in its lower course, but these terraces are as well developed in portions of the valley above the crossing of this morainic system as below that point. The lower course of the creek is on the inner border of the Outer Ridge of this morainic system, and thus is very unfavorably situated for receiving an outwash. Further- more, the gravel terraces seem to be built up in a valley which had been excavated in the Champaign drift sheet. It is highly probable, therefore, that these gravel terraces have no connection with the Champaign morainic system, but are of later date. ASSOCIATED TILL PLAINS. Between the ridges of this morainic system there are, as already noted, till plains ranging in width from 1 or. 2 up to about 10 miles in the Ilinois portion, and reaching a width of nearly 20 miles in Parke and Fountain counties, Indiana. On these plains there are occasional low knolls, but the general surface is much smoother than that of the bordering morainic ridges. Another plain having greater extent occupies the interval between the Inner Ridge of the Champaign morainic system and the Outer Ridge of the Bloomington morainic system. Its width at the northwest, near the corners of Ford, McLean, and Champaign counties, is about 15 miles, and this width is maintained across Champaign County. In Vermilion County, 240 THE ILLINOIS GLACIAL LOBE. Illinois, it decreases to 10 or 12 miles, and continues into Indiana with about the same width. On this plain, as on the plains between the ridges of the Champaign morainic system, the surface is generally much smoother than on the ridges. There are occasional knolls, however, which reach a height of 30 feet or more, and swells 5 to 10 feet in height are found in nearly every township. The thickness of drift differs from that in the morainic ridges only by the measure of the relief of the ridges. In the Indiana portion, and for . some distance westward into Illinois, rock is often encountered at a depth of 50 feet or less, but in Champaign County the drift thickness increases to 200 feet or more, for the thickness, as on the ridges, is much greater in the western than in the eastern portion of the county. The thick drift continues northwestward into Ford and McLean counties. There is beneath these plains a buried soil found at a depth of 75 to 100 feet or less in Champaign County, and at 25 to 50 feet in counties farther east. This appears to be at the base of the Shelbyville drift sheet. As yet no soil has been discovered between the Champaign and Shelbyville sheets. The drift appears to be composed more largely of till beneath these plains than in the moraines, but sufficient gravel and sand occur to afford water for wells throughout most of the region. SECTION Ili. BLOOMINGTON MORAINIC SYSTEM. The system of moraines to which the name Bloomington is applied is- scarcely surpassed in strength of development or in complexity of features by any other morainic system in the early Wisconsin series. It is one of the most important in the series, not only because of its strength of develop- ment but because it extends in places beyond the earlier moraines of the series, and for a distance of about 120 miles constitutes the border of the Wisconsin drift. It receives its name from the city of Bloomington, Illinois, which stands on a prominent portion of its chief ridge. The name seems especially pertinent since Bloomington is situated near the middle point of this morainic loop, just as Shelbyville is situated near the middle point of the Shelbyville loop. Where best developed there are two bulky ridges, constituting the outer part of the system, and two smaller ridges constituting the inner part. The four ridges are not continuously developed, however, since they inter- THE BLOOMINGTON MORAINIC SYSTEM. 241 lock im places, and the weaker ridges fade out at intervals. In places each of the bulky ridges are double crested and more or less distinctly separable, making four ridges aside from the two weaker ones. The system may be traced. satisfactorily for a distance of about 800 miles from the northern tier of counties in Ilinois around to the western tier in Indiana. In northern Illinois this system becomes so closely associated with other systems in a composite belt that further tracing seems impracticable. This northern portion from Peoria County northward overrides or becomes united with the Shelbyville morainic system, so that the latter is no longer traceable. In western Indiana the Bloomington system is overridden by moraines of late Wisconsin date, which have partially concealed its further course. DISTRIBUTION. The Bloomington morainic system (carrying with it perhaps the Shel- byville system) separates from the composite belt of moraines in northern Kane County and passes in a course slightly south of west across central Dekalb County, occupying a space about 12 or 14 miles in width. Its outer and inner borders are each characterized by a definite ridge. On the borders of Dekalb and Lee counties, in the vicinity of Shabbona and Paw- paw, it becomes narrowed to only 6 miles, owing to a reentrant angle on the outer border. Thus far the weak inner members of the system are undeveloped. Continuing southwestward it expands in northern Bureau County to a width of 18 or 20 miles. This does not include a weak inner member of the system which sets in near Earlville and leads southward along a line several miles east of the inner border of the main ridges, and whose course is discussed below. The ridge along the inner border dies out in eastern Bureau County, so that upon approaching the Ilinois River in southern Bureau County only the ridge on the outer border of the sys- tem is maintained in strength. ‘The ridge which dies out in eastern Bureau County apparently finds continuation in a ridge that crosses northern McLean County, as noted below. The bulky ridge passes southward through west- ern Marshall and northeastern Peoria counties and occupies a width of several miles. The portion in northeastern Peoria County is well shown in the Dunlap topographic sheet, where it forms the divide between Kickapoo Creek and smaller tributaries of the Illinois that flow eastward into the river. The Shelbyville moraine emerges from beneath it in eastern Stark MON XXXVIII——16 242 THE ILLINOIS GLACIAL LOBE. County, as previously noted. This feature also may be seen on the Dun- lap sheet, the point of emergence being near Lawn Ridge. The Blooming- ton ridge crosses the Illinois River just above the city of Peoria and passes southeastward across northern Tazewell County with an elevated semi- morainic tract on its eastern border, extending into western Woodford County. In northwestern McLean County, immediately east of the Macki- naw River, two prominent ridges are found in place of the one ridge farther west. ‘They are closely associated and lead across the county in a curving course bearing south of east in the western portion and north of east in the eastern portion. The ridges are more closely associated in the eastern than in the western portion of the county, but nowhere occupy a belt more than 10 miles in width. In the eastern portion the width is not more than 6 miles. The plane tract between them is only 1 or 2 miles in width. In Ford County a slight reentrant angle is formed immediately north of Gib- son, and the morainic system which bears northeastward in the western part of the county changes abruptly to a southeastward course in the cen- tral portion. The inner border of the reentrant portion extends northward as far as Chatsworth and Piper. From this reentrant angle the outer border leads from Gibson southeastward across northeastern Champaign County, passing near Rantoul and Gifford, and enters Vermilion County about 3 miles northwest of Fithian. Its course is thence directly eastward across the county into Indiana, passing a couple of miles north of Danville, Hlinois. It is very clearly defined on the Danville topographic sheet. In Warren County, Indiana, its course changes to north of east, following nearly the north bluff of Wabash River to Pine Creek Valley, near Williamsport. The moraine here swings northward and is traceable as far as eastern Benton County, where it dies away in a gently undulating plain. This system is overridden by a series of weak bowldery moraines of the late Wisconsin series in northern Warren and southern Benton counties, but is not greatly obscured along the line of the outer belts. Greater obliteration apparently occurred a few miles back from the late Wisconsin border. However, the Bloomington system apparently finds its continuation in a belt of very thick drift which leads from Benton County, Indiana, southeastward across Tip- peeanoe, Clinton, Boone, and Hamilton counties, and thence eastward into Ohio. But this belt is outside the territory embraced in the present report. Returning to the reentrant angle in Ford County, Illinois, the inner border of the Bloomington system is found to pass southward from Piper, THE BLOOMINGTON MORAINIC SYSTEM. 243 near ‘Thawville and Loda, and thence to swing eastward in a curvine course through eastern Ford, northern Vermilion, and southeastern Lro¢ jwois counties. The inner bulky ridge of the system continues eastward to Fowler, Indiana, where it terminates very abruptly a few miles west of the outer ridge. From the reentrant angle in Ford County two weak ridges are trace- able westward. The inner or Chatsworth-Cayuga Ridge leads from Chats- worth north of west to Cayuga, where for a few miles it passes beneath, or is nearly obscured by, the Marseilles moraine. Near Blackstone, in north- ern Livingston County, a ridge which is probably its continuation emerges from beneath that moraine and passes northwestward nearly parallel with the Vermilion River through or near Kernan, Grand Ridge, and Farm Ridge villages to the Illinois Valley at Utica. For a part of the course it forms the divide between the Illinois and Vermilion rivers and may easily be traced on the Ottawa and Lasalle topographic sheets. This northern part is known as Grand or Farm Ridge. North from the Ilinois its course is shghtly east of north from Utica past Hariville, where it fades out near the inner margin of the main moraine in southern Dekalb County. It is well shown in the east part of the Lasalle sheet and northwest part of the Ottawa sheet. The gaps in this ridge are narrow, and are discussed below (p. 259). This ridge probably finds its correlative east of the Ford County reentrant angle in a belt of undulating or slightly ridged drift leading east- ward across central Iroquois County. he latter belt, however, scarcely constitutes a definite moraine, being distinctly ridged only for a few miles along the north border of Sugar Creek east from Milford. It disappears beneath a moraine of late Wisconsin age near the State line south of Sheldon, Illinois. The other ridge which leads west from the Ford County reentrant angle, commonly known as Cropsey Ridge, from a village situated on it, is distinctly traceable across the northern part of McLean County, where it constitutes the water parting between Mackinaw and Vermilion rivers. It fades out in the vicinity of Gridley, and is not definitely developed toward the west or north until the Illinois Valley is passed. It seems, however, to be a continuation of the belt which fades out in eastern Bureau County, as noted above. The character of the topography in the interval between these ridges is discussed below (p. 281). 244 THE ILLINOIS GLACIAL LOBE. RELIEF, The relief on the outer border seldom falls below 50 feet and in places approaches 200 feet. ‘The average relief is probably 75 or 100 feet. The least relief is found in portions of Ford and Champaign counties, Illinois, where it is about 50 feet. The greatest relief is found in southern Lee and northern Bureau counties, where the moraine is bordered on the west by the Green River Basin. The moraine here has an altitude of 900 to 1,000 feet or more above tide, while the basin on the immediate borders of the moraine rises from scarcely 700 feet at the west to about 850 feet at the east, thus giving the moraine a relief of 150 to 200 feet. Between the ridges of this system there is very little depression in Dekalb and Lee counties. But on the inner border of the system in these counties there is nearly as pronounced relief as on the outer border. ‘Indeed, in places it exceeds that on the outer border, and probably it averages 100 feet. The relief on the inner border continues prominent southwestward into Bureau County, but falls off rapidly in that county, becoming scarcely perceptible in the vicinity of the Illmois River. The outer ridge, however, maintains its great relief throughout Bureau County and rises 100 feet or more above the plain and lower ridge on its inner border in the eastern part of the county. In southern Bureau, western Marshall, and northeastern Peoria counties it stands 150 feet or more above the narrow upland between it and the Illinois Valley. This prominent ridge probably includes both the Shelbyville and Bloomington systems, for the former separates from it in eastern Stark county, as noted above. Upon crossing the Illinois into Woodford County the uplands on the inner border of the Bloomington moraine are found to stand but a few feet lower than the crest, and eastward from this county there is generally a very gradual descent on the inner border of the main ridges, a descent seldom exceeding 25 or 30 feet to the mile. The small ridge which leads across northern McLean County has a relief of but 30 to 50 feet on its outer border and a gradual descent on its inner border. The ridge leading northwestward from Chatsworth to Earl- ville usually rises 30 to 50 feet above the outer border, but reaches about 75 feet in places in central Lasalle County. The relief on the inner bor- der is nearly as great as on the outer, but is usually more gradual THE BLOOMINGTON MORAINIC SYSTEM. 245 RANGE IN ALTITUDE. This morainic system presents a range in altitude of only about 300 feet, its highest points being slightly more than 1,000 feet above tide, while few points, aside from valleys, fall below 700 feet. The range, both along the crest and along the immediate outer border, is set forth by counties in the following table: Table showing range in altitude of the Bloomington morainic system. County, | Creat above | Outer border, | Feet. Feet. Mekalba@linoialeeweeee eee. Sea ae oe | 875- 975 | 775-850 | Ogles(lillinois) Meme m at eee eee eel Seen aca ee DoS | 875- 940] 790-820 | TECET3 (DIF HATOHES ous BS eas a aS ame ee Ee | 900-1,025 | 740-860 BUreaTu(IINGcis) eee eer le | 700- 989| 675-825 | Marshally(illinois) Meee eee eee ee oan eee aees 800- 900 700-800 Beonay (Lllinois) eee eee ee ne ee pean 700- 830] 650-775 Mazewrellli (illin 018) eesewse eee ase ove nelaiaisers te eels 700- 825 650-725 MeTeany (illinois) eset e a eenets slater estetmeiere =<) sicrai= am 775- 913 700-820 THOTACLMAN OLS) eee ea te ene kai oe 775- 860| 740-760 Champaign (Illinois) ----.-.----.------------------- 750-830) 700-760 | Vermilion’ (llinois)) sees see see. s 2-22-25 - bees eee|) 680— 790) |) 9 630=700)) | Warren (Indiana) -.-.-----.----.-------+-----------| 700- 775 625-675 Banton Cludiana wee seen et eet a el ea | 750- 825 | 675-725 SURFACE CONTOURS. A general statement can scarcely be made which will set forth the vari- ations in contour or topographic expression of this morainic system through- out its entire length. It is found convenient to discuss it in sections, beginning at the north and proceeding southward. The first section embraces the portion between western Kane County, where this system separates from the morainic complex of northern Ilinois, and the head ot Bureau Creek in northeastern Lee County, a section 35 or 40 miles in length. The second section (about 50 miles) embraces the portion drained by Bureau Creek and its tributaries. The third section (40 miles) embraces the portion along the west side of the Illinois in Bureau, Marshall, and Peoria counties. The fourth section (20 miles) embraces the portion 246 THE ILLINOIS GLACIAL LOBE. between the Illinois and Mackinaw rivers in Tazewell and Woodford coun- ties. The fifth section (50 to 55 miles) embraces the portion between the Mackinaw River and the reentrant angle in Ford County. The sixth sec- tion (nearly 100 miles) embraces the portion between the reentrant angle in Ford County, Illinois, and points where this system passes beneath the moraines of late Wisconsin age in Benton and Warren counties, Indiana. For the distribution of the several sections see Pl. VI. Between western Kane County and the head of Bureau Creek The section between west- ern Kane County, Illinois, and the head of Bureau Creek, taken as a whole, consists of a mass of drift standing 50 to 100 feet or more above the plains on the northwest and southeast borders, and occupying a width of 6 to 15 miles. Much of the surface is nearly plane, and differs but little from that of the plain on the southeast. There is, however, scarcely a square mile in which knolls 10 to 20 feet high are not present, and also shallow basins which contain ponds. The decidedly morainic expression is confined to three somewhat narrow belts, one on the outer border, another on the inner border, and an intermediate less definite belt The belt on the outer border leads from Hampshire westward into Dekalb County, crossing South Kishwaukee River just above the bend near Genoa, and then curves around to the southwest and south in western De- kalb and southeastern Ogle and eastern Lee counties. Its width is seldom more than 3 miles, and in places scarcely reaches 2 miles. From Hamp- shire west to the Kishwaukee River it is less prominently ridged than west of that stream, there being a rise of scarcely 50 feet to its highest points from the plain on the north. This portion, however, has about as much morainic expression as the higher part of the border to the west. Knolls 10 to 25 feet are closely aggregated and inclose shallow basins. The basins are usually depressed but 5 or 6 feet below the lowest part of their rims, and occupy only an acre or two. Occasionally a basin occupying as much as 10 acres is to be seen. From South Kishwaukee River southwestward through western Dekalb and southeastern Ogle counties, the outer belt consists of a series of narrow ridges with shallow sags between them, each trending with the entire belt ina NESW. course, changing to southward in Ogle County. The ridges are each a mile or less in width and stand 30 to 50 feet above the intervening sags. There are in places four ridges, but usually only two or three. Each ridge has gentle undulations on its crest and slope, seldom — THE BLOOMINGTON MORAINIC SYSTEM. Q47 more than 10 or 15 feet high. This breaking up of a morainic belt into several ridges at a salient curve is a common feature in this and other morainic systems. In Ogle and northeastern Lee counties sloughs are a conspicuous feature among the knolls. This outer belt is interrupted by several gaps, occupied by streams, which head on its inner border and pass through it to the lower outlying districts. Named in order from east to west there are the following: Coon Creek, South Kishwaukee River, Owen's Creek, Killbuck Creek, Kite River, and two branches of Willow Creek. The crest of the morainic belt is absent for a mile or more at each of these valleys. Apparently there were gaps of this width in it prior to the open- ing of the drainage lines, for the slopes bordering the valleys carry knolls and shallow basins such as characterize slightly eroded portions of the belt. As shown below, these gaps were probably formed by streams issuing from the ice sheet. The valley bottoms range in width from 60 rods up to fully one-half mile, the broadest being at Kishwaukee River. The middle belt appears in western Kane County at Burlington. A morainic spur is found to lead southwestward from the inner border of the outer belt into eastern Dekalb County, and to fade away 2 miles east of Sycamore. It is about 1 mile in width, and is characterized by numerous basins and low knolls, which give it fully as strong expression as the neighbor- ing portion of the outer belt, from which it is separated by a narrow plain 13 or 2 miles in width. There is also a basement ridge with a relief of perhaps 20 feet. For several miles west from the points where the Burlington spur dies out, knolls 10 to 25 feet high are rather numerous and constitute a probable line of continuation. Near Malta a definite ridge appears, which leads southwestward to the outer belt in the southwest corner of Malta Township, Dekalb County, and thence southward along the east border of the outer belt, through western Milan and northwestern Shabbona town- ships, passing just east of the village of Lee. For 3 or 4 miles in western Milan Township it is combined with the outer belt, but elsewhere it is separated from it by a narrow plane tract about a mile in average width. In western Shabbona Township, Dekalb County, it becomes completely united with the outer belt. This ridge, like the Burlington spur, is about a mile in average width. It has a relief of 20 to 40 feet above the bordering plane tracts. Its surface is gently undulating, but basins are rare, except where it is closely associated with the outer belt in Milan Township. The 248 THE ILLINOIS GLACIAL LOBE. altitude of the ridge just discussed is about as great as that of the outer belt, and it constitutes the source of several of the streams which lead through the outer belt, viz, Owen’s Creek, Killbuck Creek, Kite River, and Willow Creek. By returning again to western Kane County, to Elburn, where the inner member leaves the composite belt, and tracing the moraine westward, it is found to take a more direct course than the outer one. It leads nearly due west for about 10 miles, being throughout much of the distance between Elburn and Cortland in view from the Chicago and Northwestern Railway. Immediately south of Cortland it changes to a southwestward trend and joins the outer belt for a few miles in southwestern Shabbona Township, Dekalb County, and eastern Wyoming Township, Lee County, at the southwestern limits of the section of the morainic system under discussion. Throughout much of this distance it has a well-defined crest and occupies a width of 1 to 2 miles. For a few miles at the curving portion southwest of Cortland it presents two ridges separated by a sag or plane tract about a mile in width that stands 20 to 30 feet below the level of the crests of the ridges. In western Kane County several sharp gravel knolls 30 to 40 feet in height are found in this belt, and occasionally sharp knolls are found in it farther west. As a rule, however, its undulations are gentle. The crest stands only 20 to 40 feet above the district to the north, but there is a descent of nearly 100 feet within a couple of miles on the south border. On the slope there are low knolls and a gently undulating surface. At its junction with the outer border belt m Shabbona and Wyoming townships numerous basins.and sharp knolls occur. The knolls are in some cases 30 or 40 feet in height, though usually 20 feet or less. This inner moraine forms the divide between South Kishwaukee River and several tributaries of Fox River, and is not crossed by any stream east of its junction with the outer belt. Near the point of junction south of Shabbona it is crossed by Indian Creek, a tributary of Fox River, which heads im the combined belt and flows southwestward. In its course through this moraine the creek winds about greatly among the knolls and has not so broad a passage as is afforded the streams which lead northward across the outer belt. In the Bureau Creek drainage basin——The second section of the Bloomington morainic system, which embraces the drainage basin of Bureau Creek, maintains a belt on its outer border fully as prominent as that of the THE BLOOMINGTON MORAINIC SYSTEM. 249 a section just discussed, but its inner-border belt, as noted above, loses its strength in eastern Bureau County, and in the vicinity of the Illinois River rises only a few feet above the inner-border plain. With the decline of this belt a still later belt appears on the plain to the east, as noted above. The two main belts are closely associated for about 20 miles in southern Lee County, being separated only by a narrow plain 1 to 2 miles in width, through the midst of which Bureau Creek has its passage. They then diverge, the course of the inner one being slightly west of south, through eastern Bureau County, while the outer continues with a course slightly south of west along the borders of Lee and Bureau counties for a distance of 20 miles. It there turns southward through central Bureau fo) County, curving around the western border of the Bureau Creek Basin and passing just west of Wyanet and Tiskilwa. The plain between the moraines in Bureau County has a gently undulating surface and stands nearly as high as the inner moraine, but is much lower than the outer one. There is, in this plain, a slight tendency to ridging, with NE—SW. trend, which to some extent governs the course of streams. The outer belt throughout its course in southern Lee and northern and central Bureau counties maintains a width of 4 to 6 miles. This includes gradual slopes which culminate in a well-defined narrow-crested ridge that is developed along a considerable portion of the section under discussion. The crested ridge usually occupies a breadth of less than a mile, and stands 30 to 50 feet above the less sharply ridged portions on its borders. In places the sharp crest is absent and the gradual slopes occupy its entire breadth. Near Wyanet a narrow depression as low as the outer-border plain interrupts this ridge and furnishes a passage for the Hennepin Canal, now under construction. This depression is not an open valley, but has morainic knolls on its bottom and slopes. In southern Lee County the knolls and undulations on the slopes of the moraine are much less conspicuous than in Bureau County, their height usually being but 10 or 20 feet, while in Bureau County they frequently attain a height of 30 or 40 feet: Basins are common only in central Bureau County, though they are found occasionally in other parts of the moraines. The deepest are only 10 or 15 feet below the bordering - rims, and their area is seldom more than an acre or so each. On the outer face of the moraine in Lee County, from the vicinity of the Third Principal 250 THE ILLINOIS GLACIAL LOBE. Meridian westward to northern Bureau County, there are numerous sand knolls and ridges, 10 to 40 feet in height, which add greatly to the inequal- ities of the surface. These sand accumulations follow the lines of ridges or knolls in the moraine, rather than the depressions between them. The sand is still subject to slight modification by wind action, and its ridges, as well as its presence on the moraine, are probably the result of wind transportation from the Green River Basin, which borders this portion of the moraine on the west. The inner belt of this system, as noted above, is merged with the outer from the vicinity of Shabbona southwestward to Pawpaw, and presents a knob-and-basin topography along the line of junction. Upon separating from the outer belt the topography changes to gentle undulations, and there is also a tendency to ridging in the line of the belt. In places a cross section would lead over at least three nearly parallel ridges separated by narrow sags, the whole series occupying a width of scarcely 2 miles. The ridges are, however, not distinctly maintained for long distances, but are at intervals crowded together. These ridges are of about equal height and rise only 25 to 50 feet above the plain on their outer border. The relief on the inner or southeast border is nearly 150 feet in eastern Lee County, and this great relief is maintained for 10 or 12 miles southwestward in south- eastern Lee and northwestern Lasalle counties. Upon entermg Bureau County the relief decreases rapidly, as already noted, but the expression continues as strong as in the portion having greater relief. Knolls 20 feet or more in height are closely aggregated, and are disposed in chains trending in line with the belt. Upon approaching the Illinois Valley they become more scattering, and the belt fades out about 2 miles north of Depue. The feebly developed portion of this belt is shown in the northwest corner of the Lasalle topographic sheet and in the eastern part of the Hennepin sheet between East Bureau and Brush creeks. The ridge which leads south- ward from Earlville past Utica, a few miles east of this moraine, is discussed farther on, as is also the topography in the line of continuation of this moraine in Putnam, Marshall, Woodfords and McLean counties. (See pp. 261, 281.) In Bureau, Marshall, and Peoria counties ——T’he third section of the Bloomington morainic system embraces the portion of the moraine west of the Illinois River in Bureau, Marshall, and Peoria counties. This consists mainly of a large ridge, 4 to 6 miles in width and 100 feet or more in height above THE BLOOMINGTON MORAINIC SYSTEM. 2 il the districts on the west and an even greater height above the narrow plain between the ridge and the river bluff. Aside from this main ridge there are minor ridges trending parallel with it on its inner or eastern border. These minor ridges are a mile or less in width, 25 to 50 feet in height, and are maintained for only afew miles ina place. The surfaces are much smoother than that of the main ridge. They are similar to the slight ridgings found between the inner and outer belts in eastern Bureau County, and, like those ridges, have an influence on the course of drainage. One of the most con- spicuous instances of the governing of drainage is that of Senachwine Creek, in southwestern Marshall County, which owes its southward course to a low drift ridge on its east border. The main ridge has a topography similar to that of its northern con- tinuation in central and northern Bureau County. In places a sharply outlined crest is developed, but usually the higher part of the ridge is broken up into knolls and sharp disjointed ridges which rise 20 to 40 feet above neighboring basins or sags. Shallow basins are a common feature along this portion of the moraine. On the outer face the border is irregular, being indented by valley-like extensions of the outer-border plain, which in some cases reach a mile or more back into the moraine. Between these indentations there are spur-like projections. The moraine is nowhere cut through by any of these low tracts, though a line along its crest occasion- ally oscillates 100 feet or more within a space of 2 or 3 miles. On the whole, this section is scarcely surpassed in strength by any other portion of this morainic system. Between the Illinois and Mackinaw rivers— The section embraced between the IIli- nois and Mackinaw rivers has a well-defined outer or southwest border, but its inner or northeast border is difficult to determine. It merges on the northeast into an elevated tract with a gently undulating surface, whose general altitude is about as great as that of the portion of the belt which presents stronger morainic expression. This elevated tract extends as far east as Cazenovia. Should the entire district between Cazenovia and the outer border be included in the moraine, it would have a breadth of about 14 miles, or more than twice the breadth of the bulky outer ridge formed on the west side of the river. The strongly morainic expression is confined, however, to the outer or southwest face in a belt only 3 or 4 miles in width. This face presents a series of drift billows 20 to 30 feet in height, 252 THE ILLINOIS GLACIAL LOBE. among which are sags and shallow basins. The swells are usually closely agereeated, but in places nearly plane tracts of a square mile or more appear in the midst of this belt. An instance of such a plane tract may be seen south of Deer Creek village. The elevated tract on the northeast border of this moraine has only occasional low swells 10 or 15 feet in height, the greater part of the surface being as smooth as the plains farther north and east, and differing from them only 50 to 75 feet in altitude. The descent is made in a distance of 2 or 3 miles, and is therefore so gradual as to be scarcely perceptible to the eye. The relief on the outer border is more conspicuous than on the inner, a rise of 100 feet being made in about 2 miles at the prominent parts of the moraine. This border is also made conspicuous by the change from the very flat surface outside the moraine to the billowy surface presented by its outer face. Between Mackinaw River and the Ford County reentrant—Hast of the Mackinaw River, near the borders of Woodford, McLean, and Tazewell counties, the Bloom- ington morainic system presents two well-defined bulky ridges which are separated by a narrow plain or sag 1 or 2 miles or more in width. ‘These ridges are distinctly maintained from the extreme northwest corner of McLean County eastward to Padua, a distance of nearly 30 miles, beyond which, for 20 to 25 miles, to the Ford County reentrant, they are combined into a single belt. ; The inner ridge enters McLean County from Woodford County near the line of the third principal meridian and passes southeastward through Normal and thence eastward through Barnes to Padua, where it becomes combined with the outer ridge. It has a general width of 2 or 3 miles and rises 30 to 50 feet above the sag or plain on its south border. The surface is billowy, with oscillations of 20 or 30 feet between the higher swells and neighboring sags. Many smaller swells occur, with a height of 5 or 10 feet. The slope of these swells is usually gentle, and knolls 20 feet in height occupy several acres. In places this moraine presents a sharply outlined crest; a conspicuous instance was noted northwest of Padua, where a vidge-like crest with a width of only one-fourth to one-half mile stands about 50 feet above the tracts on either side. As a rule, however, the higher portion of this belt consists of a series of swells similar to those found on the slopes. For several miles north from this inner ridge the surface is THE BLOOMINGTON MORAINIC SYSTEM. 253 gently undulating and dotted with occasional knolls of considerable promi- nence, the highest knolls rising 30 to 40 feet above border districts. The outer ridge crosses Mackinaw River immediately above Mack- inaw village and leads southeastward to Bloomington and thence eastward to its point of junction with the inner ridge near Padua. It has a breadth of about 3 miles. It is crossed by several streams which head in the inner ridge, among which are three of the headwater branches of Sugar Creek, two headwater branches of Kickapoo Creek, and one headwater branch of Salt Creek. Sangamon River also leads through it, east from the junction with the inner ridge. There are thus seven streams crossing it within a space of 35 or 40 miles, admitting only about 5 miles average distance between streams. The gaps through which these streams pass, each cause a break in the crest of the moraine nearly a mile in width. They do not appear to be entirely erosion gaps, for the morainic swells occupy them down nearly to the level of the streams, or about 75 to 100 feet below the level of the neighboring crests. It is probable that streams issuing from the ice sheet at the time the moraine was forming prevented the accumulation of heavy deposits in the vicinity of their points of departure from the ice. Between these gaps the moraine usually has a well-defined crest and gently undulating surface. The crest lies near the outer border of the moraine, the outer face being, as a rule, much more abrupt than the inner. As the moraine, where not interrupted by gaps, has a relief of 100 feet, the outer face often presents the abruptness of a river bluff. It differs, however, from a river bluff in the absence of erosion contours, there being instead a billowy slope, such as characterizes moraines. The erosion effected by streams since the withdrawal of the ice sheet is very inconspicuous com- pared with the inequalities of drift aggregation. The crest is usually so gently undulating as scarcely to suggest the strength of the moraine. It is not uncommon to find it so level for a space of one-fourth to one-half mile in width and for several miles in length that artificial ditching is neces- sary to give it good drainage. In such places there are usually shallow basins, 2 to 5 feet in depth, occupying an acre or more each, which add to the imperfection of drainage. The crest varies considerably in altitude independent of the gaps just mentioned, its highest points being about 900 feet above tide and its lowest about 800 feet. The range of 100 feet in 254 THE ILLINOIS GLACIAL LOBE. altitude, however, occupies a space of 1 to 2 miles or more, and hence is not conspicuous. The slopes usually present more undulations than the crest, but their swells seldom exceed 20 feet in height. The combined belt east from Padua differs from the separate belts farther west in presenting greater complexity of features. Between Padua and Arrowsmith the trend of the principal ridges is northwest to southeast. One ridge with this trend passes immediately west of Ellsworth and consti- tutes the divide between Sangamon River and Kickapoo Creek. Another ridge leads into Arrowsmith from the northwest, which separates the Sanga- mon from the Mackinaw. From the vicinity of Arrowsmith eastward to the reentrant angle in Ford County the trend of ridges is southwest to northeast, or nearly at right angles with those west of Arrowsmith. ‘The ridges just mentioned are low, with a relief of but 30 or 40 feet. There is a prominent crest along the south border of the combined belt which is interrupted by a small gap at the Sangamon Valley. It stands about 100 feet above the plain outside the moraine, and rises from that plain with the abruptness of a bluff line. The Sangamon River winds about through sags among ridges until it emerges from this morainic belt. Aside from the ridges and broad sags the moraine is characterized by a multitude of gentle swells 10 or 15 feet in height, among which there are shallow sags and occasional basins. The reentrant in Ford County.—In the reentrant angle in Ford county the ridges on the west are crowded together in a single belt, but those on the east are in part separated by narrow strips of level marshy land which trend with the belt from north-northwest to south-southeast. The topography of the greater part of the reentrant portion is of a gentle swell-and-sag type, with undulations of only 15 or 20 feet. The ridges have definite crest lines standing about 50 feet above the marshy plains which separate them. In southeastern Livingston County, however, at the extreme north end of the reentrant, a sharp knob-and-basin topography is developed, in which knolls rise abruptly 80 or 40 feet above the basins inclosed among them. There are several small lakes and ponds among the morainic knolls, the largest of which occupy areas of 40 acres or more, but the majority oceupy only a few acres each. From this point of the reentrant angle there is more or less knob-and-basin topography developed along the inner or northeastern slope of the moraine throughout its southeastward course THE BLOOMINGTON MORAINIC SYSTEM. 255 in eastern Ford and southwestern [Iroquois counties. It is confined to a belt about 3 miles in width, and probably half the surface is of this type. The remainder is of a gentle swell-and-sag type. The expression is more subdued than at the point of the reentrant angle, and knolls exceeding 30 feet in height are rare. The basins are seldom occupied by ponds except in wet seasons. The contrast between this knob-and-basin tract and the gently undulating crest line of the moraine is quite striking. Eastward from the Ford County reentrant to western Indiana—'[‘he section of the Bloom- ington morainic system east from the reentrant angle presents a series of ridges grouped in two belts. The outer belt throughout its course in southern Ford and northeastern Champaign counties consists of a single broad ridge with billowy surface, having oscillations of 20 to 30 feet. As a rule, a well-defined crest is developed, but in places it completely disappears and the belt consists entirely of knolls and winding ridges, among which sags and shallow basins occur. Upon entering Vermilion County the outer belt soon displays a double-crest line, and in the eastern part of the county is separated into two ridges, as shown on the Danville topographic sheet, between which there is a narrow plain tract a mile or more in width that is drained by Stony Creek. This plain, however, is present for only a few miles, the ridges as a rule, being closely associated. The surface of the ridges varies from gently undulating to strongly billowy. The billows are seldom greater than 30 feet in height. The moraine varies 75. or 100 feet in altitude in Vermilion County, but the variation is not abrupt, a fluctuation of 50 or 75 feet usually occupying 2 miles or more. It rises very promptly on its south border, especially in the western part of the county. In Warren County, Indiana, this belt, or at least its inner part, curves around gradually to the northward and constitutes the divide between Vermilion River and Pine Creek. It is overridden in northern Warren County by a moraine of the late Wisconsin series, which has not obliterated it, but has simply dotted the surface with small knolls, the majority of which are less than 10 feet in height. The outer belt joins the inner in northern Warren County and the combined belt passes northeastward into Benton County, as indicated below. Between the outer and inner belts of the portion of the Bloomington morainic system east of the reentrant angle is a narrow plain with very smooth surface, there being scarcely a knoll or undulation so much as 10 256 THE ILLINOIS GLACIAL LOBE. feetin height. This plain sets in in southeastern Livingston County, within 5 or 6 miles of the extreme north end of the reentrant, and is continuous through Ford, Champaign, and Vermilion counties, Hlinois, and western Warren County, Indiana. Its greatest width is in Vermilion County, where it reaches a breadth of 7 or 8 miles, a portion of it extending into the northwest part of the area shown on the Danville sheet. Its breadth in Ford and Champaign counties is 2 to 5 miles. The inner belt of this morainic system presents two, and in places three, crests in eastern Ford County. One crest leads from the point of the reentrant southward through Melvin, between two branches of the Ver- milion River, to the vicinity of Henderson, where it crosses the eastern branch just above its junction with the western, and leads southeastward through Paxton along the north border of the river into Vermilion County. Another crest appears about 3 miles south of Roberts and leads southeast- ward, parallel with the crest just mentioned, crossing the extreme southwest corner of Iroquois County and fading out east of Paxton. A third crest leads from the extreme north end of the reentrant near Chatsworth, in Liy- ingston County, in a course east of south, past Pope’s Grove and Roberts, into southwestern Iroquois County near Loda, beyond which it is diffi- cult to trace. It is on the slope of the third ridge that the knob-and-basin topography above mentioned is developed. None of the three crest ridges which this inner belt presents im Ford County and adjacent districts have strong expression. The outer one stands 30 to 50 feet above the plain tract outside (west) of it, but is not so prominent on its inner border. The other ridges rise only 20 to 30 feet above the border tracts. These crest ridges each have a breadth of half a mile or more. In a few places the outer crest carries knolls 20 or 30 feet in height. The outer crest is also more winding than the others, and has a border indented by extensions of the plain which enter it a half mile or more. In Vermilion and Iroquois counties, [linois, and Benton County, Indi- ana, this inner belt has a well-defined crest which forms the divide between the Iroquois and Vermilion rivers and which stands 3 or 4 miles back from the inner border of the moraine. This crest and the inner slope are gently undulating, with swells 10 to 20 feet in height. There is a gradual north- ward descent of perhaps 20 feet per mile to the inner-border plain. The crest usually is similar to the inner slope, but occasionally is sharply ridged, THE BLOOMINGTON MORAINIC SYSTEM. 257 as in the south part of T. 23, Rs. 13 and 14 W., where it rises abruptly 30 feet or more above, the bordering portion of the moraine in a narrow belt a half mile or less in width. South from the crest just mentioned there is, in Vermilion and Warren counties, another ridge interrupted by occasional gaps. The ridge is continuous from the north fork of Vermilion River near Rossville eastward to its junction with the outer morainic belt at Pine Creek in northern Warren and southern Benton counties. West from Ross- ville it can be traced in a curving course southwestward to the Middle Vermilion, near Potomac, and thence northwestward up the north side of that stream. It is interrupted by a gap a mile or more in width immedi- ately north of Potomac, and is deeply indented by valley-like sloughs at points farther east. In the vicinity of Blue Grass, in western Vermilion County, there is a plain occupying several square miles which separates this ridge from the one north of it. There is also a plain between the two ridges from the bend of Vermilion River south of Hoopstown eastward into Indiana as far as the ridges are traceable. The plain is searcely 2 miles in width in the Illinois portion, but reaches a width of 3 or 4 miles in Indiana. The south ridge of this inner belt has usually a relief of about 50 feet above the plain on the south, and slightly less above the plane tracts lying between it and the north ridge. It is 2 or 3 miles in width, and its crest lies nearer the south than the north border. Its topography is similar to that of the north ridge, there being a gently undulating surface with few knolls more than 20 feet in height. The portion covered by late Wisconsin drift— This morainic system is conspicuous for 15 or 20 miles within the limits of the late Wisconsin drift, and, as noted above, probably embraces the belt of thick drift which leads eastward through central Indiana into Ohio. The north ridge maintains its usual strength to the vicinity of Fowler, Indiana, where it terminates abruptly in a marshy tract. The remainder of the belt swings around the eastern end of the north ridge and dies out in a gently undulating tract 2 or 3 miles east of Fowler. It is a question whether the ridges in Benton County have suffered much reduction by the late Wisconsin ice invasion. That invasion formed only weak moraines in this district, consisting usually of belts of low knolls only 5 or 10 feet in height, which are accompanied by a great number of MON XXXVIII——17 258 THE ILLINOIS GLACIAL LOBE. bowlders, whose distribution in belts was long since noted by members of the Indiana survey. These belts of knolls and bowlders cross the ridges and intervening plains of the Bloomington system nearly at right angles in a NNW.-SSE. course, as may be seen by reference to the glacial map (Pl. VI). They assume greater strength a few miles to the north, there being a prominent morainic belt in northwestern Benton and eastern Troquois counties, near the border of Ilinois and Indiana. In this connec- tion it may be remarked that the outer moraine of the late Wisconsin system is very variable in strength from place to place, and has a develop- ment about as weak in its passage across the Bloomington morainic system as in any part of its course. The weak moraine in eastern Iroquois County, Illinois —Of the weak moraines connected with the Bloomington system the first to receive consideration is the one which emerges from beneath the late Wisconsin series near the Ilinois- Indiana line and passes westward into Iroquois County. This is main- tained as a distinct ridge, 20 to 40 feet in height and scarcely more than a mile in width, for a distance of about 8 miles west from the State line, where it dies away on the border of Sugar Creek. It has a gently undu- lating surface, the swells seldom exceeding 10 feet in height. The probable continuation of this ridge is found in a poorly defined, undulatory belt which appears on the west side of Sugar Creek opposite the end of this ridge and leads westward to Onarga. It stands scarcely 20 feet above the bordéring plains on either side and its surface is but little more undulatory than that of the plains. Its slight relief, however, is a matter of considerable conse- quence, since it stands too high for flowing wells to be obtained, while the neighboring plains furnish a large number of flowing wells from the drift. This belt does not connect definitely with the bulky ridges at the west, but as it is separated from them by a space of only 3 or 4 miles it seems to fall naturally into the same system. Cropsey Ridge —Irom the west side of the reentrant angle in southeastern Livingston County a small ridge leads westward, as already noted, past Cropsey, across northern McLean County, forming a divide between the Mackinaw and Illinois-Vermilion drainage basins. The portion east from Cropsey stands 30 to 50 feet above the plain on the south, and in places presents a very abrupt relief on that border. Toward the north it has a THE BLOOMINGTON MORAINIC SYSTEM. 259 more gradual descent to a plain which continues descending to the Vermilion River. This eastern portion of the ridge has numerous small knoils 10 to 20 feet in height and occasional shallow basins. From Cropsey westward the expression is somewhat weaker, though a relief of fully 30 feet is main- tained as far west as the Chicago and Alton Railroad north of Lexington. There is also sufficient undulation of the surface to give this belt decided contrast to the plains on its border, swells 10 to 20 feet in height being quite common. West from the railroad the belt is definitely ridg¢ed for a few miles, but near Elpaso it becomes so obscure that further tracing and correlation has not been attempted. There are many places toward the north and west, in northeastern Woodford, eastern Marshall, southwestern Lasalle, and east- ern Putnam counties, where, for a space of a Square mile or more, the surface is quite as undulatory as in this morainic belt. It is possible that more detailed study will bring out a connection between these several undulatory tracts by which they may be thrown into a single belt. Possibly the divide between Vermilion River and tributaries of the Illinois flowing directly westward will prove to be the axis of such a belt. This divide, wherever it has been crossed by the writer, presents a slightly undulatory surface. The majority of the strongly undulatory belts, however, are found a short distance west of this divide. The surface is generally more undulatory west from the divide than east from it. Chatsworth-Cayuga Ridge—Hrom the reentrant angle at Chatsworth in south- eastern Livingston County northwestward nearly to Forrest the inner of the two weak members of this morainic system has sharp knolls inclosing basins, but their height is less than in the reentrant angle, seldom exceeding 25 feet. They occur on the slope as well as on the crest of the moraine. From the vicinity of Forrest northwestward for a few miles the moraine has a well- defined crest and is characterized by gentle swells 10 to 20 feet high. In sec. 34, Pleasant Ridge Township (T. 27, R. 7 E.), the single crest gives place to a double one, and two ridges are maintained from this point north- westward to the north branch of the Illinois-Vermilion River, the outer ridge coming to that river in sec. 14, T. 27, R. 6 E., while the inner comes to it in secs. 7 and 8, T.27, R.7 E. The outer ridge has a billowy crest, consisting of a series of slightly elliptical knolls, 25 to 40 feet high, 40 to 50 rods long, and about one-half as wide. These constitute an almost complete 260 THE ILLINOIS GLACIAL LOBE. chain leading from the river to the point of junction with the ianer ridge. The inner ridge has not such a crest but, instead, a gentle swell-and-sag topography, with undulations of 20 to 25 feet. At the east branch of the Ilinois-Vermilion River this morainic belt is interrupted by a plain nearly 2 miles in width. The ridges are, however, both presént north of the river. The outer one appears in secs. 33 and 34, Owego Township, and bears slightly west of north to Cayuga. The inner appears in sec. 31, Saunemin Township, and bears northward about 2 miles, and is interrupted by a gap through which Felkey Creek has its passage. It appears on the west side of this creek and bears northwestward, joming the outer one near Cayuga. Each of these ridges has a gently undulating surface, but upon becoming coalesced a sharply undulatory topography sets in, in which the swells stand 30 to 40 feet above the bordering sags and sloughs. From Cayuga northwestward to northern Livingston County the moraine under discussion is so closely associated on the inner border with the Marseilles moraine as to be obscured by it, and is interrupted by sey- eral gaps where creeks tributary to the Illinois-Vermilion River traverse it. These gaps occur at the following streams: Wolf Creek, Deer Creek, Baker’s Run, Mud Creek, and Blackstone Creek. The gaps are a mile or less in width, while the ridges which lie between them occupy a length of 2 or 3 miles. These interrupted ridges consist of a series of billows ranging in height from 10 feet up to 40 feet or more. The most prominent one noted is in sec. 18, T. 30, R. 5 E., and is known as ‘‘Smith’s Mound.” It occupies about 40 acres and stands nearly 50 feet above the surrounding country. Basins occur on its summit. Farm Ridge or Grand Ridge—In southern Lasalle County, just east of Streator, as noted above, a morainic ridge known as Farm Ridge and also as Grand Ridge emerges from the outer border of the Marseilles moraine. It appears to be the continuation of the Chatsworth-Cayuga Ridge. For a few miles, to Otter Creek Valley, it is separated from the Marseilles moraine by a narrow valley-like plain scarcely a mile in width. In secs. 29 and 30, T. 31, R. 4 E., it carries sharp knolls, but the remainder of the’ ridge in the interval between the county line and Otter Creek has a gently undu- lating surface. At Otter Creek there is a break a mile or so in width. THE BLOOMINGTON MORAINIC SYSTEM. 261 North of the creek the moraine consists of a series of knolls and sharp ridges standing 20 to 50 feet above bordering valleys or depressions. In the southeast part of T. 32, R. 4 E., the moraine swings abruptly westward, passing through the village of Grand Ridge to Farm Ridge post- office. It carries knolls which rise to a height of 20 feet or more. Between Grand Ridge and Farm Ridge the topography is of a subdued knob-and- basin type. From Farm Ridge to the Illinois bluff near Utica there is a smooth ridge with very gentle undulations, but with a well-defined relief of 20 or 30 feet. This ridge is in places capped by sandy knolls 10 to 15 feet in height, apparently wind drifted. The portion of this moraine north of the Illinois River consists of three disjomted ridges arranged end to end, but varying greatly in the direction which they trend. They may be traced readily on the Lasalle and Ottawa topographic sheets. The southern one has its southern termi- nus at the north bluff of the Illinois River between Little Vermilion River and Pecumsaugen Creek. It leads northward through Lasalle Township for 2 miles or more, then curves slightly and turns east of north, passing through sees. 30, 19, 17, 9, and 4, Waltham Township. It then drops down rapidly just north of the township line. The second ridge appears within a mile northeast of its terminus, and bears slightly west of north for a distance of about 3 miles, when it also drops off suddenly near Tomahawk Creek. North of Tomahawk Creek a third ridge appears, which bears northward for about 2 miles, then bends toward the northeast and comes to Big Indian Creek about 2 miles below Earlville. No well-defined continu- .ation was found on the north side of this creek, though there are occasional knolls along the divide between Big Indian and Little Indian creeks, in both Lasalle and Dekalb counties, which may mark the line of its con- tinuation, and which would connect it with the main portion of this morainic system east of Shabbona. The ridges whose courses have just been out- lined have, as a rule, a sharp crest as well as swells and sags. The southern one is spoken of by the residents as the “Backbone,” since it is quite sharp, standing in places 60 to 80 feet above the border districts, and being scarcely a mile in width. The ridge north of it has a height of 60 to 75 feet above the bordering plain, while the northernmost ridge has a height of 30 to 50 feet, except near its northern terminus, where it drops down to a height of but 15 or 20 feet. 262 THE ILLINOIS GLACIAL LOBE. THICKNESS OF THE DRIFT, The thickness of the drift in the Bloomington morainic system is prob- ably about equal to the measure of the relief above the outer-border district, which has a maximum of nearly 200 feet and which averages 75 to 100 feet along the ridges. The thickness is 50 feet or less between the ridges and on plane tracts north and east of them. Small valleys had been formed in the Shelbyville sheet prior to the Bloomington invasion, and these valleys were filled with the drift of the Bloomington morainic system. They appear, however, to have been usually but 30 to 50 feet or less in in depth, so that the thickness_of the Bloomington sheet is not greatly increased at these lines. The drift extends to some depth below the base of the Bloomington drift sheet. It is found that the earlier sheets of the Wisconsin series are present in considerable strength, as well as the Hlinoian drift. The Iowan drift is present in northern Ilinois, but its border, as already noted, passes under the Wisconsin in Bureau County. It is not known to be present beneath the Bloomington system south from Bureau County, unless it be on the inner border of the system in Iroquois and neighboring counties. This matter is discussed above in connection with the Iowan drift sheet. In determining the lower limits of the Wisconsin drift, two conspicuous lines of evidence are drawn upon. One is an abrupt change in the texture of the drift, the Wisconsin drift being fresh and soft, while the underlying sheets are harder and more aged in appearance. The other is the occur- rence of a black soil, beds of peat, or other decisive evidence of atmospheric . action, produced at the surface of the lower or buried sheet of drift prior to the deposition of the later drift. In the portion of the Wisconsin drift lying outside the limits of the Iowan it is often an easy matter to decide upon the line of contact between the Wisconsin and the Ilinoian by the change in texture alone. It is so marked that the majority of well drillers have recognized the two sheets even where no soil or peat has been preserved at their junction. Where the two lines of evidence are combined, it becomes an easy matter to decide upon the line of contact. It is not so easy a matter to decide upon the limits of the Wisconsin drift where it is underlain by the lowan, for the contrast in texture is not so great as between the Wisconsin and Ilinoian, though the Iowan is seldom so fresh in appearance THE BLOOMINGTON MORAINIC SYSTEM. 263 as the Wisconsin, even where deeply buried beneath it. There are numerous instances of the occurrence of buried soils in the portion of Illinois occupied by both the Iowan and the Wisconsin drift, and there is little doubt that such soils occur below each drift, but seldom are two soils found in the same exposure or well section. In a few cases the soils are referred with confidence to the junction of the Wisconsin and Iowan, but in the majority of cases they appear to be at the junction of the Iowan and Illinoian. An inspection of the well records presented below will serve to make clear the difficulties of interpretation. These well records indicate that buried soils differ greatly in elevation within short distances in the portion of Illinois covered both by the Iowan and by the Wisconsin drift. This difference in elevation may be due either to the presence of two soil horizons or to an erosion of a buried drift sheet. In the latter case the lower soil would have been formed in a valley, while the higher would have been formed on the uplands. Were full records of wells preserved, it might be possible to interpret such cases satisfactorily. But usually the imperfections of the records are such that interpretations can scarcely be made. It is therefore only in the portion of the Wisconsin drift lying outside the Iowan that the lower limits of the Wisconsin are clearly recognized. It is highly probable that the Peorian and the Sanga- mon soil are each represented. A brief statement setting forth the varia- tions in elevation of the buried soils in each of the counties occupied by the Bloomington morainic system will serve to make more clear the methods of interpretation as well as the difficulties of correlation in portions of the district. In Kane County buried soils appear beneath a plain southeast of Bur- lington at a depth of only 40 or 50 feet and at an elevation of about 850 feet above tide. The soil is here referred with some confidence to the Peorian interglacial stage at the base of the Wisconsin drift. On the elevated moraine southeast from this plain a soil is found at a depth of 180 to 200 feet and at an elevation of only 750 feet. It has been found in several wells in the west part of T. 40, R. 7 E. This lower elevation is probably due to its being a lower soil horizon, presumably the Sangamon soil, at the junction of the Iowan and Illinoian sheets, though the instances reported may chance to be in every case in the line of valleys cut in the Iowan. The wide distribution, however, favors the interpretation that there 264 THE ILLINOIS GLACIAL LOBE. was a plain at about this level prior to the Iowan invasion. In the neigh- boring township on the south buried soils are reported in sees. 14, 15, and 20, at 675, 710, and 720 feet above tide, which are probably Sangamon. In the village of Elburn a buried soil occurs at 790 feet above tide, which is perhaps Peorian. In Dekalb County only a few instances of, buried soil were collected. These are nearly uniform in elevation at slightly less than 800 feet above tide and are slightly lower than the plain outside the Wisconsin drift. It seems probable that they should be referred to the Sangamon soil, at the junction of the Iowan and Ilinoian. A buried soil is found beneath the Towan drift, outside the limits of the Wisconsin, in the vicinity of Deer- field, at about the same elevation. In southeastern Lee County soils occur at a level lower than the plain outside the Wisconsin drift, three instances being found where the elevation is 720 to 740 feet, while the plain is about 800 feet above tide. These seem referable to the Sangamon stage. One instance was found in sec. 34, T. 39, R. 2 E, of the occurrence of a buried soil at about the elevation of the outer-border plain; this may be referable to the Peorian. In northwestern Lasalle County there are many instances of the occur- rence of soil at 600 to 650 feet. This low elevation would suggest its reference to the junction of the Iowan and Illinoian rather than the base of the Wisconsin: This soil horizon is well preserved in eastern Bureau County. It seems to be quite uniform in elevation over several townships in which the surface of the Wisconsin has a variation of more than 100 feet in altitude. In the counties south from Bureau County the Iowan drift has not been recognized, and possibly it does not reach these counties. No records were obtained which show buried soil either in Putnam or in Marshall County. In Woodford County wells in the vicinity of Metamora pass through a soil and enter a hard till at about 140 feet, or at an elevation of 680 feet above tide. A coal shaft at Minonk, in the eastern part of the county, passes from soft till into hard till at about the same elevation, though the depth of soft till there is only 62 feet. It is probable that in both of these instances the soil is referable to the Sangamon. In northern Tazewell County exposures were found, both in the Illinois bluff and along Farm Creek, where the loess occurs beneath the Wisconsin drift at an THE BLOOMINGTON MORAINIC SYSTEM. 265 elevation of about 625 feet. In these exposures the Peorian and Sangamon both occur as noted above. Instances of buried soil at an elevation of 625 to 650 feet are reported from the vicinity of Cooper, which are probably Sangamon. The Wisconsin drift ranges in thickness from 50 feet up to fully 150 feet in this portion of Tazewell County. In northwestern McLean County instances of a buried soil and a change from soft to hard till are found at a depth of 150 feet beneath the crests of morainic ridges and at an elevation of 650 feet above tide. There are instances of “black clay” at lower levels, which may prove to be soil hori- zons. In the southwestern part of the county, in sec. 29, T. 24, R. 1 W., and sec. 3, T. 23, R. 1 W. (which are situated south of the Bloomington moraine), the fresh till extends to a much lower elevation than in neighbor- ing districts. It seems probable, therefore, that there was a valley or con- cealed lowland tract traversing these sections. In sec. 3 a black muck was found below the fresh till at a depth of 200 feet and at an elevation of but 525 feet above tide. In the vicinity of Bloomington a black soil is found at an elevation of 625 to 640 feet above tide, which probably is of Sangamon age. Another buried soil occurs near the base of the drift at an elevation of about 540 feet. ‘This is beneath a hard till and is perhaps preglacial. North- eastward from Bloomington the elevation of the surface of the Ilinoian drift sheet is found to soon reach 700 feet; at least wells in T. 24, R. 4 E. enter a hard till at that elevation. One well in sec. 4 of this township is reported to have entered hard till at an elevation of 750 feet above tide. South from this township, in the vicinity of Leroy, a buried soil is found at an elevation of 740 feet above tide, which is probably under the Shelbyville or lowest Wisconsin drift sheet. Eastward the elevation of the surface of the Ilinoian drift appears to decline to 700 feet or less, as shown by wells in southern Livingston, southwestern Ford, and western Champaign counties. The elevation continues decreasing toward the north and east across northern Ford, Iroquois, and Vermilion counties. The elevation of the Illinoian surface throughout much of Iroquois County and northern Vermilion County is 600 feet or less. In Iroquois County, as noted above, there are two soil horizons, one being at the junction of the fresh and soft till with the harder till, the other being in the midst of the hard till. There is little doubt that. the upper soil marks the base of the Wisconsin. But whether the sheet of drift which it 266 THE ILLINOIS GLACIAL LOBE. caps is Iowan or Illinoian has not been determined. Upon this determina- tion must rest the age of the lower soil horizon. Buried soils are exceptionally well preserved along much of the course of the Bloomington system east from the Illinois River, instances of their occurrence in well sections being much more numerous than ‘in districts to the north, except limited areas in Bureau, Lasalle, Kane, and McHenry counties. There is scarcely a township in which the junction of the Wis- consin drift with older sheets may not be satisfactorily ascertained, either through the presence of the buried soils or by a change in the till. STRUCTURE OF THE DRIFT. Throughout the entire length of the Bloomington system the great mass of the drift composing its moraines, and also the plains between them and on their inner borders, together with earlier sheets of the Wisconsin series, consists of a soft blue till moderately stony and strikingly in contrast with the harder till-found beneath it. The till is very adhesive, so that when excavated by a well auger it may be unrolled in great masses. The under- lying harder till is far less adhesive. The surface portion of this till sheet is oxidized to a depth of 6 to 10 feet and has a brownish color. There are oceasional developments of a pink-colored till. In places the pink color extends to great depth, but usually the blue color sets in within a few feet of the surface. The pink color is especially noticeable in the western and northern part of the morainic system, from Peoria County northward. Yellow till is also reported to occur in the midst of the blue till at many points. It apparently marks the surface of earlier sheets of the Wisconsin series. its occurrence is known by well records only, no natural exposures having been found. Its degree of leaching and its state of oxidation are not known. Associated with the till at various depths there are beds of sand and gravel, often of considerable extent, which afford a supply of water for many wells. It is not usual, however, to obtain strong wells within this drift sheet. In every county hundreds of wells have been sunk to lower horizons because of the inadequate supply found in this sheet of drift. There are very few grayel knolls in the moraines of this system, though it is found that many knolls contain gravelly pockets in the till and these have been utilized to some extent for road ballast. The amount of avail- THE BLOOMINGTON MORAINIC SYSTEM. 267 able gravel, however, seems to be scarcely adequate to supply ballast for the wagon roads of the region traversed by the moraine. The composite belt with which this morainic system connects at the northeast is much better supplied with surface gravel. As noted above, the outer face of the moraine in Lee and northern Bureau counties is heavily coated with sand, which apparently has been drifted by the wind from the Green River Basin on the west. From this sand belt southward through central Bureau County the surface of the outer ridge is in places coated with sand or a sandy loam. The texture of the moraine itself is also exceptionally sandy in that portion of the belt. Sand is found in the form of dunes along the east bluff of the Illinois River, from the bend of the river at Hennepin southward to the inner border of this morainic system. Sand deposits were also noted on the inner slope of the moraine in northern Vermilion County and west from the reentrant angle in southeastern Livingston County. It is probable that the sand deposits in both these localities are attributable to the presence of temporary glacial lakes held in front of the retreating ice sheet, whose waves worked upon the surface of the till sheet and formed the sandy beds there present. As noted below, sand in places assumes the characteristic features of beaches or shore lines in portions of the plains north of this morainic system. The surface of this morainic system from the vicinity of Bloomington northward to Dekalb County is generally coated with a loess-like loam or silt to a depth of 2 to 4 feet. East from Bloomington this surface silt is so thin as scarcely to conceal surface bowlders. The silt also extends over the plain east of this morainic system in counties bordering the Illinois River, and has often a depth of 6 or § feet on these plains. It is especially prominent on the plain between the outer and inner belts in the Bureau Creek Basin, its average thickness being not less than 6 feet. From the inner belt eastward, in Bureau and Lasalle counties, it is less conspicuous than in the Bureau Creek Basin, being scarcely 2 feet in average thickness. This surface silt was apparently deposited within a short time after the retreat of the ice sheet, for the underlying till sheet appears to have suffered no leaching prior to its deposition. The origin and mode of deposition of this silt or loess-like loam, like that on adjacent portions of the Shelbyville sheet, are as yet not clearly understood. The loess-covered plains on the west seem to afford a source of supply, and the prevailing winds, if in the 268 THE ILLINOIS GLACIAL LOBE. same direction as now, would have carried much atmospheric dust from them eastward. It is quite probable that some of the material was derived from this source, though perhaps only a minor part. It is found that this loess loam, when reaching a depth of 4 to 6 feet or more, is usually highly calcareous in its lower portion, while the loess of the outer-border districts is thoroughly leached to a depth of several feet. In all probability it had suffered considerable leaching before the ice sheet withdrew from the Bloomington morainic system. It is to be expected, therefore, that a non- calcareous or leached deposit would be made by transportation of dust from these plains. The presence of the calcareous material in the silt which caps the western border of the Bloomington till sheet seems to make it necessary to call in the action of glacial waters charged with fresh cal- careous silt. The manner in which the silt was distributed is an unsettled question and one on which further ight seems necessary. It will probably be found in a combination of aqueous and eolian agencies. As shown below, the drainage conditions on the outer border of the Bloomington system were favorable for the transportation of gravel by streams issuing from the ice margin. ‘There would appear, therefore, to have been a rapid descent for these streams to the region south and west from the ice sheet. Such being the case, we can scarcely infer that the loess which covers the elevated parts of the morainic system was deposited by a sheet of water, for this would imply a general submergence. It is suggested that there may have been portions of the border district in which the waters found inadequate drainage. In such places silts may have been spread out which were afterwards transported by wind to the moraine. ‘The matter, however, is one of conjecture rather than of demonstration. . Surface bowlders are numerous only at a few points on this morainic system, being rarely met where no sand or silt deposits are present to conceal them. But in this respect the Bloomington system is not different from other moraines of the early Wisconsin series. In Kane, Dekalb, and Ogle counties there are occasional bowlders along the crests of the ridges, but they seldom become conspicuous. On the plane tracts in these counties they are quite rare, but this is not a fair field for study because there is usually a sufficient amount of silt to conceal them. Bowlders abound along the onter face of the outer belt for a few miles in south- eastern Lee County and on the crest and outer face at a few pomts in THE BLOOMINGTON MORAINIC SYSTEM. 269 Bureau, Marshall, and Peoria counties, there being some farms on which they are a serious hindrance to the cultivation of the. soil. But much of the moraine in these counties is silt or sand covered to a depth of several feet, so that bowlders, if present, are concealed. In the portion of the morainic system between the Ilinois River and Bloomington scarcely any surface bowlders were noted, though there the surface silts are several feet in depth. From Bloomington eastward there is generally a sufficient number of bowlders at surface or at slight depth in the soil to meet demands for some time to come in supplying foundations for buildings. In places they were so numerous that farmers have collected them in piles in the fields. Such is the case in the northern tier of townships of Vermil- ion County, both along the crest of the north ridge and on its inner slope. The bowlders range in size from 8 or 10 feet in diameter downward, the ordinary size being 2 to 4 feet. Granite bowlders predominate over other classes of rock along nearly the entire belt, and a few limestones were noted. Greenstones and quartzites are also common. The bowlders are in some cases much rounded by exfoliation, a feature which seems more conspicuous than in bowlders on the Shelbyville sheet. Numerous com- parisons were made of bowlders embedded in the till with those found at the surface, and in almost every instance it was found that local or semi- local rocks are much more abundant in the till than among the surface bowlders. A much larger proportion of striated stones is also found in the till than at the surface; indeed, the surface bowlders are seldom striated. These are features which, as already noted, are generally characteristic of the till of the entire region under discussion in each of the several sheets represented. Occasionally very large limestone blocks are found at the surface or but slightly embedded in the drift. One block found a short distance northwest of Rossville, in Vermilion County, furnished several wagon loads of excellent building stone, and when first discovered was thought to be a ledge in situ, but subsequently proved to be a bowlder embedded in the till. In that vicinity the drift is about 200 feet in depth and is underlain by the Coal Measures. The nearest known outcrop of limestone is about 30 miles to the north. Numerous well sections collected along the line of this morainic system are presented in the discussion of the wells in the latter part of this report, and these will serve to illustrate the variations in structure which this morainic system presents. 270 THE ILLINOIS GLACIAL LOBE. CHARACTER OF THE OUTWASH. The writer’s examination of the features on the outer border of the Bloomington morainic system covers the portion from Bloomington north- ward, and the discussion pertains chiefly to that portion. The portion east- ward from Bloomington was examined some years since by Prof. R. D. Salisbury, but has received scarcely any attention from the writer. It will be observed that the Bloomington morainic system forms the source of several streams whose courses are southward or westward from it through the outer-border district. It also forms the source of other streams which lead northward or eastward or southeastward through the inner- border district. Still other streams flow through this morainic system from the inner into the outer border district. Of the first class the several head- water forks of Wabash-Vermilion River, Sangamon River, Salt Creek, the two Kickapoo creeks, Sugar Creek, Green River, and the two forks of Kish- waukee River are worthy of mention. Of the second class, Iroquois River, the Ilinois-Vermilion River, Bureau Creek, and the western tributaries of Fox River are illustrations. Of the third class the Illinois and Mackinaw rivers are the only examples in Illinois. An examination of these valleys brings to light important contrasts. The streams which flow away from the outer border of the moraine are in most instances found to occupy valleys which had been excavated somewhat by streams which antedated the formation of this moraine. These valleys received the outwash from the moraine and were partially filled by it. The streams on the inner border of the moraine had not the advantage of previously formed valleys, and in consequence their channels are entirely the result of stream action since the withdrawal of the ice sheet from this morainic system. It is found that the valleys which lead away from the moraine through the outer-border district have in most instances a filling of grayel or sand which is definitely connected with the morainic system as an outwash from the ice sheet. The streams which lead from the moraine across the inner-border district are not thus characterized by sand-and- grayel filling. In some cases the streams issuing from the edge of the ice sheet had sufficient force to transport gravel for many miles away from the ice border. In other instances they were able to carry the gravel but a few miles, as shown in the discussion below. The extent of the gravelly and “mM THE BLOOMINGTON MORAINIC SYSTEM. ial sandy outwash along the borders of the Bloomington morainic system is outlined in the glacial map, Pl. VI, where it may be compared with that of other morainic systems. This comparison shows that the outwash was fully as extensive as in any substage of the early or late Wisconsin. It is, how- ever, of a finer grade than in some of the later substages, a feature which seems to indicate that the attitude of the land may have been scarcely so favorable for vigorous drainage as in the later substages. In the following detailed discussion the valleys in the vicinity of Bloomington are first con- sidered. From this point the valleys are taken up in order toward the west and north, along the outer border of the morainic system. For a few miles southeast from the meridian of Bloomington there is a shallow, valley-like depression along the outer border of the moraine. It is about a half mile in width, and its surface stands 15 to 25 feet below the plain on the south and 75 dr 100 feet below the crest of the moraine on the north. Its eastern end is near the village of Downs, at Kickapoo Creek. It leads westward across the interval between Hast and West Kickapoo creeks, and also across that between West Kickapoo Creek and an eastern tributary of Sugar Creek. Both branches of Kickapoo Creek pass directly across it, but the branch of Sugar Creek referred to follows the depression westward for a distance of 2 miles, and there turns away from the moraine. The depression is found to have a filling of fine gravel and sand of con- siderable depth, so that wells 10 or 20 feet deep do not reach its bottom. The gravel was carried from this valley-like depression for some distance down each of the valleys which lead away from it, and is preserved in the form of terraces which stand 20 or 30 feet below the level of the bordering plains and about 20 feet above the present stream bed. The gravel prob- ably extends down at least to the level of the present streams. It would appear, therefore, that valleys had been exéavated to, if not beyond, their present depth prior to this filling. The gravel fillmg was traced down Kickapoo Creek beyond Heyworth, a distance of about 10 miles from the outer border of the moraine. Just north of Heyworth it is preserved in a broad terrace which has been extensively opened for gravel by the Illinois Central Railway. How much farther down the valley the gravel was transported has not been determined. On the tributary of Sugar Creek which leads away from the western end of this depression the gravel deposits were followed continuously down to a point east of Shirley. They Dike THE, ILLINOIS GLACIAL LOBE. were also noted at Funk’s Grove and at points below. The gravel was apparently transported to the junction of this fork with a more western tributary. In each of these valleys the gravel is of medium coarseness and carries a moderate admixture of sand. The presence of the sand is thought to indicate that the current was not vigorous, though it may have been somewhat stronger than that of the present stream, for the latter finds it difficult to transport the coarser portions of the material even at flood stages. As these valleys are narrow, averaging scarcely more than one- fourth mile and seldom reaching one-half mile in width, the glacial streams which occupied them can not have had very great volume. The depression on the outer border of the moraine does not seem to fit in naturally as a part of the drainage which preceded the formation of the morainic system. As yet, no satisfactory explanation of its mode of formation has been found. Possibly it was formed in connection with the ice invasion, either by the ice or by waters issuing from it. It bears some resemblance to “The Fosse” on Nantucket Island described recently by Curtis and Woodworth in the Journal of Geology, though it has not a sand plain or overwash apron on its south border.’ On the branch of Sugar Creek which leads through the west part of Bloomington there is a belt of gravel 60 to 120 rods in width, which extends up the valley at least to the Bloomington waterworks in sec. 32, Normal Township, just outside the inner large ridge of the Bloomington morainic system. At its head it is merged with the flood plain of the creek, but from Bloomington southward it stands a few feet above the flood plain. The depth of gravel at the waterworks is about 30 feet, and it appears to maintain this depth for some distance below Bloomington. There is usually a yellow-brown silt 4 to 6 feet in depth capping the gravel. The gravel contains a large amount of fine material, so that sand is screened from it for plasterers’ use. Large pebbles are rare, though it contains a few 5 or 6 inches in diameter. This branch of Sugar Creek reaches the outer border of the Bloomington morainic system about 5 miles below the waterworks. The gravel here spreads westward beyond the limits of the valley, covering the lower portions of the plain between this branch of Sugar Creek and one that leaves the moraine 4 miles-to the west. Low till swells rise above ‘Nantucket a morainal island: By G. C. Curtis and J. B. Woodworth, Jour. Geol., Vol. VII, 1899, pp. 226-236, Pl. I, Figs. 1-5. : THE BLOOMINGTON MORAINIC SYSTEM. Die the level of the gravel surface, showing that the deposit is thin. ‘The western tributary also has gravelly deposits above the point of its emergence from the moraine, but these were not traced to their head. The distance to which the gravel deposits have been carried down the two branches of Sugar Creek beyond the border of the moraine is not ascertained, but it is known to be at least 10 miles. Mackinaw River has its source on the inner border of the main ridges of the Bloomington system, but Cropsey Ridge, one of the weaker mem- bers of the system, lies north of the headwater portion of the stream. Gravelly deposits have been noted at a few points on the borders of the headwater portion. They have not, however, been traced into definite connection with Cropsey Ridge. There is not a continuous belt of gravel leading down the valley from this headwater portion. A section several miles in length was examined just below the crossing of the Lake Erie and Western Railway, in which no gravel filling appears to have been made. That portion of the valley was found to contain deposits of silt of considerable thickness which reach a level 20 or 30 feet above the present stream. Upon continuing down the valley to the inner border of the outer morainic ridge a gravel terrace is found to set in abruptly at an altitude about 50 feet above the stream. This terrace merges into low gravelly knolls at its head and on its border, and thus makes a definite con- nection with the moraine. As it stands somewhat higher than the silt-filled portion of the valley just above its head, there was probably a pool in that portion of the valley prior to the excavation of the gravel which forms the moraine-headed terrace, and the silt deposits just noted were probably laid down in this pool. Mackinaw Valley appears to have been excavated nearly to the level of the present stream prior to the formation of the Bloomington system and to have had a width of nearly a mile. The terrace has been traced down the valley continuously from the moraine to the point where the Mackinaw enters the Illinois Valley in the eastern part of Sand Prairie Township, a distance by direct line of about 17 miles from the outer border of the moraine. The altitude of the terrace decreases about 100 feet in this dis- tance, being 640 feet at the outer border of the moraine and 550 feet at the point where it joins the Illinois Valley. The stream falls 83 feet in the MON XXXVIII——18 274. THE ILLINOIS GLACIAL LOBE. x same distance (from 573 to 490 feet), and the terrace maintains a somewhat regular altitude above it, being about 65 or 70 feet above it at the outer border of the moraine and 50 feet at the border of the Illmois Valley. The terrace apparently has little fall in the 3 or 4 miles occupied in crossing the moraine. The remnants of the terrace occupy nearly one-third of the width of the valley. Several good exposures of the gravel were found, and these quite uniformly show a coarse gravel and cobble near the surface of the terrace, with finer gravel below. The coarseness of the material is such as to indicate vigorous drainage, apparently stronger than that of the present stream. A small northern tributary of the Mackinaw, Deer Creek, emerges from the moraine a few miles north from the point where the Mackinaw leaves it. This also carries deposits of gravel along the borders of the valley. It is preserved in small remnants flanking the slopes up a height of 20 or 25 feet above the creek at the point where the stream leaves the moraine. ‘The upland plain stands about 20 feet higher than the upper limits of the gravel. On Farm Creek, a tributary of the Illinois, entering opposite Peoria, there is a gravel deposit heading in the midst of the Bloomington system about 2 miles west of Washington. This has been traced continuously down to the Illinois River Valley, a distance of 8 miles. At its head it is nearly as low as the creek flood plain, being scarcely 10 feet above the stream, but its fall is far less rapid than that of the creek. The creek has a fall of about 180 feet in the 8 miles while the terrace falls scarcely 60 feet. At Farmdale the terrace stands about 85 feet above the creek and at East Peoria about 120 feet. The depth of the gravel on this terrace is usually only 15 or 20 feet, including a silt capping 3 or 4 feet in depth. The breadth of the valley in which it is deposited was apparently one- eighth to one-fourth of a mile. The present stream has in places formed a valley of greater width, but usually it is confined to narrower limits than the old valley. The valley in which the gravel fillmg was made had been nowhere cut to a depth of more than 40 or 50 feet below the bordering plain outside the Bloomington moraine, and the gravel filling has reduced this depth to about 25 feet. The work performed by the stream which preceded the gravel filling was therefore but a small fraction of the amount performed by Farm Creek since that filling. (ulajed jantues gq Aq uaye} mai,) ‘S011 SAOSV 13534 009 YO ‘Y3SAIY SIONIN7! SHL SAOSW L334 OLt LNOSVY SAGNVIS HOIHM SOVYYSL ¥Y ONIWYOS ‘SIONINT! ‘VIdOad LV 39V NISNOOSIM ATYV3 JO T3SAVYeD INX "Id IIIAXXX Hdv¥9ONOW ABAYNS 1¥DI901039 *S "nN THE BLOOMINGTON MORAINIC SYSTEM, DAD On the Illinois River Valley there are extensive gravel deposits forming a broad terrace which occupies a gap in the Shelbyville moraine just below the outer border of the Bloomington moraine, a gap through which the river passes. The north part of the city of Peoria stands on this terrace and is commonly referred to as the bluff or upland portion, since it stands about 170 feet above the Illinois River. These deposits may prove to date from the Shelbyville substage of glaciation, though from their coarseness and general relations it seems more probable that they were connected with the Bloomington and represent the height of valley filling on the outer border of that morainic system. Their freshness certainly places them in the Wisconsin series. The following reasons for referring them to the Bloomington rather than the Shelbyville substage may be mentioned: (1) The terrace corresponds closely in elevation with the gravel terrace on Farm Creek just described, which connects with the Bloomington morainic system east of the Illinois River; (2) the terrace on the Illinois occupies a shallow valley cut into the Shelbyville till sheet; (8) the vigor of drainage corresponds to that of the Bloomington and is greater than seems elsewhere to characterize the Shelbyville substage of glaciation. A view in a gravel pit on this terrace appears in Pl. XIII. The gravel wherever exposed on this terrace is composed largely of limestone pebbles. The local sandstone and shale pebbles and the Canadian crystallines constitute only a small percentage of the coarse rock material. The sand and fine material found associated with the gravel are also calcareous. In places the gravel is cemented with lime. It is probable that the large percentage of limestone pebbles is due to the great number of such pebbles in the till of the Wisconsin sheet in that vicinity. The highest well-defined terrace noted on the Illinois above Peoria, which seems referable to the Bloomington substage of glaciation, is found near the inner border of the moraine at and below the village of Chillicothe. It stands only 550 to 560 feet above tide, or 40 to 50 feet lower than the terrace on the outer border at Peoria. This difference is probably referable in part, if not entirely, to a reduction from the original height of valley filling, for a well-defined bank separates the top of the terrace from the portions of the moraine bordering it. The terrace in the vicinity of Chilli- cothe contains much coarser material than at points above or below. The extensive excavations for railway ballast reveal a mass of cobble and 276 THE ILLINOIS GLACIAL LOBE. bowlders 20 or 30 feet in depth. The excessive amount of coarse material seems referable to the contribution of such material from the overhanging ice during the building up of the terrace. For this reason the terrace has been connected with the Bloomington rather than a later substage. Possibly some cutting of the valley of the Ilinois took place between the heavy deposition of gravel on the outer border and that near the mner border of the moraine, in which case the deposits near the inner border may not have been built up to the level of those on the outer border. This view seems supported by the observations farther up the valley, no remnants higher than that at Chillicothe having been found. Down the valley from Peoria there is a rapid decrease in the altitude of the gravel terrace, a fall of 70 or 80 feet being made in the 10 miles to the mouth of the Mackinaw River, just below Pekin. There is a great expansion of the valley just below that city, in which the gravel has an elevation of 520 to 530 feet above tide, or 90 to 100 feet above the Illinois River. The gravel is capped by sandy deposits, which are in places drifted into dunes 20 to 30 feet or more in height. Gravel deposits are conspicuous down the val- ley beyond the mouth of the Sangamon River, but the material becomes finer in passing down the stream. The gravel has a height of about 500 feet above tide at the mouth of the Sangamon, or 75 to 80 feet above the level of the Illinois River. Farther down it gradually approaches the level of the river, the highest terraces near the mouth of the stream, which seem connected with the Wisconsin invasion, being but 40 to 50 feet above low water. There appears to have been no gravel outwash into Kickapoo Creek Valley in northern Peoria County, although this stream follows the outer border of the moraine quite closely for a distance of 7 or 8 miles. Upon turning away from the moraine the creek cuts through the Shelbyville moraine, and it is probable that this offered an obstruction to the rapid escape of waters from the ice margin. In southeastern Stark County there is a low plain extending back from Spoon River Valley to the Bloomington moraine which received a slight outwash from the moraine. A few exposures were found where gravel to a depth of several feet was deposited. It seems, however, to have been only a weak point of discharge, as the gravel deposits scarcely extend to Spoon River Valley, though this valley approaches within 6 or 7 miles of the THE BLOOMINGTON MORAINIC SYSTEM. PHT moraine and receives two tributaries which head in the moraine. There are other tributaries of Spoon River farther north which also head in the moraine, but these seem to have afforded only weak lines of escape for glacial waters. The portion of the moraine bordering the Green River Basin in north- ern Bureau and southeastern Lee counties, as already noted, is coated heavily with sand on its outer face. The sand. extends westward from the moraine down the Green River Valley, covering southeastern Whiteside and northern Henry counties and occupying the low tract between Green and Rock rivers. This sand is in all probability an outwash from the moraine, being too extensive a deposit to be referable to the action of lake waves. ‘The sand apparently forms, over much of the district which it occupies, a coating 10 to 20 feet or more in depth. The depth is so great that natural exposures of underlying beds are rare and only a few wells reach its bottom. It is therefore difficult to ascertain whether there is much gravel outwash. Near the border of the moraine in northern Bureau County there are, however, a few exposures of gravel at the base of the sand which are thought to be an outwash from the moraine. The gravel appears to extend but a few miles west, for in the vicinity of the county line of Bureau and Henry counties wells indicate that the sand rests upon a compact clay. At the head of the Green River Basin, in eastern Lee County, there is a gravel plain, covering about 25 square miles, whose eastern border is in the moraine. It extends back into the moraine a mile or more, along the east and south branches of Willow Creek, and there connects with gravelly knolls which dot the valley slopes and bottoms for 2 or 3 miles farther east. This gravel plain extends northward along the west border of the moraine to the south branch of Kite River at Steward. At this stream also the gravel plain connects closely with gravelly knolls which extend some distance up the valley into the moraine. The gravel extends only a few miles away from the moraine, scarcely beyond the east border of Inlet Swamp. The waters issuing from the ice sheet probably had sufficient strength to carry the gravel down the rapid slope to Inlet Swamp, beyond which they could carry only sand. There is considerable fall in the Green River Basin, but it is irregularly distributed, so that drainage even now is very imperfect. 278 THE ILLINOIS GLACIAL LOBE. On the outer border of the moraine in eastern Ogle County there is a depression due to a preglacial valley which was not completely filled. Into this depression considerable sand and fine gravel was carried by the waters issuing from this moraine. There were two lines of escape, the southern portion of the depression being drained westward through Kite River, while the northern portion was drained northward through Killbuck Creek. The sandy and gravelly deposits are thickest along the portion drained by Kill- buck Creek, where they have a depth of 20 feet or more. In the portion drained by Kite River the average depth is but 5 or 10 feet, and portions of the depressed area have scarcely any surface gravel. The deposits in this depressed tract would be classed as a gravelly sand rather than gravel, the proportion of coarse material being very small. The streams issuing from the moraine in Dekalb County (South Kishwaukee River and Owen’s Creek) have only a small amount of gravel and sand outside the moraine, and appear not to have been lines of vigorous discharge. Sandy material borders Owen’s Creek for about a mile each side the stream from the vicinity of South Grove northward to the mouth. The material is fully as fine as that on Killbuck Creek. On the Kishwaukee the belt of sand and gravel is less definitely outlined, there being places where no sand or gravel is found on either side of the valley, while at other places it extends back southward from the valley to the moraine, a distance of a mile or more. It is probable that a portion of this sand and gravel is an outwash connected with the formation of the moraine, though it connects rather vaguely with the moraine. In northwestern Kane County a plain of sandy gravel extends from the moraine westward to the valley of Coon Creek and leads thence down the valley to the north Kishwaukee. It there connects with belts of gravel which lead in from the east and north, all of which appear to be an out- wash from the western border of the composite belt of moraines in McHenry County. A broad belt of gravel leads down the north Kishwau- kee to its junction with the south branch near Cherry Valley. Below this point the valley is so narrow that gravel terraces are inconspicuous, though they continue to the Rock River Valley. The conditions of drainage attending the formations of the minor moraines is next considered. The character of the outwash from the weak moraine in northern McLean County has received but little attention. THE BLOOMINGTON MORAINIC SYSTEM. 279 Gravel deposits of medium coarseness have been observed at and above Lexington on the headwater portion of Mackinaw River near the outer border of the moraine They underlie the plain for only a short distance back from the river valley at these points. The extent of these deposits and their relation to the moraine have not been ascertained. It seems probable, however, that they are a glacial outwash. The latest of the moraines in the Bloomington system follows the east border of the Lllinois-Vermilion River throughout much of its course, a position that under present conditions would afford fair escape for the glacial waters. But at the time the moraine was forming, the channel now occupied by Vermilion River had not been excavated. The broad basin which it traverses has scarcely 20 feet descent in the 40 miles from Pontiac to the borders of the Illinois River. The conditions were favorable for the ponding or accumulation of water issuing from the ice sheet, as well as for water draining into it from the land areas on the southern and western borders. A belt several miles in width might have thus become submerged and a lake-like river formed. Even though the volume of water were great, the force of the current would be weak until the channel had been cut back several miles into the basin: The opening of this channel has been very slow, for it is now but partly accomplished, the main part of the chan- neling being in the portion below Streator. Evidence of a ponding of waters in this basin is found in deposits of sand and silt which cover it. The sand deposits are most conspicuous in the southern portion of the basin, and are there drifted in places into low dunes and ridges. From Pontiae southward the deposits consist of silt or fine sand. The ponding of waters and deposition of sand and silt probably began with the with- drawal of the ice sheet from the divide on the west border of the basin, and continued until the ice sheet no longer contributed its waters to the basin. This would involve not only the time when the moraine under dis- cussion was forming, but also that embraced in the production of the Mar- seilles moraine. Possibly the ponding continued to much later date, though in less volume than at the morainic substages As shown below (p. 290), there was a discharge into this basin from a small glacial lake held in the basin of the Iroquois River. This line of discharge followed the east fork of Vermilion River, which passes through, the moraine under discussion, 8 to 10 miles southwest of Pontiac. The character of the outwash appears 280 THE ILLINOIS GLACIAL LOBE. to have varied little during the long period in which the ice sheet dis- charged waters into this basin. For a few miles along the immediate bor- ders of the river below the point where the East Fork enters this basin a fine gravel occurs, which was probably contributed by the outlet. There may have been less ponding of water at this time than when water was contributed by the ice sheet more directly to the basin. This subject is discussed more fully in connection with the glacial lake (pp. 290, 314, 336). No doubt the Illinois Valley received considerable material as an out- wash from this minor moraine, but as yet the deposits have not been sepa- rated from those made later, and nothing is known concerning the degree of coarseness of the material. The portion of the moraine north from the Illinois in central and northern Lasalle County seems to have been no better favored for escape of water than that along the border of the Illinois-Vermilion. The plain west of it carries thin deposits of silt, but whether their deposition is largely referable to water issuing from this moraine is not known. Pos- sibly wind transportation was an important factor in the deposition. INTERMORAINIC TRACTS. EXTENT OR DISTRIBUTION. Under this topic are discussed the plains and gently undulating tracts among the ridges of the Bloomington system and a plain between the inner ridge of the Bloomington system and the Marseilles moraine. The inter- morainic tracts are of much greater extent than the morainic, for the latter are restricted to narrow belts. About 90 per cent of the area embraced between the inner border of the main ridges of the Bloomington system and the outer border of the Marseilles system is here classed as nonmorainic. This area of about 6,000 square miles ranges in width from 25 to about 50 miles, being widest in central Illinois. It has a length of about 175 miles between northern Kane County, Illinois, where it connects with the com- posite belt of moraines, and western Benton County, Indiana, where it is shut off by moraines of late Wisconsin age. GENERAL FEATURES. The portion north of the Illinois River, embracing southwestern Kane, southeastern Dekalb, northwestern Kendall, northwestern Lasalle, and THE BLOOMINGTON MORAINIC SYSTEM. 281 eastern Bureau counties, shows a marked descent from northwest to south- east and a less marked descent from northeast to southwest. Its altitude along the border of the moraine declines from about 800 feet at.the north- east to 700 feet at the southwest, or 100 feet in a distance of 50 miles. It declines an equal amount in scarcely 25 miles in passing from the border of the moraine southeastward to the bluff of Fox River. The altitude along the bluff of this river ranges from about 700 feet at the north to 620 feet at the south. Aside from the narrow morainic belt already discussed, which traverses this plain from Utica northward to Earlville, the surface is as a rule only slightly undulatory. There are, however, a few short eskers with associated chains of gravelly knolls—discussed below—and also scat- tering knolls 10 or 20 feet in height, all of which rise somewhat abruptly above bordering plains. South from the great bend of the Hlinois River the features are more varied than in the district just touched upon. The narrow strip on the west of the Illinois Valley descends rapidly from the moraine to the river bluff. It has a gently undulating surface, with a tendency to north-south ridging. East from the Illinois Valley there are nearly plane tracts inter- rupted by small areas with undulatory surface, which in places bear strong resemblance to the morainic belts. These undulatory tracts are most abun- dant in a belt a few miles in width that leads southward from the bend of the Illinois through eastern Putnam, eastern Marshall, and east-central Wood- ford counties, its eastern edge being near the divide between tributaries of the Vermilion and streams that flow westward to the Illinois. From this divide eastward to the Vermilion River the surface shows very little undu- lation. There is, however, a marked descent, the altitude of the divide being 700 to 750 feet, while the immediate borders of the Vermilion north from Pontiac stand but 620 to 640 feet above tide. The descent from this divide westward to the Illinois is very slight; indeed, in places east-west lines are nearly level from this divide to the border of the river valley. There is a small tract south of Ottawa, occupying the interval between the inner ridge of the Bloomington system (Farm Ridge) and the Mar- seilles moraine, which has a nearly plane surface. It is crossed in an east- west direction by a sand ridge, discussed below. Another sand ridge follows the south bluff of the Illinois part way across this plain. Both 282 THE ILLINOIS GLACIAL LOBE. ridges appear to mark the shores of a lake-like expansion of the Illinois River, and represents two stages differmg about 30 feet in level. In northern McLean County a tract embraced between the inner border of the main ridges of the Bloomington system and the Mackinaw River Valley is gently undulating and is also dotted by occasional well-defined knolls 20 or 30 feet in height. It has a marked northward descent, the elevation along the Mackinaw River being 50 to 100 feet below the inner border of the moraine. North from the Mackinaw River, as already noted, there is a well-defined ridge (Cropsey Ridge) crossing the country in a WNW.-ESE. direction. From this ridge there is a gradual northeastward descent toward the Vermilion River. The greater part of the surface is plane or but gently undulating. There are, however, in southern Living- ston County a few knolls and ridges of sand 10 or 20 feet in height. These knolls and ridges are probably the result of wind action rather than glacial features. East from the reentrant angle of the Bloomington morainic system in Ford and southeastern Livingston counties there is a plain which covers the ereater part of Iroquois County and extends slightly into bordering counties. The plain is bordered at the north by the Marseilles morainic system and at the east by the Iroquois moraine, a moraine of late Wisconsin age. It extends into the State of Indiana only a few miles, in northwestern Benton County. This plain descends toward the north, its altitude at the inner border of the Bloomington morainic system being about 700 feet and in northern Iroquois County only about 625 to 650 feet. It is crossed nearly centrally from east to west by a gently undulatory belt, discussed above as a possible continuation of the inner member of the Bloomington system. Aside from this belt the drift surface is nearly plane. There are, however, a few low sandy ridges in the western part of Iroquois County and numer- ous dunes in the eastern part. Some of these ridges appear to be beaches of a temporary lake, as indicated below. The dunes are, in ali probability, a result of wind action upon the sand deposits of the lake bottom. THICKNESS OF DRIFT. There are present beneath these intermorainic tracts a sheet of fresh drift of Wisconsin age and older deposits of lowan and Illinoian age. The thickness of the Wisconsin drift may be ascertained at many places by the THE BLOOMINGTON MORAINIC SYSTEM. 283 well records, which show a change from soft till to hard at the base of this deposit. It is much less than on the morainic ridges of the Bloomington system, and probably does not average more than 50 feet. In southern Kane County and thence southwest along the border of Fox River it appears to be but 20 to 40 feet, but at the inner border of the main moraine in Dekalb, Lasalle, and Bureau counties it is in places 100 feet or more. In the counties bordering the Ilinois River it is 50 to 100 feet or more, but in the Vermilion Basin it scarcely reaches 50 feet. In Iroquois County it is 50 to 100 feet. The older drift deposits are thin in the vicinity of Fox River and Vermilion River and the west-flowing portion of the Illinois River, but elsewhere within the tracts under discussion they are generally present in large amount, and there is probably an average thickness as great as that of the Wisconsin drift sheet. In portions of the Iroquois River basin 200 feet or more of the older drift is present, but in the remainder of the tract a thickness exceeding 100 feet is rare. By reference to the detailed dis- cussion of the wells in the several counties embraced within these inter- morainic tracts the variations in thickness may be seen. STRUCTURE OF THE DRIFT. Throughout the greater part of the area embraced in these inter- morainic tracts the Wisconsin drift consists mainly of a moderately stony, soft, blue till, very similar to that found in the moraines. This till js replaced by sand or gravel deposits along the line of the eskers which occur in Kane and Dekalb counties, and also along many of the tributaries of Fox River. There is also considerable sand associated with the till in a belt several miles in width along the west side of Fox River in Kane, Ken- dall, Dekalb, and Lasalle counties. On the borders of the Vermilion River in Livmgston County and southern Lasalle County sand and gravel deposits predominate over the till. With these exceptions the till greatly predomi- nates over the sand and gravel. In many localities it forms so solid a sheet that strong wells are not obtained in it, whereas in the districts in which sand and gravel predominate over the till abundance of water is obtained at moderate depths. The drift of these intermorainic tracts is capped only by thin deposits of silt, seldom exceeding 3 feet in depth, and in places too thin to conceal the surface bowlders. 284 THE ILLINOIS GLACIAL LOBE. The older deposits of drift appear to be more variable than the Wis- consin sheet within the area under discussion. The till differs from that of the Wisconsin sheet in being much harder to penetrate and in being of a gray or brown color rather than blue. It appears to contain numerous pockets or intercalated beds of gravel or sand, for strong wells may usually be obtained in it in localities where the Wisconsin drift does not supply a sufficient amount of water. The outcrops of these older deposits along the ravines or valleys tributary to the Illinois often expose a cemented gravel, in beds a few feet in thickness and a few rods in extent. These beds appear to lead through the till in horizontal bands of limited width; pos- sibly they are buried stream beds or valley gravels formed between the retreats and advances of an oscillating ice margin. The exposures are insufficient to afford a clear idea of their extent and connection. It seems not improbable that these beds which are cemented at outcrops along the valleys become open textured and water bearmg where unexposed. There are places along the Illinois Valley and its tributaries where the older drift appears to be composed very largely of sand and gravel, but as a rule the till predominates. The structure of the drift in each of the counties com- prised in this intermorainic area is shown in some detail in the discussion of wells which accompanies this report. KANEVILLE ESKER AND DELTA. One of the most interesting eskers noted in Illinois is found in the southern part of Kane County. Its eastern terminus is about 3 miles west of the city of Aurora, and its western terminus is near the village of Kane- ville, from which the esker has received its name. The esker occupies a trough-like valley cut in glacial deposits. It is probable that the valley was formed by the same stream which deposited the esker, since they coin- cide so nearly in trend and position. At the western end of this valley there is an extensive delta, apparently built up by the same stream. The trough- like valley is now traversed by Blackberry Creek in the reverse direction from the supposed flow of the glacial stream which produced the excava- tion and formed the esker and delta. The valley occupied by the esker is much larger than that of the lower course of Blackberry Creek, its dimen- sions being about 1 mile in width and 30 feet in depth, while the valley of the creek below the point where it leaves this trough is scarcely 20 rods in sd Knollsina Kanevilleesker Strize gravel plain D KENDALL COUNTIES asm] ms (E SS AN E nsandterraces KAN SY FRANK LEVERETT Scale TiGesinic Ui i plai GLACIAL MAP OF PARTS OF B Sandand gravel Bowlderbelts ij Hine we ( 4 ; i i SSS LEX OSWESO Ts j EDO = 5 i & ano; : SSA 7 rena: == } e Pry Port Tat) A J | , AT tt ; ara = ale — Vee i == : = eee : = lai ies ee a WA | = lin a Se i le = ly =—= St NN i llth, Mall Trt] K Ue, | SEE uf) as pis i _———SS : INS / i | I a i "NOV‘L “N6E'L NSC cL THE BLOOMINGTON MORAINIC SYSTEM. 285 average width and but 15 or 20 feet in depth. The trough-like valley is therefore about 30 times as large as the portion,of Blackberry Creek Val- ley below its eastern end. This broad valley was apparently cut to such depth before the creek entered it that the latter has tended to fill it by over- flows in time of freshet, and has deepened it only in the immediate bed of the stream. The eastern end of the esker is found in sec. 18, Aurora Township, on a till plain which borders Fox River. There is here a ridge of gravel some 60 rods in length and 10 or 20 rods in width, which rises but 12 to 15 feet above the bordering plain. For a mile or more west from this ridge there are only occasional small gravel deposits in the form of knolls and short ridges, but as soon as the trough-like valley is fairly entered the gravel becomes more abundant. (See Pl. XIV.) It forms a winding ridge 20 to 60 feet in height, and interrupted only by occasional narrow gaps. Its slopes are very abrupt, rising frequently with an angle of 30°. In the northwest part of see. 31, Blackberry Township, about 7 miles from the eastern end, the esker rises from the deeper portion of the valley and lies along its south slope. Here also it changes from a single sharp ridge to a tumultuous series of knolls and winding ridges, inclosing basins 30 to 40 feet or more in depth and having a diameter of but 10 or 20 rods. This belt has a width of about one-third of a mile, and extends westward nearly a mile. Just north of this main belt there are, in the deeper part of the valley, occasional gravel knolls and low winding ridges. These low ridges rise from the trough at its western end, and together with the main belt lose themselves in the gravel delta near Kaneville, the delta being built up nearly as high as the crests of the ridges. The delta occupies an area of about 8 square miles. It stands a few feet higher than the till plain which borders it on the north, west, and south. The gravel apparently extends in places below the level of this till plain, for in two cases wells have penetrated to a depth of 60 feet without reaching its bottom. In the village of Kaneville, which is situated in the midst of the delta, the wells are usually in gravel to a depth of 30 or 40 feet. In a few instances, however, clay beds were passed through in the lower portion of the wells. There are numerous small excavations in the esker which show it to be formed of sand and gravel in nearly horizontal beds. In places the beds 286 THE ILLINOIS GLACIAL LOBE. have a sharp dip toward the sides of the esker, but this does not appear to be a general attitude. The upper part and frequently the slopes consist of coarser gravel and contain less fine material than the deeper portions. The absence of fine particles is perhaps attributable in part to the action of per- colating waters, which probably have sufficient force to carry down the finer particles a few feet from the surface, but it is probable that the surface portion was originally coarser than the deeper beds. The pebbles are mainly limestone and are apparently, in large part, from the Lockport (Niagara) limestone, which outcrops in the neighboring district on the east. The sand is calcareous, but not to such a degree as in many hillocks containing sand and gravel which occur in the neighboring moraines. It seems probable that the material of which the esker is composed is a residue left upon the exca- vation of the till which was removed along the course of the valley or of material embedded in the basal portion of the ice sheet. Examinations of a sample of the till from a neighboring till plain showed that 93 per cent of the pebbles are limestone, which is about the percentage of limestone in the esker. Bowlders were observed on the esker in but one place, and this was at a slight depression on its crest. There were about 30 of them, and all were of Archean rocks. The greater percentage of Archean rocks on the surface than in the deeper portions, both of eskers and till sheets, apparently indi- cates a different source for the bowlders than that of the main body of the drift. Presumably they were carried at a higher elevation in the ice. LITTLE ROCK ESKER OR “ DEVIL’S BACKBONE.” In the northwest part of Squaw Grove Township (T. 38, R. 5 E.), Dekalb County, there is an esker about 14 miles in length, known by the residents as the ‘‘ Devil’s Backbone.” It is situated a short distance south of Little Rock Creek in sees. 5 and 6, and trends ESE-—WNW. At the eastern end its height is but 4 to 6 feet, but in sec. 6 it is 10 or 15 feet in height. It is only 8 or 10 rods in width, including slopes, and consequently presents very abrupt slopes. It winds considerably, but has a somewhat even crest line. At the western end there is a sandy tract covering about 80 acres, which is thought to be a delta formed in connection with the esker. There is no valley or trough excavated in the drift, as in the case of the Kane- ville esker, for the esker stands at about the level of the bordering till plain. THE BLOOMINGTON MORAINIC SYSTEM. 287 Wells in the delta penetrate 10 to 15 feet of sand before entering till. The esker is opened at numerous points, and there is usually 3 or four feet of coarse gravel at the surface, beneath which is a fer gravel. In places the bedding is found to have a dip toward the northwest, nearly in line with the general trend of the ridge. The coarse gravel curves over the ridge, covering slopes as well as crest. The pebbles are principally limestone and are usually well rounded. There are a few short gravel ridges and knolls east from the end of this esker in secs. 4, 11, and 12, but they do not seem to be definitely connected with one another or with the esker. Their trend, like that of the esker, is ESE—-WNW. The same system of glacial drainage which formed the esker may have been influential in forming these knolls and ridges. Mention should also be made of a chain of gravelly knolls which follows a tributary of Somonauk Creek in southeastern Clinton Township (T. 38, R. 4 E.), Dekalb County. Though following the creek border closely, they are evidently not the result of erosion by the creek, for they stand above the general level of the bordering plain. ‘They range in height from 10 to 25 feet. Their width is usually 15 to 30 rods and the length varies from one-fourth mile or less to fully one-half mile. They are chiefly on the south border of the stream, but two were observed on its north border. They are not strictly in line with each other, though a belt a half mile wide would include the entire system. The length of the system is about 4 miles, the western end being 24 miles south of Waterman and the eastern end at Somonauk Creek Valley in the southwest part of Squaw Grove Township. One of these knolls has an extensive gravel pit in which the following beds are exposed: Section in gravel pit on knoll in Clinton Township, Dekalb County, Illinois. Feet. Brown clay with a few cherty pebbles ...... ..---. ----.- +--+ 2-22-22 222 ene cee ene ee eee eee nee 4 Coarse gravel, mainly limestone pebbles ..--...-.--.---------+ ------ ++ 2-2 - e+ 2-2 eee ee ene eee 6 Fine gravel and sand in alternate layers, each 6 inches or more in thickness --....--..----.-------- 4 Several other small excavations have been made in these gravel knolls which show a section similar to the above. The stratification in every case is nearly horizontal. There are also knolls of a different type found on this plain which include much till as well as assorted material. One of these knolls, situated about 2 miles northwest of Leland, contains an extensive gravel pit which 288 THE ILLINOIS GLACIAL LOBE. displays its structure from top to bottom. The knoll is capped by a brown clay, containing few pebbles. Beneath this there is at the east side of the knoll considerable sand, but toward the center there is a series of till or clay beds 12 to 20 inches in thickness, interstratified with gravel and sand beds each 2 or 3 feet in thickness. All the beds dip toward the center of the hill at an angle of 15 degrees or more. The till is very hard and pebbly. The gravel contains a much larger percentage of crystalline rocks of Canadian derivation than is common in knolls and eskers made up entirely of assorted material, though there are many limestone pebbles such as may have been derived from ledges in the neighboring districts on the east. This knoll stands 15 to 20 feet above the bordering plain and about 30 feet above the flood plain of Little Indian Creek, which touches it on the east. COVEL RIDGE. Inthe plain drained by Covel Creek, a southern tributary of the Ilinois, entering just below Ottawa, there is a low ridge about 7 miles in length extending in a nearly due east-west direction from near the outer border of the Marseilles moraine in sec. 4, Grand Rapids Township (T. 32, R. 4 E.), to the inner slope of Farm Ridge the inner ridge of the Bloomington system in sec. 5, Farmridge Township (T. 32, R. 3 E.). It has a height of 15 or 20 feet and a width of 40 to 60 rods, and is interrupted by no gaps of consequence except the one through which Covel Creek passes in see. 6, Grand Rapids Township, and this gap is only 30 or 40 rods in width. The altitude of the crest of this ridge, as shown by the Ottawa topographic sheet, a portion of which is reproduced in Pl. XIX, is mainly between 640 and 650 feet above tide. The portion east of Covel Creek is represented to be slightly lower than 640 feet. The ridge is capped by a brown silt several feet in thickness which is readily pervious to water. This is underlain by sand which extends to a depth of 15 or 20 feet or more. The few wells which have been made on the ridge are sunk no deeper than 20 feet. The sand also extends out beneath the bordering plain a short distance both north and south of the ridge and affords water for wells at slight depth. 'The extension beneath the plain, however, seldom exceeds a mile in width or half a mile from the crest of the ridge. Border districts are underlain at slight depth by till. The internal structure, the form, and the uniform elevation of the ridge THE BLOOMINGTON MORAINIC SYSTEM. 289 suggest the interpretation that it is a beach line. However, this interpreta- tion scarcely affords a satisfactory explanation of the mode of deposition of the silty mantle; hence the question of its mode of formation is left open. There is a lower ridge following the brow of the Illinois bluff, which is well displayed in South Ottawa, and eastward from there to the border of the Marseilles moraine. Its altitude, as shown by the Ottawa topo- graphic sheet, is very nearly 610 feet above tide. Along the north bluff of the Illinois, about midway between Ottawa and Marseilles, there is another beach-like ridge leading from the outer border of the Marseilles moraine westward to the border of Fox River Valley, which is represented to stand a few feet lower than the ridge just noted, its altitude being 600 feet or less. ONARGA RIDGE. In the Iroquois Basin there are several small ridges of sand presenting the appearance of beach lines, some being found in the northwest part of Iroquois County, a short distance south of the Marseilles moraine, and others on portions of the plain farther south. The best-defined and most elevated ridge noted is one leading from Onarga westward through Ridge- ville to one of the headwater forks of Vermilion River, the west end being near the line of Iroquois and Ford counties, about 4 miles southeast of Piper. Throughout this distance of about 8 miles it has a width of only 40 to 80 rods and a height of 15 or 20 feet or less. As far as could be ascertained from the slight exposures and records of occasional wells it is composed entirely of sand. It is underlain at the level of its base by a bluish-yellow, silty, pebbly clay, which grades below into blue till. In some places the sand is immediately underlain by blue till. As a rule the ridge has a smooth surface and gentle slopes, but in places the sand is drifted into low dunes 5 or 10 feet in height. The sand is of a brown color and so far as tested shows no effervescence with acid. A short distance east from the eastern edge of this ridge a belt of low sand dunes sets in, which has a width of 1 to 2 miles. This belt leads eastward to the vicinity of Watseka, and thence northward and eastward to the Kankakee Basin, occupying much of northeastern Iroquois County. The elevation of the Onarga Ridge is about 675 feet above tide, but the dunes to the east seldom reach this elevation, the district covered by them MON XXXVIII——19 290 THE ILLINOIS GLACIAL LOBE. having generally an elevation of 640 to 650. feet. Possibly a shore line may be found south and east of the dunes at an elevation corresponding to that of the Onarga Ridge, but as yet it has not been discovered. It seems probable that this ridge marks the south shore of a temporary lake which discharged westward through the east fork of Vermilion River. If there were no obstructions at the north, a northward discharge from the Iroquois Basin would seem to be more natural, for the country descends in that direc- tion. The only known former obstruction is that caused by the presence of the ice sheet, in which case this beach may be interpreted as the shore of a glacial lake. The writer’s studies have not been sufficiently detailed to justify a full interpretation of the phenomena. Other features of similar character are discussed below (pp. 8336-338). SECTION IV. THE COMPOSITE MORAINIC BELT OF NORTHERN ILLINOIS. Numerous references have been made in previous pages to a composite belt of moraines with which the Bloomington system connects in northern Kane County, and which marks the continuation of the Bloomington system, together with that of later morainic systems which are there intimately associated with it. This composite belt admits of but little separation into distinct moraines. It seems advisable, therefore, to give it treatment inde- pendent of each of the morainic systems which lead away from it, leaving open toa large degree the question of precise correlation. This belt is made to include a somewhat distinct moraine, called the Marengo Ridge, which lies along its western border. The discussion of this ridge is first taken up; the remaining portion of the composite belt west of Fox River is next considered, and this is followed by a discussion of the portion east of Fox River. MARENGO RIDGE. DISTRIBUTION. North from the village of Hampshire in Kane County, as far at least as the State line, the Marengo Ridge constitutes the outer moraine of the Wisconsin series, and it probably continues to be the outer moraine to its junction with the Kettle moraine of the Green Bay lobe in western Wal- worth County, Wisconsin.t The ridge receives its name from the village of 1 See T.C, Chamberlin: Third Ann. Rept. U.S. Geol. Survey, p. 322; also Pl. XXXI. COMPOSITE MORAINIC BELT OF NORTHERN ILLINOIS. 291 Marengo, which is situated in the line of the ridge, but which stands in the North Kishwaukee Valley. It is the only town in Illinois in the direct line of the ridge, though Harvard in McHenry County and Hampshire in Kane County are situated near the foot of the outer slope. From the State line the course of the ridge is nearly due south to Marengo, from which point it bears southeast to the south line of McHenry County. It then resumes a southward course and continues for about 18 miles to the vicinity of Elburn, in Kane County, where it becomes united with the portion of the composite belt to the east. It will be observed that it passes by the eastern end of the outer Bloomington ridge near Hamp- shire. The ridge throughout the greater part of its course has a width, including slopes, of 3 or 4 miles. RELIEF. The relief of the outer border is seldom less than 100 feet, and in places it reaches 150 feet or more. The inner border has a relief of 75 to 120 feet, but the relief appears less bold than on the outer border, because the ascent to the crest is more gradual. This ridge is closely associated with the remainder of the belt for a few miles south from the State line, and difters but little in altitude from the district on the east. Similarly at the south, where it connects with the remainder of the belt, it has about as great an altitude. SURFACE. CONTOURS. From the State line southward to Hampshire this ridge presents a char- acteristic knob-and-basin topography, so well developed in the Wisconsin Kettle moraine and described by Chamberlin as being “‘of an exceedingly irregular, intricate character, formed by knobs, peaks, short irregular hills and spurs associated in complex order, interspersed with hollows and depressions of like irregular character, often without outlet.” The larger knobs rise scarcely 50 feet above the neighboring basins, and the average height of the knobs is probably not more than 25 feet. They are found both on the crest of the ridge and on the slopes. Aside from the well-defined basins, there are shallow, saucer-like depressions found frequently on the top of the knolls and the slopes of knolls and ridges, as well as in the sags between them. There is a marked distinction between the contours of the prairie !Third Ann. Rept. U.S. Geol. Survey, 1883, p. 307. 292 THE ILLINOIS GLACIAL LOBE. and of the wooded portion of the ridge, the contours being much sharper in the forest than on the prairie. The ridge is mainly forest-clad from the State line south to the vicinity of Hampshire and mainly prairie from Hampshire to Elburn. This difference in the sharpness of contour may be due in part to the effect of the agencies of degradation, the wooded portion of the ridge being better protected from these agencies. It is probable, however, that the prairie portion was originally possessed of smoother con- tour. It presents a series of billows, often 40 or 50 feet high and 60 to 80 rods or more in diameter, whose slopes are usually smooth and regular. As indicated below, the relation of the southern portion of the ridge to the ice margin may be somewhat different from that north of Hampshire. There are three gaps in this ridge worthy of mention. The largest is that at Marengo, through which the North Kishwaukee passes. It is fully 150 feet in depth and about 2 miles in width. The second gap occurs about 5 miles southeast of Marengo. This is nearly a mile in width, but only about 75 feet lower than the neighboring portions of the ridge. It has a nearly plane surface, and has apparently been utilized as a line of discharge for a body of water formerly held between this ridge and the one on the east. A third gap occurs in the north part of T. 40, R. 7 E. It is 60 or 70 feet in depth and about one-half mile in width. It has a nearly plane surface and was probably at one time a line of discharge for water held between this ridge and a moraine on the east. It is now utilized by a trib- utary of the South Kishwaukee River. THICKNESS OF DRIFT. The thickness of drift has been ascertained at only three points, but records of several deep wells were obtained which show that there is a heavy accumulation along the entire length of the ridge. Of the three borings reaching rock, one is in the village of Harvard and the other two are in the southern part of the ridge. At Harvard the thickness is 102 feet. In the other wells the rock was struck in one instance at 230 feet and in the other at about 250 feet. It is probable that the general thickness of the drift along the crest of the ridge south from Hampshire is not far from 250 feet, for wells on the plain west of the ridge, at an altitude 100 to 125 feet below the level of its crest, have in several instances struck rock at about 150 feet. One well on the ridge, near Lily Lake reached a depth of 336 feet without COMPOSITE MORAINIC BELT OF NORTHERN ILLINOIS. 293 entering rock. In the portion north from Hampshire the thickness is prob- ably not much greater than the relief of the ridge, for rock is encountered at a depth of 50 feet or less in much of the border district on the west. The drift referable to the invasion which formed this ridge has probably a thick- ness about equal to the relief of the ridge, which, as stated above, is usually 100 to 150 feet or more. STRUCTURE OF THE DRIFT. The ridge is composed mainly of blue till) Sand and gravel beds are not sufficiently extensive to afford a general water supply. Even weak wells are difficult to obtain in some parts of the ridge. Many wells must be sunk 100, 125, or even 150 feet to obtain an adequate water supply. In not a few instances the water supply appears to be obtained at about the level of the base of the ridge and the junction between the Wisconsin and older drift sheets. A few gravelly knolls were noted along the outer border of the ridge west of Marengo, and at occasional points between there and Hampshire. None of these rise more than 10 feet above the general level. A few gravel knolls were noted near East Burlington, in secs. 23, 24, 25, and 26, T. 41, R. 6 E., and low gravel ridges occur along the tributaries of the South Kishwaukee in T's. 40 and 41, R. 6 E. Excavations in these knolls usually show a preponderance of sand and gravel over till, though the latter is often present in considerable amount. ‘The beds have no apparent uniformity in direction or degree of dip. They are often curved and disturbed as if affected by movements of the ice sheet over them. The presence of a buried soil was noted in several well borings of which records were obtained. In the city of Marengo, on the borders of Kishwaukee Valley, it is found at a depth of 30 to 60 feet, the variation in distance being due to difference in elevation of the wells. In see. 11, T. 48, R. 5 E., a well on the outer slope of the moraine struck a buried soil at 70 feet. The soil was underlain by a soft whitish clay of slight depth, beneath which gravel, yielding water, was found. In the cases just noted the soil seems referable to the Peorian interglacial stage. A buried soil was noted in one of the deep borings in T. 40, R. 7 E., which reached the bottom of the drift. This soil, as noted on a preceding page, seems to be at a level low enough to be referred to the Sangamon. The boring is on 294 THE ILLINOIS GLACIAL LOBE. the farm of James Powell, in sec. 7, near the crest of the ridge, and the section is as follows: Section of James Powells boring near Lily Lake, Iilinois. Feet Pebblygsoilt ee eet tjaae eee nin ne alee eo eetate ens Dee Sen prea ela csi tics cic ic eine aise ese eee 1 Brownish-yellowspebblyiclay. t2-2cs see eee een ence ee eae testcase eSet ee cece Se tee eee eee eee 15 Grayvish=blueipeb bl yaclayy = eceer san eee eects See ea ete tate oem eyiele mat ioaie ce ee eee eee eee 180 Blache uc key isoi les: aa aera ae eee rain ots ate ese etna ow aie eh Sloe Se ease Tage a a SN Co en 2 Greenish: Clayiocscne cae S=e tee tee ciao axce aa eee ee ty etie citinne a ois ergwslem eteice Se cee aoa ee Iee eee 3 HardGpebblyaclay.of brownish-blneicol one seccissseeeneleeet se ayo a ean =i eee eee eee 40 SENS Scod noes scas csp Tae oss. cbbens Beoato HaSHSooHHS Shao Sanat SoS SNSaEe Robs Gos HodeHosSSedaHSeS 2 Isla PE cao Beso sanees Sapo a bacios Beds GAS S50 Ea bean SUCH Daa tacd See ae SSO see OSes CoomisoaeboCaSe ossS 8 ILFINOSIONG co ceseces oscocegucaSgue Secu se QSecOSe ean sas bea6 bose HONS SoOU CE SSO CRE SE Seon Hcoo cose 200 Notalldep thie Meee ek eee ona a ees ee ata alee alaiste fee ee ae isha nae alae ee eee 450 The thickness of the yellow till in the above well section is greater than the average, though instances were found in which the till presented a yel- lowish color to a depth of 35 feet from the surface. The average depth of the yellow till is about 10 feet. Several sections of wells along this ridge are presented below in the discussion of the wells of Illinois. The till is thought by some well drillers to be slightly more stony in the ridges than on plane tracts in McHenry and Kane counties, but the difference is not very marked. Surface bowlders are common over the entire length of the ridge, and in a few places are very numerous. They are especially abun- dant in the vicinity of the McHenry-Kane county line and also near East Burlington. Bowlders are composed mainly of granitic and other rocks of Canadian derivation, limestones and local rocks being rarely found at the surface. In the till, however, limestone rocks are a conspicuous ingredient, and also in the kames or gravelly knolls. ~ CHARACTER OF OUTWASH. Along the outer or western border of this ridge from the State line southward to Hampshire there is a nearly continuous gravel plain formed apparently as an outwash from the ice sheet. It extends out usually a mile or more from the foot of the moraine, and leads westward down the Kish- waukee Valley to Rock River. From Hampshire southward the plain out- side Marengo Ridge is nearly free from coarse outwash and carries only slight deposits of silt and sand. The gravel plains usually have a capping of loamy clay 2 to 6 feet or more in depth, which gives them great fertility. Beneath this clay are beds of sand and gravel which show considerable variety in coarseness in vertical COMPOSITE MORAINIC BELT OF NORTHERN ILLINOIS. 295 section. ‘They vary also in coarseness from place to place at the same hori- zon. On the border of the gravel plains the assorted material rests upon beds of till belonging to the older drift, and the depth is often insufficient to afford water for wells. In the middle portions of the gravel plains the wells do not reach the bottom of the sand and gravel. Along the Kish- waukee near Marengo, Capt. Fred Smith, a well driller, has in some cases sunk wells to a depth of 100 feet mainly thr« ugh gravel, but it is not cer- tain that this deposit should be entirely referred to the outwash from the ice at the time the Marengo Ridge was forming. INNER-BORDER PHENOMENA. On the inner border of the Marengo Ridge there is, in Kane County, a narrow plain 1 to 2 miles in width, separating it from the remainder of the composite belt. This plain is generally very level and in places is poorly drained. It is underlain in part by sand and in part by till. The greater part is now tributary to Fox River, but the southern portion finds a discharge westward into the Kishwaukee through a gap in the Marengo Ridge, as noted above. In McHenry County the inner border of the Marengo Ridge is largely occupied by gravel plains which are connected with the portion of the composite belt on the east. Along the borders of these gravel plains there are nearly level tracts underlain at slight depth by till. At present the gravel plains on both the inner and the outer border of the Marengo Ridge are occupied by insignificant streams which seldom fill the small ditches leading through the broad plains. They are certainly inadequate to have deposited the vast amount of assorted material here present, and the fact that these gravel deposits set in at the base of the moraines in just such positions as streams of water escaping from the border of the ice sheet would occupy, apparently leaves no room to question the interpretation that the gravel is an outwash from the ice margin. These gravel deposits, it is thought, testify as clearly, though perhaps in a less impressive manner, to the influence of the ice sheet as does the great ridge of commingled drift formed at the ice border. CORRELATIONS. The correlations of this ridge with moraines farther south can scarcely be said to be settled. Several interpretations are suggested by the 296 THE ILLINOIS GLACIAL LOBE. phenomena. By one interpretation the portion of the ridge from Hampshire northward is considered a continuation of the Bloomington system, while the portion south from Hampshire is merely a spur projecting back from the reentrant angle formed near that village. The difference in the contours of these two portions of the ridge may in this case be due to a different position in reference to the ice margin, the portion north from Hampshire being formed at the extreme margin of the ice sheet and the portion south from Hampshire at some distance back from the margin. The submarginal position would seem to be a sufficient cause for the smoothness of contour. By a second interpretation the Marengo Ridge is made later than the outer ridge of the Bloomington system, and its entire length considered a marginal accumulation. Its great relief above the outer ridge of the Bloomington system at Hampshire, where it crosses that ridge, so strongly favors this interpretation that for some years it was given more weight by the writer than other interpretations, though the absence of a gravel out- wash on the west border of the portion south from Hampshire left room for doubt. A third interpretation suggested itself when revisitmg the region with a view to reaching a more satisfactory conclusion concerning correlations. By this interpretation the outer ridge of the Bloomington system is con- sidered to pass eastward across the Marengo Ridge and to join the composite belt lying east of that ridge. The portion of the Marengo Ridge north of Hampshire would, in this case, have stood outside the ice sheet, while the portion south of Hampshire would have been overridden by it. If the weakness of the outer ridge of the Bloomington system at the point where it connects with the Marengo Ridge is continued eastward some difficulty would be experienced in tracing it over the more bulky and more sharply morainic Marengo Ridge. The abrupt change in the contour of the Marengo Ridge at the point where the outer ridge of the Bloomington system con- nects with it seems to give support to this interpretation, as well as to the first interpretation. Until further light is thrown upon the subject, the value of each of these interpretations must remain an open question. At present the writer is unable to exclude any of them, nor does any one of them seem decidedly better sustained by the phenomena than the others. COMPOSITE MORAINIC BELT OF NORTHERN ILLINOIS. 297 PORTION OF COMPOSITE BELT WEST OF FOX RIVER. GENERAL FEATURES. Aside from the Marengo Ridge just described, there is a belt from 8 to 15 miles in width, on the west side of Fox River, in McHenry and Kane counties, which is strongly morainic, there being only a few small areas, of 1 to 3 square miles each (aside from marshes and swamps included among the morainic knolls), in which the surface is level. The belt is more elevated on the west border than in the vicinity of Fox River. Its general elevation there is not markedly different from that of the crest of the Marengo Ridge. At the State line it rises above the 1,000-foot contour, one point being 1,040 feet above tide (Rolfe). A point a mile south of Alden rises above 1,000 feet. Along much of the divide between the Kishwaukee and Fox rivers, from the State line southward to Crystal Lake, the altitude is above 950 feet. In southern McHenry County and in Kane County few points reach 950 feet, but much of the divide rises above 900 feet. Fox River enters the State at an elevation of 766 feet (Rolfe) and falls about 25 feet in crossing McHenry County, a distance by course of stream of over 30 miles. In Kane County its descent is more rapid, there being a fall of 125 feet in a distance no greater than that traversed by the stream in McHenry County. The stream is in the midst of morainie knolls and ridges as far south as Geneva, beyond which it has a plain on its west border. These ridges often rise abruptly 80 or 100 feet above the level of the stream. From the valley of Fox River, in McHenry and Lake counties, marshy valley-like tracts extend back several miles to the west and 2 to 3 miles to the east. These are traversed by sluggish streams similar to the upper course of the river. Although the western border of this composite belt is, on the whole, more elevated than the district immediately bordering Fox River, it does not present so rough a surface, except perhaps in central Kane County, where a few square miles present a very sharp knob-and-basin topography. If a strip 3 or 4 miles wide along the west side of Fox River be excepted, the moraine in McHenry County presents few knolls that exceed 40 feet in height. The great majority are 25 feet or less. On the borders of Fox 298 THE ILLINOIS GLACIAL LOBE. River, as already noted, ridges and knolls in some cases reach a height of 80 or 100 feet. Numerous saucer-like depressions and occasional well- defined basins appear in all parts of this belt. In northeastern McHenry County there is a small gravel plain known as “English Prairie,” which stands about 100 feet above Fox River and occupies perhaps 3 square miles. It is about as elevated as neighboring portions of the moraine and is bordered by morainic knolls and ridges on every side. In the vicinity of Crystal Lake and Cary, in southeastern McHenry County, there is an elevated gravelly tract covering several square miles in which the surface is gently undulating and more subdued in expression than neighboring tracts composed more largely of till. The surface is not so level as in English Prairie. Immediately north of this eravelly tract, in the vicinity of Terra Cotta, there are broad swampy tracts nearly as low as Fox River which separate prominent ridges trending NNE-SSW. These ridges continue prominent throughout the greater part of Ts. 44 and 45, R. 8 E. In northern Kane County there are small plane tracts standing nearly 200 feet above Fox River which have been drained by an extensive system of ditches. These are almost completely surrounded by morainic knolls which rise 20 to 40 feet above their surface. Some of these knolls near Gilbert are very sharp. In the vicinity of the line of McHenry and Kane counties Fox River is bordered on each side by morainic tracts rismg 150 feet or more above the level of the stream, and there is scarcely any marshy land on its borders southward from this line. From the vicinity of Elgin southwestward to Lafox there is a belt 3 or 4 miles in width on the west side of Fox River in which sharp gravelly knolls and ridges abound. These ridges and knolls show a tendency to arrangement in chains trending nearly east-west, or about at right angles with the trend of the morainic belt. There are, however, not a few excep- tions to this trend, some ridges being nearly in line with the morainic belt. These gravel ridges constitute the most prominent features in this portion of the moraine, many of them being 30 to 40 feet and a few 60 to 75 feet in height. They often rise very abruptly, so that their slopes are cultivated with difficulty. In the majority of cases these chains of knolls and ridges follow depressed areas standing 40 feet or more below the general level, and the present drainage lines in traversing these low belts wind about COMPOSITE MORAINIC BELT OF NORTHERN ILLINOIS. 299 among the gravelly ridges. In a few cases the knolls and ridges appear on elevated parts of the district. In Campton Township (T. 40, R. 7 E.) the moraine is very elevated, some points reaching nearly 1,000 feet above tide, and presents a very sharp knob-and-basin topography. It has probably the sharpest knobs and the deepest basins found in the State of Illinois. The highest points rise about 150 feet above the border districts on the south and west and more than 200 feet above Fox River. Oscillations in level of 75 feet in a distance of 30 to 40 rods are not uncommon, and several beautiful lakelets of an acre or more each are sunk deeply in the midst of morainic knolls which surround them. This very strongly morainic topography appears at the point where the inner belt of the Bloomington morainic system connects with the com- posite belt under discussion. It also terminates the prominent portion of the composite belt so far as developed west of Fox River. Upon passing southward from Campton Township a much lower country is entered than that to the north, the descent being similar to that found in passing southward from the inner border of the Bloomington morainic system %n western Kane, Dekalb, and Lasalle counties. But instead of passing into a plane-surfaced tract, such as occurs on the inner border of the Bloomington system, an undulating tract is entered, which extends south to the border of Kendall County in a belt several miles wide. This tract contains a few very prominent knolls. One, known as Johnsons Mound, situated near the east fork of Blackberry Creek in see. 15, T. 39, R. 7 E., rises about 150 feet above the level of the creek and covers fully 50 acres. A second prominent knoll, known as Bald Mound, because desti- tute of trees, is situated in sec. 23 of the same township. It rises about 80 feet above the border districts and covers perhaps 100 acres. It is elongated in a north-south direction, its length being about three times its width. Its southern end rises abruptly, but at the north it descends gradually to the gently undulating tract which borders it. A third knoll, known as Wash- burn’s Mound, is situated between the other two in sec. 14, and stands about 50 feet above the bordering country. This mound is also elongated north to south, and has a length of one-half mile and a width of 40 to 60 rods. This mound has a more regular border than the other two, for they present spur-like projections which extend out 20 to 40 rods beyond a regular border. Aside from the three prominent mounds Just mentioned the knolls 300 THE ILLINOIS GLACIAL LOBE. seldom reach a height of 25 feet, and many of them are 10 feet or less. The Kaneville esker described above has its trough mainly within this undulatory belt, but the delta lies entirely west of it in a very level country. There are occasional narrow sloughs or depressed areas 10 or 15 feet below the general level, which in most cases have connection with the present drainage lines. The upper course of Blackberry Creek is through a series of slightly depressed marshy tracts which occur among the low knolls of this undulatory belt. The undulations are maintained as far south as the line of Kane and Kendall counties, the southern terminus being at a gravel plane leading down Fox River. There is a narrow till plain between this undulatory belt and Fox River from Geneva southward similar to the plain which borders it on the west. STRUCTURE OF THE DRIFT. The drift of this portion of the composite belt is much more variable in structure than the Marengo Ridge. On nearly every section except in the gravelly belts above noted wells have shown that both till and assorted material are present. The till apparently preponderates over the assorted material, for the latter usually occurs in thin beds. In the gravel plain known as English Prairie and in the gravelly belt between Crystal Lake and Fox River there appears to be little or no till within 100 feet of the surface. The drift is mainly gravel and cobble, there being but little sand. In places fine laminated clays appear at some depth beneath till and gray- elly deposits. The Hlinois Central Railway exposes such beds im the deep cuts east of Plato Center. The till appears to be oxidized at surface to greater depth on this portion of the composite belt than on the Marengo Ridge, a feature which is probably attributable to the greater coarseness or porosity of the till, for it can not be older than the Marengo Ridge. In some cases the oxidation extends to a depth of 50 feet or more. However, the till is not everywhere coarse textured, for on some of the level tracts among the morainic knolls it is very compact. On low tracts near Terra Cotta, in eastern McHenry County, there is a compact silt used extensively for tile and also for terra-cotta ware. At several other places the silt is used for tile. The presence of buried soils at great depth which are underlain as well as overlain by till is a not uncommon feature. In some cases the soils are COMPOSITE MORAINIC BELT OF NORTHERN ILLINOIS, 301 referred to the Peorian interglacial stage, for they probably occur at the junction of the Wisconsin and Iowan drift sheets. But it is possible that in many cases they are of Sangamon age and occur at the junction of the Jowan and Illimoian sheets. In the majority of cases they occur in the lower part of the drift. On the elevated portions they seldom are found at less than 125 feet from the surface, and in one instance (at Gilbert station) a soil was found at 180 feet. The drift on the elevated portions apparently averages not less than 200 feet. On the lower portions of the belt, in southern Kane County, the drift is correspondingly thinner. The buried soil is found at much less depth, but at about the same elevation above tide as in the higher portion. The occurrence of the buried soil, its depth and its relation to other beds of the drift, may be seen by reference to well sections of McHenry and Kane counties given on subsequent pages. As noted above, this portion of the composite belt abounds in knolls and short ridges which are composed largely of gravel. These are largest and most numerous along the inner slope adjacent to Fox River, but are found occasionally on the elevated parts of the moraine—for example, near the north line of Kane County. These ridges occur both singly and in eroups. They are also arranged in chains or narrow belts. They present considerable variation in structure. The majority have but little till with the sand and eravel, but some present a large amount of till in the lower portion. This is especially true of those on the elevated portion of the moraine in northern Kane County. In several cases the knolls are found to have a body of coarse gravel and cobble at their summits which extends downward in a funnel-shaped mass toward the center of the hill. In other cases the central portion of the hill is composed of sand and the gravel and cobble is found in the peripheral portion. A knoll in sec. 14, T. 42, R. 7 E., opened extensively for gravel, is found to contain alternations of till and assorted material. The till apparently forms a network of connections around lenticular masses of gravel. In most instances the gravel and cob- ble is found to extend scarcely as low as the base of the knolls. Borings have sometimes been made in the bottom of the gravel pits, and these usu- ally penetrate a considerable depth of oxidized till. Indeed, the oxidation appears to be fully as deep beneath these knolls as the average depth of surface oxidation outside the knolls. The bedding of the assorted material is seldom horizontal, but curves and dips as if the material had been subject 302 THE ILLINOIS GLACIAL LOBE, to much disturbance after deposition. In this respect these knolls and ridges differ from the bedding usually displayed by eskers. Bowlders are found in moderate number over all parts of the moraine. They are especially abundant in a belt extending from Gilbert station north- ward to the vicinity of Crystal Lake. The belt is widest near the Kane- McHenry county line, having there a width of about 4 miles. There is probably significance in the fact that this bowlder belt borders the head of the Kishwaukee gravel plain, which was an avenue of discharge for the glacial waters. The bowlders are usually crystalline rocks of Canadian derivation, but there are also present large limestone blocks, which in some cases will furnish several wagon loads of building stone. These are especially abundant west of Elgin, and are found occasionally farther north, in both Kane and McHenry counties. They are apparently derived from the ledges of Lockport (Niagara) limestone, which underlie the district immediately to the east and probably extend into the district covered by this moraine. In some cases these large masses of limestone have led the residents to suppose that the rock is in situ and that extensive quarries might be opened by the removal of a slight amount of drift. The error of this interpretation has usually been discovered upon quarrying a few loads of stene. Wells west of Elgin, in the neighborhood of these limestone blocks, indicate that the drift there has an average thickness of more than 100 feet. Whether the supposed limestone outcrop in eastern McHenry County, mentioned in the Geology of Ilinois,* is a ledge in situ or a transported block similar to those just mentioned was not ascertained. CORRELATIONS. Satisfactory correlations of this portion of the composite belt with the more clearly differentiated moraines in the districts to the south have not yet been established. ‘Two quite distinct interpretations have been suggested in the course of the investigation. By the first interpretation this portion of the composite belt is made to be the continuation of the inner part of the Bloomington morainic system, which connects with it near Elburn. The very strongly morainic tract immediately northeast of Elburn would, in this case, be situated at a sharp bend or reentrant angle in the ice margin, and ‘Vol. IV, pp. 181, 132. COMPOSITE MORAINIC BELT OF NORTHERN ILLINOIS. 303 this may account for its greater ruggedness. The undulatory tract leading southward from this sharply morainic portion might by this interpretation be accounted for as a spur extending backward from the sharp bend in the margin. The bulk of the Bloomington system is not greatly different from that of the composite belt west of Fox River and presents no obstacles to this interpretation. The topography of the composite belt is much sharper in expression than that of the Bloomington system, but changes of topog- raphy have been found to occur in other belts to as marked a degree as in this instance. As pointed out by Chamberlin, in the Third Annual Report, the Kettle moraine changes from a very sharp knob-and-basin topography in southern Wisconsin to a comparatively smooth swell-and-sag topography in northeastern Illinois and northwestern Indiana, and again assumes a sharp knob-and-basin topography when traced into Michigan. By the second interpretation this portion of the composite belt is thrown into the late Wisconsin series of moraines and its continuation found in the bowider belts and feebly developed morainic tracts lying outside the Valpa- raiso morainic system in Kane, Kendall, Grundy, and Kankakee counties. These belts can be traced into a reasonably close connection with the southern end of the undulatory belt in southern Kane County. There seems to be, therefore, no formidable gap to bridge in making this corre- lation. ‘The greatest obstacle to the interpretation appears to be found in the abrupt change in bulk which the moraine presents in the district east of Elburn. From this point southward a thickness of only 20 or 25 feet is presented by the moraine, where best developed, while to the north the thickness averages more than 100 feet. The expression also is much stronger north than it is south from this line. Perhaps by combining these interpretations a solution may be found. The great bulk of the portion north from Elburn and the very strong expression of the portion immediately northeast of Elburn may be a result of the invasion which formed the Bloomington morainic system. At the late Wisconsin invasion this region may have been partially overridden by the ice, but without greatly modifying its appearance and without deposit- ing a greater amount of drift than is found in the gently undulatory belt in southern Kane County and the feeble moraines in the district to the south. In this case the gently undulating tract in southern Kane County may be largely the result of the late Wisconsin invasion, though the interpretation 304 THE ILLINOIS GLACIAL LOBE. that it is a spur from the reentrant angle in the Bloomington system need not be set aside. The Kaneville esker lies mainly within the limits of this undulatory belt and seems to have been formed at as late a date. Its western end, together with the delta, extends beyond the line of the bowldery tracts referred to the late Wisconsin invasion. This fact seems to throw the bal- ance of evidence in favor of the correlation with the Bloomington system. Furthermore, the Kaneville esker seems to be a part of the series of gravelly knolls and ridges above mentioned which are developed along the inner border of the Bloomington morainic system in the district to the west. It is possible that chains of gravelly Knolls and ridges which lead westward from Fox River Valley in northern Kane County into the higher portions of the moraine were formed at the same time as this esker and under similar conditions. ‘The prominent knolls which occur in the midst of the gently undulating belt—Johnson’s Mound, Ball Mound, and Washburn’s Mound— may also be included in the same category. They appear to be composed largely of gravel, though their structure is known only from two well sec- tions on their higher parts and slight excavations on their borders. PORTION OF COMPOSITE BELT EAST OF FOX RIVER. DISTRIBUTION AND CONNECTIONS. From the vicinity of Elgin northward to the Wisconsin line the valley of Fox River alone separates a morainic tract on the east from one on the west side of the river, and throughout much of this interval the stream winds about through lakes and marshes among moyainic knolls without forming a well-defined valley. Southward from Elgin the composite belt separates into distinct moraines, between which are plane tracts. One of these moraines, called the Valparaiso, swings around the head of Lake Michigan; another, called the Marseilles, follows nearly the east bluff of Fox River south and west to the Illinois River. As already noted, a weak morainic system of late Wisconsin age leads southward, and the Bloomington system southwestward, from the portion of the composite belt west of Fox River. The equivalency of the Valparaiso morainic system to the eastern portion of this composite belt is established beyond doubt. Probably it should inelude all of the composite belt north of Elgin on the east side of COMPOSITE MORAINIC BELT OF NORTHERN ILLINOIS. 305 Fox River, and possibly it also includes a small part west of this stream. It may extend as far west as the east border of English Prairie, at the State line, and may embrace the tract between Fox River and Crystal Lake outlet, farther south. The equivalent of the Marseilles morainic system in this composite belt is not satisfactorily determined. From northern Kendall County north- ward it appears to have been overridden to some extent by a later advance of the ice, and is perhaps completely concealed by the later deposits within this composite belt. The portion of the composite belt east af Fox River has a width rang- ing from 6 or 7 miles at the State line to about 15 miles at the south line of Lake and McHenry counties. Between these lines it is mainly in Lake County, but includes a narrow strip in eastern McHenry County. From the south line of these counties southward to Elgin it lies mainly in Cook County, but includes the east border of northern Kane County and main- tains a width of 14 to 15 miles. This is about the width of the Valparaiso system farther south. ; GENERAL FEATURES. The general elevation of this portion of the composite belt is lower than in the portion west of Fox River, being but little more than 800 feet above tide. The highest points are found in southern Lake and northwest- ern Cook counties, and they rise but little above 900 feet. One of these, just east of the village of Volo, stands 913 feet, and one in the northwest corner section of Cook County 910 feet, as determined by the barometric survey under Professor Rolfe. There are, canes but few other points rising above 850 feet. There is a well-defined ridge-like crest standing 20 to 40 feet higher than border tracts and having a width of about one-half mile which leads southward with a somewhat winding course through western Lake and northwestern Cook counties, forming the water parting between Fox and Des Plaines rivers. East from this crest line there are only gentle swells, seldom more than 15 feet in height, among which are occasional ponds and small lakes. This district presents a slope which descends eastward at the rate of 20 to 40 feet to the mile as far as the Des Plaines Valley. West from the crest line the surface is much more varied, there being tracts 306 THE ILLINOIS GLACIAL LOBE. covering a few square miles in which a sharp knob-and-basin topography is developed, around which are gently undulating tracts, such as occur on the east slope. There are also extensive marshes west of this crest, and the drainage is generally less perfect than on the east slopes. Lakes abound in Lake County on both the west and the east slopes. They range in size from an area of several square miles down to an acre or less. They are usually bordered wholly or in part by knolls and ridges which rise 10 to 50 feet above their surface. In some cases extensive marshes border one or more sides of the lakes. These lakes, with their bordering hills dotted with groves, add greatly to the beauty of the scenery. The lakes and also basins become rare southward in Cook County. The few which occur are very small and shallow. THICKNESS OF DRIFT. Records of several deep borings were obtained which give an average thickness of about 200 feet of drift. Six borings failed to reach rock at an average depth of about 250 feet, one of them being 315 feet. As these borings are widely distributed, it seems probable that the general level of the rock surface is fully 200 feet below the drift surface. The underlying rock is limestone and presents a very uneven surface. The well borings indicate that valleys had been cut to depths of 200 feet or more prior to the drift deposition. Hence borings in the lines of these valleys, when located on high parts of the moraine, probably would encounter fully 400 feet of drift. The thickness of each of the several drift sheets here present has not been worked out so fully as in some other localities, but the drift of Wisconsin age apparently averages not less than 100 feet in depth, and may average 150 feet. a STRUCTURE OF THE DRIFT. The upper portion of the drift to a depth of 100 to 150 feet consists mainly of till. The till is usually oxidized at surface to a depth of 10 or 15 feet, beneath which it presents a blue-gray color. It is also generally soft and fresh, and seems to be referable to the Wisconsin, though it may also include the Iowan. At greater depths than 100 to 150 feet borings encounter either a hard gray till tinged with brown, probably Hlinoian, or beds of sand and gravel, or an alternation of till with sand and gravel. Wells near Lake Zurich have in several instances encountered thick beds of THE MARSEILLES MORAINE. 307 fine sand below the till, setting in at 100 to 140 feet and extending to 250 or 300 feet. At Barrington, and for several miles southwest, wells often encounter a hard till at 100 to 160 feet which contains very little sand. In the vicinity of Ivanhoe and Wauconda wells pass through alternations of sand and gravel with hard till after leaving the sheet of soft till. In southern Lake and northwestern Cook counties the sheet of soft. till is generally a poor source for strong wells, such as are required on dairy farms, though wells adequate for household use may usually be obtained at convenient depths. In the northern part of Lake County strong wells are often obtained without reaching the bottom of the Wisconsin drift sheet. The greater amount of sand and gravel found in the older drift sheets has led to the sinking of many wells to these sheets at depths of 150 feet or more. Further data are given in the detailed discussion of wells. There are but few gravel Knolls in either Lake County or Cook County, but such knolls are not rare on the borders of Fox River in eastern Kane and McHenry counties. Knolls composed mainly of till have in some cases pockets of gravel at or near the surface, which supply material for wagon roads. ‘There are few localities west of the crest where gravel may not be conveniently obtained, but east of the crest it is not so well distributed. Surface bowlders occur in moderate numbers over all of this district. They are nearly all crystalline rocks of distant derivation, there being very few limestone or local rocks. The till is thickly set with limestone rocks as well as with those of distant derivation. SECTION V. THE MARSEILLES MORAINE. DISTRIBUTION. This moraine next succeeds the Bloomington morainic system in the Wisconsin series. The name is taken from the village of Marseilles, situated at the point where the Illinois River cuts through the moraine. The moraine is readily traced as far north as South Elgin, 4 miles south of the city of Elgin, where it is lost in the composite belt just dis- cussed. For about 25 miles south from South Elgin it is combined with a till ridge called the Minooka Ridge, and follows the east side of Fox River closely, past St. Charles, Geneva, Batavia, and Aurora, the eastern parts of 308 THE ILLINOIS GLACIAL LOBE. these cities occupying its outer face. There is usually but a single crest, and it follows nearly the county line between Kane and Dupage. The width of the belt is 2 or 3 miles. The combined belt continues about 6 miles farther south than Aurora, along the line of Will and Kendall coun- ties, leaving a strip 2 or 3 miles wide between the river and the moraine. The Marseilles moraine there swings abruptly westward, coming to the river bluff between Oswego and Yorkville, while the Minooka Ridge con- tinues southward to the head of the Illinois River. The Marseilles moraine follows nearly the southeast bluff of Fox River to the mouth of the stream, its outer border being nowhere more than 4 miles and usually less than 1 mile from the stream. The width in Kendall County is only 2 or 3 miles, but increases to 5 or 6 miles in northeastern Lasalle County, near the north bluff of the Illinois River. At the Illinois Valley the moraine changes abruptly from a south- southwest to a south-southeast course. Its south-southeast course is main- tained in a belt 3 to 5 miles wide passing through southeastern Lasalle and northern Livingston counties. In the latter county, as above noted, it is closely associated with Farm Ridge, a weak inner ridge of the Bloomington system. In the vicinity of Odell the moraine swings around eastward, and near the line of Livingston and Ford counties takes a course north of east, occupying in its curving portion a width of 8 or 10 miles. This course is maintained across northern Ford, northwestern Iroquois, and southern Kan- kakee counties, to the vicinity of Ste. Anne, where it changes to southeast. From northern Ford County to this point it has a width of 8 to 5 miles. The southeast course is maintained to the vicinity of the State line northeast of Donovan. Here this moraine meets the Iroquois, a moraine of the coalesced Erie-Saginaw lobe. Its relations to that moraine are still obscure, though the courses of the two moraines seem to be nearly coincident in Newton and Jasper counties, Indiana. Its width before connecting with that moraine is 1 to 2 miles. The combined moraine has a width of 3 to 6 miles and is traceable as far as Medaryville, in Pulaski County, Indiana, beyond which it seems either to die out or to be concealed beneath the “ Lake Kankakee” sand ridges. Possibly this combined moraine constitutes an interlobate belt, but, as indicated below (pp. 318, 327), it seems more probable that it is a result of two advances differing in date as well as direction. THE MARSEILLES MORAINE. 309 RANGE IN ALTITUDE. The Marseilles moraine displays very little range in altitude. The crest varies scarcely 25 feet from the 750-foot contour, and the lower parts of the moraine stand near the 650-foot contour. Throughout much of its course the 650-foot contour follows approximately the outer border of the moraine. The immer border is somewhat higher, but as a rule falls below 700 feet. RELIEF. The above statements concerning range in altitude may be readily applied in reference to the relief of the moraine. On the outer border it averages about 100 feet; it is seldom less than 50 feet and in places reaches 125 feet. The relief on this border is least in the northern and the eastern portion of the belt, in places being 50 feet or less. The middle portion, except where combined with the weak inner ridge of the Bloomington sys- tem (Farm Ridge), has a general relief of 75 to 100 feet or more. On the inner border the relief seldom exceeds 50 feet, and for a few miles at the north scarcely exceeds 25 feet. SURFACE CONTOURS. Throughout much of its course the Marseilles moraine has a well-defined crest, and this, as a rule, constitutes a water parting. North of the Illinois River it separates the tributaries of Fox River from those of Dupage River, Au Sable Creek, and Nettle Creek. South of the Illinois it separates trib- utaries of the Vermilion River from those of Mazon Creek and Kankakee River. In eastern Illinois, however, it does not constitute an important water parting, being crossed by the Iroquois River; and in western Indiana it is crossed by tributaries of that river. The crest is sharpest for a few miles in the central part of Kendall County, south and southwest of York- ville, where it presents a narrow ridge standing 30 to 40 feet or more above bordering portions of the moraine. Usually the crest is a broad, gently undulating ridge 1 or 2 miles in width. Along the crest, as well as on the slopes, there are saucer-like depressions containing water, except in seasons of drought, and often occupied by clumps of willows. The swells are usually low, seldom exceeding 20 feet in height, and have gentle slopes. However, in parts of Livingston County, southeast of Odell, the swells in some cases reach a height of 50 feet above sloughs inclosed among them. There is 310 THE ILLINOIS GLACIAL LOBE. also a group of prominent knolls in the vicinity of the line of Kankakee and Iroquois counties, south of Hersher. Some of these reach a height of about 75 feet. At the point where the course of the moraine changes from east of north to southeastward, near Ste. Anne, there is a very prominent group of knolls, called Mount Langum, standing 75 to 100 feet above bordering tracts on the north. These groups of prominent knolls have, however, a combined area of but a few square miles. Toward the inner border throughout the entire length of the moraine the swells gradually decrease in height and become less frequent, until they can not be distin- guished from the gentle undulations of the till plain, which are commonly 5 or 6 feet in height. In a few places, aside from those noted above, a somewhat sharp knob-and-basin topography is developed. The most con- spicuous development is in Kendall County along the sharp crest, and this type of topography is characteristic of much of the crest in that county. The knobs seldom exceed 25 feet in height; but as they cover only 2 or 3 acres each, they are much sharper than the majority of the knolls. The basins are shallow, saucer-like depressions. It is worthy of note that the portions of the moraine having sharpest expression are usually covered with forest. Possibly the protection afforded by forest growth is partially responsible for the sharper contours, but it seems hardly probable that the difference in contour in forest and prairie can be entirely due to this protection. The outer margin of the moraine often extends out in spur-like pro- jections a mile or more beyond a regular border, and usually where streams emerge the margin is indented an equal or even greater amount. These spurs slope down much less abruptly from the morainic crest than the tracts between them, thus giving the appearance of low ridges running out from the crest nearly at right angles to its course. The indentations at the places where streams emerge are not referable to erosion by the present streams, but are in all probability due to the removal of material by streams issuing from the ice sheet. j There are occasional breaks or narrow gaps interrupting the crest. One about 4 miles east of Yorkville, about 75 feet in depth and one-fourth to one-half mile in width, passes entirely across the moraine, permitting drainage from the inner-border plaim to pass through the moraine to Fox River. Another gap fully as large is found in the southwest corner of « THE MARSEILLES MORAINE. Sala Kendall County and is represented on the Marseilles topographic sheet. A water parting occurs in this valley-like gap at the inner border of the moraine near the line of Grundy and Kendall counties. It stands only 640 feet above tide, while neighboring portions of the moraine on the north and west are about 100 feet higher. About 6 miles southwest from this gap there is a shallower one in which the water parting is 690 feet, or 40 to 60 feet below neighboring portions of the morainie crest. At the Illinois Valley the moraine is interrupted by a gap about 14 miles in width. It stands 675 to 700 feet above tide at the south bluff and 650 to 675 feet at the north bluff. The broad bottom of the valley stands only about 500 feet; but this, as shown below, has been lowered by the “Chicago Outlet.” These gaps, like the indentations, seem referable to streams issuing from the ice sheet during the formation of the moraine, and perhaps also during the withdrawal of the ice from the plain on the east. In eastern Livingston and northern Ford counties the main ridge lies near the north border of the belt. Outside of it, extending nearly to the east fork of Vermilion River (a distance of about 6 miles), there is an undulatory tract probably of morainic character. The surface of much of this tract is fully as undulatory as on the main part of the moraine, and stands nearly as high as the crest of the moraine. Plane tracts one-half mile to a mile or more in width and 25 to,40 feet in depth extend north from the east fork of Vermilion River nearly to the crest of the moraine, greatly interrupting the continuity of the undulatory tract just noted and giving the appearance of spurs leading out to the south. There is, however, at the east a well-defined crest in this outer belt with a trend approximately parallel with that of the main crest. This suggests the interpretation that the moraine consists of a double ridge in this region, and that its outer ridge has been imperfectly developed or greatly eroded. If the imperfection is due to erosion, it seems necessar y to restrict the eroding agency chiefly to water escaping from the ice sheet, for there has been apparently but little postglacial erosion in this locality. THICKNESS OF THE DRIFT. The thickness of the drift along the Marseilles moraine has a known range from less than 100 feet up to 360 feet. In eastern Kane and western Dupage counties the thickness along the crest is generally 100 to 150 feet. 312 THE ILLINOIS GLACIAL LOBE. In Kendall County it has a known range from 100 feet to fully 200 feet. In Lasalle County the well records show a range from about’ 100 up to 285 feet. In Livingston County the range is still greater, the distance to rock varying from 100 to 360 feet. Along the line of Kankakee and Troquois counties it decreases from about 160 feet at the west to only 60 feet at Ste. Anne, but wells between Ste. Anne and the State line penetrate 80 to 150 feet of drift. The greater part of the drift appears to be referable to the Wisconsin drift sheets. The older sheets are seldom entered at less than 100 feet along the crest of the moraine, and in some wells a fresh-looking drift (Wisconsin) is reported to extend to a depth of 160 feet. The drift refer- able to the invasion which formed the Marseilles moraine probably about equals in thickness the measure of the relief of the moraine, which, as noted above, is 50 to 125 feet. STRUCTURE OF THE DRIFT. The Marseilles moraine consists mainly of a sheet of blue till which contains only a moderate amount of coarse rock materials. A few low gravelly knolls oceur in some of the recesses on the outer border of the moraine in Kane, Kendall, and northern Lasalle counties. The sharp knolls south of Hersher, and the prominent group of knolls known as Mount Langum, near Ste. Anne, are composed largely of gravelly material. These constitute the chief instances of the occurrence of gravelly knolls along the entire length of the belt. There are often small pockets or thin beds of sand and gravel inclosed in the sheet of till, which afford a supply of water for the shallow wells. These seldom afford a sufficient amount of water for dairying or stock raising, the supply for these purposes bemg obtained either from the older sheets of drift or from the underlying rock. This moraine carries very few surface bowlders, there being scarcely enough to supply the needs of the residents for foundations of buildings and construction of bridge culverts. In one locality, however, east of Yorkville, the moraine is crossed by a bowlder belt which apparently pertains to a later advance of the ice, since the bowlder belt does not follow the moraine but passes southward across the inner-border plain, as indicated later (pp. 325-326). THE MARSEILLES MORAINE. Bi) The depth of surface oxidation in this moraine is less than on any other moraine of the Wisconsin series within the area under discussion. In Liv- ingston County the blue till is commonly entered at 4 to 6 feet, and in places at even less depth. The oxidized till, therefore, has scarcely half the depth usually found in the Wisconsin drift sheets. The slight depth of surface oxidation is probably attributable to the compactness of the till, which is nearly impervious to water. It can not be attributed to flatness of surface, because the depth of oxidation is found to be very slight on undulating as well as level portions of this drift sheet. The sections of many wells obtained along this moraine and on the inner border are presented in the discussion of wells (Chapter XIV) in the counties traversed by the moraine. These serve to indicate the great preponderance of till over assorted material in the portion of the drift referable to the Marseilles moraine. They also serve to indicate the rela- tive proportions of till and assorted material in the sheets of older drift underlying the Marseilles and other Wisconsin drift sheets. CHARACTER OF THE OUTWASH. Along Fox River, in Kane and Kendall counties, just outside the Mar- seilles moraine, there is a belt of coarse gravel. In places the deposit lies mainly on the same side of the river as the moraine, but generally it is on the opposite side. At Batavia it is chiefly on the west side, at Aurora on the east side, and at Yorkville on the west side. At Millbrook and at Mill- ington the larger part of the gravel is on the east side of the river. The belt of gravel extends but a short distance below Millington, the valley below that point being cut in till and rock strata. The origin of this belt of gravel has not been decided. Possibly it is referable to the invasion which formed the Marseilles moraine, but quite as probably it should be referred to the later advances of the ice sheet, during which the Marseilles moraine was partially overridden. ‘The gravel is so extensive in Kane and Kendall counties and so small in amount farther down Fox River as to sug- gest the interpretation that it forms an extensive delta in northern Kendall and southern Kane counties, and that free drainage or escape of the waters down Fox River had not been established. In the vicinity of the Tlinois River there are indications of a lake-like expansion of outflowing ‘waters whose borders are found in the sand ridges Bila A THE ILLINOIS GLACIAL LOBE. discussed on a preceding page (p. 288). The Ilinois Valley, therefore, appears to have been unopened along the section between the Marseilles moraine and the inner moraine of the Bloomington series. In eastern Illinois the basin now drained by the Iroquois River north- ward to the Kankakee would have been prevented from discharging in this direction by the ice sheet. It is probable, as noted above, that the outlet from this district was westward across the rim of the basin in northern Ford County to the east fork of Vermilion River. As this rim stands somewhat higher than the northern part of the basin, it may be supposed that the ice sheet terminated in a shallow body of water. The only outwash found along the outer borders of the moraine in this district consists of fine sand and silt forming a thin coating on the surface of the till. Whether this is an outwash from the ice at the time of the formation of the Marseilles moraine or is of later date can scarcely be determined in the present stage of investigation. Studies in western Indiana indicate that a lake may have occupied this region for some time subsequent to the retreat of the ice from the Marseilles moraine, and this silt-and-sand deposit may be a product of the later stage of the lake. In eastern Livingston County there may have been a fair escape for the water southward into the East Fork of Vermilion, though this is not fully demonstrated. Reviewing the above statements, it appears that, with the possible exception of the northern portion of the moraine in Kane and northern Kendall counties, the ice sheet was bordered extensively: by lakes, which prevented a vigorous outwash. But these lakes were so shallow as to inter- fere in no way with the building up of a bulky moraine. They seem also to have allowed the waters escaping from the ice sheet to form the gaps and indentations in the moraine, noted above. If these were formed either by water escaping from the ice while it overhung the ridge, or at a later date from a lake held on the east side of the ridge (the only probable agen- cies yet recognized), the existence of lakes in the outer border district may seem questionable. This seeming incompatibility may perhaps be explained by assuming that a submarginal glacial stream had accumulated sufficient hydrostatic pressure to carry a strong current into the extra-marginal lakes. THE MARSEILLES MORAINE. 5311/5) INNER-BORDER TILL PLAIN. On the inner border of the Marseilles moraine from northern Kendall County, where it separates from the Minooka Ridge, southward through Grundy and adjoining portions of Lasalle and Livingston counties, and thence eastward through Kankakee County, there is a till plain which shows a perceptible descent away from and nearly at right angles to the moraine. As the moraine describes nearly a half circle in this interval, the sloping plain converges toward a focal point, which is located near the head of the Illinois River. There is a similar descent toward the head of the Illinois from the east; thus a basin is formed, which is commonly known as the Morris Basin, from the city of Morris, which stands near its central portion. The slopes of this plain are well shown by the direction of drain- age lines, which converge from all quarters toward the head of the Illinois River. (See topographic map, Pl. III.) At present the basin is deeply notched at its western border by the valley of the Ilinois River, but at the withdrawal of the ice sheet the evidence is quite clear that the western rim stood sufficiently high to hold a lake of considerable size in the Morris Basin. The history of this lake is discussed in some detail below. On the border of this till plain next to the moraine the surface is gently undulating, but within a few miles it become an almost expression- less plain. In Kankakee, southwestern Will, and eastern Grundy counties the plain is occupied by sand dunes and beaches; elsewhere it is generally very smooth. There are, however, a few points in southeastern Kendall and northeastern Grundy counties where the drift is slightly ridged. In the vicinity of Lisbon, in southern Kendall County, the drift is insufficient to conceal the inequalities of the limestone ridges, but the surface is only gently rolling, the crests of the ridges being scarcely more than 20 feet above the sags. This area is 2 to 25 miles from north to south and 5 to 6 miles from east to west, and lies mainly in the south half of dy By lee 10, The drift along the border of the Marseilles moraine has generally a thickness of 100 feet or more, but upon descending the slope toward the head of the Illinois the thickness decreases, and there are extensive areas in eastern Grundy, southwestern Will, and northern Kankakee counties where rock is encountered at very slight depth, so that the shallow ravines 316 THE ILLINOIS GLACIAL LOBE. and shallow wells and even the cellar bottoms reach it. The drift appears to be composed mainly of till and differs in no essential degree from that found in the Marseilles moraine.. The yellow or oxidized till at surface is apparently somewhat thicker than on the moraine. At the surface there are extensive deposits of sand and silt occurring up to an altitude of nearly 650 feet, though most abundant at 575 feet or less, which in all probability are referable to the lake that occupied the basin. These deposits in some places reach considerable depth and are either accumulated in knolls and ridges or spread evenly over the surface. In other places they are insufti- cient to conceal the surface bowlders. In the greater part of this district wells may be obtained at a depth of 25 feet or less. In some cases they are obtained at the base of the surface sand; in others near the junction of the yellow and blue tills, there being not infrequently thin beds of sand and gravel at that horizon; in still other cases they enter the blue till. Several flowing wells have been obtained from the drift. These are discussed in connection with other wells, in the detailed discussion of wells given in Chapter XIV. CeHVACE THis xe THE LATE WISCONSIN DRIFT SHEETS. BASIS FOR SEPARATION FROM THE EARLY WISCONSIN. The necessity for separating the moraines of this later drift into two series was brought out by Chamberlin’s early studies in eastern Illimois and western Indiana. He discovered that the very bowldery morainic belts of Benton and Warren counties, Indiana, pass directly across the line of the earlier moraines which lead up to them from the west. The fact was also noted that the earlier series of moraines are not markedly older than the later series. In view of this freshness of the drift of the earlier series and of certain obscure tracts in the Kankakee Basin, he makes the following statement: ' The drift of this area [Kankakee Basin] bears undoubted evidence of being recent, and, though this is in considerable part due, superficially, to aqueous agencies, it seems to me probable that the region will prove to have been largely, possibly com- pletely, covered by ice in the earliest stage of the second glacial epoch. It is not, however, traversed by conspicuous moraines, at least not by any as well developed as those outlined. Low-ridged belts of subdued morainic aspect have been observed at numerous points, but their relations have not yet been traced out. A similar qualifying remark may here be made concerning a considerable area in northern Illinois, outside the moraine described in this paper. The freshness of its drift and the unsculptured contour of its surface bear evidence of recent origin. Subsequent studies by Chamberlin and his associates have brought out more clearly the evidence that the bowldery moraines are out of harmony in trend with the moraines of the early Wisconsin series. They have also shown that the bowldery moraines present a somewhat fresher surface con- tour than the moraines overridden by them. It is upon the basis of these differences in trend and in freshness of contour that the removal from the early Wisconsin has been made. As yet no soil or leached or weathered zone has been found separating the drift of the two series, and it still seems ‘Third Annnal Report U. 8. Geol. Survey, p. 331. 317 318 THE ILLINOIS GLACIAL LOBE. questionable whether the interval between their deposition was sufficiently long to justify their reference to distinct glacial stages. The shifting of the ice lobes, however, is thought to indicate a retreat of some consequence b) ? fo) between the two ice advances a retreat probably much greater than took place between the formation of neighboring moraines of the early Wis- consin series. OUTLINE OF THE LATE WISCONSIN BORDER. So far as is yet known, the oldest moraine of the late Wisconsin series is the Iroquois moraine of the coalesced Erie-Saginaw lobe. Full correla- tions, however, have not been made of moraines of this series in the several ice lobes. This moraine appears in northwestern Pulaski County, Indiana, in the midst of the sand area known as ‘‘Old Lake Kankakee,” and leads southwestward along the divide between the Iroquois and Kankakee rivers, across Jasper and Newton counties, Indiana, to eastern Iroquois County, Illinois. It there swings abruptly southward, crossing the Iroquois River between the State line and Watseka, Illinois, and soon curves to the southeast, reentering Indiana in northwestern Benton County. It thence passes southeastward across Benton and Warren counties, coming to the Wabash Valley at Williamsport. Its further continuation to the southeast is indicated approximately on the map accompanying Professor Chamberlin’s paper in the Third Annual Report. The moraine is discussed in detail in a report now in preparation, which embraces the moraines of the Erie lobe. From the point where the Iroquois moraine turns southward in eastern Iroquois County, Hlinois, a bowldery belt leads northwestward past Ste. Anne to the Kankakee River just above the city of Kankakee, being closely associated with the Marseilles moraine to that point, but apparently distinct from it at points farther north and west. This belt is discussed below as a possible correlative of the Iroquois moraine. By this interpretation the moraine occupying the divide between the Iroquois and Kankakee rivers in Newton and Jasper counties, Indiana, is interlobate in character. This interpretation would furnish an explanation for the abrupt eastern termina- tion of the moraine, there being a coalescence of the lobes so complete in the eastern part of the Kankakee Basin that no moraine was formed. Unfortunately, the features are somewhat vague in the district northwest from the point where the Iroquois moraine turns south and the interpretation THE MINOOKA TILL RIDGE. 319 is not entirely beyond question. There seem, however, sufficient grounds for referring certain features in that region provisionally to the late Wiscon- sin deposits. These features are of two classes, namely, bowlder belts and ridged drift.. These are discussed separately, since their association is not sufficiently close to make it certain that they represent a single ice advance. As indicated below, the vidging (discussed under the head “Minooka Till Ridge”) may have preceded rather than accompanied the deposition of the bowlders. SECTION I. THE MINOOKA TILL RIDGE. DISTRIBUTION. This till ridge receives its name from the village of Minooka, in north- eastern Grundy County, which is situated on its crest. As noted above, it is united with the Marseilles moraine in Kane County, and being smaller than that moraine its discrimination may be made with difficulty. In the northeast part of Kendall County it leaves the Marseilles moraine and takes a southward course along the county line between Kendall and Will and Grundy and Will counties to the head of the Illinois River. The crest as a rule lies in the eastern tier of sections in Kendall and Grundy counties, but in places touches western Will County. The width of the ridge, includ- ing both slopes, is scarcely 2 miles. It consists of a single smooth ridge on whose crest and slopes there are few swells exceeding 10 feet in height. The ridge is crossed by two valley-like depressions which unite near its western edge in sec. 18, T. 36, R. 8 E., and drain west into Au Sable Creek. These are cut down to the level of the plain on the east side of the ridge. They apparently were formed by the discharge of water from the ice margin or ponded between the ridge and the receding ice front. PROBABLE LINE OF CONTINUATION. Up the Kankakee River, from the head of the Illinois nearly to the State line, there is an occasional development of low drift ridges and gentle swells on the north side of the valley. On that side of the river, 1 to 3 miles back from the stream, there is an abrupt bluff-like rise of 25 to 50 feet, and the ridges and swells front this bluff or lie immediately back of it. This system of ridges and swells nearly everywhere stands slightly higher than the plain which lies to the north. In the vicinity of Kankakee this 320 THE ILLINOIS GLACIAL LOBE. ridged belt borders the river quite closely and part of the city stands on it. From that city it takes a course slightly north of east to Exline, cutting - across the great bend in the river opposite the mouth of the Iroquois River, Some uncertainty is felt as to its continuation from this point. It may continue eastward into Indiana parallel to the river and pass beneath the Valparaiso moraine, though it seems quite as probable that it finds its con- tinuation in the belt leading southeast from Mount Langum, above described (see Marseilles moraine). The break opposite Mount Langum is merely the width of the Kankakee Valley, scarcely 2 miles. No similar ridging occurs on the south side of the river in western Kankakee or in Will County. There is instead a gradual rise from the low bank of the river southward through a sand-covered district to the till plain which lies inside the Marseilles moraine. The greater accumulation of drift on the north side of the river, taken in connection with the occasional development of moraine-like features, apparently supports the interpretation thus made—that the continuation of the Minooka till ridge may be found along this line. RELIEF. The southern end of the well-defined Minooka Ridge (at the head of the Illinois River) stands 100 to 110 feet above the Illinois River. The general relief of this ridge above the plain which borders it on the west is 50 to 70 feet. The profile of the Chicago, Rock Island and Pacific Rail- road, which crosses the ridge at Minooka, shows a relief on the west side of about 65 feet. The relief is slightly less on the east and is also less abrupt than on the west. The blufi-like ridge along the Kankakee, where best developed, stands but 30 to 40 feet above the plains on the north, and its usual relief on that side is only 10 to 20 feet. On the side next the Kankakee there is a gen- eral relief of 30 feet or more, with occasional points where it exceeds 50 feet. Evidently a portion of this relief is due to stream erosion, but the excavation is so shallow that the stream is responsible for scarcely 20 feet of the relief. THICKNESS OF DRIFT. Beneath the crest of the Minooka Ridge, from the head of the Illinois northward, the drift is shown by wells to be 130 to 150 feet and in one THE MINOOKA TILL RIDGE. 321 instance nearly 200 feet in thickness, the thickness as compared with that on bordering plains being about as much greater as the measure of the relief of the ridge. In the portion along the Kankakee the thickness seldom exceeds 60 feet, but is greater along the higher parts than on the lower or than on the border plain, as would be expected from the relief which it presents. STRUCTURE OF DRIFT. In the ridge north from the head of the Illinois the surface portion of the drift to a depth of 8 to 12 feet consists of a yellow till containing many pebbles. It is sandy in places, but as a rule is a stiff, sticky clay, very slowly pervious to water. This yellow till is underlain by a grayish blue till containing occasional gravel or sand veins, which furnish water in small quantities. This bed of ull often has a thickness of 100 feet or more. Beneath it there is in places a heavy deposit of sand. This may not underlie the whole of the ridge, but has been penetrated in several wells along the crest in Kendall County. It furnishes abundance of water for wells. The ridge from Minooka northward carries a black surface soil several inches in depth, such as is found on the bordering plains. There are few surface bowlders, and pebbles are rare within 18 inches of the surface. The drift along the north border of the Kankakee is mainly till, and surface bowlders are more abundant than in the portion north of the head of the Illinois River. CHARACTER OF THE OUTWASH. The well-defined portion of the Minooka Ridge has a low part of the Morris Basin on its outer border. Unless the outlet down the Illinois had been opened to a level as low as this part of the basin, the basin would have held a lake, and there scarcely could have been vigorous discharge from the Minooka Ridge. Terraces on the Des Plaines River which have their head in the Valparaiso moraine and were formed in connection with that moraine indicate that a lake stood in this basin at the head of the Illinois while they were forming and that its level was about 560 feet above tide, or 60 feet above the present head of the Illinois River. his lake level is well defined also by beaches which are to be seen both north and south of the Illinois. MON XXXVIII 21. 322 THE ILLINOIS GLACIAL LOBE. Such being the case at the time the Valparaiso moraine was forming, it fol- lows that at the time the Minooka Ridge was formed the lake stood fully as high, if not higher, for the Minooka Ridge antedated the the Valparaiso moraine in its formation. The low part of the basin immediately west of the Minooka Ridge stands only a few feet above the level of the beaches referred to and would apparently have been extensively inundated during the melting of the ice sheet, even if the outlet from the Morris Basin had been cut down to the level of the well-defined beach bordering the Ilimois River. A vigorous discharge of waters across the basin could scarcely be expected. Certain features which suggest vigorous discharge will next be considered. The channels noted above, which cross the ridge a few miles north of the head of the Illinois, seem to have been made by a stream with a current having considerable volume, if not considerable strength. They are cut down to a gradient too low to give the present small stream which drains them a good eradient, and are consequently occupied by marshes. The conditions under which they were formed were probably similar to those which caused the gaps in the Marseilles moraine discussed above (pp 310, 314). A thin coating of sand is found in the portion of the basin immedi- ately west and south of these channels, a feature which implies current action, but perhaps no stronger than is consistent with the presence of a lake or very broad lake-like stream. On the whole, the evidence seems insufficient to establish the existence of good drainage conditions. Turning to the Kankakee for light as to drainage conditions accom- panying the formation of the ridge on its north border, it is found that sand deposits occur along the opposite side of the valley, forming a much more conspicuous feature than on the west border of the Minooka Ridge. The deposits extend back usually 3 or 4 miles from the present stream and reach an elevation fully as high as the ridge on the north side of the valley. They have been drifted in places into prominent dunes. This sand may be interpreted either as the direct outwash from the ice at the time the ridged belt north of the valley was in process of formation, or it may seem refer- able to subsequent stream transportation, for the Kankakee Valley was the line of discharge for glacial streams issuing from the Saginaw lobe during the period embraced in the formation of two or more strong moraines, and from a part of the Lake Michigan lobe during the formation of the Val- THE MINOOKA TILL RIDGE. 323 paraiso moraine. These glacial streams had a current sufficiently strong to excavate a channel throughout nearly the entire length of the Kankakee Basin, whose north bluff may still be seen rising 15 to 30 feet above the Kankakee marsh. A current of this strength would seem to be entirely adequate to cause the transportation of such sand deposits as are found on the lower course of the Kankakee. It may be questioned, therefore, whether these deposits may be referred with certainty to streams issuing from the ice sheet at the time the Mmooka Ridge was in process of forma- tion. The evidence here, as in the case of the channels north of the Hlinois Valley, is scarcely sufficient to establish the occurrence of good drainage conditions at that time. The peculiar association of this sand belt with a bowlder belt is discussed below (p. 326). Inasmuch as the Iroquois moraine appears to have been formed either contemporaneously with or subsequent to the Minooka Ridge, the character of its outwash may be found serviceable in drawing conclusions concerning the outwash from the Minooka Ridge. On the outer border of the Iroquois moraine in Iroquois County, Ili- nois, and also in Benton County, Indiana, the outwash is a fine sand which has been transported to the lower parts of the Iroquois Basin and down the valley of Sugar Creek, a southern tributary of the Iroquois. As this out- wash is in a district lying outside the line of discharge for the glacial streams which traverse the Kankakee Valley, it is less difficult to interpret than the sands of the lower Kankakee. Its position is such as to be favor- able for discharge of water if no lake were present, since there is a descent away from the outer border of the moraine. Yet the fineness of the mate- rial seems to indicate that very imperfect drainage conditions attended the deposition of this moraine. The feebleness of discharge is thought to indicate that lake-like conditions may still have persisted not only in the Morris Basin but also in the Kankakee and Iroquois basins. On the outer border of the combined Marseilles and Minooka moraines, in northern Kendall and southern Kane counties, there is an extensive gravelly plain, to which attention was called in connection with the Mar- seilles moraine. This plain has not as yet been definitely connected with any of the moraines of the late Wisconsin series. Three means of deposi- tion need to be considered, as follows: (1) By streams flowing down the Fox River Valley during the formation of the Valparaiso moraine and 324 THE ILLINOIS GLACIAL LOBE. spreading out a delta similar to that formed in the lower part of the Des Plaines Valley by streams issuing from the same moraine; (2) by streams issuing from the ice at the time the Minooka Ridge was forming, for the ice at that time seems to have extended as far, at least, as the western edge of the Marseilles moraine in Kane County; (3) by outwash from the Marseilles moraine, which sweeps around the eastern and southern border of the plain. In the present state of knowledge it seems difficult to draw inferences con- cerning the date at which this plain was formed, and also concerning the broader question of the character of the outwash from the ice sheet during the Minooka substage of glaciation. Whether the Minooka Ridge is to be included in the late Wisconsin series can not perhaps be decided at the present stage of investigation. If it can be clearly established that during the interval between the formation of the Marseilles moraine and the Minooka Ridge the outlet down the Illinois had been lowered from about 640 feet above tide (the level of neighboring outlets through the Marseilles moraine) to a level nearly as low as the 560-foot beach bordering the Illinois in the Morris Basin, a corre- spondingly late date for that ridge may be assumed. But at present there is much uncertainty as to the amount of work accomplished by that outlet prior to the formation of the Minooka till ridge. The bearing of bowlder belts on this question is considered below (p. 327.) INNER-BORDER TILL PLAIN. On the inner border of the Minooka Ridge, from the vicinity of Elgin southward to the head of the Illinois, there is a narrow till plain nowhere more than 6 miles, and usually but 2 or 3 miles, in width, which separates this till ridge from the Valparaiso morainic system. North from Elgin the Minooka Ridge has not been separated from the Valparaiso system. From the head of the Illinois eastward along the north side of the Kankakee Val- ley there is a similar till plain separating the ridged drift on the border of the valley from the Valparaiso morainic system. Its width is greatest on the meridian of Kankakee, where it is fully 12 miles, the usual width being only 7 or 8 miles. East from Kankakee the till plain north of the river decreases in width and extends only a short distance east of the State line. The Valparaiso system there comes to the border of the Kankakee marsh. BOWLDER BELTS. 325 An extensive sand-covered tract south of the Kankakee, in western Indiana and the east border of Illinois, is discussed below. The portion of the till plaim north of the head of the Llinois shows usually a perceptible descent away from the Minooka Ridge, accompanied by a corresponding decrease in the thickness of the drift. On the borders of the ridge the drift is 100 feet or more in average depth, while at the east border of the till plain next to the Valparaiso system it is in places but 20 to 30 feet in depth. The drift appears to be mainly soft till, referable to the Wisconsin sheets. In places it is gravelly or sandy at base. The portion of the till plain north of the Kankakee in general rises slightly toward the north. The drift is apparently only 30 to 40 feet: in average depth. In places rock ridges which carry scarcely any drift rise slightly above the general level of the plain. Such ridges may be seen near Manteno. The drift is apparently nearly all Wisconsin. A few instances of the penetration of a buried soil in wells were reported from the north- east part of Kankakee County. This soil is within a few feet of the bottom of the glacial drift. The drift north of the Kankakee contains much sand and gravel, but there is usually a capping of till a few feet in depth. The well sections of Will and Kankakee counties, presented in the latter part of this report, will set forth the variations in the structure and the thickness of the drift. SECTION II. BOWLDER BELTS. The Marseilles moraine and also the Minooka Ridge, as already indi- cated, carry a very few bowlders on the surface. Bowlders are also com- paratively rare on the inner or eastern slope of these ridges and on the till plain between the Kankakee River and the Valparaiso moraine. There is, however, a strip on the borders of the sand area along the south side of the Kankakee in Kankakee and Will counties, and in places within the sand area, where bowlders abound. This belt may connect on the southeast with the Iroquois moraine, though the connection is rather obscure because of sand accumulations. It appears to find a continuation northwestward in Grundy County along the borders of Mazon Creek, from the vicinity of Gardner to the mouth of the stream near Morris. From Morris a belt of bowlders extends northward 3 or 4 miles, beyond which, for about 6 miles, they are comparatively rare. Near Plattville a narrow belt sets in, 326 THE ILLINOIS GLACIAL LOBE. which leads northward to the Marseilles moraine and passes over that moraine, as already noted, in the vicinity of the valley-like gap east of Yorkville. The bowlders occupy the gap and also the portion of the moraine to the east. To the north from this point the broad gravel plain along Fox River interrupts the belt for a space of 3 or 4 miles, but at the north border of this gravel plain bowlders again become numerous and abound along the west side of Fox River throughout the mterval between this eravel plain and the composite belt of moraines above described. The bowlders are unevenly distributed, there being small tracts and narrow strips where they are so numerous as to constitute a serious obstruction to the cultivation of the soil, occasionally numbering several hundred per acre, but throughout most of the belts there are only a few peracre. The belt taken as a whole probably carries ten times the number of bowlders found in neighboring districts. The sand along the south border of the Kankakee is usually so heavy that the bowlders, if present, would be obscured. In places where the sand is thin, bowlders are usually abundant. These oasis-like tracts in the midst of the sand area are in some cases difficult to account for. The heaping of the sand into ridges is probably due, in part at least, to wind action, and the wind may also have been influential m sweeping the sand away from parts of the surface. It seems well, however, to introduce an alternative or supplementary explanation, though the applicability has not been fully tested. By the alternative interpretation a causal relationship is suggested between the occurrence of bowlders and the absence of sand, and the explanation found in the persistence of ice where the bowlders occur until the sand had accumulated in practically its present depth and topography. This alternative explanation would also make the ridging of the sand partly the result of glacial moldimg which has been intensified by subsequent zeolian action. This interpretation has been suggested by features found in the old Lake Kankakee district, discussed below. It should perhaps be stated that the bowlders here or elsewhere in the belt can scarcely be considered a residue from erosion of the till, for they often occur on plains where there has been scarcely any opportunity for erosion. Furthermore, they differ in constitution from the coarse rocks of the till, being almost wholly of crystalline rocks of distant derivation, while the till abounds in local rock fragments, both coarse and fine. BOWLDER BELTS. BT It seems more probable that the belt marks the position of the ice margin at some stage of advance between the formation of the Marseilles and Valparaiso moraines. Were the belt accompanied throughout by a moraine, or even a thin sheet of drift, this interpretation would seem well supported. For a few miles in the vicinity of the point where it crosses the Marseilles moraine there are low knolls accompanying the bowlders which may prove to be of the same date as the bowlder deposition. They are much smaller tnan the swells on the Marseilles moraine, being usually only 3 to 5 feet in height and covering a few square rods each. They inclose shallow saucer-like depressions, and on the whole give the surface a fresher contour than is presented by the portion of the Marseilles moraine to the west. ‘The portion of the belt from Morris northward was made a subject of joint investigation by Professor Chamberlin and the writer, and to each of us the surface contours appeared somewhat fresher along the line of the bowlder belt than in the district to the west. But the development of a new or distinct topography in connection with the bowlder belt seems at best to be limited to the immediate vicinity of the Marseilles moraine, and leads us to feel some doubt concerning the interpretation of the occur- rence of a thin sheet of drift in connection with the bowlder belt. It will be observed that the course of this bowldery strip is nearly parallel with the Minooka Ridge and its supposed eastern continuation along the Kankakee. This parallelism has suggested the interpretation that the bowlder belt may be closely related to that ridge Possibly there was a temporary advance of the ice beyond the position it held while forming the ridge, .or possibly the accumulation of the bowlders and the ridge occurred at the same time, the former being at the extreme margin and the latter a short distance back from the margin. The smoothness of the ridge apparently favors the interpretation that it is a submarginal accumulation. Another interpretation refers the formation of the bowldery strip to an advance subsequent to the formation of the Minooka Ridge. In that case the smoothness of the ridge may be due to its having been overridden. It seems highly probable that this bowldery strip is to be correlated with the Iroquois moraine and associated bowlder belts found in Iroquois County, Illinois, and Benton and Warren counties, Indiana, which are referred to the late Wisconsin invasion. The indefiniteness of the bowldery strip in the sandy districts of eastern Kankakee and northeastern Iroquois 328 THE ILLINOIS GLACIAL LOBE. counties prevents a full and satisfactory correlation. But nothing to oppose the correlation has yet been discovered. At present it seems necessary to leave unsettled both its relation to the Iroquois moraine and to Minooka Ridge. SECTION III. LAKE KANKAKEE. Nearly thirty years ago Mr. F. H. Bradley applied the name Lake Kan- kakee to a body of water which he thought formerly occupied a large part of the Kankakee drainage basin.’ The existence of a lake in this region was suggested by the occurrence of deposits of sand. outside the limits of the present Kankakee marsh. Mr. Bradley recognized the influence of wind in distributing sand over areas not covered by the lake, but considered the evidence satisfactory that along the line of the Louisville, New Albany and Chicago Railroad lake water had reached an elevation about 685 feet above tide. He had not full opportunity to explore the region; hence his outline of the extent of the lake is rather indefinite. Chamberlin touched briefly upon this sand area in his paper in the Third Annual Report, as follows:° These dunes are a portion of a somewhat extensive tract, or perhaps rather a series of tracts, in northwestern Indiana, the precise distribution and origin of which are yet undetermined. They lie mainly in the Kankakee Basin, which was formerly occupied by an extensive lake or lacustral river—“‘Old Lake Kankakee” of Bradley— and have been thought to be its shore accumulations; but their very wide extent and great mass relative to the lake area, as well as certain features of their known distri- bution, throw doubt upon the adequacy of this explanation. It would seem, from a consideration of the glacial distribution of the second epoch, that this region must have been the avenue of discharge of vast quantities of water, shed from the adjacent slopes of the great glaciers occupying the basins of Lakes Michigan; Huron, and western Erie. The great accumulations of sand probably had their ulterior origin in this exceptional drainage, and were subsequently modified by lacustrine, fluvial, and xeolian action. Their history is one of much interest, and its satisfactory determina- tion can scarcely fail to reward industrious investigation when pursued in the light of the glacial phenomena now under consideration, and may, in turn, cast reflex light upon them. But however that may be, for the present, these dunes interpose an element of uncertainty in the tracing of the moraine at what would, in any event, be a critical portion of its course, for it is impossible to determine the character of the drift which they conceal. The extent of the sand in the Kankakee Basin and in districts to the south has been further investigated by Chamberlin since the above was 1 Geology of Illinois, Vol. IV, 1870, pp. 226-229. Third Annual Report, U.S. Geol. Survey, 1881-82, 1883, pp. 330-331. LAKE KANKAKEE. 329 written, as well as by Prof. A. H. Purdue and the writer. The limits have been determined with considerable accuracy, and the general features of the area have also been studied. ‘The phenomena, as will be seen, are of a peculiarly puzzling nature, and as yet a fully satisfactory interpretation of them has not been reached. EXTENT OF THE SAND. Beginning at the northeast and passing southward, the sand is found to have its eastern limit at the border of the Maxinkuckee moraine of the Saginaw ice lobe in western Marshall County, Indiana (see Pl. VI). A few dunes occur on the moraine, but the continuous sand follows approximately the west border. Farther north, in St. Joseph County, a gravel plain occu- pies the outer or west border of the Maxinkuckee moraine. The moraine swings eastward alone the north side of Tippecanoe River in northern Fulton County, and a narrow sandy belt extends up the Tippecanoe Valley along the outer border of this moraine as far as Rochester, but the east border of the main sand area continues southward through western Fulton County and northwestern Cass County to the vicinity of Lake Cicott. Purdue reports that for about 9 miles north of Lake Cicott a well- defined sand ridge forms the east border of the till plain that descends westward to the Tippecanoe River. This ridge turns abruptly westward near Lake Cicott and is nearly continuous to the Tippecanoe Valley at Monticello. For a part of this course the ridge lies along the north slope of a moraine of the Erie lobe. After crossing Tippecanoe River at Monticello the moraine turns south, while the ridge continues in a course slightly south of west about to the Ime of White and Benton counties. From this point a narrow sand ridge has been traced by Purdue in a course north of west nearly to Kentland, Indiana. There is, however, very little sand on the surface for several miles north from this ridge, and he did not sueceed in tracing the ridge farther west. Purdue reports that there is a somewhat broken east-to-west sand ridge north of Indian Creek in southeastern Pulaski County, which passes through the village of Rosedale (Oak post-office), where it presents large dunes, and thence turning northeastward, terminates at a gravelly knoll in the north- east corner of T.29, R.1 W. The area from this ridge north to and beyond the middle of Tippecanoe Township is an extensive sandy plain, with the 330 THE ILLINOIS GLACIAL LOBE. exception of some short ridges of sand. There are also the following areas within this plain where sand is not present: (1) A small area in eastern Pulaski County, 1$ miles north of Bruce’s Lake; (2) an area south of Bruce’s Lake extending south to Little Mill Creek and west about 3 miles from the county line; (3) between Mill Creek and Little Mill Creek; (4) a small area about Star City. This ridge has an altitude nearly as great as that of the ridge south of it, but its relation to that ridge and to the border of the sand area was not clearly worked out. Another narrow sand ridge was traced by Purdue from Monon Creek, about 5 miles southwest of the village of Monon, nearly directly west for about 20 miles to Perey Junction in Newton County. This ridge con- stitutes the south border of the main sand area in Jasper County. West and northwest from the western end of this ridge there are a few low sand ridges, but these occupy only a small part of the surface and do not have definite connection with each other nor with the long ridge just mentioned. There is enough surface sand, however, to indicate that that region was covered by a body of water. The Iroquois moraine, on the north side of the Iroquois River, appears to have been partially submerged, but its highest parts probably rose above the water and shut in a bay on the south, in which wave action was not sufficiently strong to form heavy sand deposits. The south border of the main sand area follows the north slope of the moraine westward into Iroquois County, Ilinois, and there swings south- ward with the Iroquois moraine to Coon Creek, in southwestern Sheldon Township, forming apparently an outwash apron, as noted above. A belt of dunes leads westward from this sand area across Belmont and Crescent townships. There is considerable surface sand from this belt of dunes northward, but to the west and northwest only occasional low sandy ridges and thin patches of sand are found. Socces cadets teeresasessdessess 25 IDEraya Gea! OP EME CONE <5 Ses sposososcens bosses Seo ees Ga sams Sudo seo Foss ossn aseeso serosa soeSaaes 48 Sting! pina magi Gis INNO ooo scc bossco seeess sed soe soeaon coed es SSeS coe need aes seers oe ses soso Esse 5 IDE OWN nea ebos SSen Sle noses cece Seed ececas Hebe eceb rs ssasds soap Sooo sesa0es sss aSoces ste sos 78 Many wells in Geneva Township, 2, to 5 miles west of Grand Junc- tion, are in till to a depth of 25 feet, but among these are wells largely in sand or gravel. East from Grand Junction for several miles the well sec- tions are largely sand. Near Columbia Station, on the farm of Mr. Reece, THE VALPARAISO MORAINIC SYSTEM. 365 a well which was in process of boring at the time of my visit shows the following section : Section near Columbia Station, Michigan. Feet Wolloay ceil Sanndéecomsus ccbo.baates stloses Hodeeaeocsao pane Cacao ou dbadoacedouna carats saopee. coueueds 20 Sottibluerclaysapparently~pobblelesseressemsescces se eee eeeriseenenee nee eeeieeen ne aeee cece see 18 IM a LENG CacoE VN by HHO). Seo wood Souda Rbescd cSnoep Oddo pO Hobeds Coouseoo odbp aces uodascemosore 140 OBA, ooo ccen cess oodeiesob coed opag aceo bbbs CoaEeEDE adhe cmon cbed soba dhdacddbae heed osek eae 178 This sand is so fine that it can not be screened by the pump strainer, and renders the water unfit for use. In the vicinity of Great Bear Lake, south of Berlamont Station, there are several wells 100 feet or more in depth. One on a hill three-fourths mile west from the north end of the lake passes through 100 feet of dry sand and gravel, then enters water-bearing sand to a depth of 16 feet. Another south of the lake in western Bloomingdale Township was dug 100 feet through sand and gravel without obtaining water. A well south- west of the lake, in see. 25, Columbia Township, on a hill rising 100 feet above the lake, is 125 feet in depth and largely in dry sand and gravel. Between Great Bear Lake and Bloomingdale wells are sunk mainly in till, both yellow and blue, but are only 40 to 60 feet in depth. A well 2 miles south of Bloomingdale, on J. G. Miller’s farm, is 110 feet deep, passing through blue-gray till nearly the whole depth. As a rule Bloomingdale Township is underlain by till to an average depth of 40 feet, the only notable exception being the eastern tier of sections, where wells are largely in sand and gravel. This tier of sections is more elevated than the remainder of the township. A well at Mr. Merrifield’s, 14 miles north of Bloomingdale, presents the following exceptional section: Section in well near Bloomingdale, Michigan. Feet. Soll cingl Clay Wolo REMC odoo6 Sopaou bo Sbo8 ceeoau seco onecos odseos sdoobo cosbadud 655556 HaoSSSe see 20 Quneldsmel 5666 casosodoocod sssess Sascdy popes eedese suedos csoSnd oHeceo DESESH o6 sosedeaneoeE peGcee 14 Ip enmay wl Gocsec.cooosd sarbon beocueedesDE SeoLoTHSEece S6e65s cn aciss 05 cece soo gsoseoses Secsas damu5 8 Cenmemisal mney) og65so 646545 ceac dopcoptboud deco Havorseg sods pede seS4 Goon condo bono cone sede ecadesoase 12 Wallonia till oesechce cocdigbos Seed gate doce Sas aged nado dane. cote sasp ones nosh odo Ecos Scab bods andeeno Cll) Que kspraGl Or pay COO 2 cs 5656 cede dode deb ecods sacé cosbenos coco dees coos caSHoncn eabeoseacncemaes | Wylanrs canal Ald WHI SS bas cobs Bode Sooe saa0 Sees cob bascas codoSo0s Bodo sens Sone nese acer asacoreS 10 WEIS Doms RAEI ooc6 shoo ocd bned aban Bebe pose S55 Saco 3600 Shs0 seen boas ones Geos caqgoesonasuess al DED Nacod.cosbasbs secded sons cece Hessad dooseo coos acsecooBecess CobdoD aeSc ed cobe accETS bese SHES 91 A well 3 miles south of Gobles, in Waverly Township, on a prominent point called Covey Hill, is 109 feet in depth, and the entire section is made 366 THE ILLINOIS GLACIAL LOBE. up of sand beds alternating with thin layers of cemented gravel. Wells in Gobles, and for a mile or two north and south from this village, are from 50 to 60 feet in depth. They penetrate, just below the soil, a crust of cemented sand, gravel, and clay, called “hardpan,” about 2 feet in thick- ness, beneath which are alternate beds of sand and gravel, loose and dry as a rule, but cemented slightly in places. Usually a cemented layer is passed through just‘above the water. Wells in the gravel plain from 1 to 3 miles northeast of Gobles pass through 2 to 5 feet of hard, pebbly, reddish clay called “hardpan.” Below this is sand, loose gravel, and cemented eravel. Wells are about 40 feet in depth and seldom penetrate any till or clay except that just beneath the soil. A well in the northern part of sec. 18, Almena Township (T. 2 §., R. 13 W.), on the farm of Robert Clark, is 86 feet in depth, and has the following section: Section of Clark well in Almena Township, Van Buren County, Michigan. Feet, ILO Mitiky FEN pape a5 cero coe See 655550 S809 bho O5b0 nongbSSeSd oto beds bhd5 Sass Saes sSadeseS beScés cose 14 QUO RSP oSecs dsasee POSSE OD ERSO DOOn SESS S556 Soo Eat cond osco socIash sabes cdoses eos OSeSosesases t505 2 IPE EAAy THUD one koe es Seas oo0 SSc6 bac0 SoSSos Sse secane cHoS coon SoSbos HaSSHS sooSaSecbSnoRSsasauEne 40 Gemeente dyer aly e eye ae aaa a a ee 14 TONG) FENG 5 Sd esas sends coed cose asd6cncs Hoes eon aces Sha0 pgSscodoenbs A409 Hescseorsesceso seese0 16 INOUE CaSees so ccSeceseeshs seco ssebasgs case sees onde cbse Sooo sess asao SsedcosSEdoS oneg esse sone 86 Gravel and water at bottom. A large part of Waverly Township is underlain by till. Nearly half of the township is swamp land with very few inhabitants, but the portion not swampy (northeastern part) has wells 35 feet or more in depth almost entirely in till, This till is yellow or oxidized to a depth of at least 15 feet. An elevated tract in the northwestern part of the township has a loamy clay 2 to 4 feet and occasionally 10 to 12 feet in depth, below which is a reddish-yellow till. Wells are only 20 to 25 feet in depth. There is a small flowing well district in the swamp along the Pawpaw River, in the southwestern part of the township. All the wells of which records were obtained are in the southern part of sec. 30. They are each about 50 feet in depth. In one well the water rises nearly 10 feet above the surface, but in the others only 1 to 4 feet. They penetrate a slightly pebbly blue clay nearly the whole depth, there bemg scarcely any yellow clay even at the surface. THE VALPARAISO MORAINIC SYSTEM. 367 On the elevated tract north of Pawpaw River, in Lawrence, Hartford, and Arlington townships (T.38., Rs. 15 W. and 16 W., and T.2.8., R.15 W.), a considerable portion has but 6 or 8 feet of till, beneath which is dry sand or gravel. In some cases wells are sunk 100 feet im this sand and gravel before reaching water, but the majority of them obtain water at 40 to 50 feet. On the elevated land immediately north of the village of Lawrence there is much sand at the surface. Wells are often 20 to 40 feet in sand. In some places the sand is underlain by 10 to 20 feet of bluish till, and this in turn by dry sand or gravel, becoming water-bearing toward the bottom; beneath this lower sand is a blue till of various depths. Wells in southern Arlington Township, near the northern part of the elevated tract, are frequently 80 feet and occasionally 160 feet in depth. A well in sec. 23, 162 feet in depth, penetrates: Section of well in sec. 23, Arlington Township, Van Buren County, Michigan. Feet Red dish=bro wena yee ee ees sens ysrstee ere wees ctelayac fine slorsteeiisia oi cieeiste es iotetateloya es ieaeettaeiones iste cieicieleteisier 40 @uirelkemnGl sos Gacoscoedes6o0 Seen scooSb cebe poHEoe coe ppooQuedrocse eSoeoo bussed Hon Ssaogou Seas beac 10 IHlMe-aw ny wlll owes eson cooSbe ase cose cobs Gong Goedoode SoSanods coceme Bees odoca9 cane asaces aEcSs5 Saoe 110 (Gh IG! soaoub pEUdeSo.DCoc nnd ccs Cou soo Sba cuebee Car GaGOerceroten snd emepd GeoooOdS55 emoqobed SedemocdS 2 INN scos'deau Boao SoadGoosbe edoo bd Eden ease eeas do ocabodna cde0 Han Sbpaacasddodobdoa Beko dsenSS 162 In the same section is a well 80 feet in depth, which penetrates the following beds: Section of well in sec, 23, Arlington Township, Van Buren County, Michigan. Feet. IDAY GEM pao ooSoeocce oss cHcouS bs Gos6 Soso PBanes Gade sone Sones Hon obs SoeSsocossce cach doreee cae6 BHaC 40 COD @inGl GRO csac coésesSHeu cosa coco neds Soused SHS5 SScr es e558 seas aooS Coa S eecebes nosEoo gens o66e 15 Sand of gray color, streaked with red, containing limestone concretions....-.--..-.-.-.---------- 25 JROUEIL Cood.ecn5.0000 cons ose 9560 Gone GbeE OEE ESSA paEn Sdg no6G 60 O500 Saad Bodo once Baad ooDD coon EE 80 As arule, there is 12 to 15 feet of reddish-brown till above the sand and occasionally 40 to 50 feet, but in places it is wanting entirely, as in the above section. A well in sec. 20 has the following section: Section of well in sec. 20, Arlington Township, Van Buren County, Michigan. Feet. Wellonae na pRO yan WH Coos cocooce ede Bo0aes Soccoe Sede Soees code esse ceo5 S00 Sob0 Sb50 ehes camo naeSuE 10 Comomiuaal atmyll soso scocissee coda deus suds ne Babe Seaboscosase asdeco sooo sdeb pelbde BoonEoweeces sacese 8 Dry sand and gravel, with cemented gravel near bottom.........--.--..-----.------------------- 35 Brownish till, with thin beds of cemented gravel and quivksand.......-....---.---.-----.---.---- 30 WEISS lhCaBinNe PrP Nh ccodsanneo Has Sor Bee SEserad moon S6oS Coe S OS SURG HEC BHU HOOD DODO I4 POSER Ua ease 2 ID QUIN .soecddoe hoes danHeee eee nSSH BOD SSG Dbb8as Bees 6506 6000 SEB A BE SBOE EECA ARTe Sneeeee se oaee 85 368 THE ILLINOIS GLACIAL LOBE. A well on sec. 21, one-half mile east of the above, is 125 feet in depth and is almost entirely in sand and gravel. This well is on a prominent knoll. So far as observation was extended, these knolls quite uniformly show a great depth of sand and gravel, with but little till, and that, too, when till is found on the adjacent lower lands. On the elevated land north of Hartford, in see. 11, Hartford Township, ava height of 85 feet (aneroid) above the flood plain of Pawpaw River, on the farm of Samuel Keine, a well 87 feet in depth penetrates: Section in Keine well north of Hartford, Van Buren County, Michigan. Feet (Gravailky gamnaby GEN /oca6 coatss 665de0 sesso ssobes saison Sconces desu boos aces Sede Heesos ocoacoa dace Hts 10 WHOM ETD WH con ea seks Sobabe Sotass Gedo os boss. coco bhse caos edeo aoe soc H Sada esse cosseecs scoscus sess 12 Cementedvoraveliwi thi thin) clay) ed seer a= seer oleae ee eae eae eee alate eran OU) IL@OSO aN TEIl WANN, WIG sacoce ssa nnSd.Sc8e So55 Sopo eeeo secs Hada bane odosES HoEDoSoS cesb cose odes cose 5 MQ oe Sin sebd Scins Sacane oe Boas sos udds.cosd cose wncD bade soeeooad edad eesE code Soccldiserd ceoncs WH A well across the road was sunk to a depth of 160 feet. For a depth of 80 feet its section is similar to the above; below this there is a bed of blue bowlder clay nearly 80 feet thick, which is underlain by water-bearing eravel. It was on Mr. Keine’s farm, at a level about 35 feet lower than the surface at the well, that the huge limestone bowlder noted above (p. 357) was found. In Bangor Township and in the vicinity of Breedsville, in Columbia Township, deep wells are rare, the usual depth being but 25 to 30 feet. In some cases the wells are largely in till, but in others the section is prin- cipally gravel. There is but little sand on the surface in Bangor Town- ship, compared with that in Columbia Township, and it is exceptional to pass through much sand in sinking a well unless it be on a high knoll. The deepest well in this township of which a record was obtained is in sec. 17, on the highest knoll in the western part of the township, and is interesting, since it is but a few rods distant from one of the large sandstone bowlders noted above. The following is the well section: Section of well in sec. 17, Bangor Township, Van Buren County, Michigan. Feet SOG HN WN So as eos hooskoos cos cone cab Ses EER er oni aaa uaa aoc c cOAS Cao a nedanese 5 IDA ERUG) epson boa anes brine SoU aBoo dees Sosa uboeneesae dosticatosoondiaan sSeeddeeds oteedessgoce 15 Coarse sand with water ...----....--. Si a eri Seep ee ee Tafern DEVO LES ASS seme PL 3t IMDb NEE oe Be Are Beee cose Cones cf encecsss Co SD OTSA UREMEASesclscantc Sabb ceod osne SSkaidead Soseaes 7 KOMEN GENT ss e< coasoo mond soonwe DooSen sroace Sete doen ebnb boca Mesa deDocH econ ssoS Sesoebsossecos 8 SEIMNGl os co seco cese na eesn esse nned seca eS seco LosSccesbe sobs eds cesolccoadsds onto consseccostesossesoo (AS THE VALPARAISO MORAINIC SYSTEM. 369 A prominent knoll about a mile east of Bangor, rising 125 feet above the station of the Chicago and West Michigan Railroad, or 775 feet above tide, contains much fine sand which has been used in the iron furnace in Bangor as molder’s sand. There are gravel beds interstratified with it. The exposure does not show the deeper structure of the hill. In Watervliet Township and in western Hartford Township the western portion of the morainic belt has a deposit of till which is penetrated to a depth of 20 to 40 feet in wells; but in eastern Hartford and Lawrence townships the structure changes on rising to the higher portions of the moraine, and wells are in sand or gravel much of their depth. There is, however, on the lowland along Pawpaw River from Hartford to Watervliet a sandy belt a mile or more in width in which wells penetrate sand or gravel to a depth of 20 to 40 feet without encountering till. At Watervliet this sand belt is very narrow, wells 80 rods south from the railway station pene- trating much till. The sand and gravel is confined to a plain along the river, which stands at about the level of the highest beach of Lake Chicago. The ridges and undulatory tracts both north and south from this plain con- tain much till. The rolling belt southwest from Coloma has a great depth of sand, so that wells 35 to 50 feet-in depth penetrate little else. In the village of Coloma wells encounter a variety of beds, of which the following section of a well at Mr. Abram Smith’s may be taken as representative: Section of well at Coloma, Berrien County, Michigan. Feet. Claysloampoteyellonwwacol Ovsirsrsererce Ne icte pa te oie valet sat ciara cicic fo Siete eens a Ue eperate ease er ret a mINUR US Seed 8 Dry gravel and sand with bowlderets and bowlders embedded............---.--..---------------- 13 (Comemusah reels os cocdicosesécscuau ca nese eHesoe Boba uebcon edocto DonooS Sacc ue soubuybadeouueseees 8 Blueclayrapparenthyapebplelesseesesscisjeac ae esclainciels le silecle eres oeee Sete erete cece eeeenice ce 9 IDE UN 5 cade Hb60 5805 Se SeSbe0 GbsosceoRS Ssons5 bodaSY Boog SoOKHG HooSUS sobs Sad bes bodeoueDaaees 38 Wells on the ridge on the south side of the Pawpaw River, between Coloma and Watervliet, disclose much variation in structure. One well may be largely in till, another on the same farm principally in sand or gravel, while a third may have both assorted and unassorted drift. The surface is more uniformly coated with a clay loam east of Coloma than it is southwest. A well on the north side of Pawpaw River, near’ Pawpaw Lake, on the farm of Mr. Huntoon, penetrates: MON XXX VITI——24 370 THE ILLINOIS GLACIAL LOBE. Section in well near Pawpaw Lake, Michigan. Feet. NellowASheut) Weeseen eee arene aes acian steer ISOCoh cadeSn oso SUS Sadban does ocoetsoosSSsoSsdbes 10 INWErgray, Will ope ccooccos assees SSebes sacs Code sd dene tSsono See bbs case suds scbdes pose escasesocsece 10 IDA GRID Bed ocs cts ec ebodlcdoo GeodbacS cocnes S546 Sued Hecedeco SdeHne boos cosnen HscSdG00 coneodes0 6000 20 WE encHie ine farhi Cleo Sobor aaa cosoeouo ane a boda doSdes penn epoobadsoucmssonadsedoQad osopSobotee 4 IDI Sand casa bass enna teense BaUUSEes Gobo cedorspEEsEbcases Da boUS aS S ned Seas capascotbuoc os, Ai! A well at Hillside stock farm, on the north side of Pawpaw River, opposite Watervliet, penetrates till, principally of a blue-gray color, to a depth of 40 feet. A well on the northwest side of Pawpaw Lake, in the east part of sec. 9, 125 feet deep, penetrates till 120 feet. In the portion of Hartford Township east of the village, wells are in sand and gravel on the elevated land, while west from the village the elevated tracts are covered with a quite heavy deposit of till. Pine Creek seems to mark the division line, there bemg more sand and gravel east of the creek than west of it. A well in sec. 17, Lawrence Township, on a prominent portion of the moraine 100 feet or more above Pawpaw River, penetrates the following beds: Section of well in sec. 17, Lawrence Township, Van Buren County, Michigan. Feet YG GAIN THN Sa sos Boob be oanbod sobods tose boseus msen secs cosantdsecds Gaoses saodes colseSososoEsos 10 IDYA? BRING see eco tec bobdonco adseque ss bono cose oSicncote seSasceaadas cabaus bso acesed cae cooessa sensse 70 Ani esHhNGl Sebo Se Gases eeeSos sheseoSabeEs So pbss cbads9 Sess uondeg baan soSGey bass Soo edusdbecsnedoes 40 THINS) Oley 7S Moy aE INIES OWING ESS 5 So Sac6 Socae 5 soso peso shen s2S0 conse Gua OSES Jess soeo ube aSS 40 Viiv) Gbayy Gemtl 58 fA eee Se podocs posdde seSce0 coro poste esss sogseb ondood sHaacdas Sooo ssassooasc 70 IDPH on2cco basco SSbS soos Cbeenaosse DHSd Sedo sacs CboS ASSO sens Sabaossccess ete soso odonke 230 A well in the southwestern part of the same section, 103 feet im depth, penetrates only 8 feet of till, the remainder being sand. A well in the northeastern part of sec. 20 of the same township, 80 feet in depth, penetrates but 7 feet of till. The sand is coarse at top and becomes finer below. In the lower part of the bed it was fine as flour. The pipe was drawn up to within 57 feet of the surface, where the sand was sufficiently coarse to be screened by the pump strainer. Several other wells in the southwestern part of Lawrence Township are characterized by a slight depth of yellow till underlain by a great depth of sand. THE VALPARAISO MORAINIC SYSTEM. oll T. O. Sweet, a well borer residing at Lawrence, states that wells in the village of Lawrence are usually 25 to 40 feet in depth and penetrate the following beds: Generalized section of wells at Lawrence, Michigan. Feet Reddish till and sandy ae BERS a Peto Abc ya Saree SSa ise gate aye areas Be eee Oe SE eieiattamere te ieee coe 7-18 Sell owes bill erates sosenctc ae ee ieee tote lnnin nica ciele the seaio ssi cabises cee mccoeeat ecemiseerel ress Om. Quicksand .. paccObO Codd bong noas Bacau Sabo. cHoAMeEuBlcnonbbas Good ndad raac basa ano maoo Mocdmeme Ms Blue-gray till a otra In some cases the quicksand extends to a depth of 40 feet or more, so that its bottom is not reached. On the elevated land south of Lawrence there is 12 to 20 feet of yel- lowish till with sandy gravel interbedded, and beneath this is a blue till mixed with blue quicksand. Wells in some cases penetrate this quicksand to a depth of 100 feet. ~ On the outer border of the moraine, in sec. 1, Lawrence Township, on the farm of Mr. Hutchins, a well 125 feet deep penetrated sand and gravel its entire depth and encountered many bowlders and bowlderets. A well at Mr. Whipple’s, in the river valley half a mile north and about 120 feet lower at the surface than the preceding, penetrates a yellow till 12 to 15 feet, below which is blue clay, apparently pebbleless, penetrated toa depth of 25 feet. Mr. Whipple states that the valley of Pawpaw River, in northeastern Lawrence Township. is underlaid by clay of a blue color and also a blue quicksand. In one instance a well was devon into this quick- sand 80 feet without reaching the bottom. A well near the border of the Pawpaw Valley, 20 feet or more above it, on the slope of the moraine in the eastern part of sec. 11, Lawrence Township, has the following section: Section of well in sec. 11, Lawrence Township, Van Buren County, Michigan. Feet Samal eal mre oooonb cases tadcos sdesed HaceonesoDes cub boS CcéSon abe cobooy beach coaHebe ees ondecs 18-20 TOA: WU) sooo oSdeho odecks Sado cede abequd ceobEo sHorss deddso cobSes cankcoondoacu beoAneeeueoaee 48 Choemae sam CnGl tiie) par Vl po6555 beecbe coon wag coSsce deESsuU cosh cose seca beoDodmesoed esooneeses 14 IDG DUN oe 325 Coebegusddds ceddoueeense Ganeds Seamed adbaad codons oaasesououdoosD sdocee cdodes 72 A well about 60 rods north from this, at nearly the same level, pene- trated no thick bed of till, but instead alternate beds of clay and sand or clay and gravel to a depth of 76 feet. 372 THE ILLINOIS GLACIAL LOBE. A well on the border of the overwash apron in the southeastern part of sec. 12, Lawrence Township, penetrated coarse gravel and cobble 84 feet before striking water, and this well has the peculiarity of freezing over in winter. Probably the outside air has access through the spaces in the gravel and cobble beds to the water in the well. Wells along the outer border of the moraine in southeastern Lawrence Township (T.38., R.15 W.) and northwestern Hamilton (T.48., R. 15 W.) penetrate more till than do those nearer the Pawpaw River, many wells 25 to 40 feet in depth being largely in till, but there is occasionally a small tract in which no till occurs. In such a tract in sec. 5, Hamilton Township, there are two wells, each 110 feet deep, which penetrate sand and quick- sand for 100 feet before reaching any gravel. A well in sec. 2, Keeler Township, 85 feet in depth, is entirely in sand, while on adjoming farms wells penetrate a considerable depth of till. The overwash apron which borders the moraine in Pawpaw, Lawrence, Hamilton, and Keeler townships (Ts. 3 8., R. 14,3 S., R. 15,4 8., R. 15, and 4 §., R. 16), Van Buren County, has wells 25 to 70 feet deep which seldom penetrate any till, but are in assorted material, usually gravel, their entire depth. There is a hardpan of slightly cemented gravelly clay loam 2 feet or more in depth just beneath the soil over much of this overwash apron. At Keelerville wells are obtained at 30 to 40 feet. They penetrate 15 feet of loose gravel and sand just beneath the hardpan, then 12 to 15 feet of slightly cemented gravel, and strike water in uncemented gravel. On the moraine southwest of Keelerville are wells 45 to 100 feet in depth which penetrate but little till as compared with those northeast of the town. Gaba ceog Gods ened bess Ho 6e0a Goda Sono bSSSnSa6 Sonacd sooa cHoOUUGdaS 1-4 CL EMae erAKall AmGl CO)DINO. ass coodeo coda ceseoooseS Face Gsob ods onEe Sucde bco6C0 nade Sooo EdeyoneuHe 10-12 Sandy gravel of medium coarseness, cemented in places............---.-.---. 22-22-25 eee eee - 25-30 JETINO GANG! OP WOON Sa cidce asco cSes coasts sbocae Boddos BUoEGD SoEbos Sood aoNacanouS deco osE6us Sood sade 4 Bluespepplelessyclayzslaminated cal careousiiasaselel-ecitecincioetaciee sate eieniere cet ee ere eeeeciie sat 8-10 Bowlder bed, containing clay balls and a sandy clay matrix, extending to river level on east side of mound, but underlain at slight depth by limestone at west side...-..--...----------. 5-20 It is thought that the bowlder bed may be a result of interglacial erosion of a till sheet. ‘The blue pebbleless clay which overlies it is apparently a still-water deposit, formed perhaps before the ice sheet had reached such a stage of melting as to produce vigorous drainage. The upper member appears to indicate a deposit by a stream whose vigor was greatest toward the close of deposition, for at the top the cobble is swept almost free from sand. The change, however, may have been brought about by shifting of the main current of the stream, the coarse material being deposited over portions of the bed which had before been outside the main current. As only occasional remnants of this gravel filling are preserved, it is impossible to determine the original variations in coarseness in a section passing across the valley. The deposits of gravel along this valley terminate very abruptly at the south, near Channahon, there being only a fine sand on the plain in the Morris Basin at the head of the Illinois. This feature is apparently due to the presence of a lake in the low country about the head of the Illinois 378 THE ILLINOIS GLACIAL LOBE. River. The beaches of this lake and its western discharge through the Marseilles moraine down the Illinois have already been discussed. The level of the beaches corresponds so nearly with that of the upper limit of the valley filling at Channahon that the latter may, with some confidence, be considered a delta-like accumulation at the north border of the lake. It is probable that each of the small tributaries of the Kankakee, which head in the Valparaiso moraine, and also eastern tributaries of the Des Plaines, afforded lines for escape of glacial waters, but the writer has not examined these valleys with sufficient thoroughness to determine the effect of the glacial waters. On the valley of Hickory Creek, which enters the Des Plaines at Joliet, a gravel filling is conspicuous from the outer border of the main moraine in sec. 17, New Lenox Township, to the mouth of the creek. At its point of connection with the moraine it has a gently undulating surface, but about a mile west from the moraine the surface becomes plane. The gravel is built up nearly to the height of the border- ing till plain, and stands 60 to 70 feet above the present stream. The headwater portion of the Kankakee River leads through a gravel plain which descends toward the river from moraines on either side. On the north side the gravel plain’ connects with the Valparaiso morainic sys- tem, while on the southeast it connects with the Maxinkuckee moraine of the Saginaw lobe. In the vicinity of Laporte, Indiana, the gravel plain which is connected with the Valparaiso morainic system attains an elevation of fully 800 feet above tide on the immediate borders of the moraine. This great altitude, however, is apparently maintained for only a short distance, for the railway surveys show that there is a descent in it along the border of the moraine, both toward the northeast and the southwest, as well as a descent in passing southeastward from the moraine to the Kankakee River. The elevation of the gravel plain at New Carlisle on the borders of the moraine is but 770 feet, while at Laporte it is about 810 feet. At Stillwell, 7 miles southeast of Laporte, in a course directly away from the moraine, the altitude is only 730 feet, while at Wellsboro, directly south of La- porte and only 3 or 4 miles from the moraine, the altitude is 760 feet. Passing southwestward from Wellsboro, parallel with the outer border of the moraine, the altitude decreases to 730 feet at Wanatah. The moraine is bordered by a gravel plain no farther west than eastern Porter County. In western Porter County the moraine extends down to THE VALPARAISO MORAINIOC SYSTEM. 379 the border of the Kankakee marsh and borders this marsh somewhat closely across Lake County, Indiana. Whatever outwash there may have been along the border of the moraine in western Porter and in Lake County, has been removed by currents of water passing down the Kankakee. Numerous references have been made to the gravel outwash on the east border of the Valparaiso morainie system in southwestern Michigan, and the relation of this outwash to the Valparaiso morainic system has been set forth in the discussion of the border between the Lake Michigan and Saginaw lobes. The line of escape for the small bodies of water in which this outwash was formed have been only partially worked out. It seems highly probable that the escape was southward into the Kankakee from the Dowagiac Valley, and possibly this line was open for waters collected in the headwater portion of the Pawpaw drainage basin. Drainage may have been greatly obstructed at times by the Saginaw lobe, and the height to which water rose was probably greatly influenced by the oscillations of the ice margin. The great amount of sandy and gravelly material formed along the elevated eastern border of the Valparaiso morainic system appar- ently indicates the action of water at heights of 300 feet or more above the level of Lake Michigan, or about 900 feet above tide. If this height were attained by the waters held between the Saginaw and Lake Michigan ice lobes in Allegan and Van Buren counties, they might easily find escape southward to the Kankakee Basin whenever the ice lobes afforded an oppor- tunity for escape, for the head of the Kankakee Basin stands only a little more than 700 feet above tide. There does not appear to have been a uni- form filling along the line of the supposed southward discharge. On the contrary the gravel plains appear to be rather in the form of small deltas extending out for a few miles where the slopes favored drainage, but absent along the portion of the morainic border where the slopes are unfavorable to such drainage. The gravel outwash appears to be nearly constant along the Dowagiae Valley throughout its entire length, a feature which seems to favor strongly the view that southward discharge was seldom interrupted, but on the Pawpaw and Kalamazoo tributaries, as already noted, the out- wash is more restricted. Upon the whole the Valparaiso morainic system displays a coarser out- wash and gives evidence of more vigorous drainage than has been found on any of the morainic systems of the early Wisconsin series, though it is closely rivaled by the drainage from the Bloomington system. 380 THE ILLINOIS GLACIAL LOBE. SECTION V. THE LAKE-BORDER MORAINIC SYSTEM. Between the Valparaiso morainic system and the shore of Lake Michi- gan there is a series of till ridges running nearly parallel with the lake shore. In the Illinois portion three ridges are developed in Lake and northern Cook County, but in Lake County, Indiana, at the head of the lake, these ridges are wanting. On the southeast border of the lake two of them reap- pear and a third one sets in north of the mouth of the Kalamazoo River. Though usually distinct, the ridges are in places coalesced, as described below. The gap at the head of the lake is so wide that strict correlation between each ridge on opposite sides of the gap can scarcely be made, but there is little room for questioning the interpretation that the ridges on the southeast border belong to the same morainic system as those on the west side of the lake. They not only have the same position with reference to the Valparaiso morainic system, but also are strikingly similar in topography and structure. It is found convenient to take up the discussion of the ridges of each district separately. Those west of the lake, in Lake and Cook coun- ties, Illinois, are first discussed, and then those on the southeast border. TILL RIDGES OF LAKE AND COOK COUNTIES, ILLINOIS. THE OUTER OR WEST RIDGE. The outer or west ridge enters Illinois from Wisconsin on the west side of the Des Plaines River, its outer border being for a few miles followed by Mill Creek, while its inner extends to the west bluff of the Des Plaines River. Just below Gurnee the river passes through a gap in the ridge, and for several miles south follows closely the outer border. The river then bears away a short distance, and the outer border of the ridge for the remainder of its course lies a mile or more east of the stream. In Lake County the ridge is sufficiently prominent and bulky to constitute a marked feature, and has a general width of about 2 miles. In the south part of the county it sends out a weak spur to join the middle ridge near Deerfield, while the main ridge continues south into Cook County, gradually decreas- ing in strength and dying out in a plain near Mont Clare, in the southwest- ern part of Jefferson Township (T. 40, R. 12 E.). For 5 or 6 miles north from its southern terminus it rises scarcely 10 feet above the bordering THE LAKE-BORDER MORAINIC SYSTEM. 381 plains, and is distinguishable from them mainly in being more undulatory. Where well developed, as in northern Lake County, the moraine has numer- ous knolls, 20 to 25 feet in height, and these stand upon a basement ridge whose relief is nearly 25 feet. A noticeable feature of this and also of the other ridges of this system is the difference in the breadth of the outer and inner slopes, the usual breadth of the outer slope being scarcely one-half that of the inner. THE MIDDLE RIDGE. As already noted, this ridge is joined to a spur from the west ridge south from Deerfield. The combined belt finds its southern terminus near the head of the Chicago River and at the border of the Glacial Lake Chicago. A possible continuation southward is discussed below. The course of the belt is south to north, through Northfield Township, Cook County. Upon entering Lake County it becomes distinct from the spur and remains a distinct ridge for a distance of 15 miles. It there, in sec. 18, Waukegan Township (T. 46, R. 12 E.), becomes united with the east ridge and remains united with it as far north as it has been examined. On each side of this ridge there is a narrow sag or slough. ‘The sag on, the east is marshy its entire length from Winnetka, in Cook County, northward to the latitude of Waukegan, a distance of nearly 20 miles. For a couple of miles at its southern end it has a width of one-half mile or more, but the usual width is only one-fourth mile. The sag on the western or outer border contains a marsh from Rondout Station southward to the Lake and Cook County _ line, a distance of about 9 miles. . This ridge, like the west ridge, has low knolls along its crest, 8 to 15 feet in height, but the coalesced ridge in northern Cook County is more billowy and.carries knolls 20 feet or more in height. There are basins and winding sloughs among the knolls, which add to the morainie expression. THE EAST RIDGE. The southern terminus of the east ridge is at Winnetka, where Lake Michigan cuts it off. It has apparently had its entire east slope and a portion of the crest removed by the lake, there being a descent immediately from the bluff on the lake to the slough, which lies west of the ridge. Following the ridge north to-Highland Park the crest and east slope appear. 382 THE ILLINOIS GLACIAL LOBE. Continuing north to Lake Forest, a narrow till plain appears on the east of the ridge, the inner border of the ridge lying back a half mile or more from the lake front. Still farther north, at Waukegan, the inner border lies back about 2 miles from the lake front. The usual width of this ridge is about 1 mile. The crest of the ridge usually stands 110 to 125 feet above the lake. At Winnetka, the higher portion being removed, it rises but 80 feet above the lake. The till plain east of the ridge stands 75 feet or more above the lake. In this connection it may be remarked that the rate at which the lake bluff is being encroached upon by wave action has become a matter of much concern to the residents. It is estimated by early settlers that from Waukegan to Evanston there has been, during the thirty years from 1860 to 1890, a strip about 150 feet in width undermined and carried into the lake. This amounts to about 500 acres, representing, at present valuation, nearly $1,000,000 worth of property. PROBABLE CONTINUATIONS. None of these ridges have been found to have connection at their southern end with the massive Valparaiso morainic system, nor do they admit of continuous tracing around the southern end of the lake within (north of) that moraine. The weak development in that district seems the more remarkable since there is on the east side of Lake Michigan, north- ward from Porter County, Indiana, a series of ridges of similar size and complexity to that under discussion and which are probably its continua- tion. The conditions which affected the southern end of the ice lobe at the time these belts were forming are so poorly known that it may be difficult to ascertain what caused this wide gap. The question naturally arises whether the expanded lake and its old outlet may not have removed the ridges. In the case of the western ridge this suggestion seems inapplicable, since the terminus at Mont Clare is outside the well-defined beaches and above their level. The ice sheet here, however, may have terminated in water held between its front and the inner slope of the Valparaiso morainic system in the brief period required for the cutting down of the outlet to the level of the upper beach. But in that case, while wave action may have removed weak morainic features, it seems scarcely probable that there could THE LAKE-BORDER MORAINIC SYSTEM. 383 have been a complete obliteration of so strong a belt as is present in districts to the north. In the case of Middle and East ridges, as shown below, there may have been some erosion by the lake outlet and lake waves. Middle Ridge has its southern terminus as a well-defined ridge at the point where it meets the upper or Glenwood beach of Lake Chicago There is, however, near the southwestern limit of the city of Chicago, a till ridge known as “Blue Island,” and connected with it a bowlder belt, each of which may be correlatives of this morainic ridge. This ridge leads north to south for a distance of about 6 miles along the line of Calumet and Worth townships, and Blue Island village is situated at its southern end. At that end the ridge stands about 60 feet above Lake Michigan, but rises northward to an altitude 85 or 90 feet above the lake. Its width, including the slopes, is only about 1 mile. The northern portion is gently undulating and is strewn with bowlders, but the remainder of the ridge is smooth and comparatively free from surface bowlders. Around this ridge there are shore marks in the form of eroded banks and gravelly beaches at an alti- tude 55 to 60 feet above the present lake level. On its west border sand from the old lake shore is drifted into dunes that extend nearly to the top of the ridge. Blue Island Ridge owes its elevation to a thickening of the drift deposits and not to a rock nucleus, for the rock surface is as low beneath it as on border plains. A well at Morgan Park, near the crest, reaches a level 70 feet below the base of the ridge before entering limestone. A train of bowlders is traceable north from the north end of “Blue Island” through the western part of the city of Chicago to the Vicinity of the Chicago River in Jefferson Township. Although portions of the line fall within a part of the city where dwellings are numerous, the bowlders still remain in sufficient numbers to be a noticeable feature. In the thinly settled part of the city from South Lynne southward to Blue Island they remain in about their natural abundance. The belt occupied by the bowl- ders is a mile or more in width. There appear to have been several hundred surface bowlders to the square mile along this line, while on bordering dis- tricts there are estimated to have been scarcely 100 to the square mile. From the north end of this bowldery tract to the south end of Middle Ridge the interval is but a few miles, and is mainly covered by deposits of lake sand and gravel which would obscure any bowlder connection 384 -THE ILLINOIS GLACIAL LOBE. which may have existed. There seems, therefore, nothing to oppose the correlation of the bowlder train and Blue Island Ridge with Middle Ridge. From the south end of Blue Island Ridge to the till ridges in Porter County, Indiana, no line of bowlders or indication of the position of the ice margin has been found. Such features as bowlders may, however, be concealed in much of that district by the heavy deposits of lake sand. East Ridge apparently had some continuation southward beneath the present lake. Prof. L. E. Cooley, of the Chicago Drainage Commission, states’ that in a series of dredgings in the south end of the lake, made a few years since, under his direction, a bowldery belt was traced for several miles southeastward from Winnetka, the present terminus of East Ridge. This bowldery belt is probably a residue from a ridge of till which has been cut away by the lake. RELIEF. West Ridge rises with a somewhat abrupt slope about 25 feet above the plain along the Des Plaines River. On the inner (eastern) side there is a gradual descent of about 40 feet to the plain along the Chicago River, and of 20 to 25 feet to the marshy plain in Lake County. Middle Ridge has a relief of 20 to 25 feet above the marshy plain on its outer border, and a gradual slope of 25 to 40 feet to the sag or slough, which lies on its inner border. East Ridge has a relief of 20 feet in northern Lake County and 35 to - 40 feet in southern Lake and northern Cook counties above the sag on its outer border. The reliefs of all these ridges are lessened at the northern end because of increase of elevation in the sags or plains which separate them. The ridges each maintain a nearly uniform height of about 100 feet above Lake Michigan throughout their course in Illinois. THICKNESS OF DRIFT. In numerous borings, 75 to 100 feet in depth, no rock is struck and no outcrops of rock occur along this portion of the lake shore. The drift beneath the level of the base of these moraines was probably deposited by earlier ice advances. The following list of borings which have struck rock indicates that in several places at least the rock surface lies much below the surface of Lake Michigan. 1 Communication to the writer. THE LAKE-BORDER MORAINIC SYSTEM. 385 At Senator C. B. Farwell’s artesian well, in Lake Forest, rock is struck at 160 feet. The well mouth is 40 to 45 feet below the crest of East Ridge at Lake Forest and about 75 feet above Lake Michigan. At Highland Park rock is struck at 160 to 175 feet. The elevation above the lake is 100 to 115 feet. At Lloyd’s artesian well, in the north part of Winnetka, rock is struck at 150 feet. The well mouth is by surveyors’ level 78 feet above Lake Michigan. At Ravenna a well strikes rock at 164 feet. The surface level has not been accurately determined, but it is probably about 100 feet above Lake Michigan. Near Schermerville rock is struck at 147 feet. The surface elevation does not exceed 100 feet above Lake Michigan. On the crest of West Ridge, in sec. 14, Maine Township (T. 41, R. 12 E.), rock is struck at 110 feet. The elevation is probably about the same amount above the lake. STRUCTURE OF THE DRIFT. Along the lake shore the bluffs from Winnetka to the vicinity of Wau- kegan rise abruptly 75 to 90 feet and present many good exposures of the drift to this depth. There is at the surface a pebbly yellow clay 8 to 13 feet in depth, which is similar to that in the other moraines. Beneath this clay is a grayish blue till containing occasional sand pockets saturated with water. These, however, form but a small part of the drift. The bulk of the bluff is a compact till, but moderately pebbly and exposing only an occasional embedded bowlder. . It was noted that the pebbles and bowlders are usually striated. Neither East Ridge nor West Ridge nor the northern portion of Mid- dle Ridge has gravelly knolls of any consequence, but the southern portion of Middle Ridge, lying in Cook County, has many such knolls. Indeed, nearly every prominent knoll contains gravel. It seldom exceeds 15 feet in depth and appears to be confined to the knolls, for they are situated on a basement ridge of till similar to the till exposed along the lake bluff. But one complete reliable section of the drift could be obtained, which, though valuable, needs to be supplemented by other records to furnish a MON XXXVIII 25 386 THE ILLINOIS GLACIAL LOBE. satisfactory knowledge of the lower portion of the drift. The well is located at Ravinia. Its section was furnished by the driller, William McWendle, of Oak Glen. Section at Ravinia, Lake County, Illinois. Feet 1S ECON hy SC) AO Et Oe Sens Goaere Oa SaHe osoe ose Sas oee DEERE seEes HES SE eaedes cocharcecasogsob 11 25 (CRE EO POO Ky; OP Nps oe Josodsccacan SccbcesouEco Hoon ousceE HaenencapcoassHanao coesscenes 60 Sh (EneA OER G VOAT PIR a sabe mob eeens oooh +o 5b ones ndbebn SqHebesuebos BasunS mEE eso eeeciccoscos 10-12 4, Grayish-blue pebbly clay, lighter color than No. 2...-.....-.-.-.----.----.---------------- 70 Be CHENG TEST OIE: TAUINT 6 soSenn cbeo caossencao cone qubo04 SeHn e406 eAcossenecu enombetbedccon cea6 4-5 (Ry OLRNERIO NW nondabosans CoS cErssoSCD BE RHaa coSb.Connedsoccs5 SaocoMSoroSE a SReooneooss cosacdaceaad 22° ANDY GWOT oes Soo SSodeses cate scobbo eeee 2adse4 ssen bons cdoo cHageaeaSSOS cHeOSsoSess o4esDS 164 TILL RIDGES ON THE SOUTHEAST BORDER OF LAKE MICHIGAN. THE OUTER RIDGE, The outer ridge is distinctly traceable only from the vicinity of Benton Harbor, Michigan, to Wheeler, in Porter County, Indiana. It is closely associated with the Valparaiso morainic system for a few miles north from Benton Harbor, but a ridge supposed to be its continuation is found west of the “ Pine Plains” in Geneva Township, Van Buren County, and Casco Township, Allegan County. Farther north it has not been recognized and may be combined with Covert Ridge. It is separated usually from the inner border of the Valparaiso system by a narrow plain averaging scarcely more than 2 miles in width and nowhere exceeding 5 miles. From the point of connection with the Valparaiso system, east of Benton Harbor, in Berrien County, Michigan, southwestward to the St. Joseph River, a distance of 4 or 5 miles, there is only a vaguely defined morainic belt. But immediately south of St. Joseph River, about 3 miles south of Benton Harbor, a definite ridge sets in, which leads southward along the east side of the Vandalia Railway to within a mile of Baroda. A gap about a mile in width here occurs, through which Hickory Creek finds a passage and which is also utilized by the railway. The ridge sets in on the west side of the ereek, in sec. 10, T. 6 S., R. 19 W., and leads in a slightly winding course west of south to New Troy. At this village a narrow gap occurs, through which the North Galien River has a passage. From the south bluff of this stream the ridge leads southwestward past Three Oaks and comes to South Galien River about a mile north of the THE LAKE-BORDER MORAINIC SYSTEM. 387 State lme. But here there is a very narrow gap and the ridge continues in a southwestward course across northwestern Laporte County, Indiana. The ridge is very weak for a mile or more about 5 miles southwest from where it crosses the State line, and there is a narrow gap at Trail Creek. From Trail Creek westward to the vicinity of Furness, in Porter County, a distance of about 12 miles, the ridge is double and the members are separated by a marsh a mile or less in width. From Furness westward to Bailey the ridge presents but a single crest. Near Bailey a belt of promi- nent dunes which border the shore of Lake Michigan spreads out to the south in such a way as to make it difficult to trace the low till ridge. It seems probable, however, that the till ridge continues but little beyond Bailey, for no evidence of its presence could be found in railway cuttings, which are quite numerous in the midst of the belt of dunes. A possible continuation of this ridge is found toward the south in a narrow till ridge which leads southward from a point near Chrisman to the Valparaiso morainic system at Wheeler. This would involve an abrupt southward turn in the ice margin and bring it to the inner border of the Valparaiso morainic system. In Lake County, Indiana, no sharply outlined till ridge has been found, but a low ridge with undulatory surface leads westward from Deep River at Hobart along the north side of Turkey Creek, a distance of about 5 miles. It is separated from the inner border of the Valparaiso morainic system only by a narrow plain, scarcely a mile in average width. Possibly this marks the continuation of the ridge under discussion. The system of ridges is as obscure in western Porter and Lake counties, Indiana, as in southern Cook County, Illinois. It, therefore, is no easy matter to decide upon the posi- tion of the ice margin in these counties at the time the outer ridge was in process of formation in counties to the east. This till ridge governs drainage to a marked degree. In the Indiana portion South Galien River, East and West Trail creeks, and Calumet River all have their courses toward Lake Michigan checked and courses parallel with the lake produced by its presence. In Michigan the north flowing por- tion of North Galien River is, for several miles, parallel to the outer border of the ridge. The relief of the ridge scarcely reaches 50 feet where sharp- est, and is usually but 20 or 30 feet. The plain outside rises from the border of the ridge toward the Valparaiso moraine, thus leaving along the outer 388 THE ILLINOIS GLACIAL LOBE. border of the ridge under discussion a valley-like depression which forms a natural line for drainage between the gaps through which the streams pass The width of this ridge averages scarcely 1 mile and in places is but one-half mile. It has usually an abrupt outer border and a more gradual slope on the inner border. This feature is maintained where the ridge has a double crest, as well as where it is single. Although the ridge usually presents a well-defined crest, it is seldom sharply morainie. Indeed, the surface is nearly as smooth as on portions of the bordering plains. The highest knolls scarcely exceed 15 feet, and the majority are but 5 to 10 feet in height. For a few miles near the State line the crest is sharp. It is also sharp in Porter County, Indiana, west from Furness. Usually it is nearly as smooth as the slopes. COVERT RIDGE. Covert Ridge receives its name from the village of Covert, in western Van Buren County, Michigan, which stands on its crest. It lies between the ridge just discussed and the shore of Lake Michigan, and is usually but 1 to 4 miles back from the shore of the lake. In places it comes to the lake and has been partially eroded by the lake waves, as indicated below. Covert Ridge connects at the north with the Valparaiso morainic sys- tem, its point of connection being in Overisel Township, in northern Allegan County. It has, however, been traced a few miles farther north, along the inner border of the Valparaiso system, in Zeeland and Jamestown town- ships, Ottawa County, where its topography and structure distinguish it from the bordering Valparaiso moraine. No attempt has been made to trace it farther north. From Overisel Township it leads southwestward through the village of East Saugatuck to the Kalamazoo River, at New Richmond. The river makes only a narrow break scarcely more than a half mile in width, and the ridge continues southwestward coming to the shore of Lake Michigan, near the line of Ganges and Casco townships, Allegan County, exactly opposite the State line of Wisconsin and Illinois. In the middle part of the west boundary of Casco Township the lake has cut away nearly all of the ridge, leaving only a strip about one-fourth mile wide, belonging to its east slope. From this point the ridge bears nearly due south while the lake border. bears west of south, and at South Haven its inner border is nearly a mile east of the lake. It continues south nearly THE LAKE-BORDER MORAINIO SYSTEM. 389 to Covert and reaches a distance of 4 miles from the lake just north of that village. Its course then changes to southwest and the ridge comes to the lake border near the middle of the west line of Hagar Township, Berrien County (T. 3.S., R.18 W.). From this point it follows the bluff of the lake closely to the mouth of the St. Joseph River, where it is interrupted for about a mile. It sets in, however, in the city of St. Joseph and follows the shore of the lake southward for about 8 miles to the vicinity of Stevens- ville. It here bears inland, passing east of Bridgman and Sawyer, but returns to the lake shore again at Union Pier, and is nearly removed by the lake just below that point. The Galien River Valley interrupts the ridge for a space of about a mile, but the ridge reappears on its south bluff in sec. 36, 1. 78., R. 21 W., and from this point is continuously developed as far south as the State line. About a mile south of the State line it becomes vague and is represented only by occasional slight ridging. It is traceable, however, as far southwest as the valley of Trail Creek in sec. 26, T. 38, h. 4 W., about 4 miles east of Michigan City, Indiana. Possibly it finds its continuation westward in the inner member of the double ridge which leads from Trail Creek Valley to Furness, Porter County, Indiana, though it seems quite as probable that it had its continuation nearer the lake shore, and has been either removed by lake waves or concealed by the dunes, there being beach lines closely associated with its western end in the vicinity of the valley of Trail Creek. Throughout its entire length of about 80 miles this ridge maintains a nearly uniform width of about 1 mile, the only notable exception being a strip a few miles in length in western Allegan County, where it reaches a width of 2 or 3 miles. Like the outer ridge it presents usually a more abrupt slope on its eastern or outer border than on its inner border. The surface of this ridge, like the outer ridge, carries only gentle swells and shallow saucer-like depressions except at the north where it assumes a sharper morainic expression. The change in expression sets in abruptly in northeastern Ganges Township, Allegan County, in the vicinity of Hutchinson Lake. From this point northeastward knolls 15 or 26 feet in height are common and occasionally knolls reach a height of 40 feet. There are also deep basins, the most conspicuous of which is the one occupied by Hutchinson Lake, which has an area of nearly a square mile and is bordered by knolls and ridges rising 40 or 50 feet above its surface. 390 THE ILLINOIS GLACIAL LOBE. From East Saugatuck northeastward the surface is billowy without well- defined basins, and this topography is maintained for some distance beyond the point of connection with the Valparaiso morainic system, as far as the examinations have been carried. This ridge, like the outer ridge, has had considerable influence on the course of drainage. The north branch of Black River follows nearly its outer border from Hutchinson Lake southward to the vicinity of South Haven, while the south branch follows nearly the outer border from Covert northward to the same point, and the united streams there pass westward through a gap in the ridge to the lake. Pawpaw River follows the outer border of the ridge for about 8 miles in its lower course. Hickory Creek flows northward along its outer border for about 6 miles before entering the St. Joseph River. North Galien River follows the outer border for about 8 miles below the village of New Troy, where it is jomed by South Galien, and the united stream passes westward through a gap in the ridge. ZEELAND RIDGE. During the summer of 1897 the writer discovered a till ridge in north- western Allegan and southern Ottawa counties, Michigan, which lies west of Covert Ridge and which extends no farther south than the vicinity of the mouth of the Kalamazoo River, its further continuation having been cut away by Lake Michigan. This ridge is well developed immediately northeast of the village of Zeeland and it seems appropriate to apply to it the name Zeeland. The portion south of Holland, however, has been known by the residents as “May Hill.” The writer has examined it only from the meridian of Holland northeastward to Grand River, north of Hudsonville, Ottawa County, a distance of about 20 miles. The ridge stands 100 to 120 feet above Lake Michigan, where best developed, and has a width of scarcely 1 mile. It is interrupted by occa- sional gaps, the most notable being the one through which Black River passes, south of Zeeland, which is about 15 miles in width.’ From a point north of Vriesland northeastward to Grand River it lies along the west border of a large abandoned valley, and appears to have been partially ‘This Black River should be distinguished from a stream of the same name entering Lake Michigan at South Haven. THE LAKE-BORDER MORAINIC SYSTEM. 391 removed by the stream which formed the valley. The same stream also passed through the gap south of Zeeland and perhaps has widened that gap. This ridge, like Covert Ridge, is composed of a clayey till strikingly in contrast with the more porous till of the Valparaiso system. It is com- monly spoken of as a ‘‘clay ridge,” and it forms the southeast border of an extensive sand-covered plain, with which it is in sharp contrast. The ridge carries only gentle swells 5 to 15 feet in height, but its relief above the lower tracts on either side is sufficient to make it a prominent feature. It rises about 30 feet above the general level of the sand-covered districts which border it on the west and about an equal amount above a narrow plain on the east which separates it from Covert Ridge. The extent of this ridge toward the north remains to be determined, as no investigation has been made north of Grand River. An inspection of railway profiles suggests that its course may be directly north, past Coopers- ville into the southeast part of Muskegon County. The relation of this ridge to certain sand deposits found on its eastern border is discussed on a later page. RELIEF. The outer ridge and Covert Ridge each show slight relief above the districts on their outer border. The greatest relief scarcely exceeds 50 feet and the usual relief is but 25 or 30 feet. The abruptness of the outer slope, however, in each of the ridges renders this slight relief a somewhat conspicuous feature, and the ridges may be seen distinctly for a distance of several miles when viewed from their outer border. On the inner border the descent is gradual from the crest of each ridge, usually amounting to but 20 or 30 feet per mile. RANGE IN ALTITUDE, Each of the ridges show comparatively slight range in altitude. The lowest parts are nearly 75 feet above Lake Michigan and the highest scarcely 150 feet. Throughout much of its course each ridge stands about 100 feet above the lake. The crests of the ridges are usually but 40 or 50 feet above the level of the highest beach of Lake Chicago, and in places they come down nearly to the level of the beach. The plains bordering the ridges were quite extensively submerged by the lake or stood so little above the lake level as to be poorly drained until the lake level had been lowered. 392 THE ILLINOIS GLACIAL LOBE. THICKNESS OF DRIFIY. These ridges occupy a region in which the drift deposits are very thick, but it is probable that the drift deposited at the time of their forma- tion is mainly confined to the ridges, with only a thin sheet on the plain which separates them and the plain between the Covert Ridge and the lake. The relief of the ridges probably represents approximately the thickness of the drift deposited at this stage. The following list of borings which have struck rock indicate that throughout much of this district the rock surface lies considerably below the surface of Lake Michigan: At Hammond, in Lake County, Indiana, the distillery well penetrated 110 feet of drift, reaching a level 95 feet below the surface of Lake Michigan before entering rock. At Owen’s brick yards, in Hobart, Indiana, rock was entered at 150 feet, at a level 100 feet below the surface of Lake Michigan. The Blair artesian well, in the northeast part of Porter County, entered rock at 240 feet, at a level 220 feet below the surface of Lake Michigan. At the northern Indiana penitentiary, near Michigan City, Indiana, rock was entered at 172 feet, at a level 156 feet below Lake Michigan. A gas boring in Michigan City reached a level 230 feet below the lake before entering rock. At New Buftalo, Michigan, a boring penetrated 212 feet of drift, enter- ing rock at 192 feet below the level of Lake Michigan.’ At New Troy, Michigan, a well is reported to have struck rock at only 65 feet, or at a level but 20 feet below Lake Michigan. A well near New Troy, in sec. 30, T. 7 8., R. 19 W., is reported to have entered shale at a depth of 90 feet and a level about 20 feet below the lake. At Sawyer Station, Michigan, Mr. Rough sunk a well which entered rock at a depth of 123 feet and a level 56 feet below Lake Michigan. At Bridgman, Michigan, a well at the box factory entered rock at 140 feet, at a level 78 feet below Lake Michigan. At the basket factory in St. Joseph, Michigan, rock is entered at about 123 feet below Lake Michigan and at a similar level in a well at the Park Hotel. The gas well at Benton Harbor entered rock at 124 feet below the level of the lake. ‘Geol. of Indiana, 1873, p. 431. THE LAKE-BORDER MORAINIC SYSTEM. 393 At South Haven, Michigan, a well at the basket factory entered rock at 105 feet below lake level. A well on the farm of J. Irving Pearce, a few miles southeast of South Haven (in sec. 31, T. 1 S., R.16 W.), entered rock at 130 feet below lake level. A well on the farm of W. F. Conner, in sec. 84, T.28., R. 17 W., reached a depth of 220 feet and a level 125 feet below Lake Michigan without entering rock. A well in the southeast part of T. 1 N., R. 17 W., 157 feet in depth, reached a level nearly 100 feet below Lake Michigan without entering rock. Another well in sec. 29, T. 1 N., R. 16 W . 140 feet in depth, reached a level fully 100 feet below the lake without entering rock, At D. Kitchen’s, in sec. 16, T. 2 N., R. 16 W., a well reached a depth of 275 feet and a level 165 feet below Lake Michigan without entering rock. A well 13 miles southeast of Pier Cove, Michigan, 142 feet in depth, reached a level about 75 feet below the lake without entering rock. STRUCTURE OF THE DRIFT. At many points on each of these ridges there is a thin coating of sand. It is usually drifted into low knolls and ridges, and was apparently deposited in large part by wind. Where these sand deposits are 8 or 10 feet in depth wells along the ridges often pass into a blue till at the base of the sand, but where the sand deposits are thin or absent a yellow till several feet in depth occurs at the top of the blue till. In several sections, as shown below, the yellow till was found to have a thickness of but 3 or 4 feet. The usual thickness, however, is nearly twice that amount, and in places is not less than 20 feet. The ridge on the north side of the Calumet River, in Porter County, Indiana, furnishes several well sections in which the thickness of the yellow till is 15 or 20 feet. The body of the ridges seems to be com- posed of blue till having a large clayey constituent, and on the whole more compact than the blue till found in the Valparaiso morainic system. The till also is less stony as a rule than typical till. This till is occasionally replaced by sand or gravel, and it generally contains pockets and thin beds of sand and gravel of sufficient extent and at convenient depths to supply the shallow wells. There are places where a nearly pebbleless laminated clay replaces the till. Bowlders are found in moderate number along each of the ridges. They consist largely of granite rocks, though there are many other classes of rocks present. As is usual in the moraines of this region, the surface 394 THE ILLINOIS GLACIAL LOBE, bowlders are composed very largely of pre-Cambrian crystalline rocks of Canadian derivation, rocks from the Paleozoic formations being compara- tively rare. But the till contains a large number of local rocks, and its rock constituents vary from place to place, following in a general way the changes in the underlying rock formations. Large bowlders of sandstone were found on Covert Ridge in western Allegan County similar to those ‘noted on the Valparaiso moraine in Allegan and Van Buren counties. A bowlder of red jaspery conglomerate, apparently from the Huronian out- crops north of Georgian Bay, was found on the Covert Ridge, a short distance northeast of East Saugatuck. The ice movement which formed the ridge can scarcely be supposed to have brought the bowlder from the parent ledge, for the line of axial movement was southward through the Lake Michigan Basin, and the radial movement was southeastward toward this ridge. The presence of this bowlder is probably to be accounted for through an earlier ice movement which crossed Michigan and the Lake Michigan Basin in a southwestward course, strewing bowlders along its path to be taken up by the later movements and redeposited in the later till sheets. An excellent section of the structure of Covert Ridge is found on the shore of Lake Michigan a few miles north of New Buffalo, in sec. 25, T.75S., R.21 W. The lake bluff here is about 95 feet in height. At the surface there is a coating of sand in places 6 or 8 feet in depth, but in other places only a few inches. Beneath it there is a brownish-yellow till which graduates into blue-gray till within 8 or 10 feet of the surface. For a depth of about 60 feet the till shows distinct lamination and has thin part- ings of sand and laminated clay. Below this depth it is somewhat harder and the lamination is very imperfect. It is probable that the lower 30 feet of the exposure is independent of the upper 60 feet. The latter alone appears to be referable to the stage of glaciation at which the ridges under discussion were formed. About one-half mile southwest from the point just deseribed the lake bluff presents the following series: Section of Covert Ridge, near New Buffalo, Michigan. Feet Beach gravels..---.------------------ ---------- 22 teen reece tees Gg cadads bosasbodesos dens aésqcn 8 Brown laminated clay, slightly pebbly, with thin partings of sand .......---.---.--------.----- 14 Blue laminated clay, slightly pebbly, with thin partings of sand -...--.---------.-------------- 14 Coarse water-bearing sand .-.--..- 2-5. .- 222-22 222 eee en nnn se ee sens wens ee ns aa 2 Blue-gray till, very stony, interbedded with thin layers of sand in horizontal beds, extending down beneath the level of the Jake, exposed....-.-..-..-----. ---- .----- +--+ + += ene wee ee 30 el THE LAKE-BORDER MORAINIC SYSTEM. 395 It is probable that the upper 25 feet of this section is a deposit made in water, and possibly also the lower portion was deposited under similar conditions. As a talus obscures the lower portion of the bluff in places between these two sections, the exact equivalency of the beds at the base of the sections can not be established. North of St. Joseph there are exposures along the shore of the lake in which large masses of cemented gravel and sand are interbedded with the blue till. This is apparently a local feature. The till here, as in the exposures near New Buffalo, shows traces of lamination and is scarcely so pebbly as typical till. An exposure west of Hagar Station, at a point where the lake bluff is cut back nearly to the crest of Covert Ridge, shows the following series of beds: Section near Hagar, Berrien County, Michigan. Feet. Sand wvanyinestromya tewsnchesito several feeb ao. (= -c\acecis ol riaalsseelaae see et aeieeie eels eeiae ee 1-8 Mellowatill munielestamheresande sunita meron eaeee esas s sae cere eee eee eee eee 1-5 JBI) aS eV AVGLAY GUO aces a5 ccqo Ses Hine o TESS OBA SOEs te OSS Cas Se SE Eee aacH scan ect eoSodeecee ars 30 Sand, variable in coarseness, with thin clay beds...-....---...-._.------ Sera ee aia rs rs ie 20 IBMO-peay wil, CheakiS GWOWhy coocaadodoncon coda paadee sabe sucacuasdnes cfudce oSsab uaos besa oSdo neds SuaE 50 {OVEN co Sbon cass Good esas ohoddy caUcoUSHos ad Gabe oan eal BbosE RE Bouud aoneoueT ascocueHScdauene 110 An exposure in sec. 18, T. 2 N., R. 17 W., shows a laminated clay at the base of the surface sand which may be referable to the glacial lake, though it seems more probable that it was deposited beneath the ice sheet. The section of the lake bluff is as follows: Section of bluff of Lake Michigan in sec. 18, T. 2 N., R. 17 W. Feet RING eea toda hébaaSor tose Soo SE SASH BUH Eerie eA eMN IEP CEyR ese SS Al Cg eSilc rr i Te est a re a ape 4-8 Maminabedssrayeclayssliohithyan eb blivge see ace teete eee ae ee ie eee ee ae ee Se een 12 staing! anal arrmnyGll caso. coed 6008 boo cdse HESS SUB OBESE ad aH Subd Saau sboatadededcescnaded oses GSS MeCD BO na Bltre-sravavill qui verstOnyy reece cuetesec cc sie lela = os See eee elec emer eee ee eee ee cee ee 15 MO Gallet setae ects stereafa teats saers esas alta Se carol Sri ayucr a atetap eet pay tare Ge ee eves near aE Ny 36 Several sections of wells were obtained in each of the counties traversed by these ridges, which throw light upon the structure of the drift to con- siderable depth. In a few cases the entire drift series has been pene- trated. In presenting these well sections the discussion begins in Porter County, Indiana, and counties are taken up in succession toward the northeast. 396 THE ILLINOIS GLACIAL LOBE. A boring on the till ridge north of Wheeler, on the farm of Josephus Wolf, 157 feet in depth, has the following section: Section of ridge north of Wheeler, Indiana. Feet Soa yvonne saSdes code sone todsa0 eSobor hese Sebo one ceceens Sse cod boomonsdHotes senses 15 Blue clay, slightly pebbly, with occasional thin sand beds ...--..-..-.--....-. -.......---------- 140 (CXR Wel oo sh6e gooscbe boebae Doe eseooeSes aSeus seacns Sah chee So cased cdeeeb cote scechdcenestes 2 Another boring on the same farm reached a depth of 200 feet without obtaining water or entering the rock. Usually wells in that vicinity must penetrate about 90 feet of compact clay before entering a water-bearing bed, but in a few places sand with water has been found at 30 feet or less. Wells on the till ridge north of the Calumet River, in eastern Porter County, have reached a depth of 150 feet in a few cases without entering rock. One at Bailey, 148 feet in depth, has the following section: Section of well at Bailey, Indiana. Feet Stonyayell owgitillle ere ean einw a ietelnreincieteln clo iets iste ene eee eee ree een eee eee EE ee eee 18 ID ASS ceo SoS SBee SER oca SS Soe eenas BSScesCeSeTe terete eRe neo ocL au eosdnascaausdase cosodeeodd 40 Bluievqaicksam dy) P 252.52 peis a's oss ysis sy Ne Ne chapters est sere ees Span ae Cod tc eco RR Resa 40 LNT ep omeape Gsose one ceea none eneesn bo—5 bao ERE Srecs secnactcos uses Ucenen Seon ucgasanadaceseees 50 JNO GaSe e peGode Daaer Ses Eeee ce sapriScEecone chan cabo chat dcooecan Aobcigulcducsn umouar-cacadssose 148 A well immediately north of Chesterton, 97 feet in depth, has the fol- lowing section: Section of well near Chesterton, Indiana. Feet Snore culos il eee aed cose sooe Uae ou sosh eenone Ba SaSp Caub esos Hddabs dduaconocea: ssoosneadaesesed 20 Sottiblueiclay, withifew pebbles) soc. c ce aeleec epee see ere ate ae ore ce ae ee eee 50 ID RARER NG oe ao bas otkcs Sete Soe RU ee COeOrrse hee HEOE bane neSagonoon MaLnas Seanad ocucce boda. casdaacosaut 15 Sand andvoravel) witht waren, cute) o cs ee ret cre ee one hayes a eres a 12 Motalesons-sSoaeeeele Gale and ss Sed arse Dale Sis slscie See ey Se ates Sea eee 97 On the same ridge, a mile farther east, the series is still more variable, -as follows: . Section of ridge north of the Calumet River, near Chesterton. Fest. Sue aay Clon m0 USS eo oe amec tobe CoCoEo Made GacEMomesda Soc occ uonocs Gace souasoaoUd dosceanscabeoane 20 Soft;bluevelay; with few spebbles.sss208 ee Lee clad cece Se eee tere ere eats a oem ee a ae 40 I SEG eS CS EOE A AECH OS Ee SeeCIIes ann rE tnt Oren ta emer Son oe Sn Re deo sony ocedaeseEECoSesenenase 12 lee yt iG ull So becosbogorae Oboe EeeDeS GooaoneEod Sears Obosedecbedo rasa seoshe codccec Gens apobes 5 Sandsandvorawel mwithiwateressa. nem chsa = stele se aire Ghee Sse eee alee tesa teat os et 11 GT Ee cea ASPET AR GOOD OACORO COO SEEM SS ACRE ene hemes mmnecaca ddac Sosa anoeso ates a costasos 88 Near the Ime of Porter and Laporte counties the wells penetrate only 3 to 5 feet of yellow till, beneath which is a soft blue clay, with few peb- THE LAKE-BORDER MORAINIC SYSTEM. 397 bles, which extends to a depth of about 50 feet, where water-bearing sand is entered. At the Blair artesian well, in the northeast corner of Porter County, 240 feet of drift was penetrated if the surface sand be included. The well is located on low ground near the lake, only 15 or 20 feet above the lake level. The rock surface is, therefore, nearly 225 feet below the lake level. The following notes concerning the well were furnished by Mr. John Orr, of Michigan City: Section of Blair artesian well in Porter County, Indiana, Feet. iy, Rretyes same). s 354 poooeseedade Sooboo Gocco s@odcd™ Besd dedood cson S69. c500 DoSccu cHoaoseEom obomod 18 2. Alternate layers of peaty blue clay and fine sand .----..-.--..------.------------------------- 12 3. Soft blue clay, slightly pebbly, with thin beds of gravel included....-.---..----.------------ 55 4. Water-bearing: gravel bed-.-----------.---- 5 20s 222-8 one i on ne ene ee wenn oo == 2 &, TMM GMGledosseoudeds dagscasesedscode co duSu ceSoEp coguds cobSao ED ecu Scseos dodubs sonsbgosmmcoe 5 B \Wiveuiere nema eatehyGlls so costed edegos caeibob Beebe seeeo™ GSeeho bacco coeesa cpempeoEeosooOI0 5 2 7. Blue clay harder than “No.3,” apparently a typical till .......-.--..-----------. ------------ 106 S. WRU DeRling: rel so sess ooas6u Coenen bepees codes Sbauce USdeSe Seeocs asoGce paces oseasAtenos 5 9. Blue clay alternating with beds of fine sand..---....-...------------------++---------+------- 35 Oy, Genin ley ee are eG) Soo ood oobaesooda seouee eo osceba cans apaSorcusccsesé a a Pee ea ee ? I) Gray, limestone .. <2... ===. <2 -2 6 = == on ee ne oe nin nn wn er nnn 180 12. Soft caving rock, probably shale ..-.-..----..----- .----- +--+ +--+ -----+ 02-202 2-2 eee eee 30 1G}, TGR ssac ocgsuscecs ssocKs 605 sede bass co0d SHUR saus Sasnceas sso0 5555 peso sno osnobs copa aces 6 14. Soft caving rock, probably shale ..--..-------.---- +--+ 22-2 2-2 2-22-2222 eee eee cee eee 30 Tl, 1s yea INIGEO NGS S56c dosbas o6H6s Soee paoe dee a oeseic eee eobs Seapicdes Sado eacb.coos eadocioceo oooooS 370 TR, Ilene) Theses Soon cocooses cease Sees uSdens 4a cane seeo bea sans sesasa05 oSenc: HoCaon saess0 SSa0— 2 Motalidepthyc ss. sss essa Souci eSEE ce enacca- 10 (GHG scedos co ouso bogasu noSboe bee eoS cone DOn6en [OKC oO SESsensu 5ueceS SauuSs Seboce coSsenbong Sacg moee 5 Blue clay, slightly pebbly .-.--.----------------------------- +--+ 2 +222 ee reer tere eee 145 Very pebbly blue clay..-...---. ------ -----2 <0 --- eee nn een ne ne ree ne eee eee ene 22 Cobble, bowlders, and gravel..---...---..------ -------+------ +--+ -----+ +--+ ++ eee ee eer eee 15 Gravel and sand with an occasional bowlder .........--..----..----. -----------------------+----- 40 Limestone and shale as in previous section. 398 THE ILLINOIS GLACIAL LOBE. The following section of a well at the northern Indiana penitentiary, near Michigan City, appeared in an early report of the Indiana geological survey. The well mouth is 16 feet above Lake Michigan and the water will rise 22 feet above the surface. The well has an estimated discharge of 300 gallons per minute: Section of well at northern Indiana penitentiary. Feet Sin tosh cons pabosd eegdno deue en aneSsRUESsosecSasesccaoos sS6uas FoOdeDS BE SeES ConceD oobe Sonces acer 48 (CHERY sacode Shcc8d She S5h Shes Sonbss SoaSoo paces) cabotcose sep sesecsdSne stds soos desoecsbesbocsaoes 4 SHG! 35 3555 S550 anSbhe SeSeSc ebecce dou Hoocboseosts Ssoucobn ses5 2aSEn0 Gabbe Sod acbs ossoonesoese 24 THI GER) sss6 sscocG case Socceaasouas pease boSSSdesSsEbce6s Sod dosodsaconss soup ésodoosesun sce 66 Smiles asc Hoo $s bobeetosdone coebee dsecos Sede comands costa ssenes cane Gaus Suse Sasa aotocooeoD cossoe 30 Se ooo Saoksodaseooes GREER ESS FOS OE SeQGaecssods55 uscd nobsbeobEcooESdd adss Scotlbsagbsgag5 76 Woes SHEN UTES N55 55a coos oscosd cons odocos SasbSs SoSs oSdeGe ssa5 Saas so sesso Sea stoo sese 2934 TOU «oak Ss onbb Gennes bocose boeoes Sone ses Shdr asks copposS sscese aoa see Sess cose Sesc]|s 5414 The following section was observed in the bluff of Trail Creek near a mill in sec. 34. T. 38 N., R. 4 W.: Section of bluff of Trail Creek. Feet TeBrownisancd witht hin bedsoLpebb)esiessa see =sen ee =e ee eee eee ene eee eer 6 2. Brown clay, nearly pebbleless, mainly noncalcareous, but with thin calcareous bands.. ---- ---- 3 Gy) LBRO AR SERICL Oooo cena SSONESa een Hoan Seo Rob baSoco bead SSn0 Sanéesor aces Cosas Seco onde obascoeS Sees 1 Ae Brow Cl aye Slimil anole N O.2 eee ees aieene mae eee ete eee eee ee eee ate eere rte eee il ES SiGe Ch sehr cans pesnrebs Gaeta Ba SOEsoS So baaS Sos60e S5ea bbb S SOOSdaDrScLoRcnoesasooehooesee 6 Gebaminatedsblue\clayawith few pebblestes-.-ssese-seee eens eee ee eee ne eee eee eee 10 Total seas es ek che fee es oe ele Uiate eiepar te eels See epee ate eee are ELAS Seles yee setae seit mE On the south border of Berrien County, Michigan, in sec. 19, T. 8 S., R. 20 W., two wells 85 feet in depth are mainly through a soft blue till containing but few pebbles. In that vicinity the blue till is often found within 4 feet of the surface. On the ridge at Three Oaks wells usually penetrate 6 or 8 feet of yellow till before entering the blue. Soft blue till extends to a depth of 70 feet, and there water-bearing sand is usually struck. At New Buttalo, Michigan, the blue till is frequently exposed at depths of but 4 or 5 feet, and the wells in the higher part of the village usually penetrate about 50 feet of blue till before striking a water-bearing bed. On low ground near the shore of the lake flowing wells have been obtained at a depth of about 30 feet. The drift at New Buffalo, as reported in an early 1 Geol. of Indiana, 1873, pp. 470-471. THE LAKE-BORDER MORAINIC SYSTEM. 399 volume of the Indiana Survey, has a depth of 212 feet at the Michigan Central Station, whose altitude is only 20 feet above the lake.! At Sawyer a deep well made by Mr. Rough has the following section: Section at Sawyer, Michigan. Feet. SINC SANE Sood ooge céoe Daag Haag dodS cody sabe soadeS HodtnEOSoEbe dboadbobedeonenssbesancsedesboccos 8 Bluewtillswathtsandsbediatz5jteetiandiat bottomee...-+.c+s5.265 see eeeeeeee eee eee e meee ee ee ne 120 Rocksofabluishicolorsvaryin ginyhandn esses ssc aieilce areca se eee e eee eee eee ee eee 208 AOU CEN cdec cagpea goooenso Gees» - -GRoos SUE Ro eMeEaa nebo CacoLucS aces sass aessab Soacusceue 331 . An exposure in the south bluff of Galien River, at New Troy, where the till ridge is undermined by the stream, shows a slightly pebbly blue clay from the river’s edge up to a height of about 40 feet. Above this clay there is a brown till interbedded with calcareous sand, having a thickness of 12 feet. A well in the village of New Troy may have struck rock at a depth of 65 feet, though the owner of the well thinks that sand and gravel was entered below the supposed rock ledge. In case the latter interpreta- tion is correct the former is probably erroneous. At the point where the Galien River cuts through Covert Ridge, in sec. 2, T. 8 5., R. 20 W., there is sand at the top of the bluff 12 feet in depth, below which is a brown pebbly clay interbedded with sand which is quite calcareous. Both the till and the sand are in beds which are in arch- ing and oblique attitudes. On the north bluff of the river nearly opposite - this point a well 96 feet in depth entered blue till at 2 feet and continued in it to the bottom. At Bridgman a boring 250 feet in depth entered rock at 140 feet, and struck an inflammable gas at about 160 feet which would burn a jet several feet in height. The rock is apparently a shale. The upper 80 feet of the drift is mainly blue till, but the lower 60 feet is gray sand, yielding water. Along the St. Joseph River there are 2xtensive exposures of blue-gray till in the west bluff from St. Joseph southward to the mouth of Hickory Creek, but in the east bluff exposures were found in which there is a blue silt free from pebbles rising to a height of 30 feet or more above the stream. This silt is usually capped with 15 or 20 feet of sandy gravel. A well near the east bluff, 25 miles south of Benton Harbor, reached a depth of 153 feet without entering rock, and is mainly in blue clay; whether silt or till 1Op. cit., p. 431. 400 THE ILLINOIS GLACIAL LOBE. was not ascertained. East from here, in the vicinity of the mouth of Pipe- stone Creek, typical till is found in the east bluff of the river. A well on this bluff, in sec. 1, T.68., R. 18 W., 138 feet in depth, does not reach rock. It penetrated about 30 feet of gravel, beneath which it was mainly in a blue till. At St. Joseph a well at the Park Hotel, 165 feet in depth, enters rock only 4 feet and obtains a water that is slightly brackish. The upper 40 feet is mainly in blue till, but the remainder of the drift is largely a fine sand in which there are occasional beds of clay or silt carrying fragments of wood. Wood is especially abundant at about 140 feet. Rock was struck at the basket factory in St. Joseph at about the same level as in the hotel well, and a slightly brackish water was obtained. An experimental gas boring at Benton Harbor, on low ground scarcely 15 feet above lake level, penetrated 135 feet of drift and sand. The upper 20 feet was entirely sand. Beneath this is a blue clay or silt, containing few pebbles, which graduates downward into a gray sand, also slightly pebbly, and this sand extends to the rock. A well on the east border of Covert Ridge, in see. 9, Watervliet Town- ship, reached a depth of 125 feet without entering rock. It was through till with the exception of 5 feet of sand at the bottom. Another well in the same section entered blue till at 4 feet, which continued to the bottom of the well at 52 feet. Here a cemented gravelly crust was penetrated, beneath which water was obtained. A boring on Covert Ridge, in sec. 34, Covert Township, at W. F. Conners, reached a depth of 220 feet without entering rock. It was mainly through blue till and no water was obtained; a dug well only 6 feet from it found water-bearing gravel at 36 to 38 feet. Two wells just west of the village of Covert, in sec. 15, are 70 feet in depth. They penetrate 15 feet of yellow till, beneath which is a blue till extending to the water-bearing sand at the bottom of the wells. A well in the northeast corner of sec. 22, 80 feet in depth, is in till from top to bottom. A well on the west side of sec. 22, 97 feet in depth, penetrated 3 feet of surface sand, beneath which it was entirely in till to a water-bearing sand at bottom. A well in the north part of sec. 14, 100 feet in depth, passed through thin beds of sand which occur in the till at intervals of 15 or 20 feet. A well near the center of sec. 11 has a depth of 85 feet and is in till THE LAKE-BORDER MORAINIC SYSTEM. 401 from the top down to a quicksand at the bottom. A well in the SE. + of sec. 2 has a depth of 70 feet and is in till with the exception of 4 feet of surface sand. A well in the west part of sec. 25, South Haven Township, is in till from the top to a water-bearing sand at bottom. A well one-half mile southeast from South Haven, 125 feet in depth, is in till except 5 feet of water-bearing sand at bottom Several tubular wells in the village of South Haven have a depth of about 100 feet. Arter penetrating a few feet of surface sand they are in blue till nearly the whole depth. Some of the shallow wells in the village obtaim water at the base of the surface sand. A boring at the basket factory in South Haven has the following section: Section of boring at basket fuctory in South Haven, Michigan. Feet SIM ROS SENG! cone oddone onsdoo cosciSses soobEo Geen Goob HeEdIuaSoro oTSeD cSSdb4 bepeedinose no senoae Sade 10 Soft blue clay, slightly pebbly, becoming harder toward bottom and containing bowlders in the lOwIGe 2D Tees sog600 dossds cascss 266655 cou cou bUMEEEIobeSH OnDesb sane SoSe esau eoaa doo bEe cpedsedoes 130 Shalerofedankicoloravanyinoningharan essa. eateries Sse nee aees eae eee a ee ete eee eee eee. 207 HIRO Gall ee peepee cepts ee odes aes cialoya Say amjawiekits Sieeiee el Syerecn elope s Sees Sie ee ee She ae pae es isan 347 On the plain east of Covert Ridge, in sec. 31, Geneva Township, a flow- ing well was obtained 6n the farm of J. Irving Pearce. Water rises 7 feet above the surface. The drift is mainly a blue till and has a depth of 190 feet. The well was continued 40 feet into the underlying shale. A well on the plain east of Covert Ridge, in sec. 29, Casco Township, Allegan County, reached a depth of 140 feet without entering rock. After penetrating 25 feet of surface sand it passed through a thin bed of blue pebbly clay, beneath which it was entirely through fine sand. On Covert Ridge, in sec. 25,T.1 N., R.17 W., a well 157 feet in depth penetrated 18 feet of surface sand, beneath which it was mainly through a blue-gray till. Another well in the same section penetrated 12 feet of sur- face sand, beneath which it was in a blue till to a depth of 146 feet. A well in the northeast corner of the same section penetrates scarcely any surface sand; there is instead a loamy yellow till 7 feet in depth, overlying the blue till. he latter is slightly pebbly and extends to a depth of 104 feet. There is then about 10 feet of stony material of reddish-brown color. This is underlain by blue clay, which extends to the water-bearing sand at 130 to 134 feet. MON XXXVIII bo =r) 402 THE ILLINOIS GLACIAL LOBE. A well in sec. 6, on the inner slope of Covert Ridge, has the following section: Section of well on Covert Ridge in sec. 6, T.1 N., R.17 W. Feet. Surfaceisan de ole tae eee ane some ae Sete eee eee Rhos COC cates ae op a ae ae ae a seem, Blueclayaslightlypeb ply. asascs scenes nee cra e eo ceiien cs ae cieeie o sien caste eee ne eee eee 10 Minevhitewsandswithia few pebblesss veo ssee ss eee ace he tN VER av te crerce arma eyate een es 32 Cemented gravel alternating with beds of loose mpER. Ree E MO mAeS Eber ans sa coch code Sececccepssce ss 24 MO tal sre erases ete eine eect oete a hacia ac Sere aa la bah ce) eleyere Slaps ee en oe eee ee ee eee eee ee 78 In see. 12, T. 1, R. 17, also on the inner slope of Covert Ridge, wells 30 to 50 feet in depth are mainly through sand, and the lake border from this point northward is heavily coated with sand. On the outer slope of Covert Ridge, in northern Casco Township, till appears to have been deposited upon a thick bed of sand. The wells enter this sand at.a depth of 10 to 25 feet, and those sunk to a depth of 35 or 40 feet do not reach the bottom. On a swamp south of Covert Ridge, in southeastern Ganges Township, wells usually pass through a compact clay after leaving the surface muck, and find some difficulty m obtaiming water in dry seasons. SobSese5 68 el eS eee ae pe 20 Yellow sandy clay, chunsing to/sand at bottom <2. ~~ <2 522 foo se ee oe = see ee ee ee eee 30 A well in the northwest part of sec. 15, also_on the crest of Covert Ridge, penetrated 30 feet of surface sand, beneath which was a blue till extending to the water-bearing sand at 86 feet. A well on the crest of the ridge, near the line of secs. 3 and 4, at an altitude 105 feet above the lake, reached a depth of 190 feet without enter- ing rock. There is 8 feet of yellow till at the surface, beneath which the well appears to have been entirely in a blue-gray till. In the vieinity of Hutchinson’s Lake the wells range in depth from 40 to 105 feet and are largely through sand or sandy gravel. THE LAKE-BORDER MORAINIC SYSTEM, 403 At Fennville wells in some cases penetrate 50 feet of sand, with which there are thin beds of peaty material associated. A hill east of this village, which stands about 50 feet above the level of the railway station, has till at the surface. At Drenthe, on the inner slope of Covert Ridge, in southern Ottawa County, flowing wells have been obtained; one in a rayine at the sawmill has a head 8 feet above the surface and will flow 80 barrels per day from a 2-inch pipe. The water is obtained from sand below blue till at a depth of 92 feet. Another well a few rods west is siphoned into a trough in the same ravine. A well 1 mile north of Drenthe, 155 feet in depth, is mainly through blue till, except in the lower 15 feet, where water-bearing sand and gravel is found. Its head is sufficient to barely reach the surface. Many wells along the ridge east and south from Drenthe have been sunk to a depth of 100 feet or more, mainly through blue till. The till sheet extends westward from this ridge to the shore of Lake Michigan in north- western Allegan County. CHARACTER OF THE OUTWASH. The Valparaiso morainic system formed a retaining wall for waters escaping from the ice sheet along the outer border of the ridges under dis- cussion, except at the “Chicago Outlet,” and possibly at the St. Joseph River Valley. It is probable therefore that the district between the ice margin and the Valparaiso morainic system was occupied either by lakes or by very sluggish streams, except perhaps for a few miles in Lake and northern Cook counties, Illinois. There are found indications of a moderate rate of flow, accompanied by gravelly outwash, along the Des Plaines Valley below the point where the outer ridge crosses the river near Gurnee. The force of the current was sufficient to carry the gravel as far down the valley as the vicinity of Des Plaines Village and form a belt a mile or more in average width. The gravel is only a few feet in depth. Much of the low country bordering these ridges in southern Cook County, Ilimois, and in northwestern Indiana and southwestern Michigan has been covered by the waters of Lake Chicago, and the deposits made by ‘this lake can not easily be separated from any deposits of similar character which may have been formed as an outwash from the ice sheet. There are 404 THE ILLINOIS GLACIAL LOBE. places wnere wells encounter a more pebbly material at the base of the sand than near the surface, but it is not certain that these pebbles were an outwash from the ice sheet. Indeed, it seems quite probable that they may have been worked over and deposited by the waters of the lake. ASSOCIATED TILL PLAINS. The ridges just discussed occupy but a small portion of the area embraced between the Valparaiso morainic system and the shore of Lake Michigan. The greater part of the area is a plain, underlain by till deposits. The plane tracts, as is shown later, were largely covered by Lake Chicago and have received deposits of sand or gravel from the waters of that lake. ALTITUDE AND SLOPES. In the portion of the plain west and south from Chicago the altitude at. the inner border of the Valparaiso morainic system is 40 to 50 feet above Lake Michigan. From this border there is a gradual descent toward the lake, and the till scarcely rises above lake level along the present shore within the limits of the city. At the time the upper or Glenwood beach was formed lake water covered the entire plaim west and south of the city as far as the borders of the Valparaiso morainic system, the altitude of that beach being 55 to 60 feet above the present lake level. Upon passing northward this till plain is divided into several narrow plains which separate the till ridges, and these plaims soon rise above the level of the upper beach. The plain that lies between the west ridge and the Valparaiso moraine slopes eastward at the rate of several feet per mile. Its rise toward the north amounts to but 14 to 3 feet per mile. At Oving- ton Station, on the Omaha Division of the Chicago and Northwestern Rail- way, the west border next the Valparaiso moraine is but 635 feet. It rises to about 690 feet at the line of Cook and Lake counties, a distance of 18 miles, and to about 725 feet in northern Lake County, a distance of 24 miles farther. The plain between West and Middle ridges rises from 630 feet at Oak Glen to 680 feet at Deerfield, a distance of 6 miles. From Deerfield north to the State line, a distance of 24 miles, it is shown by the Chicago, Milwaukee and St. Paul Railway profile to stand at 670 to 685 THE LAKE BORDER MORAINIC SYSTEM. AO0D5 feet. Russell Station, situated on this plain near the State line, is 673 feet. The plain between Middle and East ridges rises from 630 feet, opposite Winnetka, to about 670 feet at the point where the ridges unite, 20 miles north from Winnetka. In Indiana the border next the Valparaiso morainie system stands 50 2 near the Illinois D to 70 feet above Lake Michigan, the lesser altitude bein line and the greater near the Michigan line. The plain between the Val- paraiso moraine and the outer till ridge is but 2 to 8 miles wide in Porter and Laporte counties; it however shows a descent toward Lake Michigan. There is also a perceptible descent from the till ridge toward the lake. In western Porter and in Lake counties the slope is apparently continuous toward the lake from the border of the Valparaiso morainic system, no well- defined till ridge being present. For a distance of 2 to 5 miles south from the lake the sand deposits capping the till are heavy and their base is about as low as the surface of Lake Michigan. In Berrien County, Michigan, the plain between the Valparaiso morainic system and the outer till ridge stands 60 to 90 feet above Lake Michigan and has a slight descent toward the lake. As it is but 2 to 4 miles in width, the west border is only a few feet lower than the east. The plain between the outer ridge and Covert Ridge stands 50 to 75 feet above Lake Michigan, and also has a slight descent toward the lake. Its width in places is less than a mile and nowhere exceeds 3 miles. In Van Buren and Allegan counties the lowland tract between the Val- paraiso morainic system and Covert Ridge is less smooth than the southward continuation in Berrien County. There are occasional ridges and knolls of glacial drift ranging in height from 50 feet downward to 10 feet or less. There are also numerous sandy ridges and knolls with a height ranging from 30 feet downward to barely detectible waves in the surface. The presence of the sand has tended to make the surface more uniform in eleya- tion, since it is deeper in depressions than on the higher points. The plane- surfaced part of the lowland stands usually 75 to 100 feet above Lake Michi- gan, while the knolls occasionally reach a height of 150 feet or more above the lake. This lowland tract presents greater oscillations in level in passing from north to south than from west to east. It is generally somewhat lower on the borders of the valleys than on the divides between them. If the 406 THE ILLINOIS GLACIAL LOBE. sand were removed the variations would be still greater, since the sand is thicker on the borders of the valleys than on the divides. Covert Ridge follows the shore of Lake Michigan so closely that a plain is present on its inner border along only a small part of its course from the State line northward to the Kalamazoo River. Where present it shows a descent of 20 or 30 feet per mile toward the lake. In places where the ridge is distant 2 or 3 miles and its inner border stands 60 to 70 feet above the lake the till surface drops down nearly to lake level at the lake shore. Sand deposits have considerable depth on the lower parts of this plain and bring the surface up to a height of 35 to 40 feet or more above the lake. s THICKNESS OF DRIFT. On the Hlinois portion of these plains there is much difference in the thickness of the drift. The difference in thickness is due almost entirely to the variation in the surface of the underlying rock strata, since the surface of the plains has only a slight variation in altitude. Within the city of Chicago, where the surface is especially flat, several rocky prominences come to the surface, or are concealed but slightly by drift, while among them the drift accumulations extend to depths of 100 to 125 feet or more. Mr. Samuel G. Artingstall, formerly city engineer, has prepared a map of the city showing the distance to rock in many places. This indicates that a filled valley with rock floor 100 to 125 feet below lake level passed through the north central part of the city, entering the lake south of Lin- coln Park. West from the city the rock rises over quite extensive areas nearly to the surface of the plain or to a height of 30 to 60 feet above the level of Lake Michigan. In northern Cook and in Lake County, between the till ridges as well as beneath them, the rock surface has an average altitude somewhat lower than in the low plain in the vicinity of Chicago, for the majority of the wells reach a level about 50 feet below the surface of Lake Michigan before entering rock. It is estimated that the thickness of drift in this northern portion will average nearly 150 feet, while in the low plain the average will scarcely exceed 50 feet. The thickness of drift in the Indiana and Michigan portions is usually great, as has been indicated above. (See pages 392-393.) THE LAKE-BORDER MORAINIC SYSTEM. 407 STRUCTURE OF THE DRIFT. The drift beneath the Illinois portion of these till plains, like that of the ridges, consists largely of a soft blue till, beneath which are remnants of a hard till of earlier age. The tills appear to be of direct glacial depo- sition, even in portions of the plain which lie within the limits of the beaches. The clayey matrix of the soft till seems to be less thickly set with stones than that of the underlying hard till, but in both tills many of the. stones are glaciated and show little evidence of water abrasion. The rocky constituents grade from bowlders several feet in diameter down to minute pebbles. ‘These, in the upper or later till, are made up in large part from the local upper Silurian rocks, probably less than 10 per cent being from the pre-Cambrian Canadian rocks. Fragments of Devonian rocks, apparently from ledges outcropping to the north of Chicago, are sparingly represented.’ The clayey matrix is highly calcareous, and under the microscope it is found that angular or but slightly rounded grains of limestone constitute a large proportion of the fine material. With the minute limestone fragments there appear quartz grains, bits of shale, and fragments from crystalline rocks of various kinds. Whether the rock con- stituents of the older till differ markedly from those of the newer has not been ascertained. Its situation immediately upon the Lockport (Niagara) limestone would, in all probability, result in the incorporation of an even larger proportion of fragments from this rock than appears in the upper till. One of the most conspicuous instances of the occurrence of the lower till within this area is that. brought to light in the excavation of the Chicago Drainage Canal. Immediately east from Summit the canal for about a mile extends a few feet into a very hard, partially cemented till, apparently of early, glacial age. Its hardness compared with that of the overlying till is so marked that the contractors who engaged to excavate this part of the channel were obliged to abandon the steam shovel which had been used in the soft till and to resort to blasting. It is probable that this old drift fills depressions in the rock quite extensively in this district, but as no special attention has been given its identification the instances recognized are not 'On the microscopic structure of certain bowlder clays, and the organisms contained in them, ly Dr. George M. Dawson: Bull. VI, Chicago Academy of Sciences. 408 THE ILLINOIS GLACIAL LOBE. numerous. The well drillers usually distinguish the hard till from the over- lying softer till and apply to it the name “hardpan,” while the soft till is called clay. Although the great body of the drift is till, there are found numerous thin beds of sand or gravel in which water collects in sufficient quantities to supply the wells. There are also small pockets of dry sand or gravel occupying but a few cubic feet each. Such pockets were found in the exca- vation of the main lake tunnel, and have been described by Dr. Edmund Andrews in a paper published in the American Journal of Science.t They were in some cases completely inclosed by till. On the surface of the plain both above and below the upper beach there is quite generally present in Lake and Cook counties a clay in which pebbles are far less numerous than in the till; it, however, carries occasional bowlders. It ranges in thickness from a few inches up to several feet. This deposit is perhaps a subaqueous till dropped in a body of water held between the ice front and the higher parts of the morainic system while the ice sheet was still overhanging the inner slope. The depth of leaching and oxidation is markedly less on the plain covered by Lake Chicago than on the till ridges or the Valparaiso morainic system. Numerous acid tests show the leaching on the plain to extend only to a depth of a few inches, seldom more than 2 feet. On the till ridges the leaching is usually thorough to a depth of 8 or 4 feet, while on the Valparaiso system it is rare to obtain a response with acid within 5 or 6 feet of the surface. On the plain and also on the till ridges the surface oxida- tion is usually but 3 to 6 feet, while on the Valparaiso system it is 6 to 10 feet or more. This difference in the amount of oxidation and leaching may be attributable in part to the more compact nature of the till ridges and plains, but it is probably in part due to the later date at which they became exposed to atmospheric action. There have been several deep lines of excavation made in Chicago and vicinity which have afforded excellent opportunities for studying the struc- ture of the drift. The longest line is the Drainage Canal, now under con- struction, which opens a channel 25 to 40 feet in depth from the Chicago River at Bridgeport to the Des Plaines River at Summit. Along the Des 'Am. Jour. Sei., 2d series, vol. 43, 1867, pp. 75-77. THE LAKE-BORDER MORAINIC SYSTEM. 409 Plaines also the excavation is largely in drift to the vicinity of Lemont, where the canal becomes arock channel. From Bridgeport to Summit there is little besides till, but from Summit to Lemont gravel, sand, and the coarser material deposited or left as a residue along the line of the old lake outlet form a large part of the section. In the Fullerton avenue conduit, which leads eastward into the lake through the north part of Chicago, the drift is mainly till, but surface sand is a conspicuous deposit. From its western end to within 2,090 feet of the lake the rock surface is found at a depth of 43 to 54 feet. Within 100 feet east from this point it drops down to 80 feet, passes below the conduit, and does not appear farther east. The surface sand has its greatest thickness at about 1,700 feet from the lake, where it reaches 25 feet. It decreases west- ward to only 12 feet at a distance of 6,000 feet from the lake, and entirely disappears before reaching the Chicago River Valley. Toward the lake shore also it decreases, but holds a thickness of about 18 feet for 1,400 feet from the shore. At the water’s edge the depth is but 10 feet. The profile continues out 1,100 feet beneath the lake, and there is but 3 feet of sand at its terminus Numerous borings and excavations in the south part of Chicago, in Hyde Park Township, show sand deposits ranging in depth from 5 feet or less up to about 20 feet. Till usually underlies the sand except where the rock comes near the surface. In this connection it may be remarked that the heavy deposits of sand in Cook County are found chiefly along the present lake border from Evanston southward, where there is a continuous belt of sand ranging in width from one-half mile to 8 or 4 miles and having an average depth of not less than 10 feet. Over much of the plain west of this sandy belt the deposition was so light as scarcely to conceal the surface bowlders and in places leaves only a trace of sand in the soil. The south-westward lake outlet appears to have carried away much of the sand which was brought into the southern end of the lake while that outlet was open. In the portion of Indiana between the Valparaiso morainic system and Lake Michigan sand deposits are heavy as far south as Calumet River in Lake and western Porter counties and nearly as far as the inner border of the till ridge in northeastern Porter and northwestern Laporte counties, a 410 THE ILLINOIS GLACIAL LOBE. belt whose width varies from scarcely 2 miles up to fully 5 miles. Where the dunes are highest the sand probably has a thickness of about 200 feet, for the dunes attain a height of 150 to 175 feet, and the sand, as shown by wells, extends a few feet below the lake level. Throughout much of the belt the sand probably exceeds 25 feet in depth and may average twice that amount. South of Calumet River, from the mouth of Salt Creek, near Chrisman westward past Lake and Liverpool to Griffith, there is a belt of sand a mile or more in width which has generally a depth of about 20 feet. East from Salt Creek the depth is much less. The sand is also of slight depth west from Griffith except along the lme of the beaches. Beneath this heavy deposit of sand there appears to be but little oxi- dized clay, a feature which favors the interpretation that the clay was not long exposed to atmospheric action before the sand deposition occurred. The wells usually pass immediately into a blue clay. This clay, so far as can be learned from well drillers, is but slightly pebbly and appar- ently is in places free from pebbles. It seems to maintain this character to great depth, as is indicated by sections of wells already given. It differs markedly from the blue till of the neighboring portion of the plain ix Cook County, Hlinois, and appears also to be somewhat less pebbly than the blue clay of the neighboring district in southwestern Michigan. There are few exposures afforded by the streams in the district where sand is heayy, but exposures of slight depth are numerous outside the limits of the heavy sand. From these exposures it appears that the clay has gener- ally but few pebbles, and several exposures haye been found in which it is pebbleless. The most extensive exposures of pebbleless clay noted are along Deep River, in the vicinity of Hobart, and it appears to be present over an area of several square miles between Deep River and Salt Creek. Prof. W. 5. Blatchley, State geologist, reports a similar clay at Chesterton and Michi- gan City. This pebbleless clay is oxidized to a depth of a few feet, beneath which it presents a blue color similar to that of the pebbly clay of neighboring districts. It is highly calcareous and carries numerous lime- stone nodules near the bottom of the oxidized portion. It seems even more caleareous than the pebbly blue clay. Professor Blatchley has published ‘Communicated to the writer. THE LAKE-BORDER MORAINIC SYSTEM. Anal the following analyses of samples of these pebbleless clays, made by Prof, W. A. Noyes. of Terre Haute, Indiana.t Analyses of clays of Pleistocene age. sp. lonentes | Hobart. | Cgiter | chesterton.| Michigan | ate aie res 25) nie Per cent. | Per eent. | Per cent. | Per cent. Silica eieremn emt Meryl ed L oa te 50.56 50. 37 53.02 | 50.47 HitaniumpeoNid eee cree eens 1.00 . 65 1330) ks Uivamirraseeyta Min ine ntl. | 13.11 | 9,93 10.72 | 19.77 | Combinediwaterssecs see ee yee 2.76 1.50 2.21 | 3. 14 Total clay base and sand ...| 67.43 62. 45 67. 25 67. 83 Wernicro mid CMe sar eeree etseict aioe 2.98 2.10 2254 2.44 HELOUSTO NIC Chee ee ae eer nenee 2A32) 2.05 PE OP) 2) | LOTS ae Ata Oe ee men | 10:23 8.38 Peale) MaONeSlan sat ateiaeecstes soe cs Sees 5. 06 6. 26 5.28 | 3. 22 Botashvpaeecyscccrtee ere esa. ctecn | a 3.04 | 3.25 | 3.70 | Soc aiese pase epsaee erent marta hie 70 £79 | . 86 5B Motali fusesysosee ote 2 ee. 22.67 | 24.50 22.53 | 29.78 Canbonidioxidesee er eneseeeeee 9. 62 12750) | 20%48 | 9F80 STi aller eye culties we 99.72 99.45 | 100.26 100. 41 | In explanation of the contrast in the amount of coarse material in the clays bordering the lake in northwestern Indiana, compared with those in Cook County, Hlinois, it may be remarked that it is probable that the char- acter of the underlying rocks will prove an important factor. In Cook County, Hlinois, the underlying rocks are the somewhat resistant Lockport (Niagara) limestone, while in the neighboring portion of Indiana the rocks immediately beneath the drift are the Devonian shales, which are easily com- minuted and ground into a clayey material. It is probable, however, that the conditions of deposition were slightly different in the two districts. In Cook County the southwestward line of discharge may have been open sufficiently to allow a considerable part of the fine material to be earried down the Des Plaines Valley, while in the Indiana district. it may all have been deposited without much transportation or sifting out of the finer material. The localities where the pebbleless clay are best exposed are beneath the bay-like extensions of Lake Chicago, and may possibly be 122d Ann. Rept. Indiana Geol. Survey, 1898, pp. 128, 134, 187, and 139. 412 THE ILLINOIS GLACIAL LOBE. composed of sediment which settled in the waters of the bays. The great amount of caleareous material, however, seems to indicate that they are a glacial rather than lacustrine silt. The scarcity of evidence of life in the early stages of the lake seems to indicate that but little calcareous material can be looked for from that source. SECTION VI. STRLZ WITHIN LIMITS OF SHELBYVILLE MORAINE. The table of striz given below includes all exposures of which the writer has knowledge either through personal observations or from publica- tions and correspondence. ‘There are several observations taken by Messrs. J. T. Campbell, O. P. Jenkins, A. BH. Purdue, and J. A. Udden, hitherto unpublished, which have been kindly contributed for publication in this report The bearings taken by the writer, except when so designated, are not corrected for magnetic variation. The bearings taken in western Indiana by Collett, Campbell, and Jenkins are corrected for magnetic varia- tion, but so far as known all others are magnetic. The magnetic variation in western Indiana is only about 3° east and in western Illinois 6° east.’ Table of strie within limits of Shelbyville moraine. Location. Bearing. | Observer. | eek. peste | INGare IMR, ING 2555555 SocoasonsoacoS cons eahess go5se8 | Seecuhreseeaes Collett. | Coal Creek bluff, 3 miles west of Waynetown.------ sees etes Sh IKJ2) 1} oso Sas6 | Collett. | Coal Creek bluff, 3 miles west of Waynetown a .---..-.----- Se OSV Vee Hopkins. leeNearsD arlington [ndissste een sass aon sane sere eee Ceol Os hy meee | Leverett. | lee NearaDarlin ton en Oem ameter eee eee eee ee eiaa aa | SLY cacsassece _ Thompson. | In northern Parke County, secs 27) (Dod) Rew, Wieee see §. 39° 48’ EB ..... Campbell. | | In northern Parke County, sec. 27, T.17, R. 7 W c....-...--. §.34° 30’ E..... Campbell. Walliamspont.sin dieser seins tee en = elon = sels er SbUtsIe IN Soséose | Leverett. EV aMsportslnd ade ereer 2 s85 soc. fa Ste A ae Se ee 8. 8°-10° W -..., Salisbury. aSee Collett, Geol. of Indiana 1875, p.370. Also Hopkins, Geol. of Indiana, 1895, p. 278. The observations by Mr. Hopkins indicate that the bearing reported by Mr. Collett should be S.18° W. b The striw reported by Mr. Maurice Thompson were probably formed by the Erie lobe. c Two exposures on the bluff of Sugar Creek, 100 feet apart, show a difference of 5° in bearing. The observer, Capt. J. T. Campbell, of Rockville, Indiana, has reported several exposures of glacial strie in Parke and Putnam counties, Indiana, which bear southwestward, and accordingly are referred to the Maumee lobe. They are discussed in another report now in preparation. dThe observations reported by Professor Salisbury probably represent a movement connected with the Wisconsin stage of glaciation, while the observations reported by the writer belong apparently to an earlier glaciation. Two miles east of Williamsport, on the north side of the Wabash, Professor Chamberlin found a third set of striz with westward bearing, which apparently pertain to the invasion of the Erie lobe. (See Seventh Annual Report U.S. Geol. Survey, p. 207.) ‘See map of Henry Gannett, showing distribution of magnetic variation in the United States for the year 1900: Seventeenth Ann. Rept. U.S. Geol. Survey, Part I, Pl. 11. STRLA WITHIN LIMITS OF SHELBYVILLE MORAINE. Table of strie within limits of Shelbyville moraine—Continued. 413. | Location. 3earing. Observer. | Near Fountain post-office, in sec. 4, T. 20, R. 8 W., main | S.40° EB .. 222. Siebenthal. | bearing. | Near Fountain post-office, in sec. 4, T. 20, R. 8 W., scatter- | S. 560-629 EB ..- Siebenthal. ing strice. Logansport, Ind., on bank of Hel River...--....---.---..-.- 8. 14° E. or | Leverett. | N. 14° W. | East of Logansport, en bed of Kel River..........-.-...---. S200 o Wiese | Leverett. MGM, JhNGl s Sesban booboa so Sree RO SRoetEcoecE sae asabocas Seotorh eaeeee| Chamberlin. Moron elim iat Nis sorte Ne Si sian oi ieis/aieixwnisln Dac oe ah aaa Sco lmWarnceaes | Chamberlin. Rensselaer) im deat hese ae. Seisccee Gone sec ose ates 8. 8°-14° W ...| Purdue. Qinareay, iene IkEMiEMGl: ce obedcoseos S5rad seme BoaceE Sana gues IS suiCohieeee ea Chamberlin. Quamny ane alee tl ane iciese ema spa alee eee ST WWssak soe Chamberlin. South bluff of Illinois River, near Lasalle................-.. | 8. 75° W...---.| Leverett. Mazon! Creel: biluff, ‘sec.30) To 33°N., Ro 8 H.22- 2-222... 2 -. Sra 4 OW saat Leverett. Near Morris, Il]., in sec. 24, T. 34, R. 7 H..-.-.-----.--..---- 8. 50°-55° W ..| Leverett. Near Morrissllls, inisec. 19 P34 Rae) Brecces se sase soe sccens HSE GOLAN s2e5ce | Leverett. | Near Morris, Ill., in sec. 18, T.34,R.8 E......--.----..-----.- 8. 30°-S8° W ..) Bradley. | | Near Wiloyeensy JOUL.6 Thm Gaye, ae} A Beats) Nigace socesccoescecsosos 8. 40°-55 W ...| Leverett. | aunts Don sell berets eceseere steele eye eae seme wet, Sete S508 Wireeaeee Leverett. Aux Sable Creel, west of Minooka ---. 222-2 -2----225--2-2-- | Ss. W +---------| Udden. iNuxa Sable Greele secs Owl oo sh) Hip sees ow ei yan ays S. 47° 45’ W ...| Leverett. Brodie’s Quarry, on Fox River bluff, north of Millington, Ill.) S. 9° 30’ E. to | Leverett. S$. 27° 30’ W. ittlesRocks Creeksysecisaud al hn O deena ele arsenate alee 8. 31° W., 8. | Leverett. | Be Mie S| | 40° W. Secw ses oie Ops seis sistas eeiacietateeniain see sci sesiee soak es | ShePo Wye cecese | Leverett. Slot, TSU Bi (90) «ae ae a aes MR Ree et |S. 110° 30’ W -.| Leverett. JOMei Me arepenive nul vise yer een ens eel ee eee ee aie eee SEO MW Scnoese | Leverett. Dupage River bluff, at crossing of Chicago, Rock Island | S. 42° 30’ W .-..| Udden. and Pacific R. R. | | | Kankakee River bluff, in sec. 9, T. 33, R.9 B.--.-.----.------ Sh ots MW coasos Leverett. | Near Wilmington, Ill., in sec. 31, T.33, R. 10 H.:..--...-_--- 8. 438° W Beil Leverett. Becktord’s/ Quarry, sec. 10). 33;iRo 11 Hrs 2 2 = eo saesie a= al NeoLOnWieeeseee | Leverett. | Eemont; near Des) Plaines ‘Cut-off. 2222. Ss. - s sees ee Nn OOa Wise eete | Guthrie. | Between Willow Springs and Sag Bridge---.-. ....-..------- Se SCiv\eeee ees Leverett. | Westiofp Summa tise ore sets hire) Po ic eels Ea Ae Uae ate ae Seve eS Ss bca | Leverett. | North of Summit, near Santa Fe railway bridge..----..----- SEES Wssecscs _ Leverett. a At Monon and near Kentland there are two systems of strie reported by Professor Chamberlin. In the latter instance the southward pointing striz lie in grooves and furrows in the limestone, while the westward pointing stria only affect the crests of these furrows, which have been slightly truncated by the later westward movement. (See Seventh Annual Report U.S. Geol. Survey, p. 207.) The writer made an observation of striz 2 miles east of Kentland, in which they appear at various angles between S. 4° E, and 8. 75° W., insuch manner as to suggest that more than two movemeuts affected the rock ledge. 414 THE ILLINOIS GLACIAL LOBE. Table of striw within limits of Shelbyville moraine—Continued. | | Location. | searing. | Observer. Es 5 | ~ | | yous iow Desi PlaimesaVvalleyse te ene =e aac ease a nnse eels | S. 40° W. to | Leverett. | | S.67°W. | | (Maeram fersse ssiccee es ese ees nessa eeass See Se cease eben $3542 Wis see | Leverett. | Wiestvotsbimhurstyatio danny een | se sa ae pel tere cint ale | Soe Wie soeess | Leverett. | East of Elmhurst, in sec. 17, T.39, R.12 B...--..-.-....---.- | Shae We oa scce | Leverett. Hawthorne quarries, west part of Chicago-.----...---------- S. 609-649 W...| Leverett. Quarry at Western and Chicago avenues, Chicago.......---- SOD 2) Wie eee ee | Leverett. Fullerton avenue conduit, Chicago.-........-.--------.----- Hass] O02 8 Wiese City engineer. Quarry at Eighteenth and Robey streets, Chicago....-..---- 8. 48°-55° W. ..| Leverett. Stonylsland SouthiChicacopesses-s sence eneseese eee S$. 30°-50° W . ..| Leverett. Blue Island quarries, 2 miles southwest of yillage---....---- Seo0SWieeeeees | Leverett. Blue Island quarries, 2 miles southwest of village-..-.-.----- Bi oW iscsseeees Guthrie. | Thornton, in valley east of village uw ..---..---...--.-.------ Sez Witeeneee Leverett. a Mr. Ossian Guthrie reports haying observed strie at Thornton bearing more nearly westward. (See Guthrie's pamphlet on the Lake Michigan Glaciers, map 3.) Considerable difficulty is experienced in assigning strize in northwestern Indiana to the proper ice lobe. That district was invaded from the north- ward by the Ilinois lobe and subsequently from the eastward by another portion of the ice sheet, the Saginaw-Erie lobe, which in the closing stages of glaciation became differentiated into the Saginaw lobe and the Erie or Maumee lobe. Accordingly both southward and westward bearing’ strize are found. In some places, as at Monon and Kentland, a single rock sur- face presents both southward and westward bearing striae, the westward being the later. Usually, however, the stria formed by the earlier ice movement were either protected by drift deposits from the action of the later ice movement, or they were so exposed as to be effaced by the later movement. There are striz on the north bank of Kel River in the city of Logans- port, concerning which the direction of movement is not certain. The bearing is N. 14° W. or 8. 14° E. Immediately north of Logansport lies a heavy moraine formed on the north border of the Erie lobe, which, as just noted, extended westward from the Lake Erie Basin. We may sup- pose the striz to have been formed by a northward movement toward this moraine, but it is quite as probable that they were formed by an earlier southward movement, independent of the moraine and perhaps referable to STRLZ WITHIN LIMITS OF SHELBYVILLE MORAINE. 415 the Illinois lobe.. A careful examination of the striated surface failed to disclose decisive evidence whether the movement was northward or southward. It may be remarked in this connection that just above the city of Logansport the bed of Kel River shows heavy glacial grooves bearing 8. 58° W., which are evidently the product of the movement from the Lake Erie Basin. It seems scarcely possible for the same ice movement to produce, within the limits of a single township, strize with bearing differing 108 degrees, and that too in a comparatively smooth region. But so little is known as yet concerning the possibilities of ice movement, that judgment should perhaps be reserved. : The striz of northeastern Hlimois show some interesting deviations from a general southwestward course. In the Des Plaines Valley there is a renge from $. 18° W. to S. 96° W. Three observations between Summit and Lemont show bearings 5. 84° W., 8. 18° W., and S. 60° W. The strize bearing nearest westward are accompanied by heavy grooves which seem to call for the action of a thick ice sheet, but the other exposures show only faint striation, and it has occurred to the writer that possibly this faint striation is attributable to masses of ice floating down the valley after the ice sheet had withdrawn. Another locality in northeastern Hlinois, where the striation is thought to be referable to floating ice, is on the bluff of Fox River, north of Millington, in Kendall County, where faint strize occur with bearings ranging from 8. 9° 30’ E. to 8. 27° 30° W. In a great majority of exposures in the Illinois district glaciation is heavy, with complete planing of surface and often with heavy grooves, and can scarcely be referred to floating ice. At Joliet strize were observed with bearing slightly north of west, but this bearing is almost at right angles with the trend of the Minooka. til! ridge a few miles west of Joliet, and is probably referable to the ice move- ment which produced that ridge. The same explanation probably should be given for the bearing 20° north of west, shown in an exposure a few miles west of Aurora (sec. 1, T. 37 N., R.6 E.), for a moraine with NE-SW. trend passes through the district immediately northwest of these striz. On Stony Island, in the south part of Chicago, the rock quarry where glaciation was observed has beds which dip toward the southeast with an angle of 30 degrees or more. Heavy scorings follow the line of strike, with 416 THE ILLINOIS GLACIAL LOBE. a bearing 8. 44° W. Associated with these are striz of feebler develop- ment, which vary in direction fully 10 degrees to the east and west of the heavy scorings, thus ranging from §. 34° to 8. 54° W. An escarpment of the dipping layers which rises about 6 feet above the remainder of the quarry is glaciated not only on the upper surface and nearly vertical front, but also beneath one of the lower layers, its dipping under surface being smoothly polished for about 18 inches back from the front of the ledge. A i i) CAKE ih Ani = Baht Fig. 2.—Glaciated surface in bed of Chicago drainage canal. [Drawing from a photograph taken by Chicago Drainage Commission. } photograph of this ledge has been furnished by the Chicago Academy of Sciences (see PL. XVI). . A glaciated surface exposed near Lemont in the excavation of the Chicago drainage canal is represented in fig. 2, which has been drawn from a photograph taken by the Chicago Drainage Commission. The furrows are remarkably direct for a distance of several rods, and the planing is exceptionally smooth. In the vicinity of Lemont the bed of the Chicago Outlet is extensively channeled by nearly parallel grooves several inches in width and depth and WAX “Td INAXXX HdVHSONOW “ANOLSAWIT 40 2DV4YNS YSGNN 4O NOILVIYLS A3AYNS 1VOISO1039 “Ss “Nn STRLZ WITHIN LIMITS OF SHELBYVILLE MORAINE. 417 many rods in length. A photograph of an exposure made in the diversion channel of the Des Plaines is here furnished through the kindness of the ——- eee Fic. 3.—Grooves exposed by canal in bed of Chicago Outlet near Lemont, Llinois, apparently due to abrasion by pebbles transported by water in the outlet rather than to glaciation. [Drawing from a photograph by Chicago Drainage Commission. ] Chicago Drainage Commission (see fig. 3). These channels were announced in the Chicago newspapers to be glacial grooves, but they are apparently due to water abrasion rather than glacial scoring. MON XXXVIII——27 CoH Ay PMI Bay xe le THE CHICAGO OUTLET AND BEACHES OF LAKE CHICAGO. PREVIOUS WRITERS. It is perhaps impossible to determme who was the first person to recog- nize the evidence or form the conception of a southwestward outlet from the Lake Michigan Basin to the Des Plaines Valley. Inquiry among the old residents of this region shows that many of them recognized the beaches as products of the lake, and they also noted that the lake once discharged into the Des Plaines Valley. Evidently these conceptions were entertained for many years before any notice appeared in scientific publications. Banniste.—Probably the earliest scientific account of the outlet is that given by Dr. H. M. Bannister, in 1868, in the Geology of Ilinois.* How- ever, a report by the U.S. Army Engineers upon the survey of the Illinois River, by Col. James H. Wilson and William Gooding, was published the same year, which makes reference to the former southwestward discharge of Lake Michigan. Dr. Bannister opens his discussion of the old lake outlet and the raised beaches with the following statement: It is evident with a very little observation that, at a comparatively recent period, subsequent to the Glacial epoch, a considerable portion of Cook County was under the waters of Lake Michigan, which at that time found an outlet into the Mississippi Valley through the present channel of the Des Plaines. Andrews—Qne of the early publications of the Chicago Academy of Sciences presents a discussion of the beaches by Dr. Edmund Andrews, which has attracted wide notice.© The paper, however, deals mainly with the work of the lake at its present stage. The ancient beaches are briefly 1 Geol. of Illinois, Vol. IIT, 1868, pp. 240-242. 2The North American lakes considered as chronometers of post-Glacial time, by Dr. Edmund Andrews: Trans. Chicago Academy of Sciences, Vol. II, 1870, article 1, pp. 1-24. 418 THE CHICAGO OUTLET. 419 discussed, but the outlet is not described. A map accompanying the paper shows the approximate extent of the old lake beyond its present limits from the southern end northward some distance into Wisconsin and Michigan. Chamberlin—Prof. ‘I. C. Chamberlin presented a brief discussion of the beaches along the Wisconsin shore of Lake Michigan in the Geology of Wisconsin,’ which inclides many important data concerning the shore phenomena and an interpretation of the lake history. In the twenty years which have elapsed since that report was published, the studies of the shores of the Great Lakes have brought out a more complex history than had been anticipated; hence the interpretation does not fully meet the case, though it recognizes important fluctuations of lake level. Leverett —A]though, subsequent to the publications just noted, there have been frequent references in geological literature to the southwestward outlet and the ancient beaches, no publication especially devoted to them appeared until 1888, when a paper was published by the present writer in the Trans- actions of the Wisconsin Academy of Sciences. This paper gives a o somewhat detailed account of each of the several beaches found south of latitude 42° 30’, the latitude of the line of Wisconsin and Illinois. It contains but a brief reference to the outlet.’ cooley —Prof. L. E. Cooley, consulting engineer of the Chicago Drain- age Commission, has published two papers which deal to some extent with the Chicago Outlet.* The first paper discusses the outlet as a means for improving the sanitary conditions at Chicago. The second paper deals with it as an important line for navigation, and discusses the proper means for obtaining the best results This paper contains a large amount of valu- able data concerning the regimen of the Illinois and Des Plaines rivers. Marshall—The report of the United States Army Engineers for 1890 contains much valuable material collected by Capt. W. L. Marshall con- cerning the Chicago Outlet as a channel for navigation; also references to earlier work by that organization. ‘Geology of Wisconsin, Vol. I], 1877, pp. 219-233. 2The raised beaches at the head of Lake Michigan, by Frank Leverett: Trans. of Wisconsin Acad. of Sciences, Vol. VII, 1883-1887, pp. 177-192. Published in 1888. 5It should be explained that the numerous typographical errors in the paper are due to the fact that the writer had no opportunity to correct the proof. 4 Water supplies of Illinois in relation to health: Report of the Illinois State Board of Health, 1889. Lake and Gulf Waterway. Private publication, 1891. 420 THE ILLINOIS GLACIAL LOBE. tayior.—Mr, F. B. Taylor has published in the American Geologist obser- vations on high beaches in the northern ponvion of the basin of Lake Michi- gan.’ These beaches, he thinks, pass beneath the present lake level before reaching the southern end of the basin. This being the case, they have no connection with the outlet under discussion. Davis—Prot. W. M. Davis has published a description of the Chicago Outlet in the Popular Science Monthly.” His paper was based upon a per- sonal inspection of the channel with the United States topographic sheets in hand, and is a very clear, though brief, discussion of the features. THE CHICAGO OUTLET. The name ‘‘ Chicago Outlet” has come into use by geologists and engi- neers, without definite announcement dr conference among writers, to desig- nate the line of southwestward discharge from the basin of Lake Michigan across. the low divides near Chicago and thence down the Des Plaines and Illinois to the Mississippi. It may appropriately embrace both points of discharge from the iake to the Des Plaimes—namely, the one entering at Summit and the one at Sag Bridge. When the lake was occupying the highest beach, the north or main outlet was entered about 3 miles southwest of Summit; when occupying the second beach, the outlet was entered at Summit; when occupying the third beach, the point of entrance appears to have been transferred eastward nearly to the present shore of Lake Michigan, as explained below. Simi- larly the southern outlet was lengthened eastward with the lowering of the lake, the point of entrance at the time of the highest beach being about 5 miles east of Sag Bridge, at the time of the second beach near Blue Island, and at the time of the third beach at Riverdale. This relationship of the several beaches to the outlets and the eastward lengthening of the outlets may be readily understood by a glance at the accompanying map (Pl. XVII). There have been several surveys which have contributed contour maps of portions of the Chicago Outlet and of the plain covered by the lake in the vicinity of Chicago. The Chicago Drainage Commission have prepared an excellent map with 5-foot contours which covers nearly all of Cook ! American Geologist, Vol. XIII, May, 1894. 2The ancient outlet of Michigan, by Prof. W. M. Davis: Popular Science Monthly, December, 1894, pp. 218-229. DLOGICAL SURVEY. MONOGRAPH X XXVIII PL. XVII IAUKEGAN GLACIAL MAP OF CHICAGO AND VICINITY. By FRANK LEVERETT. 1897. SCALE OF MILES NOTE.—The topography is indicated by broken profiles, the straight lines represent- ing plains, and the curved lines rolling country. With the exception of dunes and sandy beaches on the border of Lake Michi- gan the rolling surface represents morainic topography. LIST OF CITIES AND VILLAGES. 1 Waukegan 2 Gurnee 8 Hainesville 4 Fort Hill 6 Volo 6 Wauconda 7 Fremont 8 f[vanhoe 9 Diamond Lake 10 Libertyville 11 Rondout 12 Lake Forest 13 Highland 14 Ravinia 15 Deerfield 16 Half Day P. O. 17 Lake Zurich 18 Barrington 19 Palatine 2% Arlington Heights 21 Whee ing. 22 Northfield 23 Glen 24 Glencoe 25 Winnetka 26 Wilmette 21 Evanston F] page Ridge ar’ 30 Des Plaines 31 Mount Prospect 32 Schaumberg 33 Bartlett 34 Spaulding 35 Wayne 38 Itasca 39 Bensonville 40 Turner Park 41 Austin 42 Oak Park 43 Riverside 4&4 Maywood 45 Elmhurst 46 Lombard 47 Glen Ellyn 48 Wheaton 49 Turner Junction 60 Eola 51 Naperville 52 Downers Grove 63 Hinsdale 64 Western Springs 66 La Grange 66 Willow Springs 57 Summit 53 Morgan Park 59 Blue Isiand Worth 60 Wort. 61 Sag Bridge 62 Lemont 63 Romeo 64 Plainfield 69 Homewood 70 Harvey 71 Thornton 72 Hammond 73 Whiting 74 Gibson 75 Hessville 76 Griffith 77 Edgemoor 73 Clark 79 Miller 80 Wilson's 81 Hobart 82 Wheeler 83 Crown Point 84 Shermerville 85 St. John 86 Brunswick 8 Chicago Helghts icago He! 89 Mattison 90 Frankfort 91 Mokena Crete SS = RW TOPOGRAPHY DEL. Er We hramer. alltebies i. vad VES THE CHICAGO OUTLET. 421 County, and the immediate borders of the Chicago Outlet along the Des Plaines River. This has not been published, being merely a study map. The topographic work carried on by the United States Geological Survey in this region is largely published. The peculiar features of the upper por- tion of the outlet are brought out in an effective manner by the following sheets, viz, the Chicago, Riverside, Calumet, Des Plaines, Joliet, Wilming- ton, Morris, Ottawa, Marseilles, Lasalle, Hennepin, and Lacon sheets. These sheets cover something over 100 miles of the former lake outlet, or nearly one-third the distance from the head of the outlet to the Mississippi. The remainder of the outlet is shown in Prof. C. W. Rolfe’s map sheets, yet unpublished. The reduced contour map (PL. I) accompanying this report is based upon these several surveys. It serves to indicate the comparative size of the valleys occupied by the outlet and of the main tributaries of the Illinois. But to fully appreciate the features produced by the outlet, refer- ence should be made to the large scale maps just mentioned. In the interpretation of these features from the maps, care must be exercised in determining the condition of the valley at the time the outlet first became operative. The portion of the Hlinois below Hennepin, it will be observed, is a preglacial valley, and was only partially filled by the glacial deposits. This fillmg is preserved in terraces along the borders of the valley. he glacial terraces seldom rise to a height of more than 100 feet and in the lower 100 miles their average height scarcely exceeds 50 feet above the present stream. In the portion of the valley above Hennepin the stream is mainly in a glacial or postglacial course, but even here there are complications which make it no easy matter to determine the amount of erosion attributable to the outlet. Before the accession of the lake waters this valley was the line of discharge for streams issuing from the ice sheet, as possibly of interglacial streams, some evidence of which has been gathered both by Professor Chamberlin and the writer. Although the streams were generally so heavily charged with detritus as to build up rather than erode their beds for some distance below the point of emergence from the ice sheet, it seems scarcely probable that fillme would have exceeded erosion throughout the entire length of the Des Plaines and Illinois valleys. The basin at the head of the Illinois, as noted above, was apparently occupied by a lake at the Valparaiso substage of glaciation, and this would have received the greater part of the detritus borne down by the 422 THE ILLINOIS GLACIAL LOBE. glacial floods on the Des Plaines and other tributaries entering the basin farther east, thus permitting the water to issue at the western end of the basin, unburdened with glacial material. The stream discharging westward from this basin would, therefore, have a tendency to deepen the new valley opened across the Marseilles moraine, and in all probability would have extended its excavation at least through the new portion of the valley to Hennepin, there being in that section a gradient of several inches per mile and possibly at first a higher gradient. It seems not improbable, also, that some excavation was accomplished by the glacial floods in their passage over the terraces in the lower portion of the Illinois Valley, the advantages for erosion being as good for these floods as for the later ones fed by Lake Chicago. It is also necessary to estimate the amount of filling which the lower course of the outlet has received since the lake waters were withdrawn. Concerning this filling, Prof. L. E. Cooley has made some investigation and concludes that from Peru to Peoria it will average 30 feet, and is appreciable to the mouth of the Llinois, though probably somewhat less toward the mouth of the river.’ In the Des Plaines Valley the erosion of the Valparaiso moraine and of the terraces outside of it was probably very largely effected by the lake waters. An examination of this portion of the outlet will therefore be likely to afford a fair understanding of the size of the channel which it formed. From the topographic maps it appears that the bed of the lake outlet declines from about 590 feet at Lemont, in the midst of the Valparaiso system, to scarcely 500 feet at the head of the Illinois, or 90 feet in a distance of 25 miles. Of this fall, 76 feet is made in a little less than 10 miles, from Romeo to Joliet pool. The glacial terraces which border the outlet decline from about 630 feet to 570 feet between Lemont and the head of the Illinois. This deepening of the channel is shown by the maps to be somewhat irregular, ranging from 40 feet to about 70 feet, but an average erosion of 50 feet may be assumed. This deepening embraces not only the work at the time the upper beach was forming, but also that carried on during the tormation of the second and third beaches, or down to the time of the final abandonment of the lake outlet. The channel above Joliet has ‘Communicated to the writer. THE CHICAGO OUTLET, 423 a breadth of 1 to 1$ miles, averaging perhaps 14 miles. Between Joliet and the head of the Illinois several island-like remnants of the glacial terraces are preserved in the midst of the channel, making it more difficult to estimate the breadth, but it is not markedly greater than in the portion above Joliet. The portion above Joliet is cut to a slight depth into the Lockport (Niagara) limestone, which there underlies the glacial gravel. The excavation in limestone, however, amounts to not more than one-fourth the size of the channel, for the limestone seldom rises more than 40 feet above the bed of the lake outlet, and in many places its surface comes down nearly to the level of the valley floor. Below Joliet there was even less excava- tion in the rock than above. It is estimated that the rock excavation there does not exceed 10 per cent of the total cutting. In the low tract at the head of the Illinois (the Morris Basin) the depth of the excavation by the outlet is very slight, averaging probably less than 20 feet in the 10 miles between the head of the Illinois and Morris. The plain appears to have descended nearly to the 520-foot contour on the borders of the river before modified at all by lake or stream action. A low bluff formed on the north border of the basin has a height of 15 to 20 feet. On the south border there is no bluff, that side of the basin being heavily coated with sand deposits. These deposits may perhaps have been laid down in part at the time the lake waters were forming the outlet, but they are probably largely of earlier date. In this basin the lake outlet has an average width of 4 or 5 miles. In the section of the Ilnois immediately below (west from) this basin, erosion prior to the opening of the Chicago Outlet probably had brought the level of the valley bottom down to that of the upper beach line of the basin, 550 to 560 feet above tide. The bed of the Chicago Outlet is nearly 500 feet, thus leaving about 60 feet subsequent depth of erosion. Passing westward the broad bed of the Chicago Outlet declines nearly 60 feet in the 40 miles between the west border of the basin, just mentioned, and the bend of the Hlinois near Hennepin. Whether the valley had the same gradient at the time the accession of lake waters occurred is not known, but it could not have been greatly different, for the glacial terrace just above Hennepin stands about 30 feet lower than the beach lines of the Morris Basin, and this terrace in all probability had been eroded the remaining 30 to 40 feet neces- sary to give a similar gradient. 424 THE ILLINOIS GLACIAL LOBE. The width of the outlet between Morris and Hennepin averages about 14 miles. The excavation is largely in soft St. Peter sandstone, there being nearly continuous rock bluffs to a height of 60 to 75 feet above the level of the bed of the outlet. This sandstone and the Coal Measures sandstone which in places overlies it present much less resistance to stream action than the firm Lockport (Niagara) limestone. The resistance may not be markedly greater than that of the beds of: glacial drift. As noted above, the level at which excavation by lake waters began in the section below the great bend of the Illinois is less than 100 feet above the present stream, since the glacial terraces in which the lake outlet was excavated seldom reach a level 100 feet above the bed of the outlet, while below the mouth of the Sangamon they rise scarcely 50 feet above that level. If the 30 feet of filling estimated by Professor Cooley be added, it seems a liberal estimate to allow 75 feet of average excavation in this lower section of 200 miles. It may not have been more than two-thirds that amount. The width of the outlet in this lower section ranges from 2 up to about 5 miles, with an average of perhaps 3 miles. This excavation is in a loose, easily eroded bed of sand and fine gravel, which had been deposited largely by glacial streams. Summing up the above estimates, it appears that the outlet has a width ranging from 1 mile up to about 5 miles, and a depth ranging from 20 feet up to 70 feet. Its length from Summit to the mouth of the Illinois is 300 miles. The excavation is probably not less than 3 cubic miles. With the exception of about 15 miles between Lemont and Joliet and 40 miles between Morris and Peru, where rock strata have been eroded, the excava- tion is almost entirely in beds of drift. The width varies with the resist- ance to erosion, being least in the section where the resistant limestone was eroded and greatest where there were only drift beds to remove, while in the sandstone the channel is of intermediate breadth. The breadth is also to some degree dependent upon the slope of the bed, being narrower in the portions with rapid fall than in portions having a low rate of descent. Throughout the entire length of the outlet the bluffs are steep, like a river bank, and deposits made by side streams on the edge of the valley are very meager—a feature which indicates that the stream had great vol- ume, probably filling the channel from bluff to bluff, and a current suffi- THE CHICAGO OUTLET. 425 ciently strong to carry away nearly all the detritus brought into it by the side streams The rapids between Romeo and Joliet occur in a section where the limestone is friable, and it is thought by Professor Cooley that the friability is such that falls could not have been maintained, or even established. The removal of the existing rapids, the main barrier in the course of the outlet, it is estimated, would require the excavation of a channel in rock only about 20 miles in length and 25 to 75 feet in depth. This excavation would be about ten times that accomplished by the lake outlet in that part of its course. Being the outlet from a lake, the amount of sediment carried by its waters is a matter which should be weighed in discussing the slight amount of excavation. Professor Cooley has called the writer's attention to the deposits at the head of Lake St. Clair as likely to furnish an index of the amount of sedi- ment transported by the Chicago Outlet. A delta with an area of several square miles has been built in the head of Lake St. Clair, which must have derived the bulk of its material from southward-moving littoral currents along both the borders of Lake Huron. In the lake under discussion littoral currents along the west border would have transported material probably in as great volume as on either shore of Lake Huron, but those on the east and south may have contributed less, for wind drifting there is very effective. It seems legitimate to assume that at least half as much sediment was being transported down the Chicago Outlet as is carried by the St. Clair River. From this it appears probable that the waters of the Chicago Outlet were somewhat less turbid than the St. Clair. Professor Cooley thinks the contributions of sediment to the outlet through the Des Plaines were of little consequence, for this river has, since the lake waters were withdrawn, made scarcely any filling of the outlet below Riverside, where its delta would naturally accumulate. The accession of larger tributaries below may have rendered the stream slightly more turbid than on the rapids It should not be inferred that this outlet is entirely free from river débris. Beginning at the upper beach, near Summit, there is for several miles a mass of coarse material, largely limestone blocks, too large to have been transported by the current, covering the bed of the outlet. The Drainage Canal exposes excellent sections of the coarse river débris from Summit to Lemont, there being only limited areas in this interval where 496 - THE ILLINOIS GLACIAL LOBE. the solid rock comes to the surface. Below Lemont the bare rock forms much of the floor as far as Joliet. From Joliet to the head of the Illinois perhaps half the floor is covered with deposits of drift and river débris, so that the distance to rock is not known. The remainder is either bare rock or rock with a very thin deposit of coarse river débris, with a liberal sup- ply of bowlders of Canadian derivation. In the Morris Basin the rock is largely shale. This has been eroded in places by the current, and the hol- lows have been filled with sand. From the Morris Basin to the bend of the Illinois the rock floor, mainly sandstone, is generally swept clean. The St. Peter sandstone of this section is of such a texture as to break up rap- idly into its constituent grains, and these, as fast as they were set free, would haye been carried by the strong current down to the lower Illinois, and probably on into the Mississippi. The lower Illinois has only sand and silt in its bottoms. This section is now in process of silting up, the current being too sluggish to carry away the material brought in from the upper portion of the stream. Acewnulations of bowlders should be mentioned in connection with the river débris. The most conspicuous accumulation noted is that on the borders of the Sag outlet, just east of the pomt where it enters the Valpa- raiso morainie system and northeast of the village of Worth. An area of perhaps a square mile is so thickly strewn that one might almost step from stone to stone over its entire extent. There are, it is estimated, more than 4,000 bowlders per acre. Surface bowlders are not rare in other portions of the old lake bottom where sand deposits are thin or wanting, there being, perhaps, 200 per square mile on the part of the lake bottom where till is exposed. There seems, however, to be a tendency to aggregation at the entrance to the old outlets. This feature suggests that floating ice has been influential in their distribution, though there may have been a large number brought by the ice sheet, the head of the outlets being near the inner border of the Valparaiso morainic system. Some very large bowlders have been fcund along the Drainage Canal. The large ones occur in most abundance where the Valparaiso system is crossed by the lake outlet. Bowlders are also very numerous for a few miles above the junction of the Des Plaines with the Kankakee. They seldom reach the large size which bowlders in the Valparaiso system present. THE ILLINOIS GLACIAL LOBE. 4v7 THE GLACIAL LAKE CHICAGO. The name-‘t Lake Chicago” was introduced by the writer in a recent bulletin issued by the Chicago Academy of Sciences.’ The need for a name for this glacial lake and the reason for the selection of this name are set forth in the following statement: * The introduction of the name “ Lake Chicago” for the glacial lake which was held in the southern end of the Lake Michigan Basin seems convenient, if not necessary, inasmuch as its area was not coincident with that of Lake Michigan and its outlet was in the reverse direction. It is also in keeping with the custom of students of glacial lakes, who find it advantageous to employ a special name for each of the temporary bodies of water in the several basins. The name “Lake Chicago” seems especially pertinent, since the glacial lake extended about as far beyond the present limits of Lake Michigan in the vicinity of Chicago as at any part of its border. It is also a name which readily suggests @he position of the lake, and it is in keeping with the name which has come into use for the outlet, namely, the “Chicago Outlet.” The name “ Lake Chicago” is applied provisionally to all the stages at which there was a southwestward outlet, but it is not yet certain whether they were all formed during the occupancy of a portion of the Lake Michigan Basin by the ice sheet. The precise relations of these beaches to the ice sheet, or points of connection with it, have not as yet been determined. The writer’s study has been carried no farther north than to the line of Wisconsin and Thnois on the west side and to Grand River on the east side of Lake Michigan. Professor Chamberlin’s studies left the precise extent of the higher beaches undetermined. Mr. Taylor’s observations have been confined to the north- ern portion of the basin, and as yet no one has examined the intervening districts, where it appears probable that the higher beaches terminate. Probably the most favorable field for investigation will be found on the Wisconsin side, since extensive deposits of wind-drifted sand on the border of the lake in Michigan make it difficult to determine the extent of water action. The long stretches of high bluff, however, interrupt the beaches so greatly that some difficulty is anticipated in making precise correlations on the Wisconsin side. Enough is known to make certain that the general direction of retreat of the ice sheet was northeastward. The southern and western portions of the Great Lake basins were, therefore, the first to become free from ice and 'The Pleistocene features and deposits of the Chicago area, by Frank Leverett: Bull. No. 2, Geol. and Nat. Hist. Survey, Chicago Academy of Sciences. Issued May, 1897. 2 Op. cit., p. 65. 42% THE ILLINOIS GLACIAL LOBE. to be oecupied by glacial lakes. While the ice sheet was covering the present outlets of Lakes Superior and Michigan, these lakes had no connec- tion with each other, nor with the lakes to the east, and their discharge was southward or southwestward into the Mississippi, from the present heads of these lakes. A small district west of Lake Erie was also occupied by a lake that discharged southwestward to the Wabash. Upon the withdrawal of the ice sheet from the southern peninsula of Michigan and the southern portion of the Lake Huron Basin, the lake at the western end of Lake Erie became expanded and a line of discharge was opened eventually from Saginaw Bay across the southern peninsula of Michigan to the Lake Michi- gan Basin, and this being lower than the outlet to the Wabash, that outlet was abandoned. The waters of the Lake Huron Basin being held at a somewhat higher level than those of the Lake Michigan Basin, the flow of water was from the former to the latter. The glacial lake which discharged across the southern peninsula of Michigan extended over the district between Lake Huron and Lake Erie, as well as the Lake Erie Basin and the low district bordering it on the south and west. It apparently did not extend far into the Ontario Basin, as a study of moraines indicates that the ice sheet occupied that basin at the time of this discharge. It thus appears that the Chicago Outlet at one time was the line of discharge for an area much larger than the present Lake Michigan Basin. Three well-defined beaches have been recognized at the southern end of the Lake Michigan Basin above the level of the present beach, which are known as the Upper or Glenwood beach, the Second or -Calumet beach, and the Third or Tolleston beach. THE UPPER OR GLENWOOD BEACH. This beach receives its name from the village of Glenwood, on the Chicago and Eastern Illinois Railroad, a few miles south of the limits of Chicago. The name has been selected (1) because the beach is especially well developed at that village, and (2) because, being near the State line of Indiana and Illinois, the name will be familiar to residents of either State. In the Illinois portion of Lake Chicago this beach is present, except for a few miles between Waukegan and Winnetka, where the lake shore is now farther west than it was at the time this beach was formed. In Indiana the beach is present throughout the entire extent of the border of THE GLACIAL LAKE CHICAGO. 429 Lake Chicago in that State, being nowhere less than 2 and in places 12 miles back from the shore. In Michigan it is absent for a short distance at the ‘clay banks,” north of New Buffalo, where the present shore stands farther east than the shore of Lake Chicago. It is also absent for the same reason for a few miles near the line of Berrien and Van Buren counties, north of St. Joseph, Michigan. Tracing in detail the course of this beach is as follows: From the Wisconsin line southward to South Waukegan it stands only 1 to 2 miles back from the shore of Lake Michigan and comes out to that shore at the poiat where the bluff of till sets in south of Waukegan. This bluff of till stands above the highest lake level as far south as Winnetka. From Winnetka a cut bank, nearly 20 feet in height, extends south along the face of the east till ridge noted above to its terminus, perhaps 1 mile from the point where the old shore departs from the present shore of the lake. From the terminus of this ridge a bar was built out southwestward 5 or 6 miles, terminating about a mile east of Chicago River, in the west- ern part of T. 41, R.13 EK. The bar sends out two prominent spurs to the west, a distance of nearly 1 mile. These probably mark the termini in its early stages of growth. The average width of this bar is about one-fourth mile, and it was built up to a height of 10 to 20 feet above the bottom of the bay back of it. It consists largely of gravel, but has a liberal admix- ture of sand. The bay back of this bar extended to the valley of the Chicago River and has a width of 2 to 3 miles. The northern end finds a narrow extension northward in Skokie Marsh. The site of this old bay is now largely under cultivation, though some portions are still marshy. The question naturally arises whether this accumulation of gravel and sand was formed by the lake currents and waves independent of the Chicago River, or was largely formed as a delta from that stream. This deposit is not in the form of a delta built up at the debouchure of the river into the lake, but lies some distance to the east of the river valley, thus mdicating that it was formed by the lake. Moreover, to make it still more evident that it was the lake and not the river which contributed the great bulk of the beach deposit, it is found that the river valley above the point where it entered the old lake has very little assorted material, such as would accu- mulate above a delta. 430 THE ILLINOIS GLACIAL LOBE. The beach appears on the west side of the Chicago River, in sec. 19, T. 41, R.13 E., about a mile northwest from the terminus of the bar. From this point southward to Oak Park the shore is usually a cut bank ranging from 6 to 25 feet in height, with occasional deposits of beach gravel and sand along its front. At Oak Park there is an extension of gravel down the east side of the Des Plaines River similar to that of the bar east of the Chicago River noted above. ) the removal of limestone to an average depth of nearly 100 feet for a length of at least 12 miles and a width of about 14 miles. The excavation of limestone is estimated to be nearly one-third of a cubic mile. (2) A filling of undetermined amount, but apparently not less than 30 feet, correlated with the Ilinoian stage of glaciation, which is well shown by the sections at Warsaw and at Yellow Banks below the lower end of the ¢ 472 THE ILLINOIS GLACIAL LOBE. rapids (discussed on a preceding page), and following this fillmg a nearly complete removal of it along the rapids. (3) The Iowan loess filling, also of undetermined amount, but probably 15 feet or more, and following this a nearly complete removal along the rapids. (4) The Wisconsin sand filling, which seems to have raised the river bed about 50 feet, followed by a nearly complete removal along the rapids. It would be very difficult to estimate the work involved in filling, even though the depth of filling in the vicinity of the rapids were known. The filling is simply an index of the excess of the material brought in over the transporting power of the stream. To properly estimate the work done in a stage of filling, 1t would be necessary to compute the amount of material carried through the channel as well as that deposited in it. In the case of the lower rapids, it seems doubtful if such computations can be made. The uncertainties involved in changes of drainage area are fully as great as in the work of filling. Some data showing the effect of- a change of volume upon the gradient of the river are cited by General Warren. At the time when Lake Agassiz discharged through the Mississippi the stream appears to have opened its channel in the Upper Mississippi to a depth in harmony with the bed of Lake Pepin, which is about 60 feet below present low water. The lesser volume of water now passing down the Mississippi has proved inadequate to remove the detrital dam built at the mouth of the Chippewa River (which is at the lower end of Lake Pepin), and thus the bed has been raised in that vicinity about 50 feet. It is thought by General Warren that a filling is now in progress along the greater part of the Mississippi above Cairo as well as below, and that the rapids are the chief places where a marked cutting is now in progress.’ In view of all these qualifying conditions, it seems hazardous to venture a comparison of the work of the Mississippi at the lower rapids with that of the streams on which estimates have been made, or at least to base definite conclusions upon such a comparison. In closing this discussion attention is called to the contours of the blufts of the channel along the rapids and to the rate of fall in the rapids. The contours of the bluffs favor the view that excavation began soon after the ' Bridging of the Mississippi: Ann. Rept. Chief of Engineers, U.S. Army, 1878-79, pp. 912-917. THE MISSISSIPPI VALLEY. 473 Kansan stage of glaciation, and has proceeded very slowly down to the present stream level. Except at a few points where the river in rounding a curve is encroaching on its bluff, the rise is gradual from each bank to the brow of the bluff, so that a large part of the slopes may easily be cul- tivated. Although the bluffs are largely a firm limestone, they recede about as much as the bluffs formed in glacial deposits at the upper rapids. Their age, therefore, appears to be several times as great as that of the upper rapids. The work performed in cutting away the rock barrier is many times greater than at the upper rapids. No “chains” rise above the general level, as at those rapids, and the fall has been reduced to a very moderate rate." Cutting now proceeds very slowly at these rapids, for the river carries but little sediment except at flood stages, and these extend over but a few weeks of the year. If all the features of the new channel be considered, together with the fact of the occurrence of long stages of interruption from cutting, there seems little to oppose the view that the opening or selection of this course may have been at so remote a date as the Kansan stage of glaciation. REESTABLISHED STREAM BELOW THE LOWER RAPIDS. The disturbance of the Mississippi Valley drainage. below the lower rapids is mainly restricted to the first 50 miles, between Keokuk, Iowa, and Hannibal, Missouri, where the western or Kewatin ice field at the Kansan stage of glaciation seems to have covered the valley and extended a few miles beyond it. This portion of the valley was left open at the Hlinoian stage of glaciation. There is, however, a bare possibility, as noted above, that the Illinois lobe encroached slightly upon the Mississippi Valley just above St. Louis. The disturbance of drainage was but temporary at either place, and the present river is fully reestablished in the preglacial course. lts valley bottoms are as wide as those of the preglacial river and range from 5 to nearly 10 miles in width. The rock bottom of the preglacial val- ley, like that of the section above the rapids, is considerably below the level of the present stream, as shown by the table presented below. 1It¢ is probable that in the early part of the opening of this new channel the gradient was much steeper than now, and possibly falls of some height existed. But as yet few definite criteria bearing upon this early condition of the valley have been recognized. 474 THE ILLINOIS GLACIAL LOBE. DEFLECTIONS SOUTH OF GLACIAL BOUNDARY. It seems necessary to refer briefly to two slight deflections of the Mis- sissippi, one of which is below the limits of glaciation and the other near the point where the glacial boundary bears eastward away from the Mississippi Valley. The former is certainly independent of obstruction by the ice, and the ‘latter may be also. The deflection near the glacial boundary is at Fountain Bluff, Jackson County, Illinois, where a rocky point similar to that at Fulton has been cut off from the west bluff. The broad preglacial valley, as at Fulton, is still occupied by the stream at flood stages, but is much less direct than the course across the rocky point. In explanation of this peculiar feature it is suggested that the encroachments of the Mississippi upon the rocky point had so broken down the crest that a moderate silting up of the valley, which probably occurred during the loess deposition, enabled the stream to cross it. The persistence of the stream in this course is probably attributable to the more direct line of discharge. Possibly the presence of the ice in the valley immediately north and east of this rocky point was influential in diverting the stream across it. The deflection farther down the river is at Thebes, Hlinois, where for a distance of about 6 miles the river is excavating a new course across a rock point which projects westward into Missouri. An inspection of this district shows that the alti- tude of the rock in the rocky point crossed by the stream is so low that it is necessary to assume but little silting up of the preglacial channel to have made it possible for the stream to take the present direct course, probably not more than 50 feet above the present level of the river. A silting of this amount may be supposed to have occurred during the loess deposition. ROCK FLOOR AND PRESENT STREAM COMPARED. In this discussion each of the preglacial valleys utilized by the present Mississippi are included. ‘The data concerning the rock floor are obtained from well borings or from tests for bridges, but are not sufficiently full to show whether the lowest part of the valley floor has at any point been reached, much less do they indicate the lowest part at all points. It seems probable, however, that the majority are in the deep part, since they are located near the middle of the preglacial channel. They at least indicate approximately the depth of preglacial excavation, and it is thought that they throw some light upon the slope of the rock bottom. THE MISSISSIPPI VALLEY. 475 In the table which follows it will be observed that the rock bottom has a lower altitude at St. Paul, Minnesota, than at several points farther down the present stream, a feature which is thought to sustain the interpretation made by Hershey, that a divide has been crossed between St. Paul and Dubuque. In a paper prepared by the writer a few years ago! this low altitude at St. Paul and vicinity was suggested to be due either to north- ward differential depression or to a local deepening, such as might have resulted from a waterfall or from subglacial erosion by water or ice. How- ever, no evidence of the operation of these agencies has been discovered, and they could not have been operative within the Driftless Area. These suggestions do not, therefore, seem so pertinent as the interpretation made by Hershey. Altitudes of rock bottom and present Mississippi. oe Tarps eal a7 i | ] 1 | i enc ex Location [Pstance| Kigali (abeo te" ioe | | Miles. | Feet. Feet. Feet. Sib PWG MGW oe ceadooan soos séou pease baeass sasss6 0! 683 702 «| «ad83 Teak ey City MMT seenee eee ete he Ae Mite see en hen ess) 658 (?) | b495 Wanonasiviinneee sere keen tabi Sei Qn en th ga iia oe | 40 639 656 e503 HACLOSSE AVVISTE see eis aaa eek ceo eet oeieeecle states 20 628 | 643 | d504 | Jere MAN) Chit CIE Ns 3 60 seo caosbebscebese cone sees 60 604 623 | d492 IDM NTIGING), NWOWIBeccedeocsscansesoas ssoose sen cacecoco| 55 585 607 | d453 SHOE, NONE) oscoscdoeds eos5 Seedeo dase Sced seasHeaess 36 572 592 | ¢429 | | | WliintoMe MW. ~~ des snen SSoS4e cobRds sooa bUCEaS aso osoeSE | 16 566 | 587 4004 Leclaire, Iowa (new channel) -.---..---.-------..--- 20 | 562 576 550 Rock Island, Ill. (new channel) ...---..------------- 16 542 | 560 530 Muscatine, Iowa (new channel) --.-....--..----..-.- | 24 5381 547 | «506 Near Wilton, Iowa (old channel)...--...----.---.-:- JUSS ee RAN Ma aE eae ada | f400— Near Muscatine, Iowa (old channel) .--...----..---- | 2 530 | 547 =| «9 388 Mouphvotmlowarkivenseaceseeeeenee ese ee eee eee ee 18 523 539 | 445 — JAMMIN NOME) = so Sou cosoG0 coSseR coro odacss osccse | 24. 511 527 | 430— Monty Madi Sono wae eeee sane ee eee eee eer | 18 | - 502 518 | 365 | aN. H. Winchell, Am. Geologist, Aug., 1892. b Geol. of Minnesota, Vol. I, p. 17. cData furnished by Dr. U.S. Grant in letter. d Chamberlin and Salisbury, Sixth Ann. Rept. U.S. Geol. Survey, p. 223 e Data given by W. R. Oake, ex-mayor of Sabula. fA well at this point, reported by Udden, failed to reach rock at elevation 400 feet above tide. g Two wells in the valley below Muscatine, reported by Udden, reached rock at a level about 142 feet below the low water level of the Mississippi. hC.H. Gordon: Geol. of Iowa, Vol. III, 1893, p. 246. A well one-half mile north of Fort Madison reached a level about 365 feet above tide without entering rock. The channel may, therefore, be deeper than that shown by the Fort Madison wells. 1 Jour. Geol., Vol. III, 1895, pp. 740-763. 476 THE ILLINOIS GLACIAL LOBE. Altitudes of rock bottom and present Mississippi—Continued. j = 7 ; = Location. |Distanee. shove tide: | above tide. | above tide | Miles. | Feet. Feet. | Feet. Montclare, Iowa (old channel).----.--..---.---- Bans 25092505 |fassSo 050 |---------- | ads Montrose, Iowa (new channel) -..--..----------- eox4 91 500 | 514 | 490 Keokuk, Iowa (new channel) ......-.--.------------ 109) «|| 477 | 494 475 Quine yalllea(rockyshelf) ses series eee ee eee 38 | 458 | 476 5413 Hannibal Moy. csaenos << 2.2.0. Cute fast) Seca. Saeed 450 | 467 362 | Louisiana, Mo .-...---...--.----------+------------- 25 | 437 | 453 d380— evouthiosilllinoiseRiversssenet oer aes eee | 68 403 4929 (9) | Bellefontaine, Mo. (on Missouri River) ..-.---------- | 17 402 4204. | e295 aaah Sth Mouisslllessteyce! ie Solute ea a eae jo Be 380 | 414 | fagd | East Carondelet, Il]. (on rock shelf?) ---.-----..----- 6 377 412 330 Fountain Bluff, Ill. (mew channel) -.-..------------- 100 313 | 357 300 NearaWioltelnalce ll test e= crete a seisiee ise aes 15 305 | 350 g 255— leeEhebessUlle(mewichannell) ion s-snesenisea see 25 291 | 339 280 Cairo lhe sec ee oll ae La RA eae 35 Mi | Be PD) a Beck's artesian well, at Montclare; see Geol. of Iowa, Vol. III, p. 247; also this report, fig. 5. b Bridge piers rest on a rock shelf 33 to 40 feet below low water: Rept. U.S. Army Engineers, 1878. cData concerning channel piers furnished by W. S. Lincoln, chief engineer of Wabash Railroad, St. Louis, Missouri. dBed of present stream is 380 feet above tide: Rept. U.S. Army Engineers, 1878. e Missouri River Commission, Rept. for 1890. The low-water altitude here given is on the Missouri. f Data concerning depth to rock at bridge piers furnished by Robert Moore, C. E., St. Louis, Missouri. g A well made by Bolin Sublette failed to reach rock at 50 feet below river level. The fact that the rock bottom in this and other valleys of the Upper Mississippi region lies considerably below the present streams has often been cited in evidence of a great preglacial altitude of the region. This interpretation seems questionable, inasmuch as there appears to be an adequate fall to the seaboard from the rock floors of these valleys, even though the altitude were no greater than at present. In the valley under consideration the rock floor in the 210 miles between Fort Madison, Iowa, and St. Louis, Missouri, makes a descent of about 80 feet, or 43 inches to the mile, and stands sufficiently high at St. Louis to maintain a similar fall to the Gulf were a direct channel to be opened. A somewhat similar gradient appears also to be maintained in the portion above Fort Madison. Although the gradient is somewhat lower along the rock floor than that of the present Mississippi, it is about as great as that of the present Ohio, which has a fall of but little more than 5 inches to the mile in the 967 miles from Pittsburg to Cairo. MINOR TRIBUTARIES OF THE MISSISSIPPI. 477 The breadth of the valley excavation seems also to support the view that it was produced under a moderate or low rather than a high stream gradient. It seems improbable that a stream which was cutting down rapidly could have formed a valley several miles in width such as appears along the line of the Mississippi below Muscatine, or along the line of other preglacial valleys occupied by the Mississippi above Clinton. So far as known, the preglacial channels under consideration have furnished no posi- tive evidence of the existence of narrow trenches cut below the general level of their rock bottoms. A few rock shelves have been found extending out a mile or more, as at Quincy and St. Louis, but these occur at points where the river has, in comparatively recent time, been encroaching upon the rock bluffs, and may, therefore, be a more recent product than the deeper part of the valley. In the present state of knowledge it certainly seems unsafe to cite them in evidence of a preglacial gradation plane standing above a lower part of the rock bottom. ; MINOR TRIBUTARIES OF THE MISSISSIPPI. Since the Hlinoian invasion encroached only a few miles upon the dis- trict west of the Mississippi (in the southeastern part of Iowa), it has not greatly influened the course of the western tributaries. The larger western tributaries in southeastern Iowa, as above noted, were temporarily deflected southward along a course immediately outside the Illimoian ice border, but these have regained the courses opened prior to the Hlimoian invasion. The tributaries here discussed are, therefore, mainly on the eastern side of the Mississippi. The discussion begins in northern Illinois and the streams are taken up in order southward. APPLE RIVER. A few streams lie wholly within the driftless portion of northwestern Illinois and adjacent parts of Wisconsin and may, therefore, be passed by, since they maintain their preglacial courses. It is, however, necessary to mention one stream, Apple River, which lies almost wholly within the limits of the Driftless Area, but which has received a marked accession of drainage because of the blocking of a preglacial tributary of the Pecatonica. This diversion occurs just below the village of Millville, as shown in Pl. XII. For about 3 miles below Millville the stream is in a gorge but little wider than its bed. The small preglacial Apple River is then entered. 478 THE ILLINOIS GLACIAL LOBE. PLUM RIVER, Plum River lies partly within the Driftless Area, but its lower course and two important eastern tributaries traverse glaciated districts on the southeast border of the Driftless Area. By reference to the Savanna topographic sheet it will be seen that the stream passes through a gorge in southwestern Woodland Township, Carroll County, which apparently was formerly the site of a divide between the Plum River drainage and a much smaller stream entering the Mississippi at Savanna. he course of the preglacial Plum River was probably southward through the glaciated dis- trict, along a line a few miles to the east of its present lower course, but as yet the precise location of the valley has not been ascertained. Carroll Creek, one of the principal eastern tributaries of Plum River, apparently discharged southward through Johnson Creek Valley, from a point imme- diately east of Mount Carroll. It now passes westward through a series of gorges in the vicinity of Mount Carroll and enters a small preglacial valley about 2 miles west of that city. The interval between Carroll Creek and Johnson Creek is completely filled with drift for a distance of about 4 miles. The drift fillmg terminates abruptly near the point where the Chicago, Burlington and Northern Railway crosses Johnson Creek. From that point southward a preglacial valley fully a mile in width leads down to the Mississippi. No stream of consequence enters the Mississippi on the east between Plum River and Rock River. As the latter stream constitutes one of the major tributaries, its discussion is taken up farther on. We pass, therefore, to the district south of the mouth of Rock River. EDWARDS RIVER. Edwards River, a stream which has a length of about 60 miles, leads westward from Henry County through Mercer County, Illinois, entering the Mississippi nearly opposite the mouth of the Iowa River. Its head- water portion consists of several streams which converge to form two forks that unite in south-central Henry County. From the junction of these two forks a remarkably direct westward course is taken, so that from points on its bluffs views may be had for several miles up or down the stream. This portion has only insignificant tributaries and drains a very narrow belt. The directness of its course and the narrowness of its drainage basin are MINOR TRIBUTARIES OF THE MISSISSIPPI. 479 due to peculiarities of drift topography, there being in the district through which Edwards River flows a tendency to slight ridging in a general east- west direction, with broad, shallow depressions separating the ridges. Edwards River follows one of these depressions, while Pope Creek, which flows parallel with it on the south, follows a neighboring depression. A depression north of Edwards River differs from that of the two valleys just mentioned in separating its waters, a portion flowing directly west to the Mississippi through Copper Creek and a portion east and north into Rock River through Mill Creek. None of these streams, so far as the writer is aware, reach the bottom of the drift, yet it can not be assumed that they follow preglacial lines, for well sections indicate that the ridges and depres- sions are largely independent of the altitude of the underlying rock surface. HENDERSON RIVER. Henderson River, which drains much of northern Henderson, northern Warren, and part of Knox counties, Illinois, though having a length of scarcely 50 miles, furnishes a discharge through its numerous branches for an area of fully 500 square miles. The courses of the main branches seem to have no dependence either upon the underlying rock surface or upon drift topography. They traverse a very smooth district having gradual westward descent. The courses of the several streams are proba- bly the result of slight advantages in the inclination of the slopes, at present difficult to discern. These streams have now in several instances cut down into the rock, and their courses seem to be independent of pre- glacial lines. FLINT RIVER. The first western tributary of the Mississippi to claim attention is Flint River, a small stream entering the Mississippi immediately north of Burlington, Iowa. Its source is in the marginal ridge of the Hlinoian drift near New London, Iowa. The stream flows thence southeastward to the Mississippi across a gradually descending plain. It appears to disregard the courses of preglacial drainage limes, for in its upper course drift deposits extend in places to a depth of 250 feet, while in its lower course it has carved a channel through the rock ledges, whose cherty layers give to the stream its name. 480 THE ILLINOIS GLACIAL LOBE. LOST CREEK. Lost Creek, a small western tributary of the Mississippi draining the eastern portion of Lee County, Iowa, occupies a valley markedly larger than other streams of its size which have cut channels in the Illinoian drift, a feature which appears to be due to an occupancy of the valley by a larger stream than the present one prior to the Hlinoian ice invasion. The present head of the stream is in the marginal ridge of Illinoian drift near West Point. It seems not improbable that streams now draining south- ward through Sugar Creek found their outlet through Lost Creek Valley prior to the Illinoian invasion. The interpretation is rendered difficult because of the interruption made by the large stream channel of the tem- porary Mississippi, a channel which, as noted above, governs the present drainage of the streams outside the Illinoian drift from Skunk River southward. BEAR CREEK. Two small eastern tributaries of the Mississippi River remain to be considered—Bear Creek and Bay Creek. The former drains the south- western part of Hancock and the northern part of Adams counties, Illinois. It has a widely branching drainage system, and the courses of the several tributaries were probably determined by the slope of the drift plain. One of the tributaries heading near Sutter leads northeastward for a few miles along ‘‘ Big Meadow Channel,” an abandoned valley of a larger stream, but turns away from that valley to form the north fork of Bear Creek. This north fork traverses a region of very thick drift, yet it may have no dependence on the course of preglacial drainage, but the lower course of Bear Creek evidently follows a preglacial line. The abandoned valley just mentioned is described below. BAY CREEK. This stream drains much of Pike County, Illinois. Its headwater por- tion leads from the north border of the county southeastward toward the Illinois, following a sag between two Ilinoian drift ridges and nearly reach- ing the Illinois River, opposite the village of Bedford. It then curves around to the southwest, passes through a gap in the rocky ridge, which to the north and south constitutes the divide between the Mississippi and the BIG MEADOW CHANNEL. 481 Illinois, and enters the Mississippi Valley opposite the town of Louisiana, Missouri. The deflection to the west is due to the ridge of Ilinoian drift which follows the east border of the stream and prevents it from entering the Illinois Valley. The gap through the rock divide was apparently broken down below the level of the drift-filled districts to the east prior to the ice invasion, and thus offered no obstruction to the westward. deflection of the drainage. There are several small creeks entering the Mississippi between Bear Creek and Bay Creek, but which scarcely merit special mention, since they usually take a somewhat direct course to the river, following the slope of the drift surface. Those in Adams and northwestern Pike counties are in some cases deflected slightly by the drift ridges formed on the west border of the Ilinoian drift, and find passage to the river through gaps in these ridges. In Pike and portions of Adams counties these creeks in part follow preglacial lines. BIG MEADOW CHANNEL. Under this name is discussed a channel which has been excavated in the Ilinoian drift by a stream which long since ceased to flow. The chan- nel is distinctly traceable in a course about 8. 65° W. from near the town of Bushnell, Illinois, to the valley of the Mississippi in western Hancock County, a distance of 50 miles (see Pl. VI). Throughout its entire length the valley has bluff-like borders, which range in height from 20 feet to about 50 feet. In width it ranges from one-fourth to fully one-half mile. Its bot- tom is underlain by sandy and gravelly material, apparently alluvial, and there seems little question that it has been occupied and formed by a stream of considerable volume. From near Bushnell the valley is now followed westward across MeDonough County by East Crooked Creek. From the mouth of this stream the channel continues along Middle Creek (reversed) to the present divide between the Illinois and Mississippi drainage systems. In its passage across this divide it has cut a valley fully 40 feet in depth and more than half a mile in width. It is this portion which has long been known by the residents as the ‘Big Meadow.” At the west it continues down Big Meadow Creek to another headwater tributary of Bear Creek, and thence follows the course of that creek (reversed) to the divide between Bear Creek MON XXXVIII——31 482 THE ILLINOIS GLACIAL LOBE. and the Mississippi near Sutter. The valley is here well defined and nearly as deep as at the “Big Meadow divide.” From Sutter it leads down the valley of a small stream known as Rock Run, passing through a gap in the marginal ridge of Ilinoian drift just before entering the Mississippi Valley. Throughout this entire distance of not less than 50 miles its course is remarkably direct. The precise variations in the elevation of its bottom have not been determined. The eastern end near Bushnell, the “Big Meadow divide,” and the divide at Sutter, all stand very nearly 650 feet above tide. With the exception of the descent into the Mississippi Valley west from Sutter, the slope of the valley bottom probably nowhere exceeds 5 feet to the mile, and is usually scarcely half that amount. This singular valley appears to find its parallel in the valleys accom- panying some of the eskers, an instance of which in Kane County has already been discussed (p. 284). No esker, however, lies in the “Big Meadow” Valley. It seems probable that the stream which excavated this channel was confined beneath the ice sheet, and thus held to a direct course across the low divides and shallow depressions covered by the ice. The hypothesis of a piracy of the stream which formed this channel by the two ereeks which now drain it, Crooked Creek and Bear Creek, has been con- sidered and seems untenable. The valley was evidently formed by a stream having much larger volume than either of these creeks possesses at the points where they depart from this old channel. Furthermore, the course of the chamnel is such as can scarcely be supposed to have been inaugurated without the confining influence of the ice sheet, for the present courses of drainage are determined by the general slopes of the region and are the natural lines of discharge. It seems, necessary, therefore, to refer this abnormal drainage to a subglacial stream. In this connection it may be remarked that the system of parallel streams in McDonough County, all bearing west-southwest, may have been a result of slight channel development by subglacial streams along these lines. Similarly the depressions occupied by Edwards River, Pope Creek, and Copper Creek, in Mercer and Rock Island counties, may have been at first avenues of discharge for subglacial waters. There seems, however, in this latter district to have been a more decided development of ridges, parallel with the depressions, than is found in the vicinity of the “Big Meadow” channel. INFLUENCE OF THE DRIFT UPON DRAINAGE. 483 ROCK RIVER DRAINAGE BASIN. Rock River, which drains much of northwestern Hlinois, has a length of nearly 300 miles and a drainage area of about 11,000 square miles. Nearly half its length and more than half its drainage area are in Wisconsin. Its general course is southwest from southern Wisconsin across northwestern Illinois. From its source to Janesville, Wisconsin, it traverses a region covered by drift of Wisconsin age, and its basin is characterized by extensive swamps and numerous small lakes. The drainage appears to be largely independent of preglacial lines. Just above Janesville the river crosses the outer or “Kettle” moraine of the Green Bay lobe, and soon enters a broad preglacial valley filled with a gravel deposit which heads in that moraine. The bordering uplands are covered by drift of Iowan age, as well as by earlier glacial deposits of Illinoian and possibly of still greater age. Below Janesville, with the exception of a few miles near its mouth in Rock Island County, Illinois, the present stream lies within the limits of the lowan drift. The western border of that drift, however, extends but a few miles west of the stream at any point, and for a few miles below Rockford follows nearly the course of the river. The portion of this drainage basin lying outside the Wisconsin drift is generally undulating and well drained, but extensive swamps occur along Green River, an eastern tributary. The western tributaries lie mainly outside the limits of the Iowan, and the chief tribu- tary, Pecatonica River, drains a small part of the Driftless Area. The preglacial valley entered by Rock River near Janesville, Wiscon- sin, is followed southward a distance of 50 miles to the mouth of Kishwau- kee River, a few miles below Rockford, Hlinois. The river and valley there part company, the valley continuing southward and apparently con- necting with the Illinois at Hennepin, the river turning southwestward to enter the Mississippi (see Pl. XII). In this southwestward course is found a series of small valleys separated by low divides which afforded the stream a means of escape without producing a great amount of rock excavation, as will appear from the detailed description given below. f THE PREGLACIAL DRAINAGE, The preglacial valley entered by Rock River near Janesville may be traced without difficulty as far south as Rochelle, in southeastern Ogle 484 THE ILLINOIS GLACIAL LOBE. County, where a bulky moraine which forms the west border of the Wis- consin drift makes further tracing difficult. The valley has been so incom- pletely filled outside the limits of the Wisconsin drift that its rock bluffs rise perceptibly above the general level of the filling along the valley. But within the limits of the Wisconsin drift the valley has not only been com- pletely filled but the general level of the drift surface rises 100 feet or more above its bluffs. Its course can be known, therefore, only through data obtained by deep borings. These indicate that it leads southwestward across eastern Lee and northeastern Bureau counties to Princeton, and thence southward to the bend of the Illinois River at Hennepin. The breadth of the valley, in the portion exposed to view, averages about 3 miles, though it in places reaches nearly 5 miles. Its rock bottom appears to be somewhat lower than that of the preglacial valley occupied by the neighboring portion of the Mississippi. Chamberlin reports a boring at Lake Koshkonong, Wisconsin, which failed to reach rock at an elevation only 450 feet above tide. The rock was reached on the Missis- sippi in the same latitude at about 490 feet. Borings at Princeton, Peru, Bureau Junction, and Putnam, Illinois, enter rock at about 340 feet above tide, while borings on the Mississippi at Fort Madison, Iowa, which is some- what farther south, reach rock at about 365 feet, though one boring failed to reach the rock at that elevation. No borings have been made between Lake Koshkonong and Princeton which are calculated to test the depth of the preglacial valley. Borings at Janesville, Wisconsin, and Rockford, Illinois, made at the foot of the west bluff, enter rock at about 530 feet above tide. They can scarcely be supposed to represent the depth along the middle of the valley opposite these cities. Several wells have been sunk in eastern and southern Lee County and in northeastern Bureau County, Illinois, which fail to enter rock, though they terminate at an eleva- tion less than 500 feet above tide. From the data at hand it appears that the rock bottom descends from 450 feet or less above tide in southern Wisconsin to 340 feet above tide at the bend of the Illinois, 90 to 100 miles farther south. Several of the large preglacial tributaries of the old valley may be traced readily in the district lving outside the limits of the Wisconsin drift. The Pecatonica River, which is the largest of the present tributaries, is ROCK RIVER DRAINAGE BASIN. 485 reestablished along the preglacial line, though the lower half of its course lies within the limits of the glacial district. The headwater portion of one of the western tributaries of the Pecatonica—Yellow Creek—has been diverted into Apple River, a tributary of the Mississippi. This stream also makes slight deflections into the bordering bluffs in its lower course. Sugar River, the principal northern tributary of the Pecatonica, occupies its pre- glacial line, except, perhaps, at the headwaters. Many of the smaller trib- utaries are also largely in preglacial lines. Leaf River, which now drains a portion of northern Ogle County eastward into Rock River, is following a preglacial line which continued eastward across the present course of Rock River, through an abandoned channel known as, “Stillman Valley,” to the village of Stillman Valley, and thence northeastward to the old Rock River Valley in southern Winnebago County. Rock River follows the line of this preglacial valley for a few miles in the vicinity of Byron, but in the reverse direction from the stream which excavated the valley. Rock River also makes use of small tribu- taries of the preglacial Leaf River. From the mouth of the present Leaf River it passes up the valley of a small southern tributary for a few miles. Before entering the old Leaf River Valley east of Byron it has utilized a small northern tributary of that valley. Bluff Creek also, which enters the present Rock River a few miles above Byron, has a preglacial course southeastward across the present Rock River to a lower course of the pre- glacial Leaf River. The Kishwaukee River, the first important eastern tributary of Rock River south of the Wisconsin line, is in a new course for a few miles below the junction of the north and south branches. It is not clear whether the old mouth was a short distance north of the present mouth or whether the stream passed southward up the south branch to the vicinity of Fielding and thence across to the old Rock River Valley near Esmond. The north and south branches each occupy a preglacial valley for a few miles above their junction, but the headwater portions of each stream are in new val- leys. ‘The head of the north fork may not have been so far east as now, for the effect of the ice sheet generally in northern Illinois has been to force streams into the Rock-Ilimois drainage basin from the east slope of the limestone ridge which separated this basin from the Lake Michigan Basin. 4 486 THE ILLINOIS GLACIAL LOBE. Kite River, which now flows northwestward into Rock River at Ore- gon, Illinois, occupies a preglacial western tributary of the old Rock River which may be traced southeastward into the old valley at a point south of Rochelle. The head of the preglacial stream appears to have been in the hills back of the town of Oregon. 'The present Rock River therefore cuts off only the headwater portion of this preglacial valley. The preglacial drainage of southern Ogle, northern Lee, and eastern Whiteside counties appears to have been directly toward the preglacial Rock Riyer in southern Lee and northern Bureau counties. The present Rock River intersects several of these streams midway of their course and diverts them westward into the Mississippi. The lower courses of these preglacial streams are now concealed beneath the sand deposits of the Green River Basin. Probably western Whiteside and neighboring portions of Henry and Rock Island counties, now tributary to Rock River, were tributary to a preglacial stream which connected directly with the Mississippi, if they did not themselves discharge directly into the stream. PRESENT COURSE OF ROCK RIVER. At the mouth of the Kishwaukee River, 7 miles south of Rockford, Rock River turns directly away from the broad preglacial valley and for 50 miles takes its course southwestward through a much narrower valley (see Pl. XII). The narrow valley extends to western Lee County, a few miles below the city of Dixon. From this point to the Mississippi, a dis- tance of about 80 miles, the river flows in the broad lowland known as the Green River Basin. A few miles above its mouth, however, the basin is interrupted by island-like strips of upland, around which the stream takes its course, as shown in Pl. XVIII. Its main channel is south of the islands, the other channels being occupied only by sloughs and sandy plains. A somewhat detailed study of the narrow portion of the valley has been made with a view to determining the amount of rock excavation accom- plished. This study has brought to light an interesting series of changes in drainage, some of which have already been mentioned. This narrow portion is naturally divided into the following sections, taken in order, beginning at the point of deflection from the preglacial valley and passing ROCK RIVER DRAINAGE BASIN. 487 southwestward. The length of each section and estimated amount of rock excavation are also given: Table showing rock excavation in the new course of Rock River. = = ee) Distance. | Excavation. | oy Miles. Mile-feet. | (Gy AA@ROrS 8 HOOK TGR sosocooseone saad naeb socuce eenors osaocoresa5 boCC 1 a5) | (@)eUpspreclacialiBluitt@ reeks oes-s tetas soe cee sense anise ase nee 3 100 | (SB) PAtcrossyaprockydivad eeeectpes cles ele ese eee eee See eee seer 1 30 (4) Down north tributary of preglacial Leaf River...-..-.---..-..---. 3 60 | (©) BUpspreslacial eat pRiver Valley, = -j-2 4-222) -ie ees ee sees cieee 7 50 (6) Up a south tributary of preglacial Leaf River...--.....-..-..--.- 3 60 (7) Across a rock divide ....-...--...- we a SIG thee ce See ee 2 75 (8) Across Kite River Valley and associated lowlands -...--...---.---. 7 125 (OeAtcrosstasrocks divider ane cape oSci--ccy-baeiseicn cv o=,s Nese ne aeetee ne 2 40 (10) Down a preglacial valley to Green River Basin.......-....-...--. 20 500 TRASH Ln ose a ng ac es | ZoMt | eeaeO55 Throughout this narrow portion the stream maintains a width of about 500 feet, but its valley ranges in width from 1,000 feet to fully a mile. The stream makes a descent of only 60 feet, being 680 feet at the mouth of Kishwaukee River and 620 feet at the head of the Sterling rapids, where it opens into the Green River Basin.’ So far as known, it has no rock rapids in this portion of its course, and there are places where its bed lies 20 feet or more below the low-water level of the stream. The occurrence of these deep places along the river bed and the data obtained from wells along the valley indicate that the rock bottom may generally lie not less than 20 feet lower than the present stream. It has seemed necessary, therefore, in estimating the amount of rock excavation, to assume that it extended to this depth. It may have extended even deeper. Taking up now the several parts of this narrow section of the river, the following are the data upon which the estimates of the rock excavation accomplished in it have been made : _In the passage across the rock ridge between the preglacial Rock River and Bluff Creek the stream has cut for one-fourth mile at the crest of the ridge to a depth of fully 70 feet and a width of about 1,000 feet, and presents the cross section shown in fig. 6, No. 2, but on the slopes of the ‘Computed from Greenleaf’s Report in Tenth Census, Vol. X VII, 1880. 488 THE ILLINOIS GLACIAL LOBE. ridges the rock surface descends to only 20 or 25 feet above the river. The exeavation in this ridge is, therefore, not more than 15 mile-feet.’ In the three miles along the preglacial Bluff Creek the amount of cut- ting ranges in depth from 25 to nearly 100 feet and in width from 1,500 to N° 1. PREGLAGIAL AND PRESENT VALLEY OF ROCK RIVER AT ROCKFORD, ILLINOIS. N°2.PROFILE AT COL CROSSBD BY ROCK RIVER ATA PLATE XII N9Q3.ROCK RIVER IN PREGLACIAL BLUFF CREEK VALLEY N94, PROFILE AT COL CROSSED BY ROCK RIVER AT'S; PLATE XII N°S5.ROCK RIVER IN THE PREGLACIAL LEAF RIVER VALLEY AT BYRON, ILLINOIS. N96. PROFILE AT COL CROSSED BY ROCK RIVER ATC. PLATE XII N°7 ROCKRIVER N°8 PROFILEAT IN THE PREGLACIAL COL(?) CROSSED KITE RIVER VALLEY BY ROCK RIVER AT OREGON, ILL. AT'D. PLATE XII Fic. 6.—Sectious across Rock River Valley, in northern Illinois. 2,000 feet. The level at which the pre- glacial stream had cut is marked by a change in the angle of slope (see fig. 6, No. 3), that below being much steeper than that above the preglacial level. It seems safe to assume 100 mile-feet of excavation. On the divide between Bluff Creek and the north tributary of the preglacial Leaf River the cutting is estimated to be double that at the neighboring rock divide on the east, or 30 mile-feet (see fig.6, No.4). It has a depth of 80 to 110 feet and a width of 1,200 to 2,000 feet. Along the north tributary of the preglacial Leaf River the excavation de- creases from about 80 feet practically to zero. The width of excavation is about 2,000 feet, widening to nearly 2,500 feet at the border of the old Leaf River Val- ley. ‘The excavation is estimated to be 60 mile-feet. In the 7 miles along the preglacial © Leaf River Valley the excavation is con- fined to a slight cutting of perhaps 25 feet at the borders of the preglacial val- ley, which diminishes to zero before reaching the middle of the valley. The valley here is a mile wide, with gradual rise to either bluff, as shown in fig. 6, No. 5. The excavation is estimated to be but 50 mile-feet, which is. proportionately less than along any other part of this narrow portion of the valley. 1 A mile-foot embraces a block 1 mile square and 1 foot thick. ROCK RIVER DRAINAGE BASIN. 489 Along the south tributary of Leat River the limits of preglacial exca- vation are clearly marked as on Bluff Creek. The excavation on Rock River increases from 25 feet or less to about 75 feet. The width of this portion of the valley is about 2,000 feet. The excavation is estimated to be 60 mile-feet. On the divide between the preglacial Leaf and Kite rivers the excava- tion appears to have ranged from 60 feet up to perhaps 125 feet in depth, and the width is somewhat uniformly about 2,000 feet (see fig. 6, No. 6). The excavation is estimated to be 75 mile-feet. In the Kite River Valley and associated lowlands the excavation appar- ently ranged from zero to about 50 feet in depth. In Kite River Valley the width is a mile or more, but below the valley it is about 2,000 feet. An average cross section is shown in fig. 6, No. 7, which is at Oregon. The excavation is estimated to be 125 mile-feet. South of Kite River the depth of excavation appears to scarcely exceed 50 feet, and no sharply defined col could be found, for, being in the St. Peter sandstone area, the uplands are very uneven. The width of excavation is 2,000 to 2,500 feet, and the total excavation is estimated to be only 40 mile-feet. The profile shown in fig. 6, No. 8, is found at D, Pl. XII, and may perhaps cross at the site of an old col. The depth of excavation along the portion of Rock River between the place shown in this profile and the Green River Basin has not been so carefully computed as in the portions above. The river appears to follow the line of a small preglacial stream as far as the mouth of Pine Creek, whose valley has been somewhat broadened by it. Below the mouth of Pine Creek the preglacial valley has been widened but little. The average width of the valley is about one-fourth mile, and in places it reaches nearly amile. Such is the case at the sharp bend at Grand de Tour and at bends near Dixon. The rock excavation may possibly amount to 500 mile-feet in this lower 20 miles, but it seems as probable that it does not exceed 400 mile-feet, and it may be even less. Combining the above estimates, it appears that there has been not more than 1,055 mile-feet of excavation in the 49 miles of this narrow section of the Rock River Valley, and possibly it falls below 1,000 mile-teet. It may, therefore, be roughly placed at one-fifth of a cubic mile. The present discharge through this valley, based upon estimates by Greenleaf and by Rae, is somewhat more than 4,000 cubic feet per second, that being 490 THE ILLINOIS GLACIAL LOBE. the estimated average yearly flow past the city of Rockford.’ It is not known whether the present flow differs widely from that of the stream which produced this rock excavation, for the excavation appears to have been practically completed prior to the Wisconsin stage of glaciation. The drainage area and the rate of discharge may have been altered somewhat as a result of the Wisconsin invasion. Also a part of the rock cutting may have been produced by a glacial stream at the time of deflection. It is thought, however, that the glacial stream would have expended its energies at the rock divides, and that changes in drainage area are of minor conse- quence, so that the excavation may be assumed to have been chiefly accom- plished by a stream similar in size to the present Rock River. This narrow section of the Rock River Valley carries deposits of glacial gravel which appear to be the continuation of the broad gravel plain that leads down the preglacial Rock River Valley from the Kettle moraine of the Green Bay lobe. This gravel plain stands about 50 feet above the present level of Rock River at Rockford and southward from that city to the point where the preglacial and present valleys of Rock River part company. It has no continuation southward along the preglacial valley, but passes instead down the narrow valley of the present stream. Its altitude at Byron, as shown by the railway survey, is 50 to 55 feet above the low-water level of the stream at that point. At Oregon its ele- vation is about 40 feet, aud it maintaims an elevation of nearly 40 feet from there to the point where it emerges into the Green River Basin above Ster- ling. This filling apparently began a few feet below the present river level, since the wells made along the flood plain encounter gravel to a depth of 10 to 20 feet or more below the stream. However, in places on the borders of the valley it rests upon rock at a level slightly above the present stream. It may not, therefore, amount to more than would be necessary to build the valley up from its present level to a height of 50 feet. Assum- ing this to be the case, the fillmg will equal about four-fifths of the amount of rock removed from the channel prior to its deposition, or to about 0.16 of a cubic mile. The amount deposited in the 50 miles embraced in the section of the preglacial valley between the Kettle moraine and the head of this narrow section is much greater. It is at least 50 feet and may amount to 75 feet in depth. The width being 25 miles or more, it follows that ‘Seventeenth Ann. Rept. U.S. Geol. Survey, Part II, 1896, pp. 733, 734. ROCK RIVER DRAINAGE BASIN, 49] there was not less than a cubic mile deposited in this section of the pre- glacial valley, and the amount may possibly approach 2 cubic miles. The amount of excavation accomplished since the deposition of the gravel is remarkably small. The valley formed subsequent to this gravel deposition varies but little in breadth in the 100 miles from the Kettle moraine to the lower end of the narrow section. It is usually about 1,500 feet in width, and seldom exceeds 2,500 feet. Its flood plain is 30 to 40 feet below the level of the gravel plain and its stream bed about 50 feet. The stream occupies about one-third the width of this postglacial valley. The amount of excavation accomplished in the narrow section under discus- sion is estimated to be about 650 mile-feet, or slightly more than half the amount of rock excavation accomplished prior to the deposition of the Wisconsin gravel. It is a matter of much interest to ascertain the relative lengths of time involved in the interglacial rock excavation and the postglacial gravel excavation. This, however, must be left to more refined methods than are now at command. It seems safe to assert that the time involved in the rock excavation was longer than that involved in the gravel excavation, though it must be borne in mind that water may find passage through or over gravel without disturbing it, where it might be cutting rapidly in the soft St. Peters sandstone which forms a portion of the new channel of Rock River. But the greater part of the rock excavation has been in limestone, which would perhaps offer fully as much resistance to erosion as the gravel deposits which now line the valley. The deflection of Rock River into this new course certainly preceded the Wisconsin stage of glaciation, and probably preceded the Iowan. The completeness of the removal of rock barriers along its new course and the general character of the channeling seem to ally it with certain rock gorges found in portions of northwestern Hliois and southern Wisconsin, west of Rock River, which, as determined by Hershey, were largely excavated prior to the Iowan stage of giaciation.’ These gorges are discussed below and their relation to the Iowan deposits are set forth. Furthermore, the work accomplished elsewhere between the Iowan and Wisconsin stages of glaciation throws doubt upon the view that this channel was entirely excavated after the Iowan stage of glaciation. The work involved in the ' Pleistocene rock gorges of northwestern Illinois, by Oscar H. Hershey: Am. Geologist, Vol. XII, 1893, pp. 314-323. 492 THE ILLINOIS GLACIAL LOBE, channeling, therefore, seems referable mainly to the interval preceding the Iowan glaciation, and only in small part to that succeeding it. An instance of a rock gorge formed subsequent to the Iowan stage of glaciation is found in the west part of the city of Rockford, where Kent Creek enters Rock River over a series of cascades. The stage of excavation here is far less mature than in the rock gorges which were opened between the Ilinoian and Iowan stages or in the new course of the Rock River under discussion. Concerning the lower portion of the new course of Rock River, between the city of Sterling and the mouth of the stream, a few words seem necessary. The river enters the sandy plain known as the Green River Basin near the city of Sterling, a plaim which stands but 25 to 40 feet above the stream. In the 80 miles from Sterling to its mouth the river makes a descent of 84 feet, of which 15 feet occur in passing the rapids at that city, and about 25 feet more in the 18 miles between Sterling and Lyndon. The average descent, including the rapids, is about 1 foot to the mile, or nearly the same rate as in the narrow portion of its course in the 50 miles above Sterling. This lower portion of the stream is evidently independent of preglacial lines, ‘for it fre- quently encounters rock ledges, and its bed is entirely floored with rock for several miles in the vicinity of its mouth. The Green River Basin has appar- ently been deeply filled with drift, so that the stream encounters rock only in its passage across preglacial interfluvial tracts. It seems probable that the preglacial channels in this basin reach a level 100 feet or more below the interfluvial tracts, or sufficiently low to correspond with the rock bottom of the preglacial Rock and Mississippi rivers in neighboring districts. Much of the erosion accomplished by Rock River in the Green River Basin has occurred since the Wisconsin stage of glaciation, for a large part of the surface gravel and sand in which the stream has its channel appears to be an outwash from a moraine of Wisconsin age at the head of the basin. The size of the valley, moreover, corresponds to that of the post- Wisconsin Valley in the upper portion of the stream. The rapids at Sterling also ally it with gorges opened since the Iowan, and are consistent with a post- Wisconsin age. GREEN RIVER. The headwaters of this eastern tributary of Rock River are found in the elevated moraine forming the border of the Wisconsin drift in south- eastern Lee County, Illinois, and standing 950 to 1,000 feet above tide. ROCK GORGES OF NORTHWESTERN ILLINOIS. 493 The several headwater streams descend rapidly to the sandy plain outside the moraine. They there soon enter a wet prairie—‘‘ Inlet Swamp”—whose altitude is about 775 feet above tide and which covers perhaps 16 square miles. No channel is maintained across this prairie, but from the west end of the prairie a stream with a well-defined channel leads westward about 15 miles to another wet prairie—‘‘ Winnebago Swamp”—making a descent of nearly 100 feet. In this second wet prairie, which is fully 10 miles in length, the stream has only a poorly-defined channel, but apparently makes a descent of several feet. The western part of the prairie is estimated by Roife to stand only 660 feet above tide. In the next 25 miles, to the eross- ing of the Bureau-Henry county line, the stream has a poorly-defined channel, meandering about through a series of marshes among sand hills, but making a descent of 60 feet (Rolfe). In the remaining 35 or 40 miles to its mouth the stream falls about 40 feet and maintains a well-defined channel. | In the lower 18 or 20 miles (below Geneseo) it has excavated a valley fully 20 feet in average depth and nearly one-half mile in width. In this section of its course it is bordered by uplands which are far less sandy than the lowland plain known as the Green River Basin. The sand which covers the Green River Basin, as previously indicated, appears to be largely an outwash from the Wisconsin moraine. The chan- nel of Green River is, therefore, of post-Wisconsin age, although traversing a district which stood outside the limits of the ice sheet at the Wisconsin stage of glaciation. The trench which it has cut below Geneseo is entirely in deposits of silt which are also of apparently Wisconsin age. They have an elevation corresponding closely to that of the Wisconsin terrace on neighboring portions of the Mississippi, and it is thought that they are slack-water deposits connected with the swollen Mississippi during the time in which it was building up the terrace. -ROCK GORGES OF NORTHWESTERN ILLINOIS. In the portion of northwestern Illinois lying between Rock River and the border of the Driftless Area the drift is generally so thin that the streams follow in large part the preglacial lines. There are, however, several instances of the deflection of streams into the edge of the bluff or across a projecting point on the border of a valley. Such deflections usually occur where a cluster of knolls or ridges of drift greatly obstruct the valley, and they are usually only of sufficient length to pass the obstruction. In some 494. THE ILLINOIS GLACIAL LOBE. cases, however, the stream is thrown across the divide into another pregla- cial valley. The streams in cutting new courses through the rock ledges have found the material so resistant that very narrow channels have been formed which, because of their narrowness and the precipitous rock cliffs on their borders, are known as rock gorges. Several of these rock gorges in Stephenson County have been examined with considerable care and dis- cussed by Hershey.' His paper contains the following table of measure- ments and estimates of a few of these gorges. There is added a more recent measurement of a gorge on Carroll Creek just west of Mount Carroll: Measurements of rock gorges in northwestern Illinois, by Oscar H. Hershey. | | | eulbeaers | | e Vv Lato | | ~" |stream i = ree | —| | Sq. miles. Feet. | Feet. Feet. | Cu. yds. | Feet. Feet, | 1 1 mile north of Freeport. cs 950| 140 | 29 140,000 | 50 ay.) aK) gal 2 5milesnorthwest of Free- | 4 850 | 240 | 44 | 330,000 | 175 | 25 | o 1 | port. | | 3 | 3 miles south of Freeport- 10 2, 050 235 36 | 640, 000 | 200 20) 10° 31 fN @enereattey osc Awe o: | 29] 3,250| 160 | 57 | 1,100,000| 183] 25 | 5.321 5 | Cedarville ..........---- | 13| 295} 175 15} 9215875 1) 150) |e 5) esO eed 6 | 3 miles west of Freeport. 1 | 950| 100 | 25| 88,000 | 80 hess | 10:1 7 | 4 miles west of Freeport.) 5 | 1, 100) } 165") 300) 20250007)" 1455)" 10 | 14.521 8 | Carroll Creek ........--- 45 | 2miles. | 180+) 50 | 3,530,000| 180; 30) 6 :1 | | From the aboye table it appears that the gorges show remarkable variations in size, the causes for which are not made clear. The small ratio of width of bottom to width of stream displayed by the two streams hay- ing the largest drainage area raises the suspicion that the smaller streams may have had softer material to work upon and thus have been able to accomplish a greater amount of excavation than that displayed by the two larger streams. The writer has had opportunity to examine only two of the gorges, No. 1 and No.8 of the above table. These gorges are of some- what different type. The gorge No. 1, on the small stream north of Free- port, has bluffs so broken down that an ascent may easily be made at almost any point. As shown in the table, the top of the gorge has a breadth nearly three times as great as at the bottom, though the gorge is scarcely 30 feet ' Pleistocene rock gorges of northwestern Illinois, by Oscar H. Hershey: Am. Geologist, Vol. XII, 1893, pp. 314-323. ROCK GORGES OF NORTHWESTERN ILLINOIS. 495 in depth. But gorge No. 8, on Carroll Creek, has precipitous bluffs which. are often perpendicular and in places overhanging, so that the bottom width is nearly as great as the top except where the gorge is cut largely in drift; it there presents gradual slopes. Hershey’s measurements of the gorge at Cedarville (No. 4 of the table) indicate that it may be about as abrupt as the gorge on Carroll Creek. He considers the Cedarville gorge the best illustration found in Stephenson County, and has presented the following description of it.’ The Cedarville gorge (No. 4 of the table) may be taken as the type, and a descrip- tion of it will apply, with some modifications, to all the others. Cedar Creek, situated in the central part of Stephenson County, flows in a general southwest direction into Richland Creek. After traversing a broad valley, with gently sloping sides covered with drift and loess, it suddenly enters a deep, narrow gorge with steep, rock-bound walls. The contraction of the valley from 3,000 to 160 feet is conspicuous and readily attracts attention. The old valley can be traced around by the south, but is partially filled with sand ridges. The sides of the gorge are in some places perpendicular. They generally slope at an angle of about 30 degrees. The bottom is flat and con- sists of a bed of dark-brown alluvium, through which the stream meanders, sometimes touching one side and sometimes the other, undermining the walls and widening the valley. After about three-fifths of a mile the stream euters a small preglacial valley and the gorge widens, but the same canyon-like character prevails toitsend. A small tributary occupies a portion of the old valley, and when Cedar Creek again enters this valley the significant fact is learned that a stream one-tenth as large as the main creek flows in a valley ten times as large. Hershey has determined that a large part of the erosion of these gorges, estimated to be at least four-fifths, occurred prior to the deposition of the loess associated with the Iowan drift sheet. The principal line of evidence is found in the occurrence of loess within the gorges near their bottoms. In one case near Freeport a gorge was abandoned because of the large amount of loess filling, and the postloessial stream took a new course. The character of the evidence is such that the conclusions drawn by Hershey seem fully sustained. Within the limits of the Iowan drift in northwestern Illinois there are several instances of the initiation of a new course for the stream at the close of the Iowan stage of glaciation. The channels cut by streams having this date are so much smaller than the rock gorges included in the above table that it is not difficult to separate the two classes of val- leys. In the gorges under discussion the streams not only flow in valleys having bottoms several times as wide as the stream beds, but so far as known they are entirely free from falls or rock rapids. But in the streams which ' Loe, cit., p. 316. 496 THE ILLINOIS GLACIAL LOBE. haye opened new courses since the close of the Iowan stage of glaciation it is the rule to find rock rapids, and even low falls. Hershey devotes a considerable part of his paper to the discussion of the comparative amount of erosion in these valleys and those opened at the lowan and Wisconsin stages of glaciation, and concludes that the time required in their excavation is several times that of the lowan as well as of the Wisconsin. Rock gorges occur to some extent along the valleys of western Illinois south of Rock River, but they are not of a class similar to those of north- western Illinois just discussed. They occur usually where streams are opening a course entirely independent of preglacial valleys, and where after cutting through the entire depth of drift they have begun the excava- tion of the rock. These valleys often have rocky rapids and low falls. It is difficult to compare the amount of work accomplished by these streams with that accomplished by the streams of northwestern Hlinois. The streams of western Illinois have had usually a large amount of drift to remove, and consequently have been prevented from beginning the excava- tion of the rock at so early a date as was possible for streams in northwest- ern Illinois. The valleys which they have excavated in the drift show much greater cubic contents than the rock gorges of similar sized streams of northwestern Illinois. It remains to be determined whether the work accomplished in removing the drift deposits is sufficient to offset the imma- ture state of development on the rock gorges, or whether the excavation of the rock gorges of the two districts began at different dates. In western Illinois the excavation may confidently be placed after the Ilimoian ice invasion, but in northwestern Illinois the possibility of deflection by a pre- Ilinoian invasion must be considered. ILLINOIS RIVER DRAINAGE BASIN. The watershed of the Illinois River extends in a broad band, averaging 100 miles in width, in a northeast-southwest direction directly across the center of Illinois. From the northeastern extremity of this band there are two projections—one north into Wisconsin, including the Fox and Des Plaines basin; the other east into Indiana, including the Kankakee and its main tributary, the Iroquois. The name Illinois is applied to the river from the junction of the Kankakee and Des Plaines. The western side of the watershed is 20 to 40 miles in width, while the eastern is 60 to 80 miles. The entire area is estimated by Greenleaf, in his report for the Tenth Census, ILLINOIS RIVER DRAINAGE BASIN. 497 to be about 29,000 square miles. An estimate made by L. E. Cooley, of the Chicago Drainage Commission, reduces it to 27,914 square miles. The area in each of the three States is estimated by Greenleaf to be as follows: Illinois, 24,726 square miles; Wisconsin, 1,080 square miles; Indiana, 3,207 square miles. The drainage areas of the tributaries given in order from source to mouth, as estimated by Cooley, are as follows:! Drainage areas of tributaries of Illinois River. Square miles. Des Plaines River -..--.. noga sonade osdoos sacs EauuEaDe sUDEOdoNaeCE aCe Coon odoocobadems HHaee 1, 392 Kankakee River......-.-. DIO ROE GUD Soo DAS SAE AEE ec eens pepe anata Sta dL ke A be Ne 5, 146 Aux Sable Creek -...---. gocodo0Sa09 608 Fe yo as Fee ene hs ToT nn iy 218 WEVA, OBE! Soo0s opoace sessinos6 Sac0 ecco bens Goce cand sonSeodo oEadbabasedobess aaccer cous eetooece 540 1BGES IBIWER Leodpondodeo oagu Shad ORES a0 DUBE RRCO ED EOS E RESE aE Re ae Came ore Er aeccer ae Hehe ages 2, 700 CoveliCredkanmncenemelaaeeee on eter eteaice. seems sco sneeeees Base Coa rEododcoaces basesaDases 100 erm onwhiivorease em afyr-paceecser Seite si=12 5 Se ast aie = nls eye te ete eee See Uy ee 1,317 Becumsaugum Creek and MittleiVermilionRiver---) 2-2-2225. 2-2-4 see e eee eee ee eee eee oee 165 Bureaw Creeks. 2-222 ese cee 0000 JSb0 and 66 c0 sans 6505 Gcob ccE.CocU ona o SHES Sao Sabbosde Seedes 480 Sammaliy CnOdagas sods donagondcos 6550 done cd gaaneeesea epsbSsoopens Gone cbs coseae eoaodeeoube oSEE 147 Chow? OReGis (GAD) sdoe. cgoode copa poodas acus.qnee se nsab Seandde ncedee daa one casa badodcie Sone MpEuEE 226 SoMa ahne Chee) (EOMUN)) sSosde dass caosis coco eoobsSSsoses etoabs dave soca coor OBOE Ar aes eae 132 ITO OOO CREGIEoons ches sade code sgh cand pees buks desode u bohdodeu basbae seooas Sone soebosadan cece 310 WAG MEIN? IBINGSSG oa56 oneodé casa sacure GaaeCneGOC aes oe BADE ARBH Maen Ze meee Steet cise trues ees 1, 217 (COMDCHAS CRED coos coddacqde coo Las'oab5 Gene booed s cosaue ceaUse nubs Hubs Cobos HObud Kade booo uses 151 QING BING odan cade, cosa cous 9500 cere s oHoaeo SaeBeEBocEaa dabababoas ceob cdencedunnsdeuuu Geobbe 220 SJOOOR, TRING oc co mderneds sobdde Conse RUbM oboe Oa E EE CBE SRanEeHoded bass Babs oon SeoeaEue a EMIsece 1, 870 SOM GRIM IBIVER 05 cce0 co0s enone cons'co505 cbbo + bees cond BCS aosouoosoU cede ase euee BedeSk ces 5, 670 Sugai Cree kiemme sarees eset este eeen csc nese 2 ie oe eon Mee eeeep in Gag RIP Oe al Roe 180 Crookedt@ree kamen syste ere aw eit tate a aeieis fae cycles fn Sia As eo ea em ap Oe ge apes eo 1, 385 IRAN (CREC) S e656 cabs USae|anebdan oon SEECB Ren Meeps Aer ard BEOeaaCHid SES Suda OSS SCRE eae mner ten 290 IMicKees' Cree kim sng yiaeayer alate ee Siar Ayal Ace hak Sie oreo a oer EN eee ne eee we 472 NOUN EES WORKS ORIG s65 code bb od pecdee SceeEBae dean pnb Sone Sado Cobo coo obese cobs Baseabese 275 BioWsandyACTeek Mme ucwae eee as siete cis) cee SO ee a" SE — a Set Meh arene core a Loken nimi des TOPOGRAPHIC MAP SHOWING DRAINAGE FEATURES NEAR OTTAWA, ILLINOIS. Scale — ==> ———EEEEEi ed Contour interval 10 feet ILLINOIS RIVER DRAINAGE BASIN, 509 70 square miles. Like the headwaters of Mazon Creek, they flow north- eastward down the slope from the moraine to the plain. It will be observed that Mazon Creek and these streams drain the south part of the Morris Basin. A portion of this area appears on the Morris topographic sheet. FOX RIVER. For about 20 miles in the vicinity of the Marseilles moraine the Illinois receives no tributary worthy of mention, as may be seen by reference to the Marseilles topographic sheet. But just west of the Marseilles moraine, at a distance of 33 miles from the head of the Ilinois, Fox River is received. Its drainage area is about 2,500 square miles, or more than one-third as great as the portion of the watershed of the present Illinois above the mouth of this tributary. It lies mainly in Illinois, but the source of the stream is in southern Wisconsin. For a distance of nearly 75 miles from its source Fox River drains only a narrow strip among the morainic ridges of the composite belt pre- viously described. In this portion of its course its fall amounts to but a few inches to the mile, and it expands at frequent intervals into lakes and marshes, between which are short spaces having a narrow and well-defined channel. Near the point of divergence of the Marseilles moraine from the Bloomington morainic system above Elgin, Hlinois, the river begins a rapid descent to the low plain that lies on the outer border of the Marseilles moraine, and follows this plain to its mouth. The stream has no valley until it begins the descent to this plain. It there for a few miles has cut to a depth of nearly 100 feet, but in the passage through the plain its bed is sunk to a depth of only 40 or 50 feet, except for a few miles near its mouth, where it cuts deeper to enter the Illinois. The valley is also narrow throughout its entire length, and pre- sents a conspicuous contrast to the broad valley of the upper Illinois. — Its channel even in the lower 75 miles has a breadth of only about one-eighth mile and a depth scarcely half as great as that of the neighboring portion of the Illinois, yet it is better favored than the Illinois for the development of a drainage line, there being no morainic ridge to eross and a proportion- ately small amount of rock to excavate. Instead of an excavation one-third as great as that of the upper Illinois, this stream has accomplished scarcely one-sixteenth as much work. These contrasts are well shown in the Ottawa 510 THE ILLINOIS GLACIAL LOBE. topographic sheet of this Survey, a portion of which is here reproduced (see Pl. XTX). The principal tributaries of Fox River all le on the west side, there being but a narrow strip of watershed on the east side of the river. Among the tributaries may be mentioned Nippersink Creek, which enters about 6 miles south of the State line; Blackberry Creek, which enters opposite Yorkville; Big and Little Rock creeks, which unite just before entering the river, 5 miles below Yorkville; Somonauk Creek, which enters opposite Sheridan, 12 miles farther down the river, and Big and Little Indian creeks, which unite near their mouths and enter the river about 10 miles above its junction with the Hlinois. Nippersink Creek heads in the com- posite morainic belt in northern McHenry County and takes a zigzag course among its ridges through a series of marshes for a distance of nearly 20 miles before entering the river. Blackberry Creek, as previously indicated, occupies an esker trough in its middle course, whose size is many times greater than that of the remainder of the creek channel. Before entering the esker trough the creek winds about among morainic knolls near the south end of the composite belt. In its lower course the creek does not pass directly into Fox River, but follows down the valley about 8 miles, draining a portion of the gravel plain which borders the river. ‘The remain- ing tributaries above mentioned all head in the Bloomington morainic system or on the slope of its inner ridge, and take a somewhat direct south- eastward course to Fox River Valley, following the slope of the plain. They have narrow valleys and have sunk their beds but a few feet below the level of the plain, except near their mouths, where they have cut down to a level corresponding to that of Fox River. Some portions of the plain west of Fox River are naturally very imperfectly drained, but by ditching and tile draining they have been brought to a high degree of fertility. The slope of the plain averages usually several feet to the mile; conse- quently drainage is easily developed. COVEL CREEK. This small southern tributary of the Illinois drains an area of about 100 square miles lying between the Marseilles moraine and Farm Ridge, the inner ridge of the Bloomington morainic system. It enters the Ilinois ILLINOIS RIVER DRAINAGE BASIN. all about 3 miles below the mouth of Fox River. The basin drained by this stream, as previously described, carries sand ridges, which were perhaps formed by a lake-like expansion of the river prior to the opening of the channel to the west. VERMILION RIVER. This southern tributary of the Illinois should not be confused with a stream of the same name which leads into Wabash River from eastern Illinois. To distinguish these streams, the names Wabash-Vermilion and Ulinois-Vermilion have come into use. Both streams have their sources in the Bloomington morainic System at the reentrant angle in southeastern Livingston and western Ford counties. The course of the linois-Vermilion is northwestward, while that of the Wabash-Vermilion is southeastward, from the elevated district in which they have their common source. The Ilnois-Vermilion has a drainage area of 1,300 square miles, and drains the district immediately south and west of the Marseilles moraine in Ford, Livingston, and southern Lasalle counties. The main stream follows the west or outer border of the inner ridge of the Bloomington system from source to mouth, but an east fork leads through this moraine. The other eastern tributaries find their sources in these morainic belts. A southern tributary—Rooks Creek—heads near Lexington in Cropsey Ridge, another weak moraine of the Bloomington system. The western tributaries drain a plain which slopes gradually eastward nearly to the border of the moraine. The western side of the watershed is much more extensive than the eastern, yet no streams worthy of note lead across it to the Vermilion. Its drain- age is through small streams which pass directly down the slope to the river in somewhat parallel courses. The unfavorable conditions for drainage along the Vermilion have been discussed on preceding pages. The plain through which it passes, as there noted, has little descent in the lower 40 miles of the river, and was appar- ently occupied by a marsh, if not by a shallow lake, until a stream had been given time to open a channel from the Illinois back several miles into the plain. Sandy deposits on the south border of the plain are thought to be due to the existence of a lake in the portion to the north. The narrow- ness of the channel of the Vermilion River near its mouth is well shown on the Lasalle topographic sheet. by I} THE ILLINOIS GLACIAL LOBE. LITTLE VERMILION RIVER, ETC. Little Vermilion River enters the Illinois directly opposite the mouth of the Vermilion River, and sustains a similar relation to the inner ridge of the Bloomington morainic system, that ridge being immediately east of each stream. Its watershed, however, comprises only 150 square miles. The size and slope of its valley and the slope of bordering uplands, as well as the relation to the morainic ridge east of it, are well displayed on the Lasalle topographic sheet. The same sheet also brings out clearly the features of a neighboring small tributary of the Illinois—Spring Creek— which enters the river at Spring Valley. The features of another small northern tributary—Negro Creek—are brought out on the Lasalle and Hennepin topographic sheets. The same sheets also bring out the features of All Forks Creek, a small southern tributary of the Illinois, enterimg the river about 5 miles above Hennepin. All Forks Creek, it will be observed, occupies a shallow depression leading westward parallel with the Ilinois River. This depres- sion was perhaps utilized, if not produced, in the early stages of drainage development by a portion of the Illinois River. It will be observed that a similar shallow depression also leads westward on the north side of the Illinois, passing just north of the cities of Peru and Spring Valley, which may also have been formed by the river in the early stages of its develop- ment. A more careful investigation of this portion of the Illinois, where the postglacial stream enters the preglacial valley, is necessary to bring out fully the history of the development of the present lines of drainage. BUREAU CREEK. Bureau Creek, which enters the Illinois from the northwest at the great bend of the river, has a drainage area of about 480 square miles. This watershed, as previously shown, is included mainly ‘between the two promi- nent members of the Bloomington morainic system which are developed in the district north from the bend of the Illinois. In addition to the main creek there are several nearly parallel tributary streams, all flowing south- westward across the northeastern and eastern portions of Bureau County. The main stream swings around to the south and east, gathering in the ILLINOIS RIVER DRAINAGE BASIN. 513 several parallel tributaries in this curving portion of its course. Its defiec- tion from a southwestward course is caused by the change in the course of the moraine which lies on its northern and western border. This moraine furnishes only small northern and western tributaries to the main stream. The watershed, with the exception of the great moraine on the north and west borders, shows a perceptible southwestward descent, amounting generally to several feet to the mile. In the headwater portions the main creek and also its tributaries have formed only shallow ditches, but in the lower course they have trenched deeply into the drift deposits, as may be seen by reference to the Hennepin topographic sheet. Between the mouth of Bureau Creek and the city of Peoria, a distance of about 50 miles, the Ilinois River receives no important tributaries. The largest is Kast Crow Creek, which has a drainage area of 226 square miles. Sandy Creek, another eastern tributary, drains 147 square miles; and Senachwine Creek, a western tributary, drains 132 square miles. No others have an area exceeding 100 square miles. The smallness of the western tributaries is due to the close approach of the bulky Bloomington morainic system to the west bluff of the Illinois. In most cases these tributaries lead somewhat directly from the moraine down to the valley, but Senach- wine Creek has been deflected by a drift ridge into a course parallel with the moraine, and thus drains a larger area than the neighboring tributaries. The eastern tributaries lead directly westward across a slightly undulatory plain, which apparently offered conditions rather unfavorable for stream development, there being very little descent. The streams, however, have overcome this impediment by trenching deeply near their mouths, and have thus opened a fair drainage in that region. The features are well shown in the Hennepin, Lacon, and Metamora sheets. K1iCKAPOO CREEK. Kickapoo Creek, which enters the Illinois from the west at the city of Peoria, has a drainage area of 310 square miles, mainly situated on the Tllinoian drift outside the limits of the Shelbyville moraine. The headwater portion, however, drains a narrow strip between the Shelbyville and Bloom- ington morainic systems, passing through the Shelbyville moraine just below the village of Dunlap. The relation of this stream to the morainic ridges, MON XXXVIII——33 514 THE ILLINOIS GLACIAL LOBE. and also the general features of its several tributaries in the headwater por- tion, may be seen by reference to the Dunlap topographic sheet.t FARM CREEK. This small eastern tributary of the Illmois which enters directly oppo- site the city of Peoria has its source in the Bloomington morainic system. As previously noted, it carries a moraine-headed terrace which opens into the Ilinois Valley at a level about 170 feet above the stream, thus showing that at the Bloomington substage of glaciation the valley was filled to this unusually high level in that vicinity. The stream has now opened a valley down to the level of the 50-foot terrace which borders the Illinois, that offers a convenient line for approach to Peoria from the east, which is utilized by several railway lines. MACKINAW RIVER. This important tributary of the Illinois has a drainage area of about 1,200 square miles, which may conveniently be divided into three sections: (1) The headwater portion, lying inside the main ridges of the Bloomington morainic system; (2) the middle portion, comprising the section crossing the Bloomington and Shelbyville morainic systems and the narrow plain separating them; (3) the lower portion, embracing the meanders of the river througl the Illinois River bottoms. The upper portion drains a somewhat elevated till plain in north-central McLean and eastern Woodford counties, lying between the inner large moraine and Cropsey Ridge, a minor moraine of the Bloomington system. The length of this portion of the river is about 40 miles, and in much of its course it flows near the south border of the minor moraine. Several tribu- taries heading in the large moraine lead northward to the river across a sloping plain. Another tributary—Panther Creek—which drains several townships in eastern Woodford County, leads southwestward to join the river at the point where it enters the middle course. The streams in this upper portion have generally very shallow channels, seldom more than 25 1T am informed that by mistake an uncorrected photograph copy of the Dunlap sheet was sent to the engraver, instead of a corrected copy. The error involves chiefly an omission of a 50-foot contour on the uplands west of the Illinois. This should be borne in mind in the examination of the Dunlap sheet. ILLINOIS RIVER DRAINAGE BASIN. 515 or 30 feet in depth, and also very narrow flood plains. The main stream, however, begins to deepen its channel before entering the large moraine, and has a depth of 60 to 75 feet at the inner border of the moraine. In the middle course Mackinaw River has cut a channel across both the large moraines of the Bloomington system and also the Shelbyville moraine, with an average depth of nearly 100 feet. The width of the valley increases from about one-fourth mile in the inner part of the Bloom- ington belt to about a half mile at the outer part and to nearly a mile in its passage across the Shelbyville moraine. As previously indicated, its fall is very rapid, being usually several feet to the mile. The river receives but few tributaries in this middle course, and these drain only small areas. The largest tributary is Walnut Creek, which enters from the north between the two main ridges of the Bloomington system, and which drains probably 100 square miles. Another north tributary—Deer Creek—drains a portion of the plain between the outer Bloomington moraine and the Shelbyville moraine. Little Mackinaw Creek, a southern tributary, drains a portion of this plain south of the river. In its lower course the Mackinaw River winds about in a shallow channel across the Illinois Valley for a distance of about 20 miles and makes a descent of about 75 feet. QUIVER CREEK. This eastern tributary of the Illinois has its entire course within the limits of the valley of the Illinois River. It is the only stream of conse- quence found in an area comprising not less than 200 square miles of sandy bottom. It is immediately bordered by a belt of mucky alluvium, averaging perhaps 2 miles in width, whose surface stands 20 feet or more below the level of the bordering sandy bottom. This appears to have been the former course of Mackinaw River, and was perhaps occupied also by a portion of the Hlinois River. By systematic ditching much of the bordering districts have been drained into this channel. There are other bayous in this sandy bottom which are connected with the Sangamon River through Crane Creek. These also were probably once occupied by the Mackinaw River, together with a portion of the Illinois. 516 THE ILLINOIS GLACIAL LOBE. COPPERAS CREEK, This small western tributary of the Illinois drains an area of about 150 square miles in southwestern Peoria County. Several of the tribu- taries, as well as the creek itself, have their courses largely determined by preglacial drainage lines which are only partially filled by glacial deposits. There are other small western tributaries of the Illinois between Copperas Creek and the mouth of Spoon River, which also have their courses largely determined by preglacial drainage lines. SPOON RIVER. This large western tributary of the Illinois has an estimated drainage area of 1,870 square miles. It enters the river opposite the city of Havana. The sources of the stream are in southwestern Bureau County, a few miles west of the great bend of the Illinois, and the course of the stream for nearly 100 miles is west of south, nearly parallel with that of the Illinois River. It then turns abruptly southeastward, and in a distance of about 25 miles joins the Illinois. In its headwater portion Spoon River receives the drainage of the western slope of a portion of the Bloomington and Shelbyville morainic systems. With this exception the entire watershed lies outside the limits of the Wisconsin drift, occupying a region covered by Ilinoian drift, upon which there is a capping of loess. The course of the main stream, and also of several tributaries, appears to have been determined largely by preglacial drainage lines which have been but partially filled by the glacial deposits. The filling, however, has been so great that the present streams conform only in a general way to the course of the preglacial les, and thus at a few places they trench upon the projecting rock points in the bluffs of the preglacial valleys, and give the appearance of being in courses independent of preglacial lines. The river receives several tributaries, both on the east and on the west, which have a length each of 15 to 20 miles or more. These tributaries are usually widely branching, and the entire watershed displays a perfection of drainage such as does not occur within the limits of the Wisconsin drift. There appears to be on the main stream, and also on many of the tribu- taries, a more rapid descent in the headwater portions than in the lower ILLINOIS RIVER DRAINAGE BASIN, yi) courses, a feature indicating a greater maturity of drainage than is charac- teristic of the Wisconsin drift; for, as already indicated, several of the large tributaries of the Ilinois within the limits of the Wisconsin drift have their most rapid descent in the lower portion, the headwater portion being slug- gish and imperfectly drained. These contrasts in drainage are only in part due to the natural advantages possessed by Spoon River, and they furnish an impressive line of evidence of the difference in the age of the drift sheets. SANGAMON RIVER. The Sangamon River has a larger watershed than any other tributary of the Illinois. However, its drainage area, estimated at 5,670 square miles, includes extensive plains in central Illinois which are inadequately drained, but which may, by extensive ditching, be drained into it. The length of the river is about 180 miles. Its source is in the Bloomington morainic system in eastern McLean County, at an altitude of about 850 feet above tide, or about 430 feet above its mouth (the mouth being 419 feet). In the first 10 miles it makes a descent of 120 feet, thus leaving about 300 feet of fall for the remaining 170 miles of its course. The fall is far from regular, there being sections, often several miles in length, in which it is slight, between which are sections with more rapid fall. Thus in its course through Sangamon County, a distance of 36 miles, it falls only 38 feet, while in crossing Menard County, immediately below, it falls 67 feet in a distance of 30 miles, and in crossing Macon County, just above Sangamon, it falls 50 feet in about 30 miles. In the lower 23 miles, where it crosses the Illinois bottoms, its fall is only 16 feet. The main stream flows for about 90 miles within the limits of the Wisconsin drift, leaving that drift a few miles west of the city of Decatur. In this portion of its course it receives no tributaries of importance, its immediate watershed being only 15 or 20 miles in width. As previously indicated, it follows the west border of the Cerro Gordo moraine for fully 30 miles below the village of Mahomet, and that moraine constitutes the east border of its watershed. Its channel is but 20 to 30 feet in average depth in the first 60 miles of its course, but in the next 30 miles, in which it crosses the Shelbyville morainic system and the elevated inner slope of the moraine, it has trenched to a depth of 75 feet or more. Upon leaving the Shelbyville system it again enters a shallow valley, scarcely 50 feet in 518 TAE ILLINOIS GLACIAL LOBE. depth, and this it maintains nearly to the mouth of the stream. The depth, however, is increased nearly to 100 feet in portions of the course between Springfield and Petersburg. The portion lying outside the Wis- consin drift sheet, although generally shallow, is much wider than the portion within the limits of that drift sheet, and bears evidence of having been partially opened prior to the Wisconsin stage of glaciation. The amount of excavation accomplished prior to the Wisconsin stage is especially well shown on tributaries of the Sangamon River, both north and south of the main stream, which in some cases have been beheaded because of the Wisconsin deposits. Thus Lake Fork, a small stream lead- ing northwestward from the border of the Wisconsin drift in western Macon County, has a valley about 20 feet in depth and fully one-half mile in width, which was apparently formed entirely before the Wisconsin stage of glaciation, for it now carries no stream adequate to erode a chainel. The Sangamon River and several of its tributaries are found to have similar broad shallow valleys bordering narrower valleys of somewhat greater depth. By affording this means for comparing the amount and kind of erosion earried on before and since the Wisconsin invasion the Sangamon watershed becomes an important district for investigation. Several tributaries of the Sangamon have their sources within the limits of the Wisconsin drift, among which may be mentioned North and South Salt creeks, Kickapoo Creek,’ and three headwater branches of Sugar Creek. Kickapoo and Sugar creeks join Salt Creek a few miles above its mouth, and therefore fall within the limits of its watershed. South Salt Creek heads on the outer border of the Bloomington morainic system, in southeastern McLean County, and flows southwestward across a gently undulating plain to its junction with North Salt Creek, about 5 miles east of Clinton. North Salt Creek has its source between the two large ridges of the Bloomington morainic system, very near the source of the Sangamon River. It passes southward through the outer ridge and across the undu- lating plain south of it to its junction with the South Fork. Each of these streams has a length of 25 or 30 miles above their junction. The united stream passes westward through the Shelbyville moraine, entering the outer border plain at Kenney, 8 miles southwest of Clinton. The general 'This Kickapoo Creek should be distinguished from a stream of the same name entering the I1li- nois at Peoria. ILLINOIS RIVER DRAINAGE BASIN. 519 course of the stream continues westward to its junction with the Sangamon River, 50 miles below. It receives Lake Fork Creek from the south about 5 miles above Lincoln; Kickapoo Creek from the north about 4 miles below Lincoln, and Sugar Creek, also from the north, about 12 miles farther down. Its valley is much broader below the mouth of Lake Fork than above, and it seems probable that a larger stream occupied Lake Fork Valley prior to the Wisconsin invasion than occupied Salt Creek Valley. Indeed, the latter appears to be almost wholly a post-Wisconsin stream as far down as its junction with Lake Fork. Kickapoo Creek finds its source between the two ridges of the Bloom- ington system, a few miles east of the city of Bloomington. Like North Salt Creek, it passes southward through the outer morainie ridge and, as previously noted, becomes the avenue of discharge for a gravel train head- ing in that moraine. It passes through the Shelbyville moraine near the village of Waynesville and skirts its outer border for a few miles west, when it turns southwestward into Salt Creek, entering that stream about 10 miles from its point of departure from the Shelbyville moraine. The several headwater branches of Sugar Creek find their sources in the depression between the two main ridges of the Bloomington system, and pass thence southwestward through the outer moraine, where they become the avenue of discharge for the trains of gravel connected with that moraine. The several branches converge upon approaching the Shel- byville moraine and unite in the midst of the moraine. Upon emerging from the Shelbyville moraine, Sugar Creek Valley is separated from Kick- _apoo by an interval of only 14 miles, and this is largely occupied by a plain of gravel built up by the joint work of the two streams. Instead of uniting with Kickapoo Creek, however, Sugar Creek turns westward, and joins Salt Creek about 12 miles below the mouth of Kickapoo Creek. Sangamon River receives one important tributary from the south, known as South Fork. It drains the greater part of Christian County, and enters the river in Sangamon County, immediately east of the city of Springfield. An eastern branch of South Fork, known as Flat Fork, has evidently been beheaded because of the Wisconsin drift, in a manner simi- lar to that of Lake Fork. The stream has its present head in the outer border of the Shelbyville moraine, but finds a broad shallow valley, far out of proportion to its needs, down which it passes to the Sangamon River. 520 THE ILLINOIS GLACIAL LOBE. The average width of the valley is nearly one-half mile, but its depth is only about 20 feet. The Sangamon River also receives the drainage from a plain on its southwest border south and west from Springfield. This plain shows a per- ceptible descent toward the river, and the present divide between the tribu- taries of the Sangamon and several streams which flow directly westward to the Illinois apparently follows nearly the line of a preglacial rock divide. With this exception the borders of the Sangamon watershed appear to be determined by accumulations of drift. CROOKED CREEK, This western tributary of the Illinoi., which enters about 14 miles below the mouth of the Sangamon, drains an area of nearly 1,400 square miles. Its watershed lies immediately southwest of the Spoon River water- shed. It extends on the northwest nearly to the bluff of the Mississippi, there being one tributary in northern Hancock County, from which the Mississippi bluff is distant less than 5 miles. The main stream has a southeastward course from eastern Hancock County to its mouth, a distance of 60 miles. No important tributaries enter from the west, but several creeks lead into it from the east, which have lengths of 15 to 20 miles or more. These eastern tributaries present a remarkable parallelism, and take a nearly uniform direction about S. 65° W. As previously indicated, one of these tributaries, known as East Crooked Creek, occupies a valley which continues beyond this watershed in direct course to the Mississippi, and which is thought to have been formed by a subglacial stream. (See discussion of Big Meadow channel, p. 481.) Shallow channels may also have been opened by the same agency along other eastern tributaries, and have occasioned their remarkably direct and parallel courses. For a few miles near its mouth the course of Crooked Creek has been determined by a preglacial drainage line, but elsewhere the drainage appears to be nearly independent of preglacial lines. A portion of the divide between its watershed and that of Spoon River follows a low till ridge. This ridge, however, is only a partial cause for the divide, since the general altitude and slopes on its borders are such as to have located the line of separation between the watersheds at about the present divide. ILLINOIS RIVER DRAINAGE BASIN 521 MCKEE’S CREEK. This western tributary of the Illinois enters about 18 miles below the mouth of Crooked Creek, and has an estimated drainage area of 472 square miles. Its general course is southeastward from eastern Adams, County, across southern Brown and northeastern Pike counties. Within a mile of its mouth it is joined by South McKee’s Creek, which drains the northeast part of Pike County. The greater part of the divide between McKee’s Creek watershed and the small streams leading directly west into the Mississippi follows a series of ridges which belong to the system formed at the margin of the Ilinoian | drift sheet. Not only have these ridges been influential in determining the position of this divide, but, as already indicated, they have governed to some extent the courses of the small streams directly tributary to the Mississippi. The divide between Crooked Creek and McKee’s Creek is nearly free from drift ridges, and stands but little higher than the borders of McKee’s Creek Valley. Its elevation is, however, perceptibly greater than that of the immediate borders of Crooked Creek. The thickness of the drift is generally sufficient throughout this watershed to fill the pre- glacial drainage lines and render it necessary to develop lines along new courses. : INDIAN, MAUVAISE TERRE, AND BIG SANDY CREEKS. Indian Creek is one of several small eastern tributaries of the Illinois entering the portion of the valley south of the mouth of the Sangamon. It has a drainage area of about 290 square miles, situated mainly in north- ern Morgan County. Its lower 10 miles are occupied in crossing the Illinois River bottoms, where it has little drainage outside its immediate channel. Its watershed on the uplands has a breadth of about 9 miles and a length of fully 20 miles. The general course of drainage is directly westward, across a gently sloping plain, and is independent of preglacial drainage lines. The divide at the east, however, is probably a preglacial rock divide. Mauvaise Terre Creek drains a narrow strip immediately south of the Indian Creek watershed and has a drainage area of 275 square miles. It includes a strip leading westward across central Morgan County and north- ern Scott County, whose average width is scarcely more than 8 miles, but whose length is about 30 miles. Like Indian Creek, its course seems to 522 THE ILLINOIS GLACIAL LOBE. have been determined by the slope of a drift plain and is apparently inde- pendent of preglacial lines. Big Sandy Creek, the next succeeding eastern tributary of the Illinois, has a drainage area of about 190 square miles. Its watershed is broader than either of the two preceding, but is much shorter, its extreme length from east to west being scarcely more than 18 miles. It comprises a dis- trict lying somewhat below the general level of the neighbormg watershed. This fact, together with the absence of rock outcrops in the portion of the Illinois bluffs immediately north of its mouth, renders it probable that a preglacial drainage line traversed the midst of its watershed, though in a course not precisely coincident with that of the present stream. APPLE CREEK. Apple Creek has a drainage area of about 500 square miles, which includes southeastern Morgan, northern Greene, and northwestern Macoupin counties. Its course is southwestward, and the watershed has a length of about 40 miles. The greatest breadth is about 15 miles. Its lower course appears to be along the line of a preglacial valley, but the headwater portion and also the majority of the tributaries show little dependence upon preglacial lines. The drift is comparatively thi over much of the water- shed, and streams have cut down into the underlying rocks at many points. MACOUPIN CREEK. Macoupin Creek is the most important eastern tributary south of the Sangamon River, its drainage area being nearly 1,000 square miles. It draius the greater part of Macoupin County and a portion of the neighbor- ing counties on the east and west. Its watershed is widely branching in the middle portion and tapers toward either end, giving a broadly ovate outline. With the exception of the headwater portion above Carlinville, the main stream apparently has its course determined by a preglacial line, there being a broad depression, deeply filled with drift, through which the creek takes its course. he tributary streams appear to be largely inde- pendent of preglacial lmes. The extent of the watershed on the north and south appears to be determined in large part by preglacial divides, but the influence of preglacial divides is less apparent at the eastern border of the watershed. KASKASKIA RIVER DRAINAGE BASIN. 523 OTTER CREEK, This small eastern tributary of the Illinois drains an area of about 100 square miles embraced between the mouth of Macoupin Creek and the elevated rock ridge which forms the bluff of the Mississippi and Ilinois in southern Jersey County. It apparently follows in a general way a pre- glacial drainage line having about the same watershed. KASKASKTA RIVER DRAINAGE BASIN. KASKASKIA RIVER. The Kaskaskia or Okaw is the principal river traversing southern Illinois. With a length of 180 miles, it drains nearly 6,000 square miles. Its source is in the Champaign morainic system immediately west of the city of Champaign, at an altitude of about 730 feet above tide; it enters the Mississippi near Chester, in Randolph County, at an altitude of 342 feet. Its descent is generally gradual, the most rapid section of its course being in its passage through Moultrie County, where it makes a descent of 55 feet in about 18 miles, or 3 feet to the mile. In the headwater portion there is a fall of only 110 feet in the first 50 miles. In places there are pools several miles in length, the most conspicuous of these being found in St. Clair County, where, in a distance of 20 miles, the fall is scarcely 10 feet. The stream is subject to great variations in volume, for it drains a region in which the substrata are of compact clay, which promotes a rapid run off, and furnishes but little water in seasons of drought. A rise of 20 feet in its lower course is not rare, and its flood plain has been built nearly to that height above the stream bed. The upper 80 miles of this stream lies within the limits of the Wis- consin drift. ‘The stream emerges from the Shelbyville moraine at the city of Shelbyville. In this headwater portion there are no noteworthy tribu- taries, and the watershed has a breadth of only 10 to 20 miles. The channel is narrow and shallow from the source down nearly to the inner border of the Shelbyville morainic system. There it becomes deeper, with a narrow trench having an average depth of nearly 75 feet. Near its point of emergence from the Shelbyville system two railway bridges extend from bluff to bluff, thus avoiding the necessity for a descent into the valley, and vet the bridges are only about one-fourth mile in length. 524 THE ILLINOIS GLACIAL LOBE. Upon entering the older drift the valley continues small for a few miles, but is perceptibly increased in size below the point of entrance of Robinson Creek. This stream appears to follow the lower course of a drainage line whose former headwater portion has been concealed by the Shelbyville drift sheet. Its valley has a breadth of nearly a half mile, and this breadth characterizes the portion of the Kaskaskia immediately below its mouth. Upon entering Fayette County the river soon opens into a broad preglacial valley whose course farther north has been concealed. The valley has a width of about 3 miles near Vandalia, but increases to greater width farther south. Masked as it is by the drift, it presents the appearance of a broad shallow basin rather than a river valley. This basin-like valley continues nearly to the mouth of the stream, where the width contracts abruptly to about a mile upon entering the EKocarboniferous limestone which there borders the Mississippi Valley. This stream receives but one noteworthy eastern tributary—Crooked Creek—and two western tributaries—Shoal Creek and Silver Creek. Crooked Creek’ is relatively unimportant, as it drains only a narrow strip, 35 or 40 miles in length, leading from north-central Marion County south- westward past Salem and Centralia and entering the Kaskaskia a few miles below Carlyle. Coal shafts at Salem, Odin, and Sandoval show the pres- ence of a preglacial valley on the north border of this watershed, with bed 100 feet or more below the present surface, but the present stream flows through a region of comparatively thin drift. SHOAL CREEK. Shoal Creek has a drainage area of about 1,000 square miles, or one- sixth the entire watershed of the Kaskaskia River. Its watershed embraces the greater part of Montgomery and Bond counties and the western part of Clinton County. The stream enters the Kaskaskia in the southwest part of Clinton County, about 20 miles below Carlyle. In the headwater portions there are three streams, known as West, Middle, and East Shoal creeks. West and Middle Shoal creeks are each about 20 to 25 miles in length and unite near Walshville in southwestern Montgomery County. The united stream below that point is known as West Fork to its junction with East Shoal Creek, 20 miles farther south. East Shoal Creek has a length of ! This stream should not be confused with one of the same name that enters the Illinois River. KASKASKIA RIVER DRAINAGE BASIN. 525 about 40 miles, but drains a much narrower strip than that of West Fork. Below the junction of the East and West forks the stream has a length by direct course of about 25 miles. This watershed has a perceptible southward descent, the altitude at the headwaters being 700 to 750 feet at tide and at the mouth only 400 feet. The mouth of the creek is but 380 feet. The three streams have each formed channels 50 to 75 feet or more in depth and nearly one-fourth mile in average width in their passage through southern Montgomery County. A similar depth is maintained as far down as the junction of the East and West forks near Greenville. Below this point the valley is more shallow and the stream soon enters the Kaskaskia Basin, where its valley is but little lower than the basin plain. East Shoal Creek is bordered closely on the east throughout its entire length by a system of drift knolls and ridges which, as previously described, attain great prominence in eastern Montgomery County. Shoal Creek passes through a break in this system of ridges just below the junction of the East and West forks, beyond which its course is largely independent of drift ridges. Middle Shoal Creek winds about among prominent drift knolls near Hillsboro, and West Shoal Creek is deflected eastward by a ridge of drift at its junction with Middle Shoal Creek. With these exceptions the streams are not markedly deflected by drift aggregations. They pursue, as a rule, nearly direct southward courses, following the slope of their watershed. Their courses appear to be mainly independent of preglacial drainage lines. East Shoal Creek touches the line of a deep preglacial valley near Greenville, but above that point it has opened a new course, in places trenching into the rock. Even the lower course seems to be largely inde- pendent of any preglacial line of drainage. SILVER CREEK. Silver Creek has its source in southeastern Macoupin County and flows nearly due south its entire length of fully 50 miles, crossing the eastern part of Madison and St. Clair counties. Its watershed is scarcely 10 miles in average width, and has an area of about 500 square miles. At the source of the stream the altitude is fully 650 feet, but the watershed descends within 10 miles to about 550 feet, and in the next 15 miles to 526 THE ILLINOIS GLACIAL LOBE. about 500 feet above tide, while the stream falls to about 450 feet. In the lower half the watershed is diversified by drift ridges and knolls which rise abruptly in some cases to a height of 75 feet or more above border dis- tricts. These ridges for a few miles in southeastern Madison County con- stitute the east border of the watershed, but just south of the line of Madison and St. Clair counties the stream passes through the main belt of ridges, and has but few prominent ridges and knolls on its east side below that point. At its mouth the stream has an elevation of only 370 feet, and the border districts, aside from knolls, stand scarcely 400 feet above tide. This stream, like Shoal Creek, appears to be largely independent of preglacial drainage lines. It trenches into the rock at numerous points along its course, and its immediate bluffs stand at the general level of bor- dering uplands. ‘There may, however, have been a preglacial divide near the headwaters of the creek. BIG MUDDY RIVER DRAINAGE BASIN. The only remaining important tributary of the Mississippi is the Big Muddy, a stream draining about 2,400 square miles in the low district lying north of the ‘Ozark Ridge.” It is the line of discharge for the greater part of Williamson, Franklin, Jefferson, Perry, and Jackson counties and the southeastern part of Washington and the southern part of Marion County. The lower 20 miles of its course lies within the Mississippi bottom. With the exception of the elevated district on the south border, which stands 600 to 800 feet above tide, this watershed has few points rising above 550 feet. It stands mainly between 400 and 500 feet above tide. The immediate borders of the main valley fall below 400 feet, and the mouth of the stream at low water in the Mississippi is but 320 feet. The principal tributaries of Big Muddy River are Beaucoup Creek and Little Muddy River, which drain the western side of its watershed. An eastern tributary—Crab Orchard Creek—drains about 250 square miles of the district bordering the ‘Ozark Ridge.” Throughout the greater portion of its course Big Muddy River oceu- pies a preglacial line of drainage, and meanders about in the broad bottoms which have been filled with drift and alluvium to an elevation of 50 to 100 feet or more above the rock bottom. Just below Murphysboro, however, SALINE RIVER DRAINAGE BASIN. 527 the valley becomes constricted to a width of about a mile in its passage through the elevated ridge which there borders the Mississippi Valley. Little Muddy River and Beaucoup Creek, with their principal tributaries also flow through broad preglacial channels which carry heavy deposits of drift and alluvium. Possibly the watershed of Crab Orchard Creek has received important modifications as a result of glaciation. The headwater portion of the South Fork of Saline River, a tributary of the Ohio, leads down directly toward Crab Orchard Creek from the elevated portion of the ‘ Ozark Ridge” to a low plain filled to a considerable depth with glacial deposits. It there turns abruptly eastward, following nearly the glacial boundary. It probably continued northwestward into Crab Orchard Creek in preglacial times. A considerable area in northwestern Williamson County also has been filled to such a depth with glacial drift that the preglacial lines are completely concealed. Throughout the greater part of the Big Muddy watershed the drift is very thin, and rock divides separating the preglacial drainage areas are plainly discernible. SALINE RIVER DRAINAGE BASIN. This small watershed tributary to the Ohio drains the portion of south- eastern Illinois immediately north of the “Ozark Ridge.” The South Fork follows closely the base of the ridge, receiving small tributaries which descend the slope of the ridge. The lower course of the main stream is also along the base of the ridge. The Middle Fork rises in southeastern Franklin County and takes a southeastward course past Harrisburg into the South Fork, draining much of Saline County. The North Fork has its source in western Hamilton County and leads southeastward, draining the south half of Hamilton, the northeast part of Saline, the southwest part of White, and the west part of Gallatin County, joining the South Fork at the town of Equality, about 12 miles west of Shawneetown. These three forks of the Saline River, and also their principal tribu- taries, are, in the main, reestablished along preglacial lines and take mean- dering courses through broad valleys which have been filled to an elevation of 50 to 100 feet or more above their rock bottoms. As above noted, a small part of the watershed of South Fork has probably been added to this drainage system as a result of glaciation, but with this exception no 528 THE ILLINOIS GLACIAL LOBE. deflections worthy of note have been observed. ‘The South Fork follows nearly the glacial boundary throughout much of its length, but apparently occupies a preglacial channel. CACHE RIVER. A change of some consequence has occurred in the Tertiary lowland in southern Illinois. The Ohio at one time discharged either wholly or in 7 part through the ‘Cache Valley,” which crosses southern Illinois a few miles north of the present course of the Ohio. Its point of connection with the. Cache Valley was immediately north of Metropolis, Illinois, where for a distance of 4 or 5 miles a clay deposit has accumulated in the line of the old valley. The surface of this clay deposit stands only about 75 feet above the present stream and is much lower than the surface of the Tertiary deposits on either side. Wells indicate that the clay has sufficient depth to extend to river level, and it may extend much lower. The surface of this clay deposit presents much less erosion than that of the bordermg Tertiary lowland and evidently is of far more recent date. Judging from the amount of erosion displayed it is no older than the Ilinoian drift sheet. It may possibly be as recent as the white clay of southern Illinois, which seems referable to the Iowan stage of glaciation. It is not known as yet whether this channel formerly constituted the sole line of discharge for the Ohio. Possibly the river divided its waters between the Cache channel and its present channel. The cause for the filling which led to the abandon- ment of this valley by the Ohio is not clearly understood. The Ohio River falls within the limits of a district covered by another report, hence it is not taken up here. WABASH RIVER DRAINAGE BASIN. The large drainage basin of the Wabash River, with an area of about 33,000 square miles, extends from western Ohio westward across the central portion of Indiana and thence southward to the Ohio, embracing on the west side of its watershed a considerable portion of southeastern Illinois. About one-half of this drainage area was covered by the Illinois glacial lobe, and many important changes have resulted from its occupancy of the region. Indeed, there appears to be very little similarity of outline between ths present watershed and the watershed which in preglacial times had its WABASH RIVER DRAINAGE BASIN. 529 discharge through the lower course of the Wabash. The westward-flowing portion of the Wabash, with its several tributaries, traverses-a district lying mainly outside the limits of the Illinois lobe and appears to be entirely independent of preglacial drainage lines, for the drift deposits have been built up to a level above the preglacial rock divides. The headwater por- tions of White and East White rivers, which are the principal tributaries of the Wabash, seem also to be very largely independent of preglacial lines. There remain only the lower courses of the Wabash, and of tributaries entering below the great bend near Covington, Indiana, which are governed to any considerable extent by the preglacial lines of drainage. These all fall within the limits of the Illinois lobe or of unglaciated districts immedi- ately outside. Only the tributaries of the Wabash which enter within the limits of the Illinois glacial lobe are discussed in this place. The remainder of the watershed falls within the limits of a district covered by another report, now in preparation. THE PREGLACIAL WABASH VALLEY. The Wabash River enters a preglacial valley just above the city of Lafayette, which probably furnished a line of discharge for a considerable territory on the north and west. The river, however, remains in this preglacial valley for only a few miles; it soons turns southwestward across a rock point, while the preglacial valley apparently takes a longer route to the west and south, coming to the river at its great bend near Covington. From Covington southward the stream follows nearly the line of a preglacial valley to its mouth, though in a few places it cuts off rock points which -projected into the preglacial valley. Above Terre Haute this preglacial valley has been opened only a part of its width by the present stream, yet it shows a breadth of 2 to 4 miles. Below Terre Haute the bottoms of the present stream extend from bluff to bluff of the preglacial valley. The breadth increases from about 5 miles at Terre Haute to fully 15 miles near the junction of the Wabash with the Ohio. Few data have been obtained concerning the elevation of the rock bottom, but these uniformly indicate a level considerably below that of the present stream. So far as collected, they do not show a descent in passing MON XXXVIII——34 530 THE ILLINOIS GLACIAL LOBE. from north to south, but they are scarcely sufficient to prove a warping of the valley floor. A boring in the abandoned channel west of Lafayette enters rock at the remarkably low altitude of about 300 feet above tide, while at Terre Haute several borings made in the middle part of the valley enter rock at 345 to 360 feet above tide. Between these two points borings at Clinton and Montezuma enter rock at an elevation slightly higher than at Terre Haute. he elevation of the rock floor at Shawneetown, Illinois, just below the mouth of the Wabash, is shown by an oil boring to be but 240 feet above tide. As this bormg was made near the border of the valley, the rock floor may there reach a still lower elevation. MINOR DEFLECTIONS OF THE WABASH. At several points the Wabash makes shght deflections from its broad valley to cross projecting points of the preglacial bluff, the most notable instances being just above the city of Vincennes, Indiana, and a few miles below New Harmony. In each place the broad valley of the Wabash passes around the western side of the projecting point, while the stream cuts across in a somewhat narrow valley. It is not entirely certain that these deflections are due to glaciation. Possibly they have been caused by encroachments of the stream upon the rock divides in a manner suggested in explanation of the deflections of the Mississippi south of the limits of glaciation. The question of the cause of the deflection must for the present remain open. LITTLE WABASH RIVER. This western tributary of the Wabash, which drains about 3,000 square miles of southeastern Illinois, enters the river only 8 miles by direct line from its junction with the Ohio. Its source is in the Shelbyville moraine in southwestern Coles County, and its course is slightly west of south for 50 miles, to northern Clay County, beyond which point it is east of south through Clay, eastern Wayne, and eastern White counties, a distance by direct line of about 75 miles. Its most important tributary is Skillet Fork, which enters from the west near Carmi. The length of this tributary is about 65 miles, not including the windings of the stream, and it has a watershed of nearly 1,000 square miles. The watershed of the Little Wabash, including this large tributary, WABASH RIVER DRAINAGE BASIN. 531 has an ovate form, its middle portion being much broader than the upper and lower portions. It extends on the west to the watershed of the Kaskaskia, on the south to that of Saline River, and on the east to the Kmbarras and Bon Pas watersheds. The elevation of the headwaters of the main stream is about 700 feet, but the watershed falls to about 600 feet in the 30 miles to Effingham, to about 500 feet in the next 30 miles to Louisville, and to about 450 feet in the lower half. The elevation of the mouth of the stream is 323 feet above tide. The headwaters of Skillet Fork are only about 550 feet, thus giving a fall of but 100 feet in the watershed in passing across the broad middle portion from northwest to southeast. The main stream is largely independent of preglacial lines in its wpper 40 or 50 miles, but the remainder of its course is determined by a broad preglacial valley, except for a short distance just below Carmi, where it cuts across a projecting spur of hills leading in from the west. This valley, like other valleys in that region, has been filled in its lower course with drift and alluvium to a level perhaps 100 feet above its rock bottom. It thus covers low projecting points of the bluffs, and these are in some cases touched by the present stream, but the spur of hills near Carmi rises much above the level of the valley filling. The cause of the deflection of the stream across it, like that of similar deflections on the Wabash, has not been satisfactorily determined. ‘The small tributaries of Little Wabash usually enter this valley through preglacial lines, but their headwaters are somewhat independent of the preglacial drainage. Skillet Fork and its chief tributaries occupy preglacial valleys throughout much of their length. BON PAS RIVER. This small western tributary of the Wabash, with a drainage area of about 250 square miles, is the line of discharge for a district in Richland, Edwards, and Wabash counties, lying between the watersheds of Little Wabash and Embarras rivers. Its course is mainly along a preglacial line which has been filled in its lower course to an elevation of 60 feet or more above the rock bottom. The watershed outside of the preglacial line of drainage and its tributaries has only a very thin deposit of drift; hence scarcely any change of drainage has resulted from the glaciation. 532 THE ILLINOIS GLACIAL LOBE. PATOKA RIVER. This eastern tributary of the Wabash has a drainage area of nearly 1,000 square miles. Its watershed is long and narrow, being about 80 miles in length and less than 15 miles in average width, and lies between the watershed of East White River and the watersheds of several small streams which are directly tributary to the Ohio. The interesting drainage modi- fications which resulted in the production of the present Patoka River have already been considered (pp. 98-102). WHITE RIVER. The entire watershed of White River is about 11,000 square miles. Exclusive of East Fork it embraces about 6,000 square miles. The East Fork enters the district covered by the Illinois lobe only in the portion below the bend west of Shoals, and therefore lies mainly outside the field of the present discussion, which is restricted to the lower course of the main White River. Near Martinsville, in southern Morgan County, White River leaves the district which has been covered by more eastern portions of the ice sheet, and from this point to its mouth, a distance of 125 miles by direct line, lies within the limits of the district covered by the Illinois lobe. That lobe encroached only a few miles upon territory east of White River, the greatest known extension being about 20 miles, at points where it touches upon East White Valley east and south of Loogootee in western Martin County. Throughout much of the distance below Martinsville the glacial boundary is within 10 miles east of the east bluff of the present river. The valley of White River for a few miles below Martinsville, although including sections of a preglacial line or lines, has not been definitely con- nected with the preglacial line occupied by the stream in its lower course. The river crosses a rock ridge just below Ramona, another just above Spencer, while below Spencer it flows for a few miles in a narrow shallow channel among hills and ridges, there being apparently no definite pre- glacial drainage line to control its course. It occupies a preglacial valley from the mouth of Raccoon Creek down to Worthington, having a width of nearly a mile. Near Worthington the valley joins a larger preglacial val- ley, 2 to 25 miles wide, which leads in from the north along the lower WABASH RIVER DRAINAGE BASIN. 533 course of Eel River. From this point to its mouth the course of the stream is nearly coincident with a broad preglacial line. At Worthington there is a minor stream deflection. The preeglacial valley of Eel River leads southward, while the present stream passes east- ward into White River through a gap in a line of hills that continues south a few miles in the midst of the broad valley of White River. It is probable that this line of hills is the remnant of a narrow ridge separating the pre- glacial Eel River Valley from the smaller preglacial valley coming in from the northeast. Below the junction of these two valleys White River has a valley of irregular width, ranging from 3 miles to fully twice that width. Broad low tracts extend up tributaries several miles. They are conspicuous on the west side, in both Greene and Knox counties, but on the east side they first become conspicuous in Daviess County south of Greene. These lowlands are deeply filled with drift and appear to be the lines occupied by preglacial tributaries. ‘They are now mainly occupied by very small creeks. Attention has already been called to some interesting deflections of eastern tributaries of White River in Owen and Greene counties, Indiana, evidently caused by the presence of the ice sheet, deflections which were discovered by Mr. C. E. Siebenthal, of the Indiana survey. Other deflec- tions, also discovered by Siebenthal, appear to be referable in great part to drift fillmg, occurring as they do within the limits of glaciation. Thus Raccoon Creek makes a slight detour into its old south bluff 13 to 2 miles below Freeman, its former course being indicated by a slight sag or depres- sion lying north of the present stream. A similar though somewhat greater departure is made by Richland Creek near Tulip, about 6 miles above its mouth. y.reurthe (| MWOSLI | ae Todor! 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XX Bo" a ieee Counties: In a ILLINOIS i) 1 JO DAVIESS Beloit STATE. fe See KGON Et i A South Haye 4 yWaulkegan AL-ake Forest ‘\ : 2 Anamosa R (i ; A 5 7 | 18 CARROLL ( me ieee x 3 15 Rt Cédar Rapids 16 MERCER 17 HENRY 18 BOREAT 19 PUTNAI 20 LASALLE 21 KENDALL 22 GRUNDY 23 Witt 24 KANKAKEE: 25 |ROQUOIS 26 PORO 27 LIVINGSTON ) Rockisland Muscatine 34 HENDERSON 35 HANCOCK g6 MeDONOUGH 37 FULTON 38 MASON 39 TAZEWELL 40 MCLEAN 4) VERMILION 42 CHAMPAIGN 43 PIATT. 44 DEWITT 45 LOGAN 46 MENARD 47 CASS 48 SCHUYLER 42 BROWN, 50 ADAMS: 51 PIKE 52 SOOTT 53 MORGAN 54 SANGAMON 55 CHRISTIAN 56 MACON 57, MOULTRIE 58 DOUGLAS Yarmouth ( LC SJ) 19) ok vankfort - Cae tefstu teh) 7 a caer LEGEND | Wells which reach rock | Wells which do not reach rock { Gap Gir 4 70 MILES ReetOWN NOTE Data from Minois obtained from unpublished contour maps showing 10 feet interval Prepared t CW Rolfe in 1893. Data from Indiana based upon railway attitudes, personal aneroid determinations and notes furnished by the Indiana survey; In Minois the 50 feet contours ap- pear except in the southern end of the state and in the portion north of Rock river wherel00 feet contours ave given. Only100 feet contours appear in Western Indiana and South,vestorn Michig. SETA STJOSEPH S MARSHALL @ PULASKI 10 FULTON 11 CASS: 12 WHITE 13 BENTON 14 WARREN 15 TIPPECANOE 16 CARROLL (7 CLINTON 1B HOWARD 19 TIPTON 20 HAMILTON 2) BOONE 22 MONTGOMERY 29 FOUNTAIN 24 VERMILION 25 PARKE 26 PUTNAM 27 HENDRICKS 28 HARION 22 JOHNSON 30 MORGAN, 31 OWEN 32 CLAY 35 Vico 34 SULLIVAN 35 GREENE 36 MONROE 37 BROWN 38 JACKSON 39 LAWRENCE 40 MARTIN 4) DAVIESS 42 KNOX 45 GIBSON 44 PIKE 45 ounoIs 46 ORANGE 47 WASHINGTON 45 FLoyo 49 HARRISON 50 GRAWFORD S4 VANDERBURG 55 POSEY SUUUS BIEN SCOT NY MAP OF ILLINOIS Showing distribution of wells BY FRANK LEVERETT 1898 AVERAGE THICKNESS OF THE DRIFT IN ILLINOIS. 545 the average thickness for each township is 77.9 feet. In making the esti- mates care has been taken to avoid duplications; thus where several borings have been made on a single square mile which differ very little in distance to rock they are considered as one boring. If, however, borings in close proximity show a wide difference, they are each included in the computation. After averaging the drift by townships the question was considered whether the townships in which rock has been struck fairly represent the thickness of the drift. This involved the consideration of their distribution in reference to moraines and in reference to preglacial valleys, both being lines where the drift has exceptional thickness. It was found that the moraines have been about as thoroughly tested as the tracts of thinner drift separating them, but an examination into the distribution along preglacial valleys has led to the conclusion that they are not adequately represented. Of the 1,179 bormgs which reach rock, 1,065, or fully 90 per cent, enter it near the level of the preglacial uplands, while only 114, or scarcely 10 per cent, pass markedly below the general level of those uplands before striking rock. It is difficult to decide upon the portion of the surface to be included in the valleys, especially if their intricate network of tributaries is included, but it may confidently be placed at not less than 30 per cent; possibly it may reach 50 per cent. Upon computation it is found that the average depth to rock of the bormgs along preglacial valleys is 172.44 feet, while the depth of those on the uplands is 67.87 feet. If the uplands comprise 70 per cent of the glaciated portion of Illinois and the preglacial valleys 30 per cent, the average thickness of drift will be 99.23 feet. If the uplands comprise 60 per cent and the valleys 40 per cent, the average will be 109.7 feet. Ifthe uplands comprise only 50 per cent and the valleys 50 per cent, the average will be 120.15 feet. By this method of computation, therefore, the thickness appears to be not less than 99 feet, and it may be 120 feet or even more. The thickness is on the whole greater within the area covered by the Wisconsin drift than in other portions of the State. Of the 487 borings within that area which reach rock, the average drift thickness is 121 feet. Of these borings only 52, or about 10 per cent, have struck preglacial val- leys. The borings on the preglacial uplands enter rock at an average depth of 109.7 feet, while those along preglacial valleys average 221 feet to the MON XXXVIII——35 546 THE ILLINOIS GLACIAL LOBE. rock. Of the 18,000 square miles covered by the Wisconsin drift, there are about 4,000 square miles in which the thickness is much below the average. ‘This comparatively thin drift is found in five counties which border the Kankakee River and the Chicago Outlet, viz, Kankakee, Cook, Will, Grundy, and Lasalle counties. There are 254 borings in these counties which enter rock at an average depth of only 68.8 feet. Of these 243 are on preglacial uplands and enter rock at an average depth of only 63.8 feet, while 11 along preglacial valleys average 179 feet to rock. If now the Wisconsin drift area be corrected for the imperfect repre- sentation of preglacial valleys, in accordance with the corrections applied to the whole State, it is found that the average thickness, on a basis of 30 per cent being in valleys, would be 143 feet; on a basis of 40 per cent in valleys the average will be 154 feet, and on a basis of 50 per cent in valleys it will be 165 feet. The general average of the Wisconsin drift is thus 40 to 45 feet above that for the entire State. Turning to the lowan drift, there is found a markedly greater amount of drift in the counties lying east of Rock River than in those west of that stream. The few borings which have been made indicate that the thickness in the former district will average not less than 100 feet, while in the latter it is but 50 to 75 feet. The thinness of the Iowan drift near its margin is perhaps due in the main to the withdrawal of the loess which apparently has been derived in large part from the Iowan ice sheet, but has been scattered widely outside the limits of the Iowan till. In the portion of the State lying outside the limits both of the Iowan and the Wisconsin till sheets—i. e., the portion occupied by Hlnoian till and loess—there is a marked variation in the thickness of the drift. The thinnest drift of the State is found in the district lying east of the Kaskaskia, a district having an area of nearly 11,000 square miles. Of the 138 borings reported which reach rock in that district, 128 are found on preglacial uplands, and enter rock at an average depth of only 20.4 feet. The 10 borings entering rock along preglacial valleys show an average drift thick- ness of 106 feet. In the remainder of the Ilinoian drift area the borings enter rock at an average depth of about 55 feet, including 52 valley borings. The average thickness on the preglacial uplands of that region scarcely exceeds 40 feet. AVERAGE THICKNESS OF THE DRIFT IN ILLINOIS. 547 The following tabular statement sets forth the proportion of reported borings between each 100 feet within the entire district covered by the Hli- nois lobe, and includes both those which reach rock and those which do not. Number. Withz400:feetion more) ape n ee saecrecemiciacccacisceices Sos Bose lgtecs ceihceceaeeina caseteessese 4 Wii thrS00tto 400Meetinsem see ccm see ae oe i cnepeces oe ticine sieqeais ee neisigeeiiere clo ae ae clmesclooas 18 IWithy200) to: d00teebice testec anc cee lecine oc toseeb a sain set osne sccseisimemsne eee Accs tmeeemad cicliee ce 138 Wath OO\to 200 tetera sae emer cee esc ccs cosas de clgeanuesiss seeceees meter sbeeesctecce-cm. (698 Withelesssthanel OOjfee ties tcinctoetete emcee tel ete cicleratcine cave mie sacl oe mapa era eee omen eee eee crete eae Foal MONET! Sess cond cobs dosocdonecdadodasdHbes dingd obos ShoSpanenoseoconnedaccosmasacaus suse sdaree 3, 109 After the estimates just-recorded were compieted, the thickness of drift in Illinois was computed on the basis of the requirements of the topography, the data obtained by Chamberlin and Salisbury in the Driftless Area serving as a guide. The investigations in the Driftless Area led to the opinion that 150 to 200 feet of drift is necessary to fill the valleys up to the level of the divides, all the summits of the ridges being still left bare, while 300 feet would be necessary to bury the region as deeply as in the heavy drift regions of the four adjoining States.’ Upon turning to Illinois, it is found that the drift in places has filled the valleys completely and brought the surface up to a level perhaps i00 feet or more above the summits of the ridges. In much more extensive districts it has barely filled the valleys, while in fully half the State it has fallen short of filling the valleys, the amount in the different localities being two- thirds, one-half, one-third, or one-fourth as great as is necessary to com- pletely fill the valleys. It is estimated that there may be about 4,160 square miles along the bulky moraines of the Wisconsin drift in which the average thickness reaches 300 feet; but in the greater part of the Wisconsin drift area it can scarcely exceed 200 feet, for the fillmg extends but little above the level of the rock divides. There is estimated to be 10,975 square miles in which the average thickness may reach 200 feet, this district lies mainly within the Wisconsin drift but extends beyond this drift down the Illinois Valley through Mason and the adjoining portion of Logan County into Cass County. The area of Iowan drift in eastern Winnebago, Boone, and neigh- boring portions of McHenry and Kane counties may possibly have 150 ' Sixth Ann. Rept. U.S. Geol. Survey, pp. 257-258. 548 THE ILLINOIS GLACIAL LOBE. feet of drift, and so many portions of the Ilinoian drift area in Western Illinois, for they are built up about to the level of the summits of the rock ridges. It is estimated that such areas embrace only about 3,550 square miles. More than half the [linoian drift area, embracing about 19,275 square miles, appears to have been filled to about two-thirds the capacity of the preglacial valleys and to have perhaps 100 feet of drift. There is an area of nearly 7,000 square miles lying mainly in southern Illinois but embracing also portions of Stevenson, Winnebago, Ogle, Carroll, and Jo Daviess counties, in northwestern Illinois, where the average thickness can scarcely reach 50 feet, the valleys being filled only to one-third or one- fourth their full capacity. There. remain about 8,000 square miles in south-central and southwestern Illinois in which it is somewhat greater than in the districts just mentioned and may average 75 feet. Summing up the above estimates in a tabular statement and averaging the results for the State, we have the following table: Distribution, by depths, of glacial drift in Illinois. | . Depth if Area) mesic dl eerasics | State. | ae | Feet. | Feet 4,160 | 300 | 23.50 10, 975 200) |) 435 3, 550 150 10. 04 19,275 | 100 | 36.32 8, 190 75 11.57 6, 924 50 6.52 EEO | seadescoon | 129.30 i The above computations are necessarily less exact than those based upon borings, but the method may prove helpful in supplementing one based entirely on borings. It is some satisfaction to find that the results obtained by the two methods are not so widely discordant as to leave doubtful the general average thickness. As the computation just made represents the maximum estimate of thickness, it should be compared with the highest of the corrected estimates from borings. With this it is in essential agreement, being but 9 feet higher. The average thickness for AVERAGE THICKNESS OF THE DRIFT IN ILLINOIS. 549 the State may safely be placed at not more than 130 feet and not less than 100 feet; probably it lies not far from midway between these amounts, or 115 feet. ‘In the above estimates everything which overlies the rock has been included, not only glacial drift, but residuary clay, alluvium, and loess. In order to ascertain the proportion of till, a careful computation has been made from the records of 1,687 borings obtained within the the area covered by the Illinois lobe. These give the following results: Per cent. dull yincludinevallbolacialclaysimecsrecrccscecciesaiseaas-(neeen saciseeenceecneeecneteceeceeon: 69. 38 Renal, eral, emg! qullmaltyin .scoc5 succ50 cheas= Satacs coon bdacos oo dacU EoSe Soncos aataee bonos Ease 25.25 ILOESS) AG ASSOCIA SNS) Sood doedod sadt conckb Goad sadeao cone doeuoo Lesene CuoceccudbasaoBooues 4, 25 Buriedisoil presidnanygsclay ne vCmrresccrace sci asc caeeee eee ee a eee eee ee eee nee 1,12 TIQUE Sesiad toca coon conc SS oe SFhs SE Sop aS PEE TAI ReC ey ere Ever re made tee ny Se ences ae 100. 00 In this computation it is probable that the amount of residuary material is underestimated, since it is only occasionally recognized in borings. COSC GN Je IN 10) In, CLAY WELLS OF ILLINOIS. INTRODUCTION. In the Seventeenth Annual Report of this Survey the writer has pre- ? in which the wells are sented a paper on the ‘‘ Water resources of Illinois,’ discussed in a general manner in connection with other water resources. The data concerning artesian wells and the wells affording supplies for cities and villages are tabulated in that paper, but a large number of wells which do not admit of ready classification were necessarily omitted. The present discussion aims to present all the reliable records collected in the State which throw light upon the formations penetrated and the character of the water supply. CLASSIFICATION OF UNDERGROUND WATERS. The classification of underground waters given below seems to include the most important phases or classes of subterranean distribution to be found in this region. It has already been presented in nearly its present form by the writer in the Eighteenth Annual Report. In nearly all cases it is not difficult to decide from the description to which class a given well should he referred, and it has scarcely seemed necessary, in the detailed discussion which follows, to group the wells in classes. They are instead taken up by counties. However, a tabulated statement has been prepared setting forth the use made of the several classes of wells as sources for city water supply. The following are the principal classes of underground waters: class 1—Ground water, supplied by direct percolation of the rainfall into the soil and substrata, and subject to but little lateral transmission and little hydrostatic pressure. The water level rises and falls with the degree of saturation by rains. class 2— Waters in close association with streams, as in valley bottoms, in which lateral transmission is great and hydrostatic pressure is small. It 550. WELLS OF ILLINOIS. ool differs from the former class not only in the great lateral transmission, but also in being fed partly by stream percolation. The level rises and falls with that of the neighboring streams. This class should perhaps include the waters of sand plains and gravel plains which have no surface streams traversing them, for waters in such plains usually have great lateral trans- mission and but little hydrostatic pressure. class 3 — Water included in porous beds of glacial drift or other non- indurated formations lying beneath impervious beds but without strong hydrostatic pressure. Such water is supplied from more or less distant absorption areas and is less directly influenced by rainfall than the preced- ing classes. class 4— Water with strong hydrostatic pressure included in porous beds of glacial drift or of alluvium. This includes two subclasses, viz: (a) Flowing wells; and (6) wells in which water rises nearly to the surface. - Subclass (a) embraces wells to which the name “artesian” is considered applicable, while the term is not extended to wells of subclass (6). Class 5—Streams in caves and subterranean passages in the rock, fed by sink holes and brooks and also by direct percolation from ground water. class 6—Rock water with but little current and slight hydrostatic pressure. class 7—Rock water under strong hydrostatic pressure. This includes two subclasses, viz: (a) Waters which overflow when tapped; (b) waters which rise nearly to the surface. Subclass (@) embraces wells to which the term ‘‘artesian” has long been applied, and it seems a convenient term for use if properly restricted, but its extension to nonflowing wells tends to mislead and confuse those interested in obtaining a flow of water. Discrimination in selection of records—It should not be inferred that the average depth of the wells reported in the ensuing discussion represents the average of all the wells that the region affords. Attention is directed chiefly to the deeper wells, since they throw more light than the shallow ones upon the structure of the formations penetrated and upon the supplies of water. The great majority of wells in the State are the seep or ground-water wells (class 1). They are sunk to depths of but 10 to 20 feet. In seasons when rainfall is normal or excessive such wells supply the needs of the residents, ‘Compare Chamberlin, Fifth Ann. Rept. U. 8. Geol. Survey, p. 131. 552 THE ILLINOIS GLACIAL LOBE. but in seasons when the rainfall is deficient many of them fail, or yield but a small amount of water. The wells here recorded are generally those which afford a supply of water in seasons of drought as well as in rainy seasons. The well records have been obtained largely from the drillers. In some cases there is uncertainty as to the reliability of such records, but as a rule the drillers are sufficiently careful in their observations to warrant the acceptance of their statements. Records have, in many cases, been obtained from the owners of the wells, who were present during their excavation and often assisted in making the wells. The village wells have usually been recorded carefully during the excavation or drilling, and thus have a value above those whose records are given from memory. The writer has rejected such well records as are thought to be unreliable, and has endeavored to reduce errors to a minimum. It is thought that the records here presented contain few serious errors, and that the general exposition of the subject and general conditions for obtaining water are set forth with a fair degree of accuracy. The published well records in the Geology of Illinois are also included in this report and duly accredited. THE GEOLOGIC FORMATIONS. Since many of the wells enter rock, a map of the geologic formations is here introduced (Pl. X XI) which was prepared by the writer to accom- pany a paper in the Seventeenth Annual Report. It follows in the main Prof. A. H. Worthen’s map of Illinois, published in 1875, to accompany Vol. VI of the Geology of Illinois, but a few corrections have been made in northern Illinois based upon observations by Mr. Oscar Hershey and the writer. The portion covering western Indiana is based upon Dr. A. J. Phinney’s map of Indiana, published by this Survey in 1890.1 The lime- stone formations of the northern and western parts of Illinois and the sandstones and sandy shales of the southern and southeastern parts are extensively utilized as a source for ordinary wells for household use. The limestones are also a source for artesian wells or deep wells having strong hydrostatic pressure. A few artesian wells obtain water from the sand- stones of southern Illinois. In northern and western Illinois the St. Peter and Potsdam sandstones are the sources of numerous artesian wells. The 'Hleventh Ann. Rept. U.S. Geol. Survey, Pl. LXIII. sah LP NP Dh Fh | Wi wh £ ens os AB stig Se 4% AP Ft ~ (| optred a A ee) a SONSYMYT SZ , F 5) GYyO4IMVUHO + wadSvl EL WVHONI443 22 BLLZAV4 1h GNOS OL NOSIOVW 69 AaSY3ar 89 NNOH1VO LO 3N33Y9 99 NIdNOOVW So AYAWOOLNOW +9 AB13HS €9 GONVIY3EWND 29 $3109 i9 MYV19 09 uvoaga 6g sv10n00 eg ZIYLINOW Zs NOOWW 9S NVILSIYHOD SS NOWYVONYVS +9 NVOYOW &¢ 1109S 2g 31d 1g SWVQv OS NMOUS 6b Y3TANHOS Livid & NOIWdINVHO 2 NOMIWYSA Ib NV313 Ob TNaM3ZVL 6B NOSVW 8& Nona Le HONONOG4W 9é HOOONWH SE NOSH3QN3H +E N3UYYM Fe XONM ZE vidOad If Wuvis Of G40i000M 6z TIVHSYYW Bz NOLSONIAIT Lz Quod 92 SIONDOH! gz B3HVUNVH $2 THM £2 AQNNUYD zz TONS 12 aN vsv1 02 WYNiNd 61 nvauna ei AMN3H LI ¥39HaW 9) NWSI H90Y SI 30IS3LIHM +1 TIowuvO eI 337 ZI 3790 II 81vN30 O! aNVH 6 3ovana 9 009 L 3X¥1 9 AUNIJH OW GS 3NOO8 + ODVa3NNIM © NOSN3Hd3LS Z SsalAvaor | SIC senuno) Ly Li Why 4 & Vie 4 LH, YY z} yy We yared purpysy, 489.10.) aye] WOfog BYSOUDy\? oul eYpb oL8 IXX 1d II|AXXX Hd VYSONOW > ouneosnyy UPS] Yoo = Cy JUB SRT VN Y Y jou a D soypode yy —~— ONS AV or: sit a =) spidmy rep p5>y = UCN ABAAYNS 1V¥9O19071039°S'N S68L O68TS)S 1euerpy jo deur séouutyd pure c/ey stouryy Jo deur suayIo\\ WO potduro) VNVICGNI NYAHISHM GNV SIONITIT 40 SNOLIVNUOA OLDOTORD . 4 °N HLI7'09 9 NZ18 Soar = SOTO OL AaSOd SS SUNBYIONVA +S WOlNYYM ES 9° uaON3dS zs “URSKIW Usle}seMIyNOG aucoiteneibe pue euerpul usoisaq, ut seedde sanoyuo0d 4907 OOTATIO NOBINBVH/eb UPAIS 8B SINO}UOI 192 OOTPIYM JaALL oY JO you uonzod BaNH Ic 2 I I NOLONIHSWM Le 3ONVHO SF siogna Sy te aTeos reLnmyts 1taMo'q) ii : , SUOISPUKS 19}@qG4g | Ler (UeLINTIG 1aMo'7) oy} UT pue 97848 VY} JO pus usey Nos sip m1 ydaoxe seed : \ eueTey pure uo Was] -de s:moyuoo ay OG ay) Stour] Uy Aeaans Buerpuy erp Aq Mid poys tummy sojou pue suoTyeurusojep proreue [euoszed ; rected ‘sopnime Aemjrer uodn paseq vuerpuy wo Bye ‘SGgt : . 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AXXSs = ; ‘ ‘ .. > 14 WHITESIDE 15 ROCK ISLAND 16 MERCER Se z : S : ( Ee <7 17 HENRY: Towa C : P 18 BUREAU CHICAGO. vA , 19 PUTNAM 4 LASALLE 21 KENDALL Michigen Gty 22 onunay Michigan Witt (24 KANKAKEE 25 iROQUOIS 26 FORD 27 LUVINGSTON ‘28 MARSHALL 29 WOODFORD 30 STARK ‘SI PEORIA ‘32 KNOX 33 WARREN 34 HENDERSON 35 HANCOCK ~ 36 MEOONOUGH Jape \ i = 37 FULTON ‘Wapello} : Ae j 38 MASON E e f 39 TAZEWELL 4 40 MCLEAN armouth ? 3 Serr} z : atk i 4 41 VERMILION 42 CHAMPAIGN 43 PIATT 4 DEWITT 45 LOGAN 48 MENARD ne = g 47 CASS whington« u = 2 i SR, i ser i 48 SCHUYLER Denmark. 2 2 : fi aj = 4 49 BROWN, S } I Ss m | J, : SO ADAMS . t zs =e = “ K a Te ‘a 5! PIKE = “ Walp 52 scorr 53 MORGAN S54 SANGAMON. 55 CHRISTIAN 55 MACON 57 MOULTRIE 58 DOUGLAS 59 EDGAR 60 CLARK 61 COLES 62 CUMBERLAND LEGEND » q =! 5 a 1 4 ST.JOSEPH Z J L eae 5 MARSHALL 7 re 6 STARKE =< ‘ ; 5 7 NEWTON fea] conn : Ps SS 8 JASPER ‘ m e > = 2 > 1?) "] = di oo] 8 PULASKI Tertiary : : s — R poate | 10 FULTON Jn 6 i tS} f Z iB Il CASS ie Wes = F St = Fe 5 = 12 WHITE 13 BENTON 7 14 WARREN Coal Measures i C cee Z 15 TIPPECANOE a) a + 7 ; ; a 7 S = 16 CARROLL (Carboniferous) +S X J Eel 45! = 17 CLINTON ~ f 5 ES = oe 16 HOWARD = \ = * ey i - S 19 TIPTON 2 20 HAMILTON 21 BOONE | Bo- Carboniferous et rr Timer ig 2 Gneludins Kinderhool) « t : i Thy i y) 23 FOUNTAIN i eB an t “ g = s 2% VERMILION — neville 2 ee Isa] | 25 PARKE ee 9 ce 5 L ‘ vars! 26 PUTNAM : i 1G Pree : 27 HENDRICKS ; ! ted, SH a Devonian x. “ = a) S ort 29 JOHNSON : a1 SX 30 MORGAN - AM E 31 OWEN » 32 CLAY 33 vido 4 Nia re : 34 SULLIVAN ere Niagar a_ etc. - \ hawneetown 35 GREENE _ | (Upper Silurian) ‘ = 38 MONROE ks = Y, 37 BROWN ‘! NOTE 38 JACKSON Data from Illinois obtained from unpublished contour 39 LAWRENCE ludsonRiver: Shales \) Toned 4 maps showing 10 feet interval Prepared by C,WRolfe in (Lower Silurian) 1893, Data from Indiana based upon railway attitudes ; personal aneroid determinations and notes furnished by the Indiana survey. In Illinois the 50 feet contours ap- Trenton and Galena 5 SS ) pear except inthe southern end of the state and in the (Lower Silurian) r \ 0 ON ’ ‘4 portion north of Rock river wherel00 feet contoursare given A . /; =. $ Only100 feet contours appear in Western Indiana and Southwestern Michigan. StPeter § $ > St.Peter Sandstone Seal S4 VANDERDURO. cale 5 Posty (Lower Silurian) GEOLOGIC FORMATIONS OF ILLINOIS AND WESTERN INDIANA Compiled from Worthen'’s map of Illinois 1875 and Phinney’ map of Indiana,U.S.G.S.1890 BY FRANK LEVERETT 1898 WELLS OF ILLINOIS. 553 Lower Magnesian limestone is also used for artesian supply. Portions of the Coal Measures yield brackish water, and for this reason they have not been extensively utilized for water supply. In some localities, however, it has been found necessary to make use of these formations because of no adequate supply from the drift or overlying rocks. In such places the presence of beds yielding comparatively fresh water has been made known. In the detailed discussion which follows, the degree of development of the several rock formations is set forth. ATTITUDE OF THE STRATA. The attitude of the strata is very favorable for producing a strong hydrostatic pressure in deep wells throughout much of the State. A north- to-south section shows a gradual southward dip of the formations (see figs. 7 and 8), terminated at the south by an axis of upheaval which, as above noted, leads eastward across the southern end of the State from Grand ‘Tower to Shawneetown. The descent probably amounts to 2,500 or 3,000 feet in the 350 miles from the north to the south end of the State. There are slight undulations carrying the strata up or down 100 to 200 feet or more from a uniform grade, but so far as known no prominent west-to-east axis of upheaval crosses the State north of the one just noted, none adequate to prevent the southeast passage of the water. East-to-west sections are less uniform in the inclination of strata than the north-to-south sections. Sections across the northern part of the State present two blocks of strata, each dipping gradually to the east, separated by an abrupt fold or line of disturbance (see fig. 9). At this fold the block on the east rises abruptly several hundred feet above the neighboring portion of the western block. It is along this line of disturbance that the St. Peter and Lower Magnesian strata are brought to view on the Illinois and Rock rivers and on Elkhorn Creek. Its trend from the Lllinois River northward is about southeast to northwest. Sections in the lead region indicate that it continues in subdued form some distance into southwestern Wisconsin. Its southward continuation from the Illinois is readily traceable as far as Livingston County by disturbances shown in coal shafts, as noted by the Illinois survey. Farther south its course is less definitely known. There is, over much of western Illinois, a gradual descent from the western border of the State to this line of disturbance. In the latitude of THE ILLINOIS GLACIAL LOBE. 554 i por- y different The eastward descent across western t creat] 1s ho t averages about 7 feet per mile, and 1a 1 Peor her north. art tate f: Ss tions of the OOO FT AT. 4 | WISCONSIN SEA LEVEL 1000FT BT 2000F TAT 3000F7 BT lek Fre = ‘Cambrian 4000FT BT Tic. 7.—Section A—A; from Wisconsin River in western Wisconsin southward to Cap au Grés, Dlinois. This section shows a line through a region where wells are very successful. Northward from Aledo the section shows but one shale bed (the Hudson River), and this is wanting north from But south from Aledo the Kinderhook and Coal Measures shales comprise a considerable portion of the section. Vertical scale is 40 times 4£FAINGHAM 1000 FT-AT- = sae q ieee eh = — OR | 1000 FBT ae 2000 FT BT. ine. reba bly Including onan ee eee : 3000FT BT AMER CTL -¢ 5 ORS RASS 60 Se emesis 4000FT ae eerste Oo *__ formations ot FE Ee ps ae a So00FT Br Tig. 8.—Section B—B; from Galena to Olney, Ilinois. This section leads through the deep part of the Coal Measures basin from Lasalle to Olney. Wells are successful from Minonk northward. Vertical scale is 40 times tho horizontal. Galena & Trenton. w Peterss. Lower Mapnesian Potsdam SS ®Q ~= ¥ Roig = 2 Reg a geuie 8 § : ; 3 N § 2 i Rupa IS g 3 g . § s u g in aN g < by 5 e ¥ t £ S 3 Na q ry = N ai S 8 3 N s ——= ——s : = = = = hea URS eens se ee : eae cS sey eee LowerMagnesian., SS = = = =i |Lower Magneis/an I oad ac acl ead EE wed er eR ieee ee Nn Shh NGL un wma oa mS) and Potsda. ie ite 2000FT BR Fic. 9.—Section C—C; from Davenport, Iowa, to Joliet, Minois. This section shows the monoclinal fold which passes just east of Lasalle, with the nearly horizontal blocks on either side. Vertical scale is 20 times the horizontal. south as the Cap au Grés s, and, so far as known to the writer, far gradual as ntinue ‘0 Illinois appears to ¢ mol. upheaval, near the mouth of the Ill WELLS OF ILLINOIS. }935) there is no marked disturbance along the Mississippi north from that point. From the Cap au Gres disturbance southward to the Ozark Ridge, in south- ern Illinois, a different field is found. Disturbances are frequent along the Mississippi. There is also in this district a more abrupt descent in the floor of the Coal Measures within a few miles east of the Mississippi. Thus, in passing from the east bluff of the river in western St. Clair County to Belleville a descent of 650 feet is made within a distance of 10 miles. ESSENTIAL CONDITIONS FOR ARTESIAN WELLS. Since the essential conditions for obtaining artesian wells have been discussed at some length by Prof. 'T. C. Chamberlin in a report of this Sur- vey,’ only a brief outline of their conditions is here attempted. ‘The essen- tial conditions for artesian wells are: (1) A suitable exposure of a porous rock in a humid region, i. e., a favorable absorbing area; (2) the extension of the porous bed from the absorbing area out underneath regions having a lower altitude, i. e., a favorable transmitting area; (3) a partial or full obstruction to the escape of the waters at a lower level than the absorbing area. The porous rock is usually confined between beds which are less porous and which act as a partial or complete obstruction to the escape of the waters. It is not necessary, however, that these beds should be per- fectly water-tight; indeed, such is rarely the case. It is only necessary that the confining beds should be such as to prevent most of the water from escaping. In some cases the water contained in semiporous beds overlying the porous rock aids in preventing the escape of water from the porous bed at points between the absorbing area, or fountain head, and the well. In connection with this condition Professor Chamberlin remarks:* I conceive that one of the most favorable conditions for securing a fountain is found where thick, semiporous beds, constantly saturated with water to a greater height than the fountain head, lie upon the porous stratum and occupy the whole country between the well and its source. This is not only a good but an advan- _ tageous substitute for a strictly impervious confining bed. Under these conditions limestone strata reposing on sandstone furnish an excellent combination. This condition prevails extensively in northern Illinois. The absorbing area for the artesian waters of northern Illinois is found in southern Wis- consin, the porous rock thence dipping southward to northern Illinois. ‘Fifth Ann. Rept. U.S. Geol. Survey, 1885, pp. 131-173. 2 Loe. cit., p. 140. 556 THE ILLINOIS GLACIAL LOBE. Between this absorbing area and the wells is a district in which the porous bed is overlain by limestone or semiporous rock, and also by drift beds, which afford much opportunity for absorption of water. These overlying beds, however, have altitudes fully as great as portions of the absorbing area, and hence, when filled with water, the downward pressure equals or exceeds that of the upward pressure of water from the porous beds, and thus they prevent escape as effectually as a series of impervious beds. The variability of head displayed by wells in northern Illinois which obtain their main supply from the St. Peters formation is probably largely due to the influx of water from overlying beds in the district between the fountain head and the well. The main absorbing areas for the Potsdam and St. Peter formations are shown in Pl. XXII, which is compiled chiefly from State geological maps and was first published by the writer in the Seven- teenth Annual Report of this Survey. A topographic map of the St. Peter sandstone, showing also the dis- tribution of artesian wells and deep borings and of the principal areas where flowing wells are obtained from the drift, is presented in Pl. XXIII, a map already published in the Seventeenth Annual Report. The three sections in figs. 20, 21, and 22 illustrate the above statements concerning the attitude of the rock formations and correspond to the lines A—A, B—B, and C—C on Pl. XXIII. The data used in figs. 7 and 8 are largely obtained from records of wells collected by the writer, but some of the data are from a report by Daniel W. Mead, bearing upon the hydrogeo- logy of the Mississippi Basin.1 The data in fig. 9 are largely based upon a special study by Prof. J. A. Udden of a line leading from Rock Isiand eastward across Illinois, which was made for the Illinois Board of World’s Fair Commissioners.” It brings out clearly the monoclinal fold separating the two blocks of eastward-dipping strata just noted. For a more complete discussion of artesian-well conditions in Illinois, reference may be made to the report by the writer contained in the Seventeenth Annual Report of this Survey. Many records of wells appear in the detailed discussion below. 1 Hydrogeology of the Upper Mississippi Valley and some of the adjoining Territory, by Daniel W. Mead, C. E.: Jour. Assoc. Eng. Soc., Vol. XIII, No. 7, July, 1894. 68 pages, with 6 maps. 2 See Final Report Illinois Board of World’s Fair Commissioners, 1895, pp. 115-151. SURVEY. ; MONOGRAPH XXXVIII PL. XXII 92° WK / St a at po FETS Zz olf IF 4, | Aa ae Haywardy Bi CZ | °Qa.A4c cours | ORE t: DA p ly) 28 3 Ces © SAD Rhinelander” a J Menomigin : OF — p53} feesh k VEioy, Vz. conto «6 O°? ais ean fein! sSonir (BL eS AS ill (> \ sf A. va. Almapee cad REWAUN, Aw gee Bay, Kewaunee KC a \ AOS Twin River Pt ere ‘Two Rivers 1 Manitowoc a4) PIyiaquiap heboysan ae ebqygan Falls N oy kette | Sea lingle IRKTON f Kenosha OSTA Potsdam sandstone (Cambrian) (Outcropping or within reach of surface water ) St.Peter sandstone (Lower Silurian ) {houléd } A Ye NE ae a NE BIEL ERS 90° 89° 88" o 92 : 91 AIN ABSORBING AREAS FOR THE POTSDAM AND ST. PETER FORMATIONS COMPILED CHIEFLY FROM STATE GEOLOGICAL MAPS “BY FRANK LEVERET'T 1896. Seale 25 oO 25 50 75 100 MILES. _——— = = SS i JULIUS BIEN & CO.N.Y. ae Bike NOLNI19 62 NOISYW 82 AWID LL GNVIHOIY 92 SONSYMY1 SZ GQYOJMVHO +L Y3adSvP eZ WWHONIS33 22 SLLZAVS 12 QNOS OL NOSIGYW 69 AaSYaE 89 NNOHIV9 L9 3N33u9 99 NIdNOOWW So AXIWOSINOW $9 ASTSHS £9 GNV1Y838WND ZO $3109 19 MYV19 09 uvod3 6S sv19no0 es JIdLINOW és NOOVW 9S NVILSIYHOD SS NOWVONVS +S NVOYOW > 1100S eo ) kone Sy y [ ENG S : o ea avid 1S SWY¥aY OS NMOS 6b H3TANHOS 8 divid oy J) i ene i ty - th “aS NOIWd WHO 2 a a 4 E ‘: NONIWYS3A Ib NV3TOW OF WWIM3Z¥1L 6E NOSYW ge NOLIN4 LE HONONOGSW SE HOOONVH Se NOSH3QN3H +& N3euWM £e XONM 28 Lape ous Nyy ; vitO3d | <=> " eae T Q ZS = . \ fae 5 a J 5 es HuWIS OF j - Cor z x f Saray VST Yoo Se au0id00M 62 |! : d z TVIVHSYYW 82 NOLSONIAI Lz guOs 92 siondowl sz BIAXVANYYH be TUM &2 AGNNYD 22 TVIVGNIH Iz § 3a1vS¥1 02 | WYNLNd 6! Nvaune AYN3H y30ugW ONWISI H90u JOISFLIHM TIOwYXVO AN UBS LOY 7, ‘+ ooo da sopys iS i) } — § a f > AAO) ten] ‘J.9\ 1 rp watort | spidpy re] Yared puepysar Jsa.10,] eT ue san, i" / oy 7 5 r “4 P pay | es y 5 — \ (p>, e UWOAPT] INOS { S' : | j 3 \ Hers = aK AG / = : clr : 7 ee A Lys orpourye \ : AYUNGH OW S 3NO008 OOVASNNIM © NOSN3HKd3LS SS3iAvaor SIONT TTL eysouvy { j j ~ | { =, L ole | < - } : ‘7 a | L =. — = — a = = = = L. — e 2. s_ — mo — | AAAYNS 1V91I901039'°S'N IIXX Td INAXXX Hd VYOONOW B68l LALLA SINVU AEE Ssuliog deep pue S{[jaM URISO},Le JO UOTINQrNStp Burmoys ee, WNVIGNI NUGLLSOIM CNV SIONITT TO ANOLSCANVS ULL TIS AHL LO dVIN ODIHdVu9OSdAH ae ww 7 \ MOlP1asO YOTYM STIOM IJLTP WIL s191gstq . \ \\\ nop. n) : aon rn] 1d}VM LO] posn jou ssuitog daeq \ i Aasod ss f| | \o. OENBYRGNYA +S Hcl Se ———— ° nb MOIMH¥rA £S uaON3dS 2S Auuad IS QxOsMYHO OS NOSISYWH Gr GAOld Sr NOLONIHSWA L+ 3ONVUO Ob siognd se Byld vr NOSB8ID oF XONY 2b SS3IAVO It NILYVIN OF BONZYMV1 GE NOSHOVr Se NMOUS LE JOYNOW 9E 3N33u5 SE NWAITINS +e OOIA ce AV19 ZE N3MO If NYOBOW OF NOSNHOP 62 NOISY 82 SHOIMGNSH LZ WYNLINd 92 3Xuvd St NONING3A $2 NIVLNNOS €z AYSNODLNOW 2% 3NOOS Iz NOLIIWWH 0@ NOldil 61 GYYMOH 8! NOLNITD ZI min ie)-t-) £eas-1) BONWO3dd/1 SI NBYuYM +1 NOLN3S EI SLIHM ZI ssvo i NOliN3 oO} IwSwind & uadSvP 8B NOLM3N L 3XuvLs 9 TIVHSYEYW S + € 4 URSNPOYY Usla}saw'yNoG pure vuRIpY] Utoisa\y ut cedde samop10d joa} OOTATUQ. | | “UaAIS ate SAN]. \ LOALL OY JO louonaod — | | oy UI pue 919}S JO pus Udey Mos stp ut jdeoxe aved | | aM ) Jaaj OE oY) STOUT] UW] AoAaMs BueTpuy eyy Aq UIULI1d)ep plossue feuosaad Uy WoL B}PECT EGE jog} QL SuLMOYS sdeur snojuoo peysyqndun woay poureyqo stouqy wow ere ALON Ap MOTJLIAO JNOUIIM S[TOM TNYSSavonsg @ ! ~0cbE 0p MO[JIAAO YIM STTIM [NJSsedongG 2 | —— ; JoAX]T BIS | e \ MOTAQ OXI OOG ULY) B10; ; JPAIT BAS MOTOq Joey OOS MLW AyUTeW, JAATT BAS VAOQE ATUTeTY | STAO'TAiS Hd3soris giu0dy) g3140d 3yv7 1 VXVICIN (XV OVSSYW Zoi IHSW1Nd 101 Y3Z0NVX3TV OO} NOINN 66 NOSNHOP 86 3d0d 16 NIGUWH 96 ANILYIIWO Sé -ANIIVS +6 NOSWYINIIM £6 NOSHOVE 26 NIDINWYS 16 NUH AES (Atonement U.S.GEOLOGICAL SURVEY. MONOGRAPH XXXVIII PL. XXIII. pe Monroe @Mancheste ste ie Anaiios A @\ Savayys Cedar Rapid = Maquoketa Se = Towa C efipton S26 2. fe Riel Rock Isla teh 4 Muscatine ie vapello’ , a @ THO uth aioe fe) Mt Pleasant rlinetor Denmark, LEGEND STLOVIS FI sso 0.08 sea tev | Mainly within 500 feet J below sea level | More than 500 feet below | sea level Successtul wells with overflow Successful wells without overflow O Deep borings not used for water i ’ Cape Girabdeau Districts with drift wells whieh overfaw HYPSOGRAPHIC MAP OF THE ST. PETER SANDSTONE OF ILLINOIS AND WESTERN INDIANA WISCONSIN $4 (it 2 cine nosha ~ = =} | South Have > — ' } ai 1 ake Forest - ehtand Park Hy el aA =o pinami C ~ 7 — ea ensselhe om ea es, = I Co ndton) 2 [= nt lis | CoagegsFaesitte = hawAeetown NOTE Data thom linois obtained from inpublished contour maps show 1883 Data personal ar byt 0 pear c . dof the state and in the portion north of Rock river whe Onty 104 O feet interval Prepared by CW Rolfe in 100 fwer contours are Sven contours appear in Western Indiana and rn Michigan = 7 Showing distribution of artesian wells and deep borings BY FRANK LEVERETT 1898 — We ‘} Counties ' ix PL ILLNors + wooavieEss NN CBAGO @ BOONE SMO NENAY © MAKE 4 wHTESio€ 15 ROOK ISLAND 16 MERCER 17 HENRY 18 BUREAU 19 PUTNAN 20 LASALLE 2) KENDALL 22 GRUNDY 23 wie 4 KANKAKEE 25 IROQUOIS 36 FORD 27 LIVINGSTON 2B MARSHALL 29 WOODFORD 90 STARK 3) PEORIA 32 KNOX S3_WARREN 34 HENDERSON 35 HANCOCK 36 ME DONOUGH 37 FucTon 3 MASON 39 TAZEWEUL VERMILION DEWITT 45 LOGAN 46 MENARD 47 CASS 48 SCHUYLER 42 BROWN > ADAMS 20 HAMILTON ti BOONE Md LAWRENCE 40 VARTIN Fyn Se oy BoA I ae i “SONSNMYT SZ OYOIMVHD $2 wadsvr &L WYHONI443 22 ALLA IL QNOB OL NOSIGVW 69 AaSHaP 89 NNOHIVO £9 "9N3auN9 99 NIdNOoWW so AUZWOOINON +9 AQTIHS £9 anyiyaaWnd 29 $3109 19 MYVIO 09 uvoaa 6S sv19noa 8s 3IHLINOW ZS x j 3 ] : LS 5 NOOWW 9S a & } | ‘ ? ; = : 2S 4 = NVILSINHO SS = S : y : 7 = E 2 PuUOSIpRy NOWVONVS +S : : : ire ; eae: ‘ = = z 7 PRIN NVOXOW €9 ; : : 2) 1100S zS SOLS ae : 4 \ : 5 i 5 = : Me) awld 1S 7 [ . \ ; [ i f tb = : : : SWVGW 0S 2 NMOS 6 H37ANHOS & ssvo Lt QUYN3N 9+ u NV901 St = f 5 JUVSROT AVN LLIM3G +b TAR ; aoe a f HS oars = = oe eee THN Livid & z yt SS waa | NOIWdWWHO 2 = = NOIMIWYRA [+ NVITSW Ob q1aMazvi Ge NOSYW 8 Nolin LE HONONOGS 9E MOOONWH SE NOSH3GN3H +e : ; ee : , : > NawYYM EC 7 : rea od pe 2 ; g ; j a y XONH Ze El ce By: lay y F ‘ foes 3 = 5 F = 3 FE 5 < ~-— ; i f f ; es Bi ouTROSNyy vidO3d If WHWLS OF auOId00M 62 TWHSUYN 8z NOLSONIAIT 22 aHO4 92 siondoul sz B3HXVANVH bz { = 2 : a a A TM £2 5 — Z 5 A: i \= AQNNUD cz Kc 2 = { 3 TIVON3Y IZ . is ie [ i sS b LOTUT[) ‘ =| anivsv1 oz Hy | j i j ; ae WYNiNd 61 . { h at } iY ah ATO, PMO] Nvaune 8 y eaTiT tant 2 is ~| AYN3H LI 2 <1) i =) ee Sahl _— y30H3W 9} .——— QNWISI D0" SI | HEA i: all ; HEE vyexonb Sas 30IS3LIHM +1 Rea \ : : é vit BRS 9, pidey reps Toweva el BARS y 337 2l as _X 3790 II F ) | MPd PUYLSTH K BivH30 Oo} : Sovana 8 = 18 9-TO.T ONE TN EL | = | } y { > W009 L paren ee | : PA 2 ? j |) Mi ; ool RIGA . poe eos cs 3NOO8 + MaAvpy WINOS ODVEaNNIM & | ) ; : ep — ROBE sheets z \toT og NISNOOSIM SIONITI pysousy : o0atto]® dasop3s rhiyy, 4 4 }Soljpour\e I SOrUnO,) au eyf “AIXX 1d IIAKXX HdVYOONOW “ASAYNS 1VO1901039'°S'N eekene LLAMIAMT SNVUA XL ST]JOM ATeUTPIO ot{} O01 YIP [ETOeTH stp Jo UONRJoL oy} SUIMOYG VNVICNI AN Hill 02 8 N3i8 SANA NGALSHM GNV SIONITIT JO dVW A3aSOd SS SYNEYIONVA +S MOIBYVM eS Y3ON3dS eg AYu3d IS GuYOIMVHS OS NOSIYYVH Gr GAOli 8 NOLONIHSYM Le BZONVWHO Ob SIOGNO Sb Bid +e NOSBID OF XONH Uy SS3IAVO It NILYYW OF SON3IYMY7 6E NOSYOWr Be NMOS LE SOY¥NOW SE 3N33u9 SE NYAITINS ve § OSIA ce AW19 2€ N3MO Ie NVOYOW OF NOSNHOP 62 NOISY BZ SHOIYGN3SH LZ WYNLNd 92 aynvvd Se NOMINY3A $2 NIVINNO4 €2% A¥AWOOLNOW cz 3NOO8 12 NOLIIWVH OZ NOldii 6) QOYYMOH §! NOLNITD ZI T1088Wd JI SONVO3ddil SI N3YyeVM +1 NOLN38 Ef SLIHM Zi ssvo 1 NOl1N3 O! ImSvind 6 yadSwr 8 NOLM3N L ayuvLS 9 TIVHSYYW S Hd3SOF4s + 3Ll¥Odw & waldod Z 3yv7 I VXVICNI CNY OYSSYW 20/1 IHSV1Nd 101 YH30NWX31Y OO! NOINN 66 NOSNHOP 86 3d0d 46 “NIGHYH 96 SNILWIIVO S6 3NIVS +6 NOSWYITIIM &6 NOSHOWN Zé NITNNWHS 16 QUO) IVF OOTITOYM JIALL YOO JO Y 9S dp) JO pula WreyNos op ut yd ‘soppytye Aeajrea uodn paseq vueIpUy Woay BLE, 'SERT | Ul aJOY MAD Aq poredoagqea.sojiut joey OT Summoys sdeur nojuo9 paysyqudun wos poureygo stomp wogy erecy 9OXO TRO ALON UMOJIOT \ Ruts) SP | | i | (3902 woYWS WOpyaS STIaM) e10UL 10 j929j OOL YMG Qpo.t tayue Ajpenbea.y stam) 199F C/-GG WIC Qoou UL ATTensn s{[aa.jsaq) 1993 OG-O] WII (J@AeIS IO pues UT S|[aM) ATeN.£3,, porerersuyy) (SYIO.1 UE STAM) 910Z09[eg pele roesuy amt HATE il uf JEST ELL EL OEES PARLE | GN43941 al i OOTXOT © ae U.S.GEOLOGICAL SURVEY MONOGRAPH XXXVIII PL XXIV. a, Manchester ~ \ Maguey South Hay i ; mi ‘i : Highland Park Ph. ae we F MEN) ha “4 a pac ar Rapids —-& Ws dH healt, a , > = Byrransion as ian \ je \¢Tipton qs aa H f i | i : CHICAGO ¥Z Nt “ + CASALE | Reait é Mictugan Gi 23 Coamues: i~ ILLINOIS 7 < - - A 7 UVINSS TON Rocktislan 9 28 waesnal Muscatine a a tI Sf : Sy ; 37 MUATON Wape 34 MASON ) Yarmouth 40 MCLEAN MtPleasant asp INDIANA 4 } f \ uae f .. 2 PORTER 3 Aponte 4 Stlosten sills LEGEND Unglaciatod Paleozoic ' Bh a +9) of La Plast english 3 4s 45... ducweuriwiguh fwells in rocks Buse 5 ar Nes: 4 vs wm WP el ya i} eri r > » By a Unglactated Tertiary f } XS YS ats fi ‘ ' teal A jh wells in sand or ¢ravel dd if hy “ nsan fray \ } i a = Yeupsvile) ope wllle! Barents as x Wit ant in} 7s ° _ _ ; ¥ IP alt ) . -€ flockport iHiiH} Hy Deere 10-50 feet . iN it HII ‘\ - ‘ “a WANN ibestwells usually in rock . Re ; ; Drift 25-75 feet Wells frequent enter rock “I Anna * ~ APizabetupyég Drifl 100 feet or me rat Mopma “i i py Wells seldom enter r @ape Gi SS Ul + < Sy pe ee moloonda = ~ Mound City QCaire ~ MAP OF ILLINOIS AND WESTERN INDIANA Showing the relation of the Glacial drift to the ordinary wells BY FRANK LEVERETT 1898 34 HENDERSON AS HANCOCK 36 WE DONOUEK Sas a as Rereerte MEN I“ 1 Y : 1 RTT : fem 2 Taruwea WELLS OF ILLINOIS. 5D7 RELATION OF THE DRIFT TO ORDINARY WELLS. The general relation of the drift to the ordinary wells of Illinois and western Indiana is set forth in Pl. XXIV. It will be observed that with the exception of a few counties in the northern and southern ends of Illinois the wells are largely obtained from the drift. This relation is shown in detail in the discussion which follows. GAS WELLS. Wells which yield an inflammable gas are found in many counties of the State, instances of which are presented in connection with the water wells. This gas in some cases appears to be derived from the decay of vegetal matter contained in the drift, either in the form of peat and muck beds or as timber scattered through the drift. It is probable, however, that the underlying rocks are an important if not the chief contributor, in which case the pressure of the gas within the drift is due to the resistance which compact drift beds offer to the escape of the gas. Not only the shales but certain limestones in this region have been found to contain gas. But it does not seem to have accumulated in such great quantities as in the gas fields of the neighboring States of Indiana and Ohio. It rarely reaches a pressure of 20 pounds per square inch. TABULATION OF SOURCES FOR CITY WATER SUPPLY. The following table embraces all the cities and villages in Hlinois hav- ing water works whose source of supply has been ascertained. It is based, in part, upon data collected by the writer, and in part upon data found in the Manual of American Water Works for 1897." Through the aid of this publication the statistics have been properly rounded out and brought down to date. In towns with the letter ‘““M” appended the Manual of Water Works is the authority. The wells are classified according to the scheme above outlined (pp. 550-551). Many details concerning the city water supple appear in the pubseducnt discussion by counties. ‘The Manual of American Water Works, 1897, edited by M. N. Baker, Engineering News Pub. Co., New York. Contains the history and descriptions of the source and mode of supply, pumps, reser- voirs, standpipes, distribution systems, pressures, consumption, revenue and expenses, cost, debt, and sinking fund, etc., of the water works of the United States and Canada. 558 THE ILLINOIS GLACIAL LOBE. Sources of water supply for towns in Illinois. Population in Town. Source. AT eC On ee ne eer ate wane Sen cam waa n ete eee | 1,601 | Rock, class 7. INES (0) oon ee eee ee eRE EE ee eon | 562 | Drift, class 3. INGO WIN. 65" 55 565.5555 55es000 asemcn SasaCe scghess osac5 | 300 | Springs. INO 2305 aSeeas cad CoE acoSobees CoSEBaodagse 950sa0 Scab 10, 294 | River. IMMINOR/ 6 cose coo6 deca ea Ee Sness oles scepeosenoea Saccbacche 2,257 | Rock, class 7. AOD) dosboeacéceseosces Seangny sosabebScuor Asso Scostcan 1, 733 | Drift, class 3. INGERNIE, Coo odo sacs sab ceo cede soap DaeS BaSdee Gacoeg cos 1,178 | Drift, class 3. INTO So necoseesr Beeces cede nooene seases cobDEososceg|onco 19, 688 ; Rock, class 7. UNC Bari eee ee SMUD LE a en | 4,051 | Rock, class 7. Hearn (GN ioe a PRR aa Son | 692 | Rock, class 6. THAN obo seco dc ceso aed aecnecse neem docoed seise baee sdesss 1, 354 | Rock, class 7. DF ae (ND) oScaos esebesoeae passes ssonsooossosSean scacus | 3,543 | River (?). TEMG IO a esopeceeeo sone seG5 Doccos conSse oS eases cose.do06 | 4,226 | Drift, class 4. BrNlennilicy ase puesesondeaaseesuesuece sae cee ncoSconsecce 15, 361 | Creek. Belvidere: 45a ALS. Lhe RIERA te RE | 3,877 | Rock, class 7. BOmment eae oe ec oe) en | 1,129 | Drift, class 3. Blegominw tones ec are dn ee _..| 20,484 | Drift, class 4. TBO dehy (MD) pacebesoosée coedeoconedde cdeead Soeeds Seactc | 433 | Drift, class 4. Bird aeeeas cea is eas esis Ney Sip AOE AR eek eae | 990 | Rock, class 7. ~ BEG ose sR Sosos cece ssossass Sdoess sey Sons deRssedo0c | 2,314 | Drift, class 3. G@aibery (MD) ooo nno- oom an ee a eee anil 342 | Well, 240 feet, class 3 (?). (OHIO) Sob Sse SOE BU REE aeEO Sean Boba doeaosmore coos seus dan5 | 10, 324 | River. @ambrid gel) a= 2 eam nineteen ele mae 940 | Deep well, class 7 (?). (CANIM sc Sago reset a esco Senos SauccossSsESeEadcadS econ. coe]? 5, 604 | Rock, class 7. (Chadian 18 hUNU (GYD) 3 aie eens copeceeepaccos coSsSao cesocSdo (?) Rock, class 7. Carlinville ......-.----- ci UToe Si oe ee Balla gigas Cress (OPH soso dco sbotce dodo caso scon code shea Goes pastesco | 1,784 | River. (Cemmi(ND), cososocseboeasbiesed seedsu sgaa nado usou sees secs 2,785 | River. Chipman: sesass seeks esse ssee cetiad he Scscstcas osesases | 2,258 | Rock, class 7. (Chin RO 35 Sec sa sotess combl a dese cobece se secbcess cesses 1, 654 | Rock, class 7. Cem: sossdoeesh doses ecoobauceess cooacs Cobden seca 4,763 | Creek. Oineahi@es Sau saacstea seas Ssonleereareeres seaoesocod Sape (2) Rock, class 6. (CUNT DEES sc cos Sooo Sess Sees sedaredseens 65> ese gasses | 5, 839 | Drift, class 4. Girarloeton ate 4 FE Sh okie Th ie Ue ee | 4,135 | River. (CHERIENSO@MEIM sSoise SopceSaor doce ce pspSsaco ceeses sesso Sst0 | 827 | Drift, class 3. (CINGOB sore nonce se beso nodded saa eee cou seEres coUSed ces 1, 226 | Rock, class 6. CUMMCEYR®).. so-jo 5 done soesea deseoudenS secs oscoedScodosseds 1, 099, 850 | Lake. @hicaroshelo hide epee stes= eee eee teeter (?) Rock, class 6. C@hillicothess sees ee se eee see ee a = lee ee 1, 632 | Alluvium, class 2 (Chega Iams (WW) sos6 eos cse S25 Soentedss see Seeeesce Sa05 (2) Drift, class 4. Clay tom ((M) oe ooo ae ene ele = en ieee lm 1, 033 | Rock, class 6. Clinton ...----------------------- +--+ +--+ +222 2222-220 2,538 | Drift, class 3. Collinsville -.--.-...--- ---- ------ ~~ == = ne eos one 3,498 | Rock, class 7. WELLS OF ILLINOIS. 509 Sources of water supply for towns in Illinois—Continued. Town. @rescent: (MD) i Sat eee nes ches Sane Sas es. acs DAN VOLS seas -peisene cece eiceneee eens cio cns soe ou teses Downers! Grovel(M)esesayee se ees soesi- saccise cece cenecete DUD ee ee aaa ee terse sete sere eee een isn ae eciiek se Bocose Hasty Dubuque. sere seein eens sacs e\iee:s-s ce a- oss cace Bashy beUOUIs perro tee scenes os acces ene cebee ease JORDIN hs coeGoce ceg4 GRo non CbaEsEisd Sosa eee oe SEE aSerale EISTGTE ONIN con see ada0 cac0nd sade nncos coEseeuone coro usae Rarmin gto ny (My) meee lerece ete eases) se sey Sen ei eaerydateee Hlanni cane (MD) Peeecetrser stamecte = se sae ao sesee eae aeons HOLLOR tigers eee sani taste oe ka a swe snes maw eee a4 See SE PCCP OTe teciemism eens neste ce he a eckie aeiin dase cee eee LOTIONS Ge os Ge ah Clete ae Reis aes Bo ee ae a Rea Ga Oras Steerer eS oral aoersan eo cdictacie Soo eran Galesburg iacen acest eee teas Beco oes gen Bose aeee Galwialk (Mi) Memeros seteeisem sees cio Sao ek wae helen ueeeeee Genescomane: Sacre ss Menon se ane eae ceieles Sond eee Gene vara saree se eae ee ea ec atts es oc os be eee Gilbsonesas dese ha nee ae aie tee bec acai: an atee See Granitey (Mh) resis sh setieeecioard. otiee dee scien sasceees: See Grayvillletecon toner aceaallss wise scee ee sac anaemic ene Greenville were fa see cevasceysasetsaces «<= sc Sacsaoeneeeeee Population in 1890. 505 11, 491 16, 841 2, 579 1, 176 986 Source. Drift, class 4. Drift, class 3, River. River. Rock, class 7. Drift, class 3. Rock, class 6. Rock, class 7. Deep well, class (?). Springs. Drift, class 4. JRock, class 6. (Drift, class 4. Rock, class 7. River. River. River. Spring. Rock, class 7. Drift, class 3. Drift, class 3. Lake. Rock, class 7. Drift, class 4. Rock, class 7 (?). “Artesian well,” class (?). Drift, class 3. Rock, class 7, fAlluvium, class 2, lRock, class 7. Rock, class 7. Rock, class 7. J Rock, class 7. \prift, class 4. Well, class (?). Rock, class 7. Rock, class 7. Drift, class 3. Drift, class 4. River. River. ‘ Drift, class 3. Rock, class 7. Or ep) iS) THE ILLINOIS GLACIAL LOBE. Sources of water supply for towns in Illinois—Continued. Town. | Population in | 1890. Source. Havana ..---- oA eee oe CAAA eS Sen DO a AsOcS | Plenne pM see eee ae a ae a ae an ie el Highland Park..-..---------.---------------+-+--+------ TSM Ns): song ooasoe eaaooeas beso pooSeGesoaaS sodposcscocs SEN eos apne tsiaeeeemerer see dokoud boop. csseotececce Jerseyville .....-..----- .----------------++-------+- bods VOI 5022 sssesa chases esccas 4ooses a5seee Jone Seasedasec Namkwkee@ sas == oer ae Jeo ee eee eee een cee Keithsburg.-.---.-------------------+--------------+---- Kempton (M)..-----.----------- ---- +--+ ------+-+-------- | INGA s soo cee pa aosceeconbe Heda Sasesa Sasse> Saco segses Tego eyr@@l (WD) Gessse SteGes cepeco cease saasoscossescosece ensue) sens eaceee s56000 sesco5 ceebre pagans Geos psos cose IL AWGN (Oi) -pooo0 neehod psc oca ese ss caeees Hoos oScene esdec0 Juagrange ..---.---------- ------ 22-922 e222 222 roe | Wuaharpe.--.-----------2 ---- = --- ~~ = one een Lake Forest.------.----------------- -------------------- | Lexington (M)..-.-------------------------++-+----+-+---- hme ost os bR odode ost b ence depo seeeuopeeces cose esse nite hte diseseee ase eee ee Bie da ae eR eRe eee aS | Lockport. .-..-------------- ------------ ++ +--+ 227-7 ---- | WMIEQO IN Gono poo Eae Bonoescd GeeRepeeee Sens oosaed cone. Soeed NEGO =a oa06 Gacmosu be coc RSE EO Soo Ee =ebopEenccomeSesSocc MIRO RG IO ar gains Soe oe 4 ot sono beconS nee etogarna acne Eaeaes NViE@ iN -aooooaeeo Soe rooeeSEe CopSraSuaacepsSeeaceo sarmS Marengo ..-..-------------------- ------+------ ---+->-->-| TWENRO EA eae BASGOs GU Boe POU ROS ESTEE React eebo goes esod IWR AROTO) 8 is aero nostes SSoe Comosn oocit SUD SSe eeRCnsomp me peace oc Maywood (M) ..---.------------ -------+---- 2-222 ------ Winiynncs 4 adeeaoao os saseSene cath Sse crag saseds a395 9695 Men do tance cece ae ee ee aol ta nla mite = lain iniaimmrehntateal 2,500 1, 584 1,911 667 12, 935 3, 207 23, 264 9, 025 1, 728 1, 649 2, 314 1, 113 1, 203 1, 295 6, 725 5, 811 2, 449 4, 052 819 55 (?) 1, 445 1, 164 1, 869 6, 833 2, 076 640 3, 542 sAlluvium, class 2. \prift, class 4. Rock, class 7. Lake. Springs. Rock, class 7. Rock, class 7. Rock, class 7. | Rock, class 7. Rock. class 7. Rock, class 7. River. Alluvium, class 2. | Drift, class 3. Rock, class 7. | Rock, class 6 (?). Rock, class 7. Well, class (?). | Rock, elass 7. | Drift, class 3. Lake. Drift, class 3. ) Wee class 7. Springs. | Rock, class 7. | Deep well, class (?). | Drift, class 3. Alluvium, class 2. | Well, class (?). | Creek. Creek. | Rock, class 7. | Rock, class 7. | Drift, class 3. Drift, class 3. | River. | Drift, class 4. | Drift, class 3. | Drift, class 3. Drift, class 3. | Rock, class 7. | Rock, class 7. Rock, class 7. WELLS OF ILLINOIS. Sources of water supply for towns in Illinois—Continued. D061 Town Ropalavion in Source. MO CANOLA sa: 5 Samer er ne eet Slots widl jst leiele Surarey aie ele | 758 | Drift, class 3. WIG TONS sopescssd codons ccéeebbeocbe oded Hace nOSebeOBSe 3,593 | River. MT ane Sect rece SUOMI ese Nees AMM 692 | Rock, class 7. Milford (M) ..-.---.--, 2a daoS Sdacoeenee SencEBeScsebeobeas | 957 | Drift, class 4. WUMTGIN? Scosconsoseeassolee coodee séee coooee cate sodece snes | 2,316 | Rock, class 7. Moline peticc eae. sees A eee see oe ce Piece i: | 12,000 | River. WIG MINOT opcode Gedces adag doudicnde sobs Baa aaoSaHeaceas 5,936 | Rock, class 7. IMonticellowas ane y retenae secaer seme er rue, meme ln aii | 1,643 | Drift, class 3. Morgan: Park W252). s Soa eet cc etevettecece seed 1,027 | Rock, class 7. WIG) co5do5c0 sede Soca sagecs SouSSo sone essed oadoAD coneae 3, 653 | Rock, class 7. MIGEEGI Gog540 shone déoase sedan dobbs nbadeosdensaasoes 2,088 | Springs. Morrisonville nieces eter ee tee ee 844 | Drift, class 3. INIOIEIO) Np meaeg SECC OS BSS OnS HEC Can CORO IEE SG Serer eeeee 657 | Drift, class 3. MountiCanrmeliemasssee astra eae acai a seen iee cea see ee 3, 376 | Alluvium, class 2. MountiCarrolleemecet msec ete eet ceelsa sees sBedods boSSDH 1,836 | Rock, class 7. Moun tiMorrissasscaice eee cieisece cinch ee eects nate 895 | Rock, class 6. MountiBulaskii(M) sot rit eee cece an o> eee nocosmace see 1, 357 | Well, class (?). Moun tiSterlin gy eemnmeenmaseseieeen ee ensieei ates cise 1,655 | Drift, class 3. W@W WEE NON cosoo cab ous soomes pSeeScopoNECDEoaoES SaDane 3, 233 | Impounded water. Moweaqual (MD) iseccnemcesee ne en ecb =insee nae eae see 848 | Well, class (?). MIMO EL OOo coGhs ssoods odoabobecdco cseces DASE CeSSLOECS 38, 880 | River. ING WitONsssian ayer eee meals ws inne ssc cle sis eeoe a smee 1, 428 | River. INDROINITT Sosa cdqdao ated ond GonH Ore peE Bonne Cone soen ceca 1,305 | Drift, class 3. NonwoodeParkss saree cmseas Yes cence. sles e ce eecaae (?) Rock, class 7. Oalke Par ease ie ccaye oma aera nee eis a oles eieats areata aoe 4,771 | Rock, class 7. ODO pees aclomeiscetaee aren sitet eee Saya os ealvenis@ameces 360 | Drift, class 3. OUIG heeds Sastodoce shh Saes OS cen EE anes EOE OS Reeeeernen | 3, 831 | River. OTE Goss canbe coeens Bada sbaceEiadooEs 5665 SpoonbeHOns 994 | Drift, class 4. Orange eyalle pe erer ee ese ener eerie eles eee 347 | Rock, class 6. OnayaOn iD) cose Goss cacao caoo aseg SeesReDEEcee uosbeE san6 1,566 | Well, class (?). Oswerol (Mi) ies oe nee ase ese eigaaa Gdob qaeOUBeEHOESLS boos 641 | Well, class (?). Ottawarscn eee eats re aise eee ened settee sisi su mee 9,985 | Rock, class 7. TE issosecissScoossusice stob babes SeEeoR SHB Dse baberapsece 5, 077 | Drift, class 3. Parked gen) esses see css sais e cae clecieiere stem ereeerseee 987 | Rock, class 7. ATL Siete eter tee ee a ee soln Ginnie sees eee 4,966 | Drift, class 3. ley DE hicance Sonbdo sSobad cabs HasO aE Sar ppece Receecsarcose (2) Rock, class 7. EER aION Sooo cess se0n Saab acos Haag ooaSHUoHScCEsecsa case cbs 2,177 | Drift, class 4. Recatonicagnest eo etree ener eel = nena a cece ria seers 1,059 | Springs. JET Gb G6 aedesadood Soon BEC ero DARE MEER Cea Bea ceEaoe bons 6, 347 | Drift, class 4. (POOL 1a) seas eases, See See saree eine Samick centednise eee sS 41,024 | Drift, class 4. IEE cbc dSadde SaURBSdees Head asad BeOEne rene papened oneal 5,550 | Rock, class 7. Potersburg ee eee eee ee asia ens 3au Sue eeNS 2,342 | Alluvium, class 2. MON XXXVIII——36 562 THE ILLINOIS GLACIAL LOBE. Sources of water supply for towns in Illinois—Continued. Town. Population in 1890. | Source. Pinckneyville Ibititsheldereesneee acces see eea eines ea E aes a eerece ee PAO (iD) o ose coped obdden Bose Hobe Sone soaece Sono ceeees Pontiac (M) Princeton AYN) coca te Hebe nS05 enosebe oSesbe bond coscics chccsaqccacs Ippya nw! (QMO) oa5 sdooco cobean Sopess Sosecneddhodesccecéo Riverside Rochelle Rock Falls IRON Wileocooc cosomb peo aoe copSSecensos Cooesciscessecaccs Roseville (M) Rossville (M) Rushville (M) Sandwich SERINE 6S655deGc0 codéd0 boecee DoDS oneo obeosSbDSScS dub Shannon Sheffield (M) Shelbyville ...--. Bvehsue ree da: Sadtaereeeee eee eatesen Sornmnmiic (WWD)sc cou6e5 obec Coosbasoesec paGsadindoaesadesst Springfield. ..---.-----.-----.-----.-------------------s SUAGUTTONS - 5060 desnbh sodaéobbsoao sShéec Heyes cogs Boece SGM oto Secgdndedoes os acessaccoeus cacy socoseounsse Shayla ran GUY) Soe sess coos bekdor popouoses Streatorsecote tices see se care oe ee ahem el aeeeoe ee meeeiocs Sullivan SWVCRNNORO 346 conmed cedced ction Soudes dees soseed essa sous Mawlouvailleweeoc- ae aeeee eal Tolono (M) Wenn -3 oo Yacagteecbs sence ngeuosesnboessecusccose ceases Ojaoee AMON a tods Sodadasdes seeded ocodas bdokonsotasone ss NEG CNN oo GaoEso bade ConaeUAOOPEOrESbEe Cbmeud scabs auSso WENN os sosotedSetoring Secu cosas eons bass oposoneSoo cas DWiairre Mere eyes eent male [atelere Warsaw Washington MVE SOs cotoes sano Sededc Sebese tose Se ekeSas conSSsosdsec Wivnrenrinmimn (iW ))o5-s6 sc dbendseucucssobesa nso oponsa coDoeS Watseka Waukegan 1,298 2, 295 1, 825 2, 784 3, 396 Rock, class 7. Rock, class 7. Rock, class 7. River. Rock, class 7. River. Drift, class 3. Rock, class 7. Springs. Rock, class 7. Rock, class 7. River. Well, class (?). Well, class (?). Springs. Drift, class 4. Rock, class 7. Rock, class 6. Well, class (?). River. Well, class (?). Alluvium, class 2. Impounded water. Rock, class 7. Well, class (?). River. Drift, class 3. Drift, class 4. Drift, class 3. Well, class (?). Drift, class 4. Alluvium, class 2. River. River. . Drift, class 3. Rock, class 7. Rock, elass 7. Drift, class 4. Impounded water. Well, class (?). Drift, class 4, Lake. WELLS OF ILLINOIS. 563 Sources of water supply for towns in Ilinois—Continued. Town. | population in | Source. ze = : i > Wiaynes ville; (ML) 22st s eae See eee clos nien | 368 | Drift, class 3. WOOO Ape SS iCaGs osu Gos0 6ads pdesds Bend bsakedse cons osesbe | 1, 053 | Rock, class 7. WWesternyS prin g's (Mi) paseereeereeie seer eisiseis sea ia teeter ca | 451 | Well, class (?). WAI CANOM Gob sagacdas ceAsas Hoonce ombous cosises bse aseR00n 1, 622 | Rock, class 6. Weil mettores See ieatsye Mei Nome Meas ecw kD eo | 1, 458 | Lake. Viumllnrinyainnt sacs copcaptocs nono aan“ Soseuoonds becaeeaoeSse 1,576 | River. NTNU i Seo shone beso cedolceno ddas SobdioSed SHOSEE BEBE Ee | 1,079 | Lake. WYCOTEMOOIS oos6 cobb hove 665550 '455 congue sa 4s Sou USE ES Soe 1,683 | Rock, class 7. orleyillog: eras ye tree OSS Sd OE Se | 375 | Springs. From the above table it appears that in 69 cities and villages, or about one-third of the number in Ilinois now having waterworks, the supply is obtained from rock wells either flowing (artesian) or with strong hydrostatic pressure. Of the 250,000 inhabitants of these cities and villages it is prob- able that more than one-half are dependent upon the public water supply. In some cities and in many of the villages a large part of the population prefer to obtain their supply from private wells or cisterns, a preference which is due in part to inability to meet the city water tax and in part to objectionable properties of the water. It should be stated, however, that throughout much of northern Illinois wells of this class furnish wholesome and very palatable water. It should be noted that wells of this kind are extensively used in various industries in the city of Chicago and in several other cities in northern Illinois, the aggregate amount of water thus obtained in Chicago approximating that furnished by the city waterworks. In contrast with the extensive use of this class of rock wells as a city supply is the use of rock wells having weak hydrostatic pressure. Only twelve villages, with a combined population of scarcely 10,000, are known to depend upon the latter class of wells. It is possible, however, that a few others reported in the Waterworks Manual may be of that class. Such wells rarely furnish an adequate supply for a large town. x The table indicates that aside from Chicago, with its population of more than one million, there are 52 cities and villages, with a combined population of nearly 300,000, in which surface water constitutes the public supply. In Chicago the population is mainly dependent upon such water. 564 THE ILLINOIS GLACIAL LOBE. In the other cities, and especially in the villages, private wells and cisterns are used extensively. Turning to drift wells, it is found that 22 cities and villages, with a combined population of about 100,000, obtain their public supply from wells in glacial drift which have strong hydrostatic pressure, many of them being flowing wells. In 88 other cities and villages, with a population ageregating about 60,000, drift wells are in use which display no marked hydrostatic pressure. There are only three cities with a population of more than 2,000 in which this class of wells constitutes the public supply, namely, Mattoon, Pana, and Paris. ‘There are 9 cities and villages, with a combined population of about 50,000, in which the public supply is obtained from beds of alluvium. Among these cities Springfield has been included, its supply being from infiltration wells along the bank of the Sangamon River. The supply at Freeport is from wells sunk below the level of the Pecatonica River, and these may possibly be referable to class 3 rather than to this class. However, the material penetrated appears to be alluvial rather than glacial. DETAILED DISCUSSION. With this brief statement concerning the sources for supply in the cities of Illincis, we pass to the detailed discussion of wells by counties. The counties are taken up in the order of their numbering on PI. XX. The discussion begins in the northern tier of counties and passes back and forth in successive tiers, terminating at the southern end of the State. The unglaciated counties at the southern end of the State are discussed as a single district and very briefly, though they present probably -a greater variety of sources for water supply than almost any other area of equal size within the State. The writer’s examination of that district has been too incomplete to enable him to treat adequately of its water resources. JO DAVIESS COUNTY. GENERAL STATEMENT..- This county is situated in the extreme northwest corner of the State and has an area of 663 square miles. The greater part lies within the Driftless Area, the glaciated portion occupying only about 100 square miles on the eastern border. The driftless portion, however, is covered with a nearly continuous sheet of loess, the thickness of which along the borders of the WELLS OF JO DAVIESS COUNTY, ILLINOIS. 565 Mississippi will average about 20 feet, but the average for the county will probably not exceed 10 feet. Along the Mississippi Valley on the west borders of the county there is a filling of sand and gravel about 150 feet in depth, as shown by wells on the Iowa side at Dubuque and Sabula. The tributaries of the Mississippi m this county have been silted up to a level corresponding with the filling in the Mississippi Valley. The material in these tributaries is usually a rather compact clay. Wells in the valley of the Mississippi obtain water at depths of 20 to 40 feet without entering the rock. In the tributaries of the Mississippi a few wells obtain water from the clay deposits, but as a rule the residents depend upon either springs from the limestone bluffs or wells sunk into the rock. The wells on the uplands in the unglaciated part, and to some extent in the glaciated part, obtain their water from limestone at depths ranging from 40 feet to 150 feet or more. Usually a good supply may be obtained at less than 100 feet. In the glaciated portions of the county the drift is generally too thin to afford strong wells. There is, however, just north of Stockton a preglacial valley filled to a depth of at least 140 feet, which furnishes strong wells, some of which overflow. Throughout the county the water is of excellent quality, although very hard. he expense of sinking wells to rock being heavy, many of the residents resort to cisterns for a water supply. Impounded water is also used quite extensively to supply the stock on farms. INDIVIDUAL WELLS. The city water supply at Galena, the county seat, is obtained from an artesian well sunk to a depth of 1,200 feet and obtaining its supply from the Potsdam sandstone. It has a head 85 feet above the surface and a capacity estimated at 166 gallons per minute. An analysis made by the State Board of Health appears in the Seventeenth Annual Report of this Survey.’ Wells are obtained in the vicinity of Galena from the limestone at depths of 60 to 200 feet. At East Dubuque the town well is artesian and has a depth of 940 feet. The water is obtained from Potsdam sandstone and has a head nearly 100 feet above the surface and a capacity estimated at 420 gallons per minute. Aside from the artesian well there are a few shallow wells obtaining their supply from the gravel and sand of the Mississippi Valley. 1 Part IT, pp. 820 and 827. 566 THE ILLINOIS GLACIAL LOBE. At Warren and in that vicinity the best wells are 50 to 150 feet deep and obtain water from the Galena limestone. The altitude being high (about 1,000 feet above tide), the water level in the wells is so low that windmills are usually employed to raise the water. A large proportion of the residents of the village depend upon cistern water. The Manual of American Waterworks (1897) reports that a well has recently been sunk to a depth of 900 feet which furnishes the public water supply. No data were obtained concerning wells in other villages of the county, but a few records were obtained of wells in the glaciated portion between Stockton and Nora. These usually enter rock at 20 to 30 feet, but occa- sionally the drift is thicker. In the preglacial valley referred to above, which passes in an east-west course midway between these villages, several well records were obtained which are tabulated below: Wells in a preglacial valley north of Stockton. Owner. Ghaenioy Depth. Head from surface. | | Feet. Feet. MirKepling eras serene ecclesia iter 930 50 | Overflows. INS AS SIMNUNTCT TE Saocas SoSoos Sosa 5a SSeebS S85 coos oseocs 950 72 | 10 feet below. An Odrewisimmons-eseeer eee seee ese eee etal 950 77 | 10 feet below. Charles# Wap pastes sem eee eae ela eet eeaete ea 950 105 | 10 feet below. MheodorevHoplins teres tes eeee aes eee ee 940 134 | 3 feet below. Wo IUGR one beds an boos sete snsasee coon stee cons | 940 135 | 3 feet below. Winks IW bp OnOMnc Coe cba asangoeussocsuoceodsa ooLOsagS 940 40 | Overflows. Mrs Misi Crouse sa -ja ss co accie ses eee eee eee eees 930 140 + Overflows. GERWEY Crartis cea 8 a Seo. ee Fe Pee aaa 950 96 | 15 feet below. Isa ke WAOWEINE iscoocs Saso eed seoass Sdosconsse choses 935 110 | 10 feet below. Wish JOrai hy Otol Ge Sh56 Gouaes sono coSesocao sees Seer 970 135 | 35 feet below. IG WG RIE CGS Sooo SeeeeS aEeen Bee sone Ad adastese Boas 970 | 85 35 feet below. Richardt@liverest so .ccose - desc eeye a= beets cee meee 970 60 | 35 feet below. The majority of the wells in the above list penetrate 50 to 70 feet of compact clay before entering a water-bearing bed, and at Mrs. Crouse’s deeper well 130 feet of clay was penetrated. The last three wells in the list are situated on a low drift ridge and their sections show a larger propor- tion of gravel and sand than the wells on the plane surface. The strong hydrostatic pressure probably results from an absorption of water on the neighboring higher land. None of the wells in this list entered rock, WELLS OF STEPHENSON COUNTY, ILLIN DIS. 567 although they are all situated within 5 miles of the glacial boundary, and some of them within 2 miles. STEPHENSON COUNTY. GENERAL STATEMENT. Stephenson County is situated immediately east of Jo Daviess County, on the north border of the State, with Freeport as its county seat, and has an area of 560 square miles. It is drained chiefly by Pecatonica River, which traverses its northern and eastern portions. With the exception of a few square miles in the northwest corner, this county is covered with glacial drift. The thickness of the drift is insufficient to conceal the main preglacial valleys, and extensive upland tracts have rock within a few feet of the surface. The average of the well sections reaching rock so far as collected are as follows: Forty-eight wells on uplands and slopes, 31 feet; 12 wells along preglacial valleys, 130 feet. Of these, 17 wells are in Freeport and vicinity, and average 50 feet, The drift, as already noted, is frequently aggregated in small knolls and ridges having a gravelly con- stitution. At such places it has exceptional thickness. Aside from the preglacial valleys and the knolls and ridges just referred to, the drift is usually too thin to be depended upon as a supply for wells. Most wells in this county, as in Jo Daviess County, obtain water from the Galena limestone at depths ranging from 30 or 40 feet up to about 200 feet. Their average depth is somewhat less than in Jo Daviess County. In the preglacial valleys and in some of the drift knolls and ridges strong wells are obtained at convenient depths—25 to 50 feet. The highest portions of the county are very thinly coated with drift, rock usually being entered at 15 to 20 feet or less. A few instances, how- ever, are reported in which the drift has a thickness of 80 feet or more. The lowlands are generally covered to a sufficient depth to afford an ade- quate supply of water without entering the rock; but there are small areas within the lowland districts in which rock is very near the surface. These contrasts in the thickness of drift, both on highland and lowland tracts, are set forth in the table of wells given below. 1 Many of the well records were collected by Mr. Oscar Hershey during or prior to his connec- tion with this Survey. 568 THE ILLINOIS GLACIAL LOBE. INDIVIDUAL WELLS. The public water supply for the city of Freeport is obtained mainly from a series of tubular wells sunk to a depth of about 40 feet through the alluvium and possibly through glacial deposits of the Pecatonica Valley. The supply of water is derived from sand just above the rock. The Manual of American Waterworks (1897) reports that a part of the supply is from wells about 200 feet in depth, which enter the St. Peter sandstone. This sandstone is stated by Mr. Hershey to set in about 110-130 feet below the surface of the Pecatonica flood plain at Freeport. Several private: wells in Freeport have been sunk to the St. Peter sandstone, and this sandstone is occasionally encountered in wells in the north part of the county. Near Orangeville the St. Peter sandstone comes nearly to the surface. The waterworks supply for that village is from a well 142 feet in depth, which is mainly through St. Peter sandstone. The public water supply at Lena is from a deep well, but the precise depth has not been ascertained. Rock is usually entered in that vicinity at about 15 feet. In the vicinity of Kent rock is entered at about 30 feet. The railway well at Kent Station is 275 feet in depth and obtains its supply in lime- stone. ‘The limestone ridge south of Kent has rock at surface, there being scarcely enough drift to form a soil. The following table of wells is made up largely from data furnished by My. Hershey: Table of well sections in Stephenson County, Illinois. Owner or location. Vepaeenaeyl Depth. Remarks. Feet. | Feet. Baier & Ohlendorf, at Free- 765 240 | Enters St. Peter sandstone at 167 feet; drift, 34 feet. port. J. Wareham, Freeport ---.-----. 770 212 | St. Peter sandstone at 186 feet; drift, 85 feet. D. Hoover, Freeport .--------- (?) 60 | Depth of drift, 35 feet. Millner’s Brewery, Freeport. -- 780 57 | Strong vein of water in limestone; drift, 30 feet. Electric light plant, Freeport - 760 | 240 | Drift, mainly loess, 30 feet. Stover M’f’g Co., of Freeport.. 795 112 | Enters St. Peter sandstone; drift, 100 feet. Vinegar Works, Freeport - ---- 750 | (?) Penetrates drift 85 feet. Triple Factories, Freeport --.. 770 (2) Drift, mainly loess, 38 feet. H.S. Gochenour, Freeport eoone 825 | 80 | Rock entered at 6 feet. D. Sweeny, East Freeport. ---- 760 50 | Wells in East Freeport 30 to 50 feet in depth do not reach rock, WELLS OF STEPHENSON COUNTY, ILLINOIS. 569 Table of well sections in Stephenson County, Ilinois—Continued. No rock entered; over old valley of Yellow Creek. Enters rock at 120 feet; drift, mainly blue till. Owner or location. Scene Depth. Remarks. Feet. Feet. Secuzd leo ae eieececeetess 750 30 | Rock not entered. Sec. 30, T. 27, R.9 E ...-.-. ere 765 82 | Enters rock at 62 feet. W. 4H. Fulton, Rock Grove .-... (?) 65 | Rock entered at 20 feet. IDEAS ENON Sos5ncesKacouKed 900 80 | Drift in places, 80 feet. SeCh2owlaai hi Gpiwers setts 825 72 | Enters rock at 10 feet. Seba, MUSA Gl in tf 1D) Sho 555 Sonos (2) 80 | On a low gravel ridge. Secn29eDs27o RS) bysasseseeees 820 150 | Enters rock at 6 feet. Secvol phn orate Oban ae se sees 840 100 | No rock entered. Secu oeRniebyeneeee pe eees 785 60 | Enters rock a short distance. SecwloeTs26UR jt eeeser ame 5 800 72 | Enters rock at 20 feet. Sec lan 26Roadebicos ecco. 800 100 | Enters rock at 98 feet; drift, gravelly. NE. $ sec. 7, T. 26, R.8 E....... 790 31} Enters rock at 10 feet. Secu alco ReGibieeereseeeees 770 45 | Enters rock at 35 feet. Secu be 26phsostieeeeecerecs 770 60 | Enters rock at 9 feet. SeciG.Da26sRatMipcesscee oes 900 80 | Enters rock at 15 feet. Sec. 13, T. 26, R.7 E ........-.. 840 90 | No rock entered; drift, mainly clay. Sec. 14, T.26,R.7 E....-...... 850 100 Sec wll 26uRe Sib seen 850 85 | Entirely fine gravel and sand. See530)T).26,R. 8H - 2222-2 -2. 850 90 | No rock; drift mainly sand. Secen5; D526 7R. Si Bisco secs sn 785 104 | Enters rock at 50 feet. “See, TOR 186} 39) cocoss conse 775 110 | Enters rock at 76 feet. G@ounty Infirmary .----.-...-. 775 161 | Enters rock at 131 feet. Secwl ows 26 phat a igectstssrtetete ele 800 100 | Enters rock at 61 feet. Secwl2 IN 26 Ra Eecnces ccc 850 192 | Enters rock at 175 feet. Secs urs 26 ,Re@hnmesense se 850 248 | Enters rock at 183 feet; drift, blue till. Sect ume 2 Guha Hiweeeseeacn 850 128 | Enters rock at 115 feet; drift, variable. Sey 183 WES AS det 1/09) Gacecooeuee 825 165 | Enters rock at 141 feet; drift, variable. Sech 24a 26s ve hineeee es fone 800 128 | Enters rock at 112 feet; drift, variable. SecqoGs la 2G mya te bnese cise aes 900 186 | Enters rock at 140 feet; drift, variable. Sech20sia260Ra8B ose seecce. 850 87 | Enters rock at 70 feet; drift, variable. Shs Pal Mi Osh 1st} 19} Sceeeraccao 850 142 Mr. Bolton, Bolton Station -.-- 819 70 | Mainly blue clay; rock at bottom. Sec. 31, T. 26, R.7 HE -...- eee 900 70 Clay, 25 feet; remainder sand and gravel; rock at bottom. WINNEBAGO COUNTY. GENERAL STATEMENT. Winnebago County is situated on the north border of the State midway between the Mississippi River and Lake Michigan, with Rockford as its county seat, and has an area of 552 square miles. The eastern portion of 570 THE ILLINOIS GLACIAL LOBE, the county is traversed from north to south by Rock River, the northwestern portion is traversed from west to east by the Pecatonica, and the southeast- ern portion from east to west by the Kishwaukee River. The portion of the county west of Rock River has generally a thin coating of drift, except in the preglacial valleys. The majority of wells on the uplands enter rock at less than 20 feet. There are, however, occasional wells located probably over tributaries of the preglacial Rock or Pecatonica which penetrate 75 feet or more of drift without reaching the rock. EExcel- lent exposures of the drift may be seen along the line of the Ilinois Central Railway between Rockford and Freeport. Like the drift of Stephenson County, it is generally very stony and contains a considerable amount of gravel and sand. Much of this portion of the county is covered with a loess-like silt 4 or 5 feet in thickness, which furnishes an excellent soil. The portion of the county east from Rock River carries a heavy deposit of drift, rock seldom being found at less than 100 feet, and it is probable that along the valley of Rock River and its immediate borders the thickness exceeds 300 feet, for borings to the north and south show that the rock floor of the preglacial valley stands 250 to 300 feet below the present stream bed. The drift of the eastern portion of the county embraces a sheet which extends but little west of Rock River and which, as indicated above, is referred to the Iowan stage of glaciation. INDIVIDUAL WELLS. A large number of well sections were collected by Mr. I. M. Buell during his investigation of the drumlins and bowlder distribution of Winne- bago and Boone counties. But few records have been obtained by the writer. Mr. Buell has kindly turned over these well records for presenta- tion in this report, and they appear in the table below. They are chiefly found in the district east of Rock River. Table of well sections east of Rock River in Winnebago County, Illinois. Owner or location. | Altitude. | Depth. | Remarks. | Feet. Feet. | Sec. 14, T. 46, R.2 E .-.....---- | 900 60 | Largely sandy drift; no rock. 850 60 | Drift till; strikes rock. 900 65 | Brow of bluff; no rock; gravel, 20 feet; blue clay, 35 feet. WELLS OF WINNEBAGO COUNTY, ILLINOIS. DUCA Table of well sections east of Rock River in Winnebago County, Ilinois—Continued. Owner or location. Altitude. Feet. Sexon IGS MN ep) Se yes 800 750 Secwlne4a> Reo hhyees ease see 925 900 Sec. 2), 045, R.2 5B 2 eteo lee. 900 900 900 Secya wa 4o tea Bytes 900. 850 Sec. 4, 1.45, R. 2H ..---2 22 .2-. 850 750 750 Sec. 15, T. 45, R.2 BH .--2. 2222... 850 850 850 Sec. 22, T.45,R.2 EB ...-------. 825 Church N. of Argyle ..-...---- 900 Secns2Ty 45s Reo Hee o2 5: 825 Stoo, fa 10,21 9, 10) see ean 800 Sots Ate b N52) 18 cSoGad sousee 825 825 825 825 825 Stora i AO OTP oh ye 825 825 825 Sec.19, 7.44, R.2 BE ....2.....- 825 Seci20 Te 44RNonwe se 825 : 825 Sec. 32, T. 44, R.2 BE ....-.. 2... 850 850 850 850 Secui ules ek OuRicccmieseseece 800 Sec. 18, 1. 43,R.2 BE -..2...-2-- 775 32 140 140 80 50 45 103 107 98 46 75 30 Remarks. Till with gravel at bottom. Foot of bluff; drift till; no rock. Rock entered at 40 feet. Till, 65 feet; gravel, 16 feet; till, 10 feet; sand, 30 feet; no rock struck. Mainly till; upper part stony; rock at bottom. Bottom of well in eravel. Till, 75 feet; remainder sand. Rock at 50 feet or less. Rock struck at 65 feet. Brow of bluff; till, 80 feet; gravel, 20 feet; no rock. Foot of bluff; gravel (partly cemented), 46 feet; clay and sand, 9 feet; no rock. Rock river bottom; till, 43 feet; sand, 22 feet; no rock struck. In gravel at bottom. Rock struck at 57 feet. Gravel at bottom. Gravel at bottom. In sand at bottom. Brow of bluff; gravel at bottom. Brow of bluff; ferruginous drift conglomerate. No rock; drift gravelly. = Entirely till; no rock. Till; no rock. Till with cemented gravel at bottom. Sand at bottom. Dug through till; drilled through cemented gravel; loose gravel at bottom. Till, 100 feet; cemented gravel, 40 feet; no rock struck. Similar to preceding, and 40 rods distant. Till, 74 feet; gravel at bottom. No rock; mainly gravel. Similar to preceding. Wood in gravel below till at 75 feet; no rock struck. Till, 40 feet; sand at bottom. Sand at bottom, Rock struck at 45 feet. No rock struck; much ferruginous drift conglom- erate in that vicinity. Drift, 30 to 40 feet in that vicinity. HT THE ILLINOIS GLACIAL LOBE. Table of well sections east of Rock River in Winnebago County, Tllinois—Continued. Owner or location. Altitude. Depth. | Remarks. Feet. Feet. Sec.30; 0543, Ro 20h esse. 800 40 | Mainly till; no rock. Across road from preceding - -- 800 40 | Largely gravel; rock at bottom. Sec. 34, 1.43, R.2 EH .......-... 775 95 | No rock; mainly till. Hills at higher levels in that vicinity have thin drift. James Hested, SE. part of T75 100 Drift, mainly till; rock struck. county. Mr. Davis, SE. part of county -- 7715 60 | Drift ranges from 10 to 60 feet on the farm. Mr. Watson, SE. part of county 800 90 | No rock struck. W. E. Corlett, S. of New Mil- 7175 140 | Bluff of Kishwaukee; no rock struck; quarries at ford. a higher point toward the east. Sec. 25, 1.43, R. 1 EB ----.------ 800 55 | On gravel knoll: no rock. The waterworks station at Rockford is located near the base of the west bluff of Rock River Valley in the north part of the city. Five wells are sunk to the Potsdam sandstone, from which water rises barely to the surface (719 feet above tide). With a diameter of 6 inches, each well fur- nishes about 200 gallons per minute by pumping. The drift ranges from 125 to 190 feet in depth. The upper portion is sand and gravel, but the lower portion is largely blue clay. No wells have been sunk in the midst of the valley at Rockford of sufficient depth to reach the rock. The distance to rock is probably much greater than in the wells at the waterworks." At Pecatonica wells usually obtain water in the limestone at depths of 80 to 125 feet. The drift in that vicinity is but a few feet in depth. The waterworks is supplied from springs. In the vicinity of Winnebago Village the distance to rock ranges from 20 to at least 80 feet. Wells are usually obtained without entering rock, though several have been sunk some distance into the rock. In the vicinity of Elida the drift is usually about 50 feet, and a few wells pass into the underlying limestone. West from Elida and also north- west, over an area of perhaps 50 square miles, wells usually obtain water im the rock at depths ranging from 40 to 100 feet. The drift in that locality is thin, seldom exceeding 20 feet. Mr. Buell, however, reports two wells in sec. 3, T. 26, R. 10 E., 50 and 60 feet in depth, which do not strike rock. Another well in the same section enters rock at 40 feet and is carried to a depth of 110 feet. Still another well Wena on a drift knoll enters rock at ‘The data from Rockford have been EEE by Daniel W. Mead, C. E., of that city. "4 WELLS OF BOONE COUNTY, ILLINOIS. 73 30 feet. In the neighboring section on the north there are several outer yps of limestone, though one well in that section fails to reach rock at 106 feet. A well in see. 1, T. 26, R. 10, 114 feet in depth, enters rock at 50 feet. In the northwestern one-fourth of the county rock is usually entered at slight depth except in a narrow belt along the Pecatonica and Sugar rivers. But here, as in the southwestern portion of the county, occasional wells on the upland reach a depth of 80 feet or more before entering rock. BOONE COUNTY. GENERAL STATEMENT. Boone County is situated immediately east of Winnebago County, on the north border of the State, and has an area of but 290 square miles. Belvidere, the county seat, is situated near the southern edge of the county, It is drained chiefly by the Kishwaukee and its tributaries, which oceupy gravel plains leading westward from the moraines of the Wisconsin drift sheet in McHenry County. These gravel plains are in places a mile or more in width and afford an abundance of water at shallow depth, wells seldom exceeding 25 feet. The drift is thinnest in the southern portion of the county, there being numerous quarries in the two townships on its south border. In the north- ern part of the county the drift is probably not less than 75 feet in average depth, and it may possibly be as deep as in the neighboring portion of Winnebago County, from which the list of wells in the above table was prepared. Water is usually obtained at depths of 30 or 40 feet in that portion of the county from beds of gravel or sand associated with the till, the greater part of the drift being a typical till. In this county the glacial drift with its bowlders is not covered by deposits of loess or other silt as in counties to the west, and the surface sheet of drift, like that of eastern Winnebago County, is referred to the Iowan stage of glaciation. INDIVIDUAL WELLS. The city of Belvidere obtains its public water supply from a well sunk to a depth of 1,950 feet. The well is cased only to the limestone, 58 feet, and water is found at several horizons above the Potsdam (in which the well terminates) as well as in that formation. The head is but 6 feet below the well mouth, or 757 feet above tide. Though only 4 inches in diameter in its lower portion, it is found to have a capacity of 400 gallons per minute. The hardness of the water suggests that it is largely derived 574 THE ILLINOIS GLACIAL LOBE. from limestone. The private wells in this city usually obtain water from oravel at a depth of about 26 feet. A few in the south part of the city, outside the limits of the Kishwaukee gravel plain, are sunk to greater depth, but seldom exceeding 40 feet. At the village of Caledonia, wells usually obtain water from beds of gravel beneath till at a depth of 30 or 40 feet. The following table of wells on farms in the neighborhood of Caledonia will serve to illustrate the varia- tions in depth in the northern part of the county. It will be noted that only two of these wells enter the rock, viz, those in sec. 30, T. 46, R. 3 E., and sec. 7, T. 45, R. 3 E. Depth of wells in northern Boone County. Feet. Aan Nein Asay oR yy RES SHEE te CG 5281) 55 Soe oadesc sopohs ssboew ceceos eoes SoSsosEOsS coSesecanSeS 42 sya tana Millard: eceGo, cE 4G, IRs Al ilo ee ne ee rare Stes Pepey oe pe me Nee 34 Wiilliarnd Gini she seqe 26.1454 RY es Whale ote ie ae APE aE eS ea a a Sk to, eee 63 TERI GS, ei en Chg heen elih NSCs Mints eae ee ke ook ao con een edcen econ eee re eee Meena wen tSoe 60 Stay SL0), 10 AUSSIE IIG (CxO e BIG HL) WEI) Coa5 docolcdso seas edacos coosas sose een5 Coed zosadosond sees Cees 150 Secniubedoohto)by.| (rocks atin £eeb) eras eine iste serene oie aie ei ee eee eee eee oT) Secwt ala ohn aby en (SGVeLalawielllS)) seme iseaeseiate see mise a ataeetate eee a ae eet eee tetera 30-40 1D} Sa IKONS RECS BR ato) It BD) eso doG ccs sSScas cabo rccess ccdo scene seas ceeeeoeeeocces ceeSseouse 35 Aala's Tenet yy ECeey Mla llay Moai See6 koe oe cron be cedo Sbao saSdes SoonKh Boob cons SHeO osenencausctcee 30 JohnkChurchysecs2, lado, aor bnteacms ese ren ie te oles Aogus Se Ropu ae ieee aes ay tee Ue 35 TDD, RAVENS EES TE AS Gy 1853} 19) Gane Seog 6 6bccod saeco comosb HStete ooSeboossese odos daonso cbse Gacd 21 ID wb CoG TEMS REG dts ey GD) Sees soo ben soesehnons aboScocs sche 06os09 csdaas seuSee sees cosose 24 ReteravicintyrejssecG indo phuyubipsses enna meee ecaies eee SOS See eee eat ee eet 25 IPG ORs EC Choy dines Ine DIDS SAE EB See Bon ee oe ee tee eek eeceen coscosuccoaues sodose 22 JoOhnistallisecs4wi doy kite biee nate meee SPER: Mette Ren CPCS en hip ee Pele Fail deat Sates 76 To WYNN Gras ees RG BBY G0 Rd Ea Os ed hoe rian aab soodae seaae Sonus Soba seacco nbod sade soko 63 @leyNelson;isecsa, L.45, oR 4 hyo ana. ei eee ete et dees ee tae RSet e eae 65 PDS BOWIMAN SCC, 4 5. hv. by eee ae eee eter Be eee oe Sects Sree a cre taueee ee pan ees 48 TESA AG MOWING EES ot aR CID) cheese deb oeo edad icons ceotes cence bacu Sonede Sous sce Hee oCosees 35 In Bonus Township, situated northeast from Belvidere, the wells on the upland between the Kishwaukee River and Piscasaw Creek in several instances reach a depth of about 60 feet without entering rock. Although rock is usually struck at comparatively slight depth in the southeast township (T. 43, R. 4 E.), a well at a cheese factory in sec. 15 did not reach rock at a depth of 83 feet. Several wells in sees. 8, 9, 16, and 17 of this township enter rock at depths ranging from 4 feet to 20 feet on an upland standing about 900 feet above tide. On Coon Creek gravel plain, in see. 3 of this township, at an elevation less than 800 feet above tide, a well 45 feet in depth does not reach rock. A well at Mr. Ryan’s, in sec. 33, at an elevation about 775 feet above tide, is 86 feet in depth and strikes rock at 33 feet. Wells in sec. 23 reach a depth of 30 or 40 feet without entering rock. WELLS OF McHENRY COUNTY, ILLINOIS. 575 In the southwest township of the county, in the vicinity of Irene, wells are usually sunk into the rock, though the drift in places exceeds 30 feet. The Illinois Central Railway cutting, immediately west of Irene, shows an extensive exposure of black soil containing molluscan shells underneath a sheet of till. The soil appears to separate the Iowan till sheet from the Ilinoian in which case it is referable to the Sangamon interglacial stage. McHENRY COUNTY. GENERAL STATEMENT. McHenry County is situated immediately east of Boone, on the north border of the State, Woodstock being its county seat, and has an area of 624 square miles. Its western portion is drained by the Kishwaukee and tributaries westward to Rock River, while the eastern portion is drained southward through Fox River, which has its course near the eastern border of the county through a series of lakes and sloughs. This is one of the most elevated counties in the State, several square miles on its northern border being above the 1,000-foot contour, while much of the county stands above 900 feet. The greater part of the county is occupied by a system of moraines formed at the Wisconsin stage of glaciation, there being only a narrow strip on the western border of the county, scarcely a township in average width, which lies outside its outer morainic system. This is underlaid largely by a gravel overwash from the moraine, and is therefore of Wisconsin age. There are a few outcrops of rock near the Kishwaukee in the western portion of the county at an altitude about 800 feet above tide, but these appear to stand above the general level of the rock surface and represent probably the tops of preglacial ridges or hills. Several deep wells scattered widely over the county have shown the presence of a very thick deposit of drift. It is probable that the average depth is not less than 200 feet, or nearly twice the average depth of drift for the State. The wells for household use usuaily obtain water at moderate depth (20 or 30 feet), but wells for stock are often sunk to depths of 100 or even 200 feet. Dairying being one of the principal industries of the county, a large number of farmers have sunk deep wells to supply their cattle. The records of only a few of these were obtained, but they are thought to be representative. 576 THE ILLINOIS GLACIAL LOBE. INDIVIDUAL WELLS. The northwestern township of the county (Chemung) is occupied chiefly by a gravel plain, in which wells are obtained at a depth of 25 to 35 feet. In the vicinity of Chemung, however, the wells encounter till, and their depth ranges from 20 feet to 70 or more, water being obtained in beds of grayel associated with the till. The railway well at Harvard, in the southeast part of Chemung Town- ship, is sunk to a depth of 900 feet, and is thought to terminate in the lower portion of the St. Peter sandstone. The following strata were penetrated : Section of the railway well at Harvard, Illinois. Feet Vela ayn OG) HU oo S6 Sece sos ose Soe seas Saco ses S50 6855 cesses eSoccoSosace SsSba5 tooced Osean" 36 Gravelsamd) bowl ders ie ayaa ya ete ee ee 24 Sandeandwloosey crave srs state eae eer te ee er eo 15 (CEO SREMG coomeo bonhes doe sso Sonbeo sce SocoSs coSacoonoses Sosa SebeuO cbed Osos SHO Sede ssasceSs 15 OS Ta IEG ON os 5 Soc Sts eon6 onde coodes Ae Sesd coedes SéSser Senos eSase doesne Hees cosseonsoses des Sdaheo 12 Tyimestone 2322282: Ss See eee Rrra eee Naas ati Sialciaia shee neler ae oleracea er ER 108 SHANG) ooobe0 cosa tosbScosds Ssos Osos cS Epo ess SadeSs cosas soass cso Sod Soe coes BOSS aceoHecS saNSec 85 Wein allie WRENS 5 coco htoe sesooeses cSocad esSoee saSese oososs sobesy JotaDS SabScosccbSo cass coos 345 Wem hy GOMGIIONG) 62 c6c6 codecs soso eeoe Sess Stoo cos ood odds Soon Shands pe eeeo con ese deSses ced ceo cdos 240 The water is hard and is apparently largely derived from the limestone. It rises within 41 feet of the surface, or to an altitude 894 feet above tide. The well is cased only to the rock (102 feet), and has a diameter of 7 inches below the casing. The capacity is estimated at 90 gallons per minute. Many private wells are obtained in Harvard at a depth of about 25 feet. The west part of the village is on a gravel plain, with a sheet of water at 20 to 25 feet or less. The railway station and east part of the village stand on the slope of a moraine. In the township east of Chemung only one well record was obtained— that at the cheese factory in the village of Alden. This well reached a depth of 150 feet without entering rock, and has the following section: Section of well at a cheese factory in Alden, Illinois. Feet. (Chr al ONGl EAC loess oaomeo cosoas coon as OoCnSe Loss SSSons dasbisdaces addebs sone ores uoUStecoscososodes 15 Ihr Me ee See Soe Cee SoS som soos aS COS Seices SSE EOC SRS Sats Heese ees 100 Layee ert Bac oasis Good OSS a BROS IEH RECA DDoS HaGato Cold cqaSoomeey Seon ages eoSU Gobo Scho oes 2 TH Wofablaisbicolorsesmeeresas cece nce e oo eee cece iae eee eee eee Se a esate arte ane rneeeene 33 It is probable that the soil struck at the base of the blue till marks either the junction between the Wisconsin drift sheet and the Iowan, or between the Iowan and I[llinoian. The well is on a moraine. WELLS OF McHENRY COUNTY, ILLINOIS. HTT In the vicinity of English Prairie post-office, in the northeast part of the county, there is an extensive gravel plain standing at an elevation slightly above 800 feet, in which occasional wells have been sunk to a depth of 150 feet without reaching rock, mainly through gravel. At Woodstock, the county seat, a boring was made some years ago which struck a black soil at about 160 feet, beneath which was till, in which the well terminated at a depth of 180 feet. This soil, like that at Alden, probably marks the junction between the Wisconsin and Iowan drift sheet, or possibly between the Iowan and Illinoian. A well has been sunk in Wood- stock to a depth of 1,014 feet, but no accurate record of the strata penetrated appears to have been kept. The drift has a thickness of 230 feet. The well is said to terminate in sandstone, probably St. Peter. A water-bearing “sand rock” was entered at 825 feet. The water is reported to be soft and of a pleasant taste, and has a capacity of 150 gallons per minute from a pipe 64 inches in diameter. The head is 60 feet below the surface. Many private wells in Woodstock and vicinity obtain water at depths ranging from 20 to 60 feet. They are mainly through till, though beds of sand and gravel occur. At Marengo the wells vary greatly in depth, those on the gravel plain along the Kishwaukee being but 20 to 25 feet, while those on the slope of the moraine in the south part of the city are often 60 to 80 feet, and occasionally 125 feet or more. So far as ascertained, no wells reach the rock. The drift is largely of gravelly constitution. A well belonging to Mr. P. 'T. Parkhurst, 100 feet in depth, penetrated a black muck at about 60 feet, from which inflammable gas issued. This muck probably underlies the Wisconsin drift sheet. A similar muck was struck on the farm of James Smith, 3 miles northwest of Marengo, at a depth of only 28 to 30 feet. The well stands on the slope of the outer moraine of the Wisconsin drift, slightly above the level of the older sheet of drift tothe west. The soil in all prob- ability is at the base of the Wisconsin drift and above the Iowan drift. At a cheese factory south of Marengo, in sec. 11, T. 43, R. 5 E., a well struck a black muck beneath blue till at a depth of 70 feet. As the well is situated on the moraine at about 70 feet above the Iowan drift plain to the west, the soil probably caps lowan drift. At the village of Crystal Lake wells usually obtain water at depths of 50 to 70 feet and are largely through gravel. A well about 4 miles south- west of this village, in sec. 12, T. 48, R. 7 E., reached a depth of 210 feet MON XXXVIII——37 578 THE ILLINOIS GLACIAL LOBE. without entering rock. Water is obtained in gravel near the bottom, the greater part of the well section being till. In the vicinity of Cary wells are 60 to 100 feet in depth. They usually penetrate about 50 feet of dry gravel, beneath which is till, having water-bearing beds associated with it. At Algonquin, in the southeast corner of the county, an artesian well was sunk to a depth of 2,527 feet by the Illmois Condensing Company. Rock is struck at about 100 feet, and the well probably terminates in. Pots- dam sandstone. At last reports the use of the well had been discontinued because of the corrosion of the pipes by the water. The public water sup- ply for this village is from springs. Many wells on the low ground obtain water at about 12 feet. A few have been bored to depths of 60 or 80 feet. They enter till after penetrating 12 to 20 feet of gravel. Occasional flow- ing wells are obtained in this vicinity. One in the valley of Crystal Lake outlet, about a half mile above Algonquin, has a depth of 60 feet. One at a blacksmith shop in the north part of Algonquin is 62 feet im depth, and has a head 14 feet above the surface. The bordering uplands rise to a height of about 100 feet above the level of the wells, and thus furnish an absorb- ing area of sufficient height to give a strong hydrostatic pressure. At South Riley, in the southwest part of the county, rock is usually entered below blue till at a depth of about 60 feet, or at an elevation not far from 800 feet above tide. Rock is also struck in several wells on the plain northwest from Marengo, in the southwest part of T. 45, R. 5 E., and northwest part of T. 44, R. 5 E., at a depth of about 60 feet. The general elevation of the region is about 850 feet above tide. A short distance east from these wells, however, a well on the farm of Mr. Alsing, sec. 35, 'T. 45, R. 5 E., reached a depth of 100 feet without entering rock. The following sections of farm wells are of interest because of their depth. They are located on or among the moraines of the Wisconsin drift sheet and none of them reach the rock: Deep drift borings in southeastern McHenry County. Feet. Moses Dimon, 2 miles south of Marengo. .-----.--------------.--------- -------+----------------- 125 R. Cooney, sec. 14, T. 45, R.6 E...----. ---------------- ---- ---- +--+ +--+ ++ 222+ 2 eee eee eee ee ee 94 Harmony post-office .----. ----~------------- we Sas bina seiko Sots See ee ieee wisisle steiaterete tec eerenone 112 Ibe Olan, new Coatere Ope de CBE IMA Deo eee Be en eke cooces obe eso cece peosho rece obo coesedas 180 Well 80irods east'of preceding ~~~ oe. on ce ee eno eee ne =i 86 AW ANAM AIC NONGy, JoeB} 17/10) 5 2k eo gees Ses ce rsnds Sasson csS6 cosas shibo SeipSoa See eesead a0ccs 100 Mrs Gumminessmean Eumtl eye aslo eete= leant = eel eee eee OS George Bunker, T. 44, R. 7 E..---.----- -- +2222 2-22 2222 ene eee ee ene eee eee eee eee eee ees BF WELLS OF LAKE COUNTY, ILLINOIS. 579 The well at Mr. Cummings’s overflows, although at an altitude about 900 feet above tide, and that at Mr. Whittemore’s rises nearly to the sur- face. The absorbing area is probably on a moraine south of the wells, which rises to a higher elevation than that of the well sites. All the wells in the above list are mainly through till. In this connection it may be remarked that the moraines of this county appear to be composed chiefly of till, the principal exception being a gravelly area occupying a few square miles in the vicinity of Crystal Lake and thence eastward to Fox River. LAKE COUNTY. GENERAL STATEMENT. Lake County is situated in the extreme northeast corner of the State, on the border of Lake Michigan. It has an area of 490 square miles, and the county seat is Waukegan. ‘The eastern portion of the county is traversed from north to south by the Des Plaines River, while the western portion is touched by Fox River. ‘There are numerous lakes in the western half of the county, situated among the knolls and ridges of the Valparaiso morainic system. ‘There are also extensive marshes and sloughs bordering these lakes and Fox River. The Valparaiso morainic system, which occu- pies much of the western half of the county, stands 200 to 300 feet above Lake Michigan. Other moraines, occupying a narrow belt between the Des Plaines and Lake Michigan, stand 100 feet or more above the lake. The drift of this county probably has an average thickness of more than 200 feet. The few wells which enter rock find a rock surface lower than the level of Lake Michigan, and several other deep borings penetrate below the level of Lake Michigan without entering rock. It is scarcely probable that the rock surface will average an elevation as great as the level of the lake (580 feet above tide). The upper portion of the drift, to a depth of about 150 feet, is chiefly a soft blue till, thought to be of Wis- consin age. Beneath this occasional borings in Lake, as in neighboring counties on the south and west, enter a hard till, thought to belong to the earlier stages of glaciation. The wells in this county usually obtain water at moderate depths, from gravel or sand associated with the till. Such wells, however, are often weak, and farmers have occasionally sunk to depths of 200 feet or more in order to obtain a larger supply. 580 THE ILLINOIS GLACIAL LOBE. INDIVIDUAL WELLS. At Waukegan the public water supply was formerly obtained from artesian wells, but since 1895 it has been obtained by pumping from Lake Michigan. Three wells were sunk to depths of 1,135, 1,600, and 2,005 feet, respectively. The first well is reported by Mayor De Wolf to have obtained water of fair quality, though rather heavily charged with iron. The second well obtained an unpleasant water with bad odor, thought to be sulphurous. The wells were discontinued because of the hardness of the water, it being unfit for boiler use. The water also was found unsuit- able for sprinkling lawns, it being destructive to grass. The Lake Michigan water is not too hard for boiler use and in other ways is more satisfactory than the artesian water. The present intake is at a distance of 1,700 feet from the shore, but it is proposed to extend the tunnel to a distance of about a mile. At Lake Forest, wells which will yield 30 barrels per day are usually obtained at a depth of 40 feet or less. An artesian well at the residence of Hon. C. B. Farwell reached a depth of 960 feet and obtained a flow of water whose head was originally 50 feet above the surface, or about 125 feet above Lake Michigan. The drift at this well has a thickness of 160 feet. At Highland Park there are four artesian wells with depths of 1,800 to 2,200 feet. Mr. P. T. Dooley, a well driller, residing at this village, reports that wells 5 inches in diameter yield about 150 gallons per minute. A strong flow of water is obtained at about 900 feet and also at about 1,300 feet, as well as at lower horizons. The wells all flowed when first made, but at present scarcely reach the surface. The elevation of the well mouths is 110 to 115 feet above Lake Michigan, or 690 to 695 feet above the sea. The thickness of the drift is about 175 feet. At Milburn, in the north part of the county, on a plain between the Valparaiso moraine and Des Plaines River, several flowing wells have been obtained, and the wells on this plain usually show marked hydrostatic pressure. In some cases they are but 20 feet in depth, and rarely exceed 75 feet. Near Wauconda, in the western part of the county, several wells reach a depth of 70 or 80 feet, though shallower wells are common. WELLS OF LAKE AND COOK COUNTIES, ILLINOIS. 581 Near Lake Zurich, in the southwestern part of the county, a few wells have been sunk to depths of over 200 feet without entering rock. One in the village of Lake Zurich reached a depth of 240 feet; one on the Fletcher farm in sec. 32, a depth of 230 feet, and one about a mile east of the village reached a depth of 297 feet. The latter has the following section : Section of well near Lake Zurich, [linois. Feet. Mellow; tills sana eee ere alae ane siege tata cizia bocjels a euiig snicersi ee ee E Mare tne Reine easnens es noeieee 12 WB Ue Ga ie eae fore ete Sere eee Se afar ercicisie: SiS SSS snail a cml nieteloia beac SENS ee aoe ears era mtn 88 IPMS ZS a ys Dey eee etsy Sate a eee ile eee See el oe Sil SStSic lars icicl sisie aie dy dois ia mj etere clei nal See Se Teele tae ace Ga 197 Motallese sei sheet ce eee eee emerate cress Seer ante Se helo Soca lei ices © sg esse Pele eee e See ooee re eee OOT Gravel at bottom. A well driller states that much sand is found at depths of 100 feet or more beneath the crest of the Valparaiso moraine in the vicinity of Lake Zurich. At Barrington, on the south line of the county, two wells enter rock at 254 and 258 feet, respectively. They encounter considerable coarse gravel and cobble at about 160 feet. The remainder of the section is mainly till. Itis thought that this cobble bed occupies the junction between the Wisconsin and earlier sheets of drift, there being a change to a harder till beneath it. At Hainesville, in the north central part of the county, good wells are usually obtained at 80 or 90 feet, but one boring is reported to have reached a depth of 287 feet without obtaining water or entering rock. Another unsuccessful boring is reported to have been made at Gilmer, in the south central part of the county. It reached a depth of 213 feet without entering rock. At Deans Corners rock was struck at 290 feet. At Ravinia, in the southeast corner of the county, a well 186 feet in depth entered rock at 164 feet. COOK COUNTY. GENERAL STATEMENT. Cook County, of which Chicago is the county seat, has a wide frontage on Lake Michigan and extends back to distances of 15 to 30 miles from the lake, there being much irregularity in the western border. It is one of the largest counties of the State, the area being 960 square miles. The Chicago River, whose main branch heads near the north line, flows south- ward near the eastern edge of the county and enters the lake through the 582 THE ILLINOIS GLACIAL LOBE. midst of the city of Chicago. Calumet River enters the county from Indiana, and after running westward to Blue Island, a distance of about 12 miles, it turns abruptly eastward. As previously noted, it formeriy returned into Indiana and discharged at the head of the lake, but the present mouth of the river is at South Chicago, in Illinois. The Des Plaines River flows southward from the north line of the county to Summit, having an average distance of about 10 miles from the lake. It there turns southwestward, leaving the county near the village of Lemont. The extreme northwestern portion of the county is tributary to Fox River. Drainage lines are poorly developed in both the elevated and the low-lying portions of the county, a feature which is characteristic of several counties in northeastern Illinois. The eastern portion of the county is a plain rising gradually westward to the borders of the Valparaiso morainic system. A large part cf this plain stands only 10 or 15 feet above Lake Michigan, but on the western border its elevation is 40 to 60 feet or more. The plain is interrupted by a small drift ridge leading north a few miles from Blue Island. There are also drift ridges near the border of Lake Michigan, i the north part of the county, which rise to a height of 75 or 100 feet above the lake. The por- tion of the plain standing within 60 feet of lake level, as already noted, has been occupied by Lake Chicago, whose discharge was southwestward through the “Chicago Outlet.” The Valparaiso morainic system passes across the northwestern part of Cook County in a southward course, and, after crossing Dupage County, again enters Cook, occupying the southwestern borders of the county. This system stands in its higher parts fully 200 feet above the lake, and a small area in the extreme northwest part of the county reaches an elevation more than 300 feet above the lake. The drift is comparatively thin on much of the plain in Chicago and to the south and also along the Chicago Outlet, rock quarries being numer- ous and many instances of wells encountering rock at slight depth being found. There are, however, occasional wells which reach a level 100 feet or more below Lake Michigan before encountering rock. The available’ data seem to indicate that a buried valley enters the lake near Lincoln Park, whose course can be followed for several miles back from the lake WELLS OF COOK COUNTY, ILLINOIS. 583 in a westward direction. Wells along this valley reach a level 115 to 125 feet below the lake before encountering rock." In the northern part of the county the rock surface appears to be gen- erally lower than in the southern, though the drift surface is higher. The thickness of drift is found to be in places 250 or even 300 feet, while the average probably exceeds 200 feet. Well sections reaching the rock have been obtained in all parts of the county at frequent intervals, except in the portion occupied by the Valparaiso moraine on the southwest border, or in about 800 square miles of the 960 embraced in the county. Sixty-two wells are found to show an average of 83 feet to rock, while 47 fail to enter rock at an average depth of 79 feet. The drift is largely a compact till, except in the northwest part of the county, where thick deposits of sand and gravel are frequently found beneath a sheet of blue till. Beds of sand:or gravel are, however, associated with the till in sufficient amount to furnish a fair supply of water for wells. In a few instances wells in the northwest part of the county have penetrated a black soil below till at depths in some eases of over 100 feet. It is thought that the drift above such soils should be referred chiefly to the Wisconsin stage of glaciation. The soil may, however, in some instances be found below the Iowan drift. INDIVIDUAL WELLS. In the city of Chicago several sources have been drawn upon for wells, but the public water supply is pumped from Lake Michigan. Since the drift is generally thin, there are only small.areas where wells or rather where pure water may be obtained above the rock. The north part of the city, however, obtained water from the drift in the early days of settlement. The danger of contamination of such wells by sewage or otherwise is so great that their use is largely discontinued. The Lockport (Niagara) limestone, which underlies the city, has been drawn upon for water from the early days of settlement, but the use of water from this source is decreasing, in part because of danger from contamina- tion, and in part because of a sulphurous odor which often characterizes the water. Artesian wells have come into extensive use within the past thirty 1 The position of this valley was noted first by Mr. Samuel Artingstall about 1886, while city engineer of Chicago. 584 THE ILLINOIS GLACIAL LOBE. years. The first well was sunk in 1864 in the northwest part of the city, on the highest ground then within the city limits, and at an altitude of 31 feet above Lake Michigan, the precise location being at the corner of Chicago and Western avenues. This well was sunk by a band of Spiritualists with a view to prospecting for petroleum, and it is reported that the site of the well was determined by Mr. James, a so-called medium, while entranced. Only a small amount of oil was found, but at a depth of 711 feet a strong flow of water was struck, which rose to a height of 80 feet above the surface, or 111 feet above Lake Michigan. A second well only a few feet distant was sunk the following year, which obtained a flow of water at a depth of 694 feet. The history of these wells is set forth im an interesting manner in a pamphlet entitled ‘History of the Chicago artesian well,” by George A. Shufeldt, jr., issued by the Religio-Philosophical Publishing Association of Chicago in 1867. Mr. W. T. B. Read, who drilled the wells, still resides in the city... He reports that the head has decreased to such an amount that the water now stands 15 or 20 feet below the surface, or nearly 100 feet below its original head, and that the wells are not in use. These wells apparently obtained their supply of water from the Galena limestone, the depth being insufficient to touch the St. Peter sandstone. Within a few years after the drilling of the wells just noted, several deeper ones were sunk in the city and strong flows were obtained. The earlier ones usually reached the St. Peter sandstone, but it is probable that much of their supply came from higher strata. At the present time there are several hundred wells within the city used by the various industries which demand large quantities of water. A large part of them penetrate only to the St. Peter sandstone, but many enter the underlying limestone and not a few reach the Potsdam sandstone. ‘The deepest ones are about 2,700 feet. At this depth water is much more saline than in the St. Peter sandstone or Galena limestone. The disadvantage resulting from salinity will probably restrict the boring of wells in the future to depths of not more than 2,500 feet. The boring of so many wells within a limited area has led to such an excessive drain upon the rock strata that the head is kept below the normal, and an overflow is now rarely obtained. The deepest drift encountered in Cook County, so far as known to the writer, is in a well at Samuel Church’s, near the center of the northwest 1 At 950 West Chicago avenue. WELLS OF COOK COUNTY, ILLINOIS. 585 township (sec. 22, T. 42, R.9 E.). This boring reached a depth of 315 feet without encountering rock or obtaining water. As the altitude there is about 825 feet, the boring reached a level only 70 feet below that of Lake Michigan. Another boring 5 rods distant obtained a strong well from glacial gravel at a depth of 170 feet. Between this well and the city of Elgin several wells are found to enter rock at depths of 220 to 240 feet. Two wells east of Elgin are reported to have passed through an old soil beneath the till. In one well the soil occurs at the base of the drift at a depth of 67 to 70 feet. In the other it occurs at about 165 feet, while the rock is entered at 192 feet. The wells in that vicinity penetrate a bluish till, but on the borders of Fox River a brown or reddish till is reported to extend to considerable depth. A well one-half mile west of Spaulding Station, 137 feet in depth, enters rock at 120 feet. The drift is mainly blue till. At Bartlett several wells reach a depth of 90 or 100 feet, mainly through till. At Ontarioville the wells of greatest strength are found at depths of 60 feet or more, and occasionally reach 140 feet without entering rock. _ In Palatine Township a large number of deep wells have been sunk, partly because of the difficulty in obtainmg water at shallow depths and partly for the purpose of obtaiming an overflow. At the time of the writer's visit to that township, in 1887, there were not less than 25 flowing wells. They are located principally in the central portion, near the village of Palatine, but occasional flows are obtained in other parts of the township as well as in neighboring townships. In the southwest part the altitude is too great for a flow, but several wells have been sunk there to depths of 150 to 180 feet without reaching rock. The following wells in the village of Palatine serve to show the differences in depth of the wells and the relation to rock strata: Flowing wells at Palatine, Illinois. Feet Palatineswownwell enters rock ati152) feeb). oo ssssceeclere = sales eee lees eee ne 160 Palatine railroad well}crust of rock at bOttome can jjee eleeiseis eee ise eee neice leo eee 165 Palatine deep artesian well, enters rock at 147 feet.........--....--.--...-:--.---------------- 1, 656 Palatine Flax Mill, does not reach rock ..---...----..--- Dio Gea degesuc or MEE pea ease een ereme 170 Oneyblocks¢monthvotelaxe Mall m0tcOn 0 C kg eee eee eee eee eee ae ee eee eee ere oe 70 Palatine) Cheese! Hactory, crust of rock at bottom <---- 20.55... 222. = won eee ee ee 163 The well at the cheese factory, when first made, would rise into the second story, and that at the flax mill to a level 10 feet above the surface. 586 THE ILLINOIS GLACIAL LOBE. The other wells show a rise scarcely so high, though their mouths are at an equally low elevation. The well 70 feet in depth has a strong flow of chalybeate water. The strongest flow is from the cheese factory well—60 gallons per minute. The crust of rock reported in these wells is perhaps a ferruginous incrustation of gravelly drift, such as is often formed above water beds in the drift. In the deep artesian well a strong flow of water is reported from a depth of 800 feet as well as from near the base of the drift. The collecting area for the shallow wells is thought to be in the portion of the Valparaiso moraine west and north of Palatine, which attains an altitude of 100 to 120 feet above the station. The superficial drainage is very poor along this moraine, and much of the water must evaporate or find outlet by underground passages. The collecting area seems adequate for supply- ing the flowing well district. The following section of a well at the flax mill will illustrate the character of the deposits penetrated in each of the wells : Section of well at Flax Mill, in Palatine, Illinois. 3 Feet Welly nll ee oe aoe ee cocaboricso qeSasu donc bece Sono sclcess bndees Jaoce9 cee EET OReDOSoSSD oOODOF 10-12 Pedi WSs oe Ghose coe ednoeees ceded deen tobatase coaches codcod sosane sesh acesesaddsoszasoosas 25-30 Wrater=bearino STAVE) ele. = = <2 s ale meal ae laa ay earl 3-4 Blue till, with occasional thin beds of sand and gravel, yielding water...--.---.-------------- 125 The lower portion of the till is said to be more sandy than the upper. In the north part of Palatine Township there are several wells ranging in depth from 80 to 165 feet, which show strong hydrostatic pressure. On the lowest ground they occasionally rise within 5 or 10 feet of the top, and in two or more instances they overflow. In the township adjoining Palatine on the south (T. 41, R. 10 E.) flowing wells have been obtained along a tributary of Salt Creek in sections 23,25, and 26, at depths of 27 to 45 feet. Being'so shallow they differ but little from springs which occur in that vicinity. A few deep wells have been made in the western part of this township. The following section is from one in its northwest corner, at an altitude about 825 feet: Section of a well in northwest part of T. 41, R. 10 E. Feet. WONG Ain) e555 Gece sen Sco weseee bones soemeUBeneCo Saddias sadend code ohads osocsucansasis socee6 10-15 Wo nwih se Koa ne ook Ree Seopa eon ae epee ewes Meno caso cose bdCmod SoneRo ee toeo esos kesoosaess 125 IDEA LOU ene sooaes soeeb ool od SSD Son seSooodd Boece Soop orcdsagSs ono mss sash StiéseSotos sss ccas 4 Sandy till. 22 one ne an ae wn nn ow nn in mnie wm clam = = elm 50 Gravelinwit haw telaeseesetce sete steele elaine tela a wna ee eee eee ere ete et 2 NRG Nac ase toes agoe peta Sess coSoners See Soe adcg sass seer eceticinss ooon Seas mee Serco se te 195 WELLS OF COOK COUNTY, ILLINOIS. 587 At Arlington Heights a well drilled to a depth of 800 feet penetrates 128 feet of drift. No further data concerning the well were obtained. A well in this village penetrated a black soil beneath blue till at a depth of 70 to 75 feet, beneath which it entered another sheet of till. A well 25 miles north of Arlington Heights entered rock at a depth of 195 feet. At Des Plaines Village, which is situated on a gravelly plain, wells penetrate about 12 feet of gravel before entering till. Some obtain their supply in this gravel, others from gravel associated with the till. The depth seldom exceeds 30 feet. The public supply is from an 8-inch well 200 feet in depth." A well on the farm of John Back, near Schermerville, 162 feet in depth, enters rock at 147 feet. In the village of Schermerville wells are often 60 feet, and in some instances over 100 feet in depth, and obtain water from gravel beneath the till. At the village of Oak Glen several flowing wells have obtained water either near the base of the drift or in the upper part of the underlying limestone at depths of 90 to 120 feet. Mr. F. N. Hoffman’s well, 118 feet in depth, struck one water vein in gravel at 78 to 80 feet and another at the top of the limestone at 114 to 118 feet. Water in this well rises 4 feet above the surface. A well near Oak Glen, in see. ‘25, 160 feet in depth, does not reach rock, though its mouth is scarcely 60 feet above Lake Michigan. At Park Ridge, at an altitude 660 feet above tide, an artesian well enters rock at 103 feet. The drift is mainly till. No further data were obtained. A well about 3 miles north of Park Ridge at slightly higher altitude enters rock at 110 feet. At Winnetka, at the residence of Mr. Lloyd, a well 1,570 feet in depth enters rock at 150 feet. The water rises to a level nearly 40 feet above Lake Michigan. Wells are obtained in this village at depths of 20 to 50 feet in beds of gravel associated with the till. At Wilmette rock is entered at about 140 feet, or nearly 100 feet below the level of Lake Michigan. A deep well has a head about 20 feet above the lake level. No further data were obtained. An artesian well at Evanston, 1,602 feet in depth, enters rock at 72 feet, or about 42 feet below the level of Lake Michigan. Water rises to a ' Manual of American Waterworks, 1897. 588 THE ILLINOIS GLACIAL LOBE, height 34 feet above lake level, or 614 feet above tide. The well reaches the Potsdam sandstone. An analysis of the water is presented in the Seventeenth Annual Report of this Survey.’ The temperature of the water is 61.7 degrees Fahr. Many wells are obtained in this city at a depth of 35 feet or less near the bottom of the beach sand. The peaty deposits which occur at that horizon in some cases give the water an unpleasant odor. The use of private wells is decreasing, bemg supplanted by the publie supply which is pumped from Lake Michigan. In the vicinity of Niles Center several wells strike rock at depths ranging from 85 to over 100 feet. The gravel and sand of the lake beach is 8 to 12 feet in depth. The underlying glacial drift is mainly till. At Morton a well 115 feet in depth enters rock at about 100 feet. The drift is mainly blue till. In Bowmanville and vicinity several wells near the Chicago River reach a depth of 80 feet without striking rock. In some instances they penetrate about 20 feet of beach gravel. A well at Rose Hill Cemetery, near Bowmanyille, strikes rock at 100 feet. The upper 30 feet is gravel and sand, beneath which is a compact till extending to the rock. In several suburbs in the northwest part of Chicago rock is struck in artesian wells at 60 to 100 feet, as follows: Drift in artesian wells in northwest part of Chicago. Feet Jefferson Park .-.......-...... SSO Rae BOaSSe DAE SOS canoes Hse doe Se paca todos SoeSorséboas descr oascos 68 Ibe IPR Ae Shee oS oeasop coSpSoo cEpESd Oocede aseScg Hobocdodensta saomes DocoRc boScooabodes cosoas 79 IMIOIMNDKS jot oo soo econcSens bee sob sas oee Sones paecacndogsas scescs seboos Ho Sac0 oc abaS A= NamcccabosS 60 WowwOOEl MMe eso kaos Sab bog eouoKsbeoedandoboo stools Ssbcdd socens codoowaca adEeebedhan bead sco 90 INGE Clominiiy INANE 6658 Shad hone Saoeos SabGo6 cupacoroccos onb eon saSrod s doSScu dsosedseseas cacnos 71 Rin Iknenlliiny Sessooesece5 obs cosees ocaas sesso sedeercoosemascsas couaad sabSoc soccer sada Seese6 101 (Opie PHI Soo Sen peotos SSS 5nd Bone soSens ca Seas So Sore coos ososSsaede acudco seen coe seasc0 65, 85, and 45 INi@ane Chain. 6 cae boo echo caaeos ebseoAesuE sabe csSdse sscacs secaca c6S050 SacaEe soOben coSeaie cosose 20 In all of these wells the greater part of the drift is blue till) The beach gravel and sand seldom amount to more than 5 or 10 feet. A well at River Park, near the Des Plaines River, 115 feet in depth, enters rock at 100 feet. A well at Turner Park obtains water from sand below till and just above the rock at a depth of 80 feet. Mr. Koch, near Dunning, has a well 114 feet in depth which did not reach rock. Wells in the vicinity of Galewood, 66 feet in depth, are mainly through till and do not reach rock. Wells at Maywood, 40 feet in depth, do not reach rock, 1 Part II, p. 827. WELLS OF COOK COUNTY, ILLINOIS. 589 but within 2 miles west of Maywood rock is struck at about 30 feet. The Manual of American Waterworks (1897) reports that the public supply is from an artesian well. A well in the Des Plaines valley near the Twelfth street bridge does not reach rock. At Riverside the water supply is obtained from artesian wells about 2,200 feet in depth, which reach the Potsdam sandstone. The supply is partly from the St. Peter and other strata above the Potsdam. The wells originally overflowed, but the head is now 20 feet below the surface, or about 600 feet above tide. With a diameter of but 34 inches, the capacity of one of these wells is estimated to be more than one million gallons per day. At Lagrange the public supply is from artesian wells, but no data were obtaimed concerning their depths and capacities. In the east part of the village a flowing well is obtained from the drift at a depth of 21 feet. Rock outcrops within the limit of this village at a higher elevation than the mouth of this well. On the plain east of Lagrange rock is frequently struck at about 20 feet. The drift there is mainly a blue clay, there being only 5 or 6 feet of yellow clay at surface. In some cases sand and gravel occur just above the rock. West of Lagrange, in the vicinity of Western Springs, wells often reach a depth of 40 or 50 feet without entering rock. Borings in the vicinity of Summit show the depth to rock to range from 10 feet or less to fully 40 feet. The beach gravel in the south part of the village is shown by a gravel pit to have a depth of 20 feet. Beneath this gravel is blue till. On the plain southeast from Summit several wells are sunk 45 to 55 feet without reaching rock. : i At Washington Heights a well at Klein’s Hotel enters rock at 70 feet, penetrating the following beds: Section of well at a hotel in Washington Heights. Feet (EREND onos pci6ec6 Sane BSE E Bae RSG ERED See ahaa daakes decd a rcstd is Waste ten eee 3 TODO CI oaaeiesce 2oas BSES pee Beea Seinen BP 5E.335 so bcereo nese Soon ULNA E Een a ee aes 5 HBO Ol aes cade oe 5e sac ns Beno BEAR Saeed Has ieeoss occu osbuedeubonoda ses ueuete dem beets a alin Lule 63 TUNEESIONO: acchne ashe bacbonGuEEeH cee BeRee BACs GSE d68 sed ase edeqer Wcbnney ge udenl lin nUNEn DING Tl 3 Other wells are obtained in that vicinity at shallower depths. The public water supply is from a deep well.! A well at Morgan Park, on the crest of the Blue Island till ridge, 1,046 feet in depth, has a head 594 feet above tide. Limestone is entered ata ‘Manual of American Waterworks, 590 THE ILLINOIS GLACIAL LOBE. depth of 163 feet, or about 100 feet below the level of Lake Michigan. The well record indicates a soft till extending from the surface to a depth of 86 feet, beneath which there is a harder material called shale, but perhaps a till, 77 feet in depth. Another well in Morgan Park is reported to have struck limestone at a depth of only 90 feet. At Riverdale rock is entered at about 45 feet, at Dolton at 35 or 40 feet, and in the vicinity of Harvey at 20 or 25 feet. The public water supply at Harvey is obtained from deep wells, one of which derives its water from the St. Peter at 1,300 feet and another terminates in Potsdam at 2,075 feet. At Blue Island wells usually reach water in sand, connected with the lake occupancy, at a depth of about 25 feet. On ‘Lanes Island,” in the Sag outlet, several wells reach a depth of 30 feet without entering rock. After penetrating 4 to 8 feet of sand they are mainly through till. At the village of Worth wells usually obtain water at about 16 feet in sand below till. Rock is exposed along the Sag outlet in that vicinity at about the level of Lake Michigan. A well 4 miles east of Worth, in sec. 23, T. 27, R. 13 E., reaches rock at 55 feet. The drift is mainly till. On the island-like tract of moraine between the Sag outlet and Des Plaines, northwest of Worth, several wells reach a depth of about 80 feet without entering rock. They are mainly through blue till. On the Valparaiso moraine, in the south part of Cook County near Alpine, several wells have a depth of 80 feet without entering rock. Small amounts of inflammable gas have been found in some of these wells. In the vicinity of Matteson and northward in T. 35, R. 13 E., wells frequently reach depths of 50 to 65 feet without entering rock. In the vicinity of New Bremen, in T. 36, R. 13 E., the wells are frequently 75 feet in depth and obtain water in gravel beneath the till. In the vicinity of Glenwood wells along the beach penetrate 8 to 12 feet of gravel before entering till, and strike rock at about 30 or 35 feet. A flowing well was obtained by Mr. Winterhoffe on his farm in sec. 6, T. 35, R.15 E., at a depth of 75 feet without reaching rock. It was through till the entire depth. A néighboring well at Lewis Peter's enters rock at 85 feet, but the water level is 14 feet below the surface. Another well, in sec. 12, T. 35, R. 14 E., strikes rock at 85 feet and there obtains water, which WELLS OF DUPAGE COUNTY, ILLINOIS. 591 rises within 2 feet of the surface. Still another well, in sec. 7, T. 35, R. 15 E., only 60 feet in depth, encountered rock at the bottom, which may possibly have been a bowlder. The public water supply for Chicago Heights is obtained from four wells about 200 feet in depth located on the plain north of the village. The head is not sufficient to cause an overflow. The drift in the vicinity of this village is but 20 or 30 feet in depth and some of the private wells enter the rock; occasionally they are sunk to a depth of 80 or 90 feet. In the dis- trict east of Chicago Heights, as far as the State line, wells are usually obtained at a depth of about 35 feet, from gravel below till. DUPAGE COUNTY. GENERAL STATEMENT. Dupage County is situated west of the middle portion of Cook County, and has an area of but 340 square miles. Wheaton, the county seat, is situated near its geographic center. Its drainage is southward, the eastern border being tributary to Salt Creek and the middle and western portions to the Kast and West Dupage rivers, respectively. Like the portion of Cook County on the north, it is poorly drained, although stand- ’ ing much above the bordering plain on the east. The eastern two-thirds of the county is occupied by the Valparaiso moraine, which carries numerous sloughs and basins among its knolls and ridges. It affords excellent pas- ture lands and is extensively used in dairying, the leading pursuit of the county. On the dairy farms wells are frequently sunk to depths of 100 feet or more. The thickest drift section obtained is 162 feet, and 20 wells which reach rock show an average depth of 86 feet, while 17 of the deep wells which fail to reach rock show an average depth of 94 feet. From these sections, which are distributed widely over the county, the thickness of the drift may be inferred to average not less than 100 feet. he drift is thin- nest in the southwestern portion, on the borders of the West Dupage River, where numerous quarries of limestone have been opened. Rock also comes to the surface near Elmhurst, in the southeast part. The drift in this county, as in northwestern Cook County, consists mainly of a blue till, but beds of sand and gravel are associated with the till at various levels and supply the water for wells. 592 THE ILLINOIS GLACIAL LOBE. INDIVIDUAL WELLS. In the northwestern township of the county, sections of three deep wells were obtained near Wayne, one of which in sec. 7, 105 feet, and one in sec. 8, 150 feet, in depth, do not reach rock, but one in see. 33 enters rock at 162 feet. In the first two wells a large amount of sandy material was penetrated, but the third well penetrated nothing but till. In the middle township of the north tier several wells have been sunk near Roselle to a depth of 100 feet or more without entering rock. The majority of them are mainly through till. In the northeast township several flowing wells have been obtained in the vicinity of Itasca at shallow depths along a tributary of Salt Creek. The depths are but 20 to 30 feet, and the water rises scarcely 5 feet above the surface. There are also numerous shallow flowing wells along Salt Creek between Salt Creek Station and Elmhurst. It should be noted that this flowing-well district is adjacent to that of Cook County, discussed above. The altitude is 75 feet or more lower than at Palatine, being scarcely more than 650 feet along Salt Creek Valley, and about 690 feet at Itasca. Neighboring portions of the Valparaiso morainic system on the west rise fully 100 feet above the wells at Itasca, and it is probable that this moraine constitutes the absorbing area. A well at Bensonville, about 2,000 feet in depth, penetrates 97 feet of drift. No further data concerning the well were obtained. At Elmhurst records were obtained of two wells which strike rock at 70 and 98 feet respectively. Within a mile west of these wells a limestone quarry is opened at a level only 15 or 20 feet below the well mouths. About 3 miles south also a quarry is opened on the bluff of Salt Creek. The public water supply is pumped from a spring about 3 miles distant from the town." Along the valley of Salt Creek, south from Elmhurst, wells are in places sunk to a depth of 50 feet, mainly through gravel. At the village of Fullersburg, however, wells obtain their supply of water in gravel at a depth of but 12 feet. At Hinsdale the public water supply is obtained from a well 864 feet in depth. This is reported by the Manual of American Waterworks to afford 1,000,000 gallons per day. The last edition of this manual reports a ‘Manual of American Waterworks, 1897. WELLS OF DUPAGE COUNTY, ILLINOIS. 593 second deep well in use. The drift in the ,vicinity of Hinsdale is about 100 feet in depth and is mainly till. On the moraine west and northwest from this village several wells show the drift to be over 150 feet in thick- ness. One at a brickyard, in sec. 10, T. 88, R. 11, 190 feet in depth, enters rock at 159 feet; another near Clarendon Hills, 160 feet in depth, does not enter rock. In each of these wells and in all the wells in that vicinity the drift is mainly a blue till. In the well near Clarendon Hills a very hard till was entered at a depth of 130 feet, which is perhaps an older deposit than the soft till above it. In the vicinity of Downers Grove several wells have been sunk to a depth of over 100 feet without entering rock. One well enters rock at a depth of 130 feet. In these wells sand is usually found below the blue till at depths of 100 to 120 feet. The Manual of American Waterworks (1897) reports that the public water supply is from two 10-inch deep wells. Near Lisle the drift is of gravelly constitution, and wells are usually obtained at about 50 feet. A well south of the village, in section 12, is 157 feet in depth and entered rock at about 100 feet. This well was mainly through till. : At Wheaton the public water supply is from a well 178 feet in depth and 10 inches in diameter, which is estimated to yield 300 gallons per minute. The limestone was entered at a depth of 116 feet. About 2 miles northeast of Wheaton, at an equally high elevation (750 feet), rock was entered at a depth of only 70 feet. Several wells have been sunk in the vicinity of Prospect Park and Lombard, which obtained water from gravel at about 50 feet. The drift in that vicinity is gravelly. In the vicinity of Turner Junction wells are occasionally sunk to a depth of about 100 feet without encountering rock. A well 3 miles south- west of the village entered rock at a depth of 116 feet. A deep well has been sunk by the Chicago and Northwestern Railway Company at Turner Junction, but no data concerning it have been obtained. At Naperville wells usually reach water in gravel at a depth of about 30 feet. The drift east and south from this village is gravelly. It ranges in thickness from a few feet up to 100 feet or more. In several places near Naperville limestone quarries have been opened. West from Naperville in the vicinity of Kola the drift is about 100 feet in depth, mainly till. MON XXXVIII——38 594. THE ILLINOIS GLACIAL LOBE. KANE COUNTY. GENERAL STATEMENT. Kane County is situated west of Cook and Dupage, and has an area of 540 square miles. It includes the thriving cities of Elgin and Aurora, and its county seat is Geneva. Fox River flows in a southerly course through the eastern part of the county and is the le of discharge for most of the drainage. The greater part of the county has such imperfect drainage that large areas have been artificially drained. It is in the center of the great dairy district of northeastern Hlinois, and the greater part of the county is devoted to dairying. Numerous deep wells have been sunk on the farms, some of them reaching depths of over 200 feet before encountering rock, but in the southeastern part of the county rock is exposed extensively in the bluffs of Fox River and is struck at comparatively shallow depths in the wells. The portion of the county north from the latitude of Geneva is, as previously described, largely occupied by a complicated system of morainic belts, but the southern portion of the county has generally a nearly plane surface. These moraines were formed at the Wisconsin stage of glaciation and, like the Valparaiso morainic system to the east, consist largely of a soft blue till. In several of the deep wells a black soil has been found beneath the blue till, and under this soil a hard till is penetrated. This hard till is apparently of much earlier age than the drift of the Wis- consin stage. INDIVIDUAL WELLS. Tn the northwest township records were obtained of several wells near the village of Hampshire which reach a depth of over 100 feet without entering rock. A well at the brick yards in Hampshire is 102 feet, and one at the Warner Lock Company factory is 118 feet, each being mainly through blue till. On a farm near Hampshire one well reached a depth of 180 feet. On the crest of a moraine east of Hampshire, near Briar Hill Station, at an elevation 975 feet above tide, a well 175 feet in depth is entirely through till except one foot of sand at the bottom. On this same moraine records of several wells were obtained which find water in abun- dance at a depth of 20 to 35 feet, and the great majority of wells in the township are less than 40 feet in depth. WELLS OF KANE COUNTY, ILLINOIS. 595 In the middle township of the north tier the following records of deep wells were obtained: Deep drift wells in northern Kane County. Feet+ MraKie lly sseCe3ais soe ccsisacecmete se aenees ssicee sais cn/a cscs Ss cre ecep se RE eee Set Tete cin Sain asie ss 130 Wiles J ROK NETH OLD ee Seo iGchc BasedH acd CHSC SSO hU ORCS Eee ReEEEtSEeaHCaecas cobcc unoone th pose SHSosess 161 NURS Js ITT STOPS Gogo pace bo SOU C SRE CHO TS eSER be CCEME EERE Eee SSpc coe erecoobade PoC Same meres 106 NeanGilibertiS tation insect ferermmanisscise see cisco = = a1 oo eens Pence eee eee cee eee eee 293 In the last of these wells an old soil was penetrated at the base of the blue till, at a depth of 180 to 183 feet, beneath which was a hard till extending to the rock, which was entered at 217 feet. At Dundee, in the northeast township of the county, wells on the gravel terrace along Fox River are about 60 feet in depth. The public water supply is obtained from springs, but in the part of the village east of Fox River private wells are stil] in use. Mr. Francis Perry obtained a flowing well in Fox River Valley north of Dundee, near the top of the limestone, at a depth of 181 feet. An old soil was struck at about 155 feet. Water will flow from a pipe 16 feet above the surface. This well is but a short distance from the flowing wells in McHenry County, near Algonquin, reported above. The city of Elgin obtains its public supply by pumping from Fox River. ‘There are, however, many private wells within the city, and a few deep artesian wells. The wells usually obtain water without entering rock at depths of 50 feet or less. The thickness of the drift in a well at the Elgin Shoe Factory is 123 feet, and an old soil was struck at 108 to 113 feet. The drift above the soil is mainly gravel and cobble, but below it is a red- dish till. Usually rock is struck at a depth of less than 100 feet. The following data concerning artesian wells were furnished by W. 8. Gamble, city engineer. A well at the Elgin Watch Factory, at an elevation 715 feet above tide, has a depth of 2,026 feet and a diameter of 6 inches. It obtains sulphurous water from St. Peter sandstone at 650 to 700 feet, and soft water from Potsdam at 2,024 feet. A well at the Hospital for the Insane, at an altitude 735 feet above tide, has a depth of 2,230 feet. This also obtains water both from the St. Peter and the Potsdam sandstone. The Elgin Creamery Company have a well 1,400 feet in depth, which obtains water from the Galena limestone at 487 to 514 feet, and from sand- stone at 650 to 700, 972, 1,208, and 1,398 feet. The upper veins are more sulphurous than the lower. The Illinois Condensing Company have a well 596 THE ILLINOIS GLACIAL LOBE. 1,876 feet in depth, which apparently obtains the greater part of its water from the St. Peter sandstone at 650 to 700 feet. The heads at the several wells vary from 716 to 742 feet above tide, the lowest head being at the creamery and the highest at the watch factory well. An analysis of the water from the well at the Hospital for the Insane is published in the Seventeenth Annual Report of this Survey. A well on the farm of Judge Wilcox, northwest of Elgin, in see. 4, T. 41, R. 8 E., 127 feet in depth, passed through an old soil at 111 to 114 feet and obtained water without entering rock. The altitude at the well is about 125 feet above Fox River Valley at Elgin, or 850 feet above tide. Sections of three deep wells were obtained in the township west of Elgin, as follows: ; Deep drift wells west of Blgin, Illinois. Feet MrsRussellsecal valtibude S25) fee ree tate ete alate feat re teller eee ate a totale 100 TiReadssecuo2z7al titnde donee eet as ee = cee eee eee ee eae eee ae eee eee 219 iWielliimisecyopetaltit ude 190 Oke etiam meee tee lalate 146 None of the wells enter rock, and in each well the drift is mainly a blue till. In the last one an old soil was passed through at 131 to 137 feet. In the next township to the west, T. 41, R. 6 E., several flowing wells have been obtained on a plain between morainic ridges at an altitude about 865 to 880 feet, and at depths ranging from 56 to 86 feet, as follows: Flowing wells from drift in western Kane County. Feet Sec. djaltitndes?o feet-<= 2 oe ee sadasd gpooes 6esbes Rodded SoSSrD SESS eases ence eesces 75 CUB Godtreysecs15.altitudels80)tecte= pase eee ese eee en eee ane eee aie caer ee eee area 72 GSH Brownysece22, alttiuders(o teeters sass eee eee eee eee eee eee eee eee ae area eeer 64 1D)s Weoley, SEZ NU MOYO case Goskoe cogeso Rose sed coed os cone oo56 oesosa SESS cooU.socgemEce 70 1D, LO phon Aen eK CManNANGKS) tele) aR Wen S ose Soo6 Soe seo ce sons Cs85s0 coSeen Ss des saseeas essoboedes sopess 56 SaRaMlMithorp; sec. 27, altitude. 8(o teeth) sass ee eee eee ieee eee eee tae tae lame Seb ease0 86 A well at John McDonough’s, in sec. 26 of this township, 125 feet in depth, strikes an old soil at 40 feet. This soil is probably referable to the Peorian or post-lowan interglacial stage. The altitude is not greatly different from that of the flowing wells, yet a flow was not obtained. . A well at the mill in the village of Burlington, 165 feet in depth, is in rock a few feet. A well at a hotel in the village reaches a depth of 100 feet and obtains water in gravel below blue till. In the vicinity of Burlington several wells exceed 100 feet in depth. One in sec. 5 is 114 feet and another 99 feet. One in sec. 17 is 117 feet in depth. 1 Part II, p. 827. WELLS OF KANE COUNTY, ILLINOIS. 597 In the vicinity of Richardson several wells have been sunk to depths of 80 to 120 feet, mainly through till, and obtain water in sand and gravel without entering rock. Mr. Richardson has two wells, one 84 feet, the other 87 feet; Mr. Dayton, one well, 117 feet; Mr. Frank Paul a well 120 feet. Other deep wells in that township range from 50 to 100 feet or more, with an average about 75 feet. Such wells are much stronger than those obtained at shallow depths. In T. 40, R. 7 E., there is an elevated morainic belt in which the drift probably averages over 200 feet. Each of the wells which enter rock pene- trate more than 200 feet of drift, and one well reaches a depth of 336 feet without striking rock. In several wells an old soil is found at the depth of about 200 feet, which in some instances is probably between the Iowan and Ilinoian drift or the Sangamon interglacial stage. The following wells serve to illustrate the above statement. At J. Powell's, in sec. 7, altitude about 950 feet, buried soil is struck at 195 to 200 feet and rock is entered at 250 feet. The wellis continued about 200 feet into the rock. At M. W. Powell’s, in sec. 8, on nearly as elevated a point as the preceding, a well about 500 feet in depth penetrates 234 feet of drift. At a cheese factory in section 19, at an elevation of 950 feet, is a well 336 feet in depth which did not reach rock. An old soil is found below the blue till at 198 to 200 feet, with a greenish subsoil beneath it. A hard till of light gray color sets in at 240 feet and extends to the bottom of the well. Mr. Beith, in sec. 28, has a well 228 feet in depth, which is thought to strike rock at the bottom. The altitude is probably 925 feet. Mr. L. R. Read, in sec. 32, has a well 226 feet in depth, which passed through an old soil at about 180 feet and entered rock at 214 feet. The altitude of the well is about 925 feet. In the vicinity of St. Charles in T. 40, R. 8 E., several wells have been sunk to a depth of 75 feet or more. One in sec. 1 strikes a black soil below blue till at a depth of 72 to 74 feet, and one on Mr. Dunham’s farm, in the east part of the township, passes through a buried soil at 75 to 78 feet. The altitude at these wells is about 750 feet, or nearly 200 feet below that of the deep wells in the township on the west just noted. At Geneva a well at the court-house was sunk to a depth of 2,500 feet, and the Glucose Company have a well 2,000 feet in depth; this company also has a well 400 feet in depth. No further data concerning these wells have been obtained. The village stands on a gravelly plain at a level 598 THE ILLINOIS GLACIAL LOBE. about 40 feet above Fox River. Wells are usually obtained, without sink- ing below the river level. In the vicinity of this village rock is often encountered at depths of but 15 or 20 feet. The drift continues thin south- ward past Batavia, and many wells in that village enter the rock. Upon passing westward from Fox River the drift increases markedly in thickness within the township limits, though the elevation remains about the same. Several instances of the occurrence of a buried soil were found in this township and the one adjoining it on the west. The following represent the deepest wells in T. 39, R. 8 E., of which sections were obtained; they are all at an altitude of about 750 feet: Wells near Batavia, Illinois. In see. 4, old soil at 120 to 126 feet, gravel at bottom. East part of Batavia on bluff, rock at 60 feet. Sec. 24, good wells at 72, 81, and 112 feet in drift. Mr. Carr, sec. 20, well strikes rock at 48 feet. Mr. Davenport, sec. 19, three wells in drift at about 100 feet. Daniel Frydendall, sec. 31, old soil at 80 feet; depth of well 90 feet. In T. 39, R. 7 E., wells are usually obtained at 40 to 75 feet, but a few exceed 100 feet. The following embrace the deepest of which sections were obtained: Wells in T. 39, R. 7 EH. Cheese factory at La Fox; depth, 126 feet; rock at 65 feet. C. G. Morse, sec. 3; depth, 83 feet; no rock struck; lower half a harder till than the upper. Mr. Outhouse’s well, north of Elburn; altitude, about 900 feet; depth, 100 feet. Tile factory well at Elburn; altitude, 850 feet; depth, 70 feet; old soil at 60 feet. C.F. Field, sec. 10; altitude, 800 feet; depth, 96 feet; reck at 85 feet. P. Washburn, sec. 14; altitude, 825 feet; depth, 169 feet. The well is on a gravel knoll 50 feet in height and penetrates: Gravel and sand, 50 feet; brown till, 97 feet; black muck, with log embedded, 24 feet; yellow till, 7 feet; sand and gravel, with water, 10 feet. Mr. Sheets, sec. 20; altitude, 750 feet; depth, 47 feet; soil, with wood, at 40 feet. Blackberry P. O., sec. 21; well from gravel below till at 70 feet. F.S. Morrill, sec. 21; altitude, 750 feet; depth, 60 feet; mainly blue till. Mr. Kigling, sec. 22; altitude, 750 feet; depth, 50 feet; rock at bottom. D. C. Greene, sec. 22; altitude, 750 feet; depth, 40 feet; wood near bottom. Johnson’s Mound, see. 15; altitude, 800 feet; depth, 180 feet. The well is on the slope of a knoll 80 feet above bordering plain. Another well passed through a bed of leaves and muck at about the level of the base of the mound. Neither well entered rock. William Beler, sec. 17; altitude, 750 feet; depth, 46 feet; rock at bottom. Annis estate, sec. 29; altitude, 700 feet; depth, 66 feet; mainly blue till; wood and black muck at 64 feet. Well is thought to have struck rock at bottom. Russell Benton, sec. 30; altitude, 700 feet; depth, 75 feet; entirely in gravel. In the vicinity of Kaneville, as noted above, there is a delta-shaped plain of gravel formed at the western end of an esker (see Pl. XIV). Near the western border the gravel is but 20 feet in depth, but at the eastern border, near the esker, wells 60 feet in depth do not reach the bottom. At WELLS OF KANE COUNTY, ILLINOIS. 599 Kaneville wells have a depth of 35 or 40 feet and penetrate both gravel and till. At Charles Benton’s, east of Kaneville, in sec. 25, a well 54 feet in depth is thought to have struck rock. It penetrates clay 25 feet, sand 25 feet, gravel 4 feet. Near the center of the township, in sec. 15, a well on a knoll is entirely in gravel to a depth of 44 feet. In Sugar Grove Township the thickness of drift varies from 16 feet or less up to fully 75 feet. In the village of Sugar Grove the deepest wells are 50 to 70 feet without entering rock. In some instances they are through gravel and in others mainly through till. A well at Mr. Hatch’s, in see. 7, 70 feet in depth, obtains water in gravel at bottom and penetrates alterna- tions of clay and fine sand. Mr. Dorr, in see. 8, has a well in a basin at the side of an esker which is entirely in clay to a depth of 20 feet. On the borders of the basin the drift is gravelly, like that of the esker. Mr. S. E. Sheppardson, in sec. 16, has a well 75 feet in depth, which is entirely through sand and cemented gravel. Mr. Chapman, near Sugar Grove, has a well 90 feet in depth, which entered rock at 60 feet. It was mainly through till. Mr. Potter, in sec. 32, has a well on a knoll, which reaches a depth of 70 feet without entering rock. The upper 40 feet is gravel and sand; the remainder is sandy till. At Aurora the public water supply is from a series of deep artesian wells 1,388, 2,270, and 2,255 feet in depth. The first obtains water from the St. Peter and the others from the Potsdam sandstone. The water has a head about 60 feet above the surface, or 710 feet above tide. An analysis of the water from each well appears in the Seventeenth Annual Report of this Survey! The water from the St. Peter sandstone contains a remarka- bly small amount of saline matter and is of excellent quality for domestic use. The Potsdam water is more saline than the water from the St. Peter sandstone. Private wells are obtained in Aurora and vicinity at about 40 feet in gravel. Rock is extensively exposed along Fox River in the city and below as far as the county limits. DEKALB COUNTY. GENERAL STATEMENT. Dekalb County is situated immediately west of Kane and near the middle of the second tier of counties from the north. It has an area of 650 square miles, and Sycamore is the county seat. The greater portion of ' Part II, p. 820. 600 THE ILLINOIS GLACIAL LOBE. the county drains northward through the south fork of Kishwaukee River. The southeastern part is tributary to Fox River. Like the counties to the east, it is so imperfectly drained that much artificial drainage has been made, both by surface ditches and by tiling. The Bloomington morainic system which crosses the central portion in a northeast-southwest direction rises about 100 feet above the district on the outer border. There is on the inner border a gradual descent to the valley of Fox River across a plain dotted with only occasional knolls. The drift is probably as heavy as in any of the counties of northern Illinois (except perhaps Bureau County), there being in 22 borings which reach rock an average thickness of 151 feet, while 68 other deep wells which do not reach rock show an average of 101 feet. The portion on the north border of the county outside the morainic system has scarcely 50 feet of drift, and as it comprises an area of fully 100 square miles it materially reduces the average for the county. As in the counties to the east, the drift is largely a blue till, and occasional instances of the occurrence of a buried soil near or perhaps below the level of the base of the Wisconsin drift have come to notice. In a large part of the county dairying is the principal pursuit, and many deep wells have been sunk to supply the stock or to furnish water for the creameries and cheese factories. Many of these wells exceed 100 feet in depth, and wells 200 feet or more in depth are not rare. INDIVIDUAL WELLS. In the northwest township of the county there are few deep wells, water usually being obtained at 25 to 40 feet. A well in sec. 36, however, reached a depth of 75 feet without entering rock. At several points within the township the rock outcrops at a level not more than 25 feet below this well mouth, or about 800 feet above tide. A flowing well in sec. 35 is sup- plied from gravel below till at a depth of 22 feet. In T. 42, R. 4 E., rock outcrops are nearly continuous along the Kish- waukee Bluffs up to an altitude about 750 feet above tide. A few wells in the vicinity of the river penetrate 40 feet or more of drift. On the south border of the township there is a rise of 100 feet or more to the morainic system referred to above, and wells here exceed 100 feet in depth without reaching rock. One at Mr. Leander Roberts’s, in sec. 32, has a depth of 132 WELLS OF DEKALB COUNTY, ILLINOIS. 601 feet. Another in the same section, at Mr. Keague’s, has a depth of 110 feet. At Genoa, in the northeast township of the county, the wells are 25 to 60 feet in depth and obtain their supply from gravel below till. A well in sec. 26, near New Lebanon, at an altitude about 850 feet above tide enters rock at 90 feet, and has a depth of 122 feet. The south border of this township is occupied by the outer moraine of the Wisconsin drift, but no records of deep wells were obtained. In the township to the south, however, records of several wells were obtained which show the drift to reach a thickness of 150 to 200 feet or more. For example, in sec. 9., T. 41, R. 5 E., a well 156 feet in depth does not reach rock and is mainly through blue till. The altitude is about 900 feet. At Mr. Marshall’, in sec. 11, at a similar altitude, a well has a depth of 111 feet. At John Haine’s, in sec. 2, a well is obtained at 86 feet. Near the center of the township, in sec. 15, Mr. E. Devine made three unsuccessful borings for water to a depth of about 200 feet without reaching the bottom of the drift. The altitude at the wells is about 875 feet. Four wells in sec. 25 each have a depth of about 125 feet, and a fifth well has a depth of 170 — feet. They are all mainly through blue till, and none enter the rock. In secs. 35 and 36 three wells have a depth of about 100 feet, a fourth has a depth of 148 feet, and a fifth a depth of 151 feet, all mainly through blue till. In T. 41, R. 4 E., records of wells show the depth of drift to exceed 100 feet, while one well in sec. 31 reaches a depth of 113 feet without teaching rock. This well is thought to have passed through an old soil at about 80 feet. Another well in the same section has a depth of 112 feet. The wells of this township are mainly through blue till, but one, in see. 11, is reported to have passed through 35 feet of yellow till and 10 feet of sand before entering blue till. The well has a depth of 98 feet, and terminates in a cemented gravel. ; A portion of township 41, R. 3 E., is outside the above-mentioned morainic system and wells there are seldom more than 80 feet indepth. A well at Dustin post-office, 77 feet in depth, is reported to have struck rock near the bottom. Another, in sec. 8, 76 feet in depth, penetrates about 2 feet of rock at bottom. At a schoolhouse in this section, however, a well strikes rock at 12 feet. he altitude at each of these wells is about 825 feet 602 THE ILLINOIS GLACIAL LOBE. above tide. At Deerfield post-office an old soil was found beneath the blue till at a depth of 35 or 40 feet. As this stands outside the Wisconsin drift sheet, the soil is to be referred to an earlier interglacial stage than that immediately preceding the Wisconsin stage of glaciation, probably the Sangamon stage. A well on the moraine in sec. 27, about 75 feet higher than Deerfield, enters a black soil at a depth of 125 to 130 feet, or at nearly the same level as that at Deerfield, and perhaps to be referred also to the Sangamon interglacial stage. The following records of deep wells were obtained along the moraine in the southeast part of this township: Wells in T. 41, Rh. 3 E. Feet Mr. Casey, sec. 13, altitude 875 feet --.--- --- <2 -o- oon on nao nn wn 130 John Lloyd, sec. 27, altitude 900 feet -------.:-------------------------------------------------- 130 Sergis Lloyd, sec. 34, altitude 900 feet -.---.---------.------------------------------------------ 190 James Gibson secseonaltitndes50 teecbee setae sme meee ee eae ee tea eae ole ae ee 90 James Renwick, sec. 28, altitude 900 feet, enters rock at 230 feet ..-------.---------------------- 230 In T. 40, R. 3 E., a well in sec. 3, 183 feet in depth, enters rock at 176 feet. The altitude of the well mouth is about 900 feet. A well in sec. 20, 109 feet in depth, is reported to have passed through a black soil near the bottom. The altitude is about 875 feet. A well a mile east from this reached a depth of 123 feet. In T. 40, R. 4 E., records of several wells which reach rock were obtained. One at Mr. Barlow’s, in sec. 31, 153 feet in depth, enters rock at 140 feet. One at Mr. Gurlev’s, in sec. 32, also enters rock at about 140 feet. The altitude at these wells is 860 to 875 feet. A well at William Barr’s, in sec. 31, at similar altitude, failed to reach rock at 183 feet. At Dekalb one of the artesian wells reaches rock at 126 feet, another at 195 feet, and another at 309 feet. South of Dekalb, in sec. 33, a well enters rock at 225 feet. The altitude of these wells in the vicinity of Dekalb is between 865 and 900 feet. Records were obtained of seven wells between Dekalb and Malta having a depth of about 100 feet each, and one well having a depth of 150 feet, none of which enter rock. The city water supply of Dekalb is obtained from a well 890 feet in depth, which terminates in the St. Peter sandstone. Several other deep wells have been made in the city which terminate in that sandstone. A well at the public square was drilled to a depth ef 2,470 feet and terminated in the Potsdam sandstone. Mr. Elwood sunk a well near Dekalb to a depth of 700 feet. None of the wells mentioned overflow. The well at WELLS OF DEKALB COUNTY, ILLINOIS. 603 the city waterworks stands about 65 feet below the surface. It is prob- able that all obtain water from horizons above the St. Peter as well as from that sandstone. The well at the public square penetrated till 145 feet, below which there was 50 feet of sand and gravel. The well in sec. 33, noted aboye, penetrated a till, mainly of bluish color, 145 feet; sand, 20 feet; blue till, 59 feet. Mr. Elwood’s well had about 100 feet of till at surface; the remaining 200 feet was mainly sand and gravel. The city water supply at Sycamore is obtained from several flowing wells, which obtain water at a depth of about 65 feet, from gravel beds below blue till. There are several other flowing wells of similar depth along the Kishwaukee River Valley in the vicinity of Sycamore. Wells are usu- ally obtained in this township at depths of 50 to 85 feet, there bemg appar- ently a sheet of gravel and sand below blue till at this horizon. In the western part of Dekalb County, in T. 39, Rs. 3 and 4 E., several wells have been sunk to the rock, as follows: Wells in western Dekalb County that reach rock. Locality. | Altitude. | Depth. Feet. | Feet. Tin 8@Gs 2,0 SY) 1B Dolce cass sooner Sosae soobos DONbHS 066 ebs Sabhos socoancomssd sess | 875 224. VWiviting TGA BEG Cb 1M 8 Bis 555 ceenee cones cobeds peesesoodecs ascocs coascs cendaccs | 900 170 Talonhinomny JEyRE, Sele TOL 1B} Bi ous esncka code eddoHp HoDSoS SUSE be SeSa0e coauad cobncaOY 900 260 DheodoresBurghy sect Oye Oyo. eraiizia) slate aleleinie lee ele alata el heia eat lalla leaf | 925 228 ANNES ISWERIN, Ep IGE Io} 18) Geos cooass boned coecos cosecedaoEcpaceHco saan eons | 925 2 ohn \h/AHH OM, See Ae} dit B90) os sees cnooos spoeponeencs poeces coosSo osre cosesocooS 890 162 EX Wie LEON enRels BEG HO} it 6) Bie poe ecn pecesbooaEeu osanns 6oosec HocedorSsdese sosdcdne 925 | 175 AndrewaNicholsonssecy20 wha hus secs e ee erence sia eine nee a ees sate | 925) | 199 Hi.iGerler, secs5, T.:39)R. 4 Be. - 2 2 ann a on ane iw ee en 860 140 All these wells, with the exception of Mr. Nicholson’s, terminated after penetrating rock less than 10 feet. But Mr. Nicholson’s had penetrated 25 feet of rock at the depth above given. A boring in sec. 7, T. 39, R. 3 E., at an altitude about 925 feet, reached a depth of 230 feet without entering rock or obtaining water. Another boring on the same farm obtained water in gravel at a depth of 192 feet. A well in sec. 9 obtained water in gravel at a depth of 172 feet In T. 38, R. 3 E., a well im sec. 8 strikes rock at 152 feet, though located on an elevated part of the moraine nearly 950 feet above tide. Several other tubular wells in that vicinity reach rock at depths of less 604 THE ILLINOIS GLACIAL LOBE. than 200 feet, but one well reached a depth of 212 feet without encoun- tering rock. Two wells in the west part of the township, on the farms of Taylor Thompson and William Storey, at altitudes about 950 feet, struck an inflammable gas in gravel at depths of 125 to 150 feet. The drift is mainly till above this gravel. Strong wells are obtained from gravel in that vicinity at 100 to 150 feet. On the plain in the southeast part of the county wells are usually obtained at depths of 30 or 40 feet. The railroad well at Hinckley, how- ever, was sunk to a depth of 190 feet and entered rock at about 100 feet. The altitude is 750 feet at this well. At Sandwich, where the altitude is only 655 feet, the wells for the public water supply are sunk to a depth of 113 feet without entering rock. Several tubular wells are driven in the bottom of a large well. Private wells in Sandwich and vicinity usually obtain an abundant supply at about 30 feet. In the southwest part of the county several flowing wells have been obtained from the drift at depths of less than 30 feet. Ten such wells have been made on sec. 32, T. 37, R. 3 E., whose depths are but 22 to 27 feet. A well in sec. 31 is 24 feet. The altitude at these wells is about 725 feet above tide. This flowing well district extends southward to Earlville in Lasalle County. The absorption area is probably from the moraine on the northwest. A well in sec. 2, T. 37, R. 3 E., 67 feet in depth, passed through an old soil at 55 to 60 feet. The altitude at the well is about 800 feet. OGLE COUNTY. GENERAL STATEMENT. Ogle County is situated west of the northern part of Dekalb County, and south of Winnebago and Stephenson counties. It has an area of 780 square miles, and Oregon is the county seat. Rock River traverses the county nearly centrally in a course west of south, and the county is drained by small tributaries of that stream. The greater part of the county is — covered but thinly with drift, and preglacial ridges and valleys are in many cases readily traced. The outer moraine of the Wisconsin drift touches the southeast corner of the county, and the drift there is 250 feet or more in thickness. The large preglacial valley, thought to be the old course of Rock River, traverses the eastern part of the county in a north to south WELLS OF OGLE COUNTY, ILLINOIS. 605 direction. It is filled nearly to the level of the bluffs, and judging by the distance to rock in portions of the valley to the north and south, there is probably not less than 400 feet of drift filling. Along the present course of Rock River there are continuous biuffs rising to heights varying from 75 up to fully 200 feet. On the uplands, in fully three-fourths of the county, wells commonly enter the rock at 10 to 40 feet, and obtain water at depths ranging from 50 feet up to about 300 feet. Along the lines of preglacial valleys water is usually obtained at a shallow depth'in gravel. There are belts of gravelly drift of esker type in the western part of this county similar to those in Stephenson County on the north, and with a similar east to west trend. Aside from these gravelly strips the drift is usually a compact till. There are, however, as in Stephenson and Winnebago counties, many places where it is made up largely of coarse stony material. In the portion outside the Wisconsin drift there are two drift sheets of widely different age. The later of these, the Iowan, appears to extend but little west of Rock River, thus leaving only the Ilinoian, in the western part of the county, unless a sheet older than Ilinoian is found to be present. INDIVIDUAL WELLS. In the northwest part of the county, in the vicinity of Foreston, a till sheet 30 to 40 feet in thickness is generally present. Some of the wells are obtamed without entering the rock, but the stronger wells are usually drilled into the limestone. The public water supply at Foreston is obtained from a well 300 feet in depth, in which water rises within 20 feet of the surface. The private wells are 35 to 80 feet in depth. At Mount Morris the public supply is from a well 502 feet in depth, whose head is nearly 200 feet below the surface and near the top of the St. Peter sandstone. At Adeline the drift is gravelly, the village being situated on a plexus of knolls and ridges associated with an esker which leads westward along Leaf River. Wells here obtain water at depths of 30 to 75 feet in gravel. At Hazelhurst, on the west border of the county, there is an esker in which a well was sunk to a depth of 135 feet before striking rock, though the well mouth is 50 feet below the highest part of the esker. Between 606 THE ILLINOIS GLACIAL LOBE. Hazelhurst and Polo rock is usually entered at 20 feet or less and the drift is of variable constitution, there being abrupt changes from gravel or sand to till. There is a general capping of loess in that vicinity 6 or 7 feet in depth. The public. water supply at Polo is obtaimed from a well 2,100 feet in depth, which terminates in the Potsdam sandstone. It is situated in a creek valley, and has but 37 feet of drift. The water is of pleasant taste and is obtained in sufficient quantity for the needs of the town. A well at French’s tile yard at Polo penetrates about 80 feet of drift. The upper 13 feet is loess and sandy material, but the remainder is a compact till. East of Polo, on the divide between Elkhorn and Pine creeks, there are several wells which penetrate about 60 feet of drift. They are in a blue till from 20 feet downward to the rock. At Strattord the village well is 45 feet in depth without entering rock. The railway cuttings immediately east of this village expose two sheets of till separated by a fossiliferous silt. The upper sheet as stated above (p. 138) is apparently much younger than the lower and is probably of Iowan age. Within a mile east of Stratford rock ledges occur at an elevation as high as the railway station (820 feet). At Oregon the wells range in depth from 20 to fully 200 feet, but are usually about 30 feet. The public water supply was pumped from Rock River until recently, but the Manual of American Waterworks (1897) reports the present supply to be from wells. A railway cutting between Oregon and Mount Morris exposes a buried soil below till at a depth of about 25 feet. This probably separates the Iowan from the Ilinoian till sheet. At the village of Grand Detour wells on a terrace in the valley of Rock River obtain water in gravel at a depth of 20 feet. At the village of Byron, which is situated on a terrace standing about 50 to 55 feet above Rock River, wells are usually sunk through a gravelly sand to the level of the river. In the vicinity of Stillman Valley the drift is gravelly, and wells are usually obtained at a depth of 25 feet or less. On the uplands bordering the valley in which this village is situated rock is usually struck at a depth of 10 or 15 feet. WELLS OF OGLE COUNTY, ILLINOIS. 607 At Davis Junction a town well 53 feet in depth enters rock at 18 feet, and the rock outcrops in many places toward the south. West and north from Davis Junction wells usually penetrate 50 to 80 feet of drift. A well made by F. H. Baker, 13 miles west of Davis Junction, is 190 feet in depth and strikes rock at about 80 feet. Northeast and east from this village wells reach a depth of over 100 feet without entering rock, this being the position of the old valley of Rock River referred to above. The deepest well noted is at Mi. Kerr’s, in see. 11, which obtains water from gravel at a depth of 120 feet. There appears to be a heavy sheet of till along this preglacial valley, wells 80 to 120 feet in depth being mainly through that deposit. At Monroe, which is situated on the east side of the old Roek River Valley, rock is usually struck at 5 or 10 feet, but Mr. Tyler’s well pene- trated 44 feet of drift before entering rock. The railway cutting immediately west of Monroe also exposes drift to a depth of over 30 feet. Records of several wells were obtained in secs. 27, 28, 29, 30, 31, 32, 33, and 34, T. 42, R. 2 E., which are about 30 feet in depth, and but one well enters rock. Kast from these sections as far as the county line rock is usually entered at a depth of 10 to 20 feet. Two wells in see. 2, T. 41, R. 2 E., enter an old soil below till at a depth of 20 to 22 feet, which is thought to separate the Iowan sheet from an underlying older one. This soil in all probability represents the Sanga- mon interglacial stage. About 2 miles south from these wells, at James Ashbrook’s, a black muck was struck at 67 feet, which yields an inflammable gas. The altitude at each of these wells is about 780 feet above tide and the buried soils are probably all referable to the same stage. In the vicinity of Lindenwood rock is struck at slight depth (12 to 25 feet). The preglacial valley of Rock River appears to lie entirely north and east of this village. A well at William Stocking’s, near this village, in sec. 1, T. 41, R.1 E., reached a depth of 100 feet without entering rock. It is probably over the line of a tributary of the Rock River Valley, for neighboring wells enter rock at 12 to 30 feet. In the vicinity of Kings Station, and thence westward past Paines Point, wells usually enter rock at about 10 feet and obtain water at 30 to 50 feet. At Rochelle the public water supply is obtained from springs issuing from an old rock quarry. Wells are usually obtained at 30 or 40 feet and 608 THE ILLINOIS GLACIAL LOBE. enter limestone at about 10 feet. The old valley of Rock River passes east of this city. At Creston, which is situated on the outer moraine of the Wisconsin drift, a well at the tile factory, 256 feet in depth, enters rock at 250 feet. Several other wells in this village and vicinity are 150 feet, but probably the majority of wells average not more than 50 feet. They are mainly ‘through a soft blue till. LEE COUNTY. GENERAL STATEMENT. Lee County is situated south of Ogle and west of the southern portion of Dekalb. It has an area of 740 square miles, and Dixon is the county seat. Rock River crosses the northwest corner, but drains by direct tribu- taries only a small portion of the county. The central and southwestern portions drain into Green River, the main southern tributary of Rock River. The southeastern portion of the county is drained by Bureau Creek, a tributary of the Illinois. The portion drained by Green River is largely a marsh, but artificial drainage has brought much of it under cultivation. The outer morainic system of the Wisconsin drift occupies the eastern and southern borders of the county, and stands 100 to 150 feet or more above the neighboring portions of the Green River marsh on its outer border. The preglacial Rock River apparently passed through this portion of the county. It is probable that where the elevated portions of the moraine coincide with this old valley there is not less than 600 feet of drift, the rock floor of the old valley being known to be at a level that much below the crest of the moraine. Northwestward from the Green River marsh the drift is generally of slight depth, many wells entering rock at 25 feet or less, while outcrops of the limestone are common on nearly all the streams in that part of the county. Wells are usually obtained at moderate depths in the rock, seldom more than 50 feet. On the moraine in the eastern and southern portion of the county the wells in several instances exceed 200 feet in depth without entering rock, and in portions of the Green River marsh the drift is known to exceed 200 feet. The usual depth of wells on the moraine is, however, not more than 100 feet, there being considerable sand and gravel associated with the till which forms the body of the drift. WELLS,OF LEE COUNTY, ILLINOIS. 609 INDIVIDUAL WELLS. At Dixon the public water supply is obtained from three artesian wells, 1,637, 1,710, and 1,810 feet in depth, which terminate in the Potsdam sandstone. The wells overflow into a reservoir, from which the water is pumped to a standpipe. An analysis of the water, published in the Seven- teenth Annual Report of this Survey,’ shows a very small amount of salt and a moderate degree of hardness. The water is considered of pleasant taste and excellent quality. The wells are cased only about 50 feet. The water in each well has a temperature 55° F. At Nachusa wells are usually obtained at about 30 feet without entering rock. A well one mile northwest of the village reached a depth of 95 feet without striking rock. Within a half mile of this well, however, rock outcrops at a higher elevation than the well mouth. At Franklin Grove, and also at Ashton, wells usually enter rock at 30 or AO feet, and there are numerous outcrops of rock in that vicinity. In several instances coal has been found in the drift in the vicinity of Ashton. As this point is north of the border of the coal field, it suggests a northwestward movement of the ice in this region, though the occurrence of coal here may perhaps be due to the presence of outliers north of the main coal field. As indicated below, coal apparently underlies the southeast corner of this county. The drift is thin over the southern half of T. 39, R. 1 E., and northern half of 'T. 38, R. 1 E., but north and east from this locality wells occasion- ally reach depths of 50 and even 100 feet without entermg rock. The deepest section of such a well, noted in T. 39, is that of Robert Peile, in sec. 23, which reached a depth of 108 feet. The well has the following section: Section of Peile well in T. 39, R. 1 E. Feet: Soll Amal Toyah 65555. cocds euosbe pecs ShOcoD OSBOne cobpos Socedc socmanncccod usopocoSeeSooneese 10 Growl) copssenoseou cdoooubeeonS sudden bee cos abuean bnoece toncda spO6e5 Gubmsolodenda Gaocnu cacHedoaseca 1 JOO Oo eed Cag ROS a CHOBE HRS Do SUB SRES SREIREESas Ota SabloSGShe GoCoSe Sa seeu LOCKE OBES DSSSee eerste 20 GHEE ccosse ccoooo copceao cou souseEneon HeebeS Sen ons ceeSao sonenT COdOSE CO5S00 JESSEN S5 5555 CODES CBO SS5 5 Brownish till, with occasional gravelly beds -...--.-.--..--..-----....-....---.-----.-----..----- 72 The upper 36 feet of this section should perhaps be referred to the Iowan stage of glaciation. Blue till is occasionally entered in that vicinity at only 6 or 7 feet below the surface, or at a much shallower depth than in the drift of the [linoian stage. ' Part II, p. 827. MON XXXVIII——39 610 THE ILLINOIS GLACIAL LOBE. At Amboy shallow wells are obtained at 12 to 20 feet, many of which ~ enter the rock. At the waterworks the supply is obtained from an artesian well 2,000 feet in depth. Water veins which overflow were struck at 390, 1,100, and 1,700 feet. The lower veins do not increase the head, but evi- dently increase the quantity, for the upper flows could be readily lowered by pumping, while the lower ones can not. The discussion of wells on the moraine which follows begins in the northeast part of the county, from which point the moraine is followed southwestward. Table of deep wells in eastern and southern Lee County, Illinois. Location. Fareteny Depth | Remarks | Feet. Feet Seon3n 139) RaQ iB ieeso- ne eee | 925 168 | In gravel below till. Sexo Y HU Bi) 18 10) a ans cae | 925 | 200 | Old soil at 100 feet; no rock struck. SOCHO2 ele oO wikwer ae Magee feeateael= | 875 45 | Gravel below till. Secu bi ooukiaon bee eee | 950 200 | Gravel below till. Sec. 12, 1.38, R.2 EH .----- ----- 950 | 50 Gravel below till. Secwl 6s o@.phisau beast 875 40 | Entirely in gravel. SecalauMssukeonbi assays 875 60 | Mainly sandy drift. Sec. 36, T. 38, R.2 E ..---.----- 950 217 ‘In gravel below till; no rock. SG SBh AG Step i 1) ese eames 820 114 | No rock; old soil at 80 feet. Seb IR Ut eyh lite 24 0) S5e5—sSesos | 800 115 | Driller reports coal at bottom. 3 miles S. of Pawpaw ---.----- 800 100 | Driller reports buried soil at 80 feet, sandstone at | | 90 feet, and coal at about 100 feet. Sec.36, Dij37, Reo2) my .---=5- 800 | 155 | Old soil at 78 to 81 feet; drift mainly till; no rock | struck. Secrcosilita (iveo Mies =e 5 | 100 | Mainly sand and gravel; no rock. Sec l9sM 37, Re2h 2-5-5) 950 | 287 | Old well, 45 feet; sand, 5 feet; blue till, 190 feet; | | greenish clay, 19 feet; rock (?), 6 feet; blue till, | 15 feet; cemented gravel, 14 feet; loose gravel at | bottom. Stes BEA IS Ola 182118) bose sose 925 | 200 | Not known whether rock was struck. Secas0MiassiRelebneass=n cess 800 | 84 | Soil and wood near bottom. SEO RISRU ME Steele lO) Sse coke 800 90 | Wood and leaves at bottom. Seca elon rvep lp hype eee 935 218 | Little, if any, rock penetrated. SPAMS TIE) IND coded Scene 660 | 200 | No rock struck. SEOs Bia}, IM TS), Uke 8} oS ob ocebc | 800 | 200 | Terminates in sand. Wood, with inflammable gas, at 140 feet. Sec vINSONRAStE Reseee et aeee | 700} 105 | No rock; beds of sand and gravel in blue till. Sec. 28; 1.20, R.3 BH .-- <=. ----- 690 | 166 | No rock struck; sand, 25 feet; remainder blue till. WELLS OF CARROLL COUNTY, ILLINOIS. 611 The last edition of the Manual of American Waterworks (1897) reports that the village of Pawpaw, in the southeast part of the county, obtains its public supply from an artesian well 1,018 feet in depth. CARROLL COUNTY. GENERAL STATEMENT. Carroll County borders the Mississippi River in the second tier of counties from the north and has an area of 440 square miles, with Mount Carroll as the county seat. The northwestern portion is drained by Plum River and Carroll Creek, its main tributary, directly to the Mississippi Valley at Savanna. The southeastern portion is drained southward through Rock and Elkhorn creeks into Rock River. The surface is rolling and drainage good throughout the upland portion of the county. With the exception of the northwest corner, which is unglaciated, this county is covered with a sheet of drift of moderate depth. Records of 14 wells on the uplands, distributed widely over the county, show an average of 54 feet to the rock, the greatest depth being about 100 feet. In the Mississippi Valley below Savanna there is probably 150 feet or more of drift, as indicated by borings at Sabula, Iowa, and Fulton, Illinois, which reach a level nearly 150 feet below the Mississippi before entering rock. The valley drift is largely sand or fine gravel. The drift on the uplands is in places a gravelly or stony material, but usually has a large clay admix- ture, such as characterizes the typical till. In every township of the uplands numerous wells enter the rock, but a still larger number obtain water from gravel or sand asscciated with till at various depths from 20 feet or less up to about 100 feet. INDIVIDUAL WELLS. At Savanna the public water supply is from an artesian well 1,430 feet in depth, which terminates in the Potsdam sandstone. It discharges at the rate of 500 gallons per minute and has a pressure of 35 pounds per square inch at the level of the well mouth, about 600 feet above tide. The head is, therefore, about 675 feet. At Mount Carroll the public water supply is from a well 2,502 tees in depth, which has a head sufficient to rise nearly to the well mouth, about 700 feet above tide. Water was struck in the limestone at 65 te 100 612 THE ILLINOIS GLACIAL LOBE. feet, but a much stronger supply was struck at about 1,200 feet. The drift is largely gravel and has a depth of 61 feet The well is situated in a valley about 100 feet below the bordering uplands, and rock appears in the uplands near by at a level fully 50 feet above the well mouth. A well at the railway station in Mount Carroll reaches rock at a depth of 60 feet. The altitude there is 816 feet above tide. This well penetrated a complex series of beds of gravel, sand, and till. A boring at William Petty’s, 4 miles southwest of Mount Carroll, is reported to have penetrated about 300 feet of drift. On the farm of R. Hostetter, 3 miles southeast of Mount Carroll, a well strikes rock at the depth of 72 feet; the drift is mainly a blue clay. Hon. James Shaw reports a well section near Mount Carroll, which struck a black mucky clay, apparently a soil, at a depth of about 50 feet; another well at the farm of F. O’Neal, 3 miles from Mount Carroll, passed through a soil and wood at 15 to 20 feet. The latter is perhaps at the junction of the loess with the underlying glacial drift, but the former penetrated a sheet of glacial drift above the soil, and its section is as follows: Section of a well near Mount Carroll, Illinois. Feet. Sonik solos canal Win Ob ys S85 eso essa cose nose ones Soon Send code cose paso oss soosSscoueScod caso cose 15 Reddishaclayean dy craiyel aes ape ee ae a ee eee ee eee eat ee eee 15 dttomvelh (HIG) GEN? oss ossbHtoo ecos cess cbcd odes esco seas Sone cbs soos Seo coos cosh oneD Uses Coce esse conc 2 (COPHIO MING soo céa bobo bond Sse Shag cose beadinaapiedss SodisHe céds Hons soos Edd desde oooceoOSEssSScocses 3 Wow? GEinG i no6 So oneses sed Sabd cece aces Bodo sas5 Hond ca Ssos cdise osc coos bs coe saseescosestecesss5, Ill BlackamuckyiCl aye. east cle cc ence See eee ne eee ae ree epee ep er eee ola ta sean oe A deep artesian well has been sunk in a creek valley about 4 miles south of Mount Carroll, which overflows with considerable force. No further data have been obtained. At Lanark the public water supply is from a well obtained near the top of the limestone at about 100 feet. The following drift beds were penetrated: Clay, 12 or 15 feet; gravel and sand, 12 or 15 feet; blue clay, with few pebbles, 75 feet. A well at L. Sprecher’s, 1 mile west of Lanark, enters rock at about 100 feet and there obtains water. In the township east of Lanark wells are reported to differ greatly within short distances in the amount of drift penetrated, some entering rock at about 20 feet while others penetrate 100 feet or more of drift. ‘ Geology of Illinois, Vol. V, p. 80. WELLS OF CARROLL COUNTY, ILLINOIS. 613 At Shannon wells near the railway station enter rock at 15 or 20 feet, but on a rock ridge in the south part of the village, at an elevation proba- bly 30 feet higher than the railway station, or 950 feet above tide, rock is entered at 8 or 10 feet. The public water supply is reported by Manual of American Waterworks (1897) to be from a drilled well. In the south part of the county, in the vicinity of Ideal, several wells enter rock at 30 or 40 fect. The loess in that locality is about 15 feet in thickness. At Argo, in Johnson Creek Valley, 125 feet of sand and gravel were penetrated before striking rock. At Fair Haven (altitude about 875 feet) the creamery well has the following section, furnished by the driller, Mr. J. Schlemming, of Chadwick: Section of well at Fair Haven, Carroll County, Tllinois. Feet IDWabis comes ouidedo poe Su OR SUES COdeES OSSHES Ge Unda Ben eda HEtode Sa SeOs EaEeEs corona EUS E eS Scockb Rese 40 Niagarajlimestonerandichertesscretn ese soae eee e cect eee eee eee e eee eee eee 60 NIEHS? CINE 6 dabiods papane SS CRE. chbS Rape Been Osc ecCR Beate ssod Sab SEy SESchic = ube baseunaeed BeceeEtee 210 (Cy? INGO .o55cc6 osaSes bdo sac G6s BookaEs BES Seo BaKd dacbos Boonod aSan dees conDeodS Aeenonoabaease 15 MEN COBO ES ED ae CECE ROE EA SE REE Ea EEE SIS EE Oe iat ein roeia ey ity techs, ot AS ged ASAE 325 Mr. Schlemming states that the wells in the south part of Fair Haven Township often obtain water in the cherty beds above the shale; otherwise they must be sunk to limestone beds beneath the shale. At Chadwick the public water supply is from a well 215 feet in depth, which enters rock at 59 feet. The rock is entirely a gray limestone and appears to be the same formation which was entered near the bottom of the Fair Haven well. The drift is mainly clay, there being but little sand or gravel. The head is about 40 feet below the level of Chadwick railway station, or 735 feet above tide. The well has a diameter of 52 inches and is estimated to furnish 400 barrels per hour. In the vicinity of Milledgeville the best wells are about 180 feet in depth and are probably from Galena limestone. The town well has a depth of only 80 feet and enters Galena limestone at 12 feet. Many wells obtain weak veins of water at about 30 feet near the top of the limestone. 614 THE ILLINOIS GLACIAL LOBE. WHITESIDE COUNTY. GENERAL STATEMENT. Whiteside County borders the Mississippi River in the third tier of counties from the north line of the State and has an area of 700 square miles, with Morrison as its county seat. Rock River leads through the county from the eastern border to the southwest corner and receives the drainage of the greater part of the county, only a narrow belt on the north- west being directly tributary to the Mississippi. The southern half of the county is a lowland tract standing but little above the level of Rock River, its general elevation being about 650 feet above tide. The northern and western portions have an altitude corresponding with that of the uplands in Carroll and Ogle counties, the altitude of a considerable part being above 800 feet and in places reaching nearly 900 feet. Two narrow low- land tracts, resembling river valleys, connect the Mississippi River with the lowland bordering Rock River, one of which, on the southwest border of the county, is known as Meredosia Slough, and one, leading from near Fulton to Fenton, as Cattail Slough (see Pl. XVII). These sloughs stand so little above the level of the Mississippi and Rock rivers that they are occupied in flood stages of either stream, and the direction of flow depends upon the stream which chances to have the higher stage. On the uplands the drift is of variable thickness, but is generally thinner in the northern and northeastern portions than in the western por- tion of the county. The general thickness, however, seldom falls below 50 feet even on ridges. In the western portion, from near Fulton south- ward past Garden Plain to Erie, there appears to be an average thickness of fully 150 feet. Were this drift removed, the elevation would differ but little from that of the lowland tracts bordering Rock River, for rock is often found at slight depth beneath these lowlands except in the southeast portion of the county. In the uplands of the northern portion of the county some wells are sunk to considerable depth in the rock. In the west- ern portion they usually obtain water in the drift or at slight depth in the rock. On the lowlands north of Rock River the wells are generally shal- low and often enter the rock a few feet. In the southeastern part of the county much of the land has not been brought under cultivation, the sur- WELLS OF WHITESIDE COUNTY, ILLINOIS. 615 face being either sandy or marshy, and comparatively few deep wells have been sunk. Deep wells in the neighboring portions of Lee and Bureau counties penetrate over 200 feet of drift, and it is probable that a similar depth extends over three or four townships in the southeast part of this county. INDIVIDUAL WELLS. At Fulton, in the Mississippi Valley, in the northwest corner of the county, the city water supply is from an artesian well 1,246 feet in depth, which terminates in the Potsdam sandstone. a See ene 15 MGW Ain eso Sebo aascaae sagaae Base Cone hae er teem anne Mee es nie Cae Le May Gon ane 10 or 15 Binge llwatherhinybedstofysan dites sary} Secs celes Part II, p. 828. 638 THE ILLINOIS GLACIAL LOBE. At the village of Utica many artesian wells have been obtained in the Lower Magnesian limestone. The strongest wells are obtained at depths of 215 to 330 feet, but many are of much less depth. The water rises toa height of about 50 feet above the surface, or 525 feet above tide. The strongest wells have an estimated capacity of about 150 gallons a. minute, or 200,000 gallons a day. - The city of Ottawa formerly obtained much of its public water supply from shallow wells piped to a reservoir on the south bluff of the river and distributed by gravity to the city. It is now supplied from six artesian wells and Fox River. Geol. of Illinois, Vol. VII, p. 50. 640 THE ILLINOiS GLACIAL LOBE. Wells along the Marseilles moraine in eastern Lasalle County—Continued. Owner or location. Cpeteeey | Depth. Remarks. | Feet. Feet. Selthay Is 6th Io bd oto 5 Seep oess 675 160 | Till, 100 feet; sand, 10 or 15 feet; clay, 10 or 15 feet; Coal Measures shale, etc., 35 feet; St. Peter sand- stone near bottom. Steen iS a 6b) 10) See eposooee 700 196 | St. Peter sandstone near bottom; hard brown till | below blue till at 166 feet. SOCHOmUrot hy OMB eee mee eetem =i 650 100 | Mainly sand and gravel; no rock. Sos) Shee Mb) soee Saco use] 675 210 | No rock struck. Sec. 16, 1.34, R.5 EB ...-.-.--.. 700 200 | St. Peter(?) sandstone entered near bottom below drift. Secs Silos kyon Meee eels 700 200 | In gravel at bottom. Secsaiaplerod shoe bieee eee eee 650 160 | St. Peter (?) sandstone at bottom. Sec22s Sh mop Ey sere eei ees = 700 185 | No rock struck. Sec. 24 T.34,R. 5B)... 2-2. - 2. 650 100 | Coal Measures sandstone at bottom. Sie 243} NS ah 1h) 1D) Sc oeae cone 700 180 | Mainly till; hard rock at bottom. Secs sass ewes sele ss 650 195 | Till, 93 feet; gravel, 7 feet; ‘‘potter’s clay,” 40 feet; sandstone, 55 feet; St. Peter sandstone near bottom. Sec. 14,.0..34, R.4 Boo. ooo. 650 100 | In sand below till. Danway and vicinity. -.-.---- 690 100 | Several wells 100 feet deep do not enter rock; mainly through till. Secalo los pear ei rae /setlaeers 675 107 | Three wells, 100 to 107 feet; mainly through till; no rock. Sec. 23, 7.34, R.4 BH -..-...-..- 650 118 | Yellow till, 15 feet; blue till, 75 feet; black clay or soil, 8 feet; sand, 20 feet; no rock. Secvo4. Dod chia c ne sesecl- 620 68 | Soft till, 28 feet; hard, dry till, 40 feet; rock at bottom. Sec. 35, T.34,R.4 BE .--.-. ease 650 85 | No rock; mainly blue till. Secs. 3 and 4, T.33,R.5 EB ..... 650) |2eeeeeee Molluscan shells in sand at 6 to 10 feet; wells, 10 to 33 feet. A. Irwin, bluff north of Seneca 610 108 | No rock; mainly till. Secwo0 misoo wh na bieeee sees. 630 215 | Drift, 40 feet; St. Peter sandstone at 215 feet. Seci26.0e33) Rady bn aces ieeeae 740 219 | Till, 170 feet; sand and till to bottom. Sec. 26, 1.33, R.4 EB .--.. 2.2... 720 252 | Till, 198 feet; gray, sandy clay, 38 feet; sandstone, 14 feet; shale, 2 feet. Blutf south of Marseilles. ----- 675 184 | Till, 165 feet; sand and gravel to bottom. Sec. 36, T. 33, R.4 E-.... odedo5 700 177 | Till, 170 feet; sand at bottom. Sec. 21, T..33, R.5 B----.-..--. 675 80 | Yellow clay, 10 feet; gravel, 70 feet. Secu yooh eas i pseeeesteer cee 740 232 | Till, 150 feet; remainder sand and till. Seca2vinod tie pee mmole er 725 220 | Till, 150 feet; remainder sand and till. Secs2; 032) Roa Boece ae cce == 725 194 | Till, 116 feet; sand and till to bottom. Sec. 35, I. 32, R. 4 B .--.--..--.. 700 108 | Entirely through till. Sec, 29, 1..32,\R.5, Ei ----- 2.2 700 180 | Entirely through till. Sec. 30, T. 32, R.5 E ..---..-..- 700 128 | Tili, 125 feet; sand at bottom. WELLS OF LASALLE COUNTY, ILLINOIS. 641 Wells along the Marseilles moraine in eastern Lasalle County—Continued. “Owner or location. epee tae, Depth. Remarks. Feet. | Feet. | Secu eherolsheo rte =e eee 720 181 | Rock? at bottom. ec 4 oleh Ossie eteeee 690 | 103 | Mainly till; rock at bottom. Mr. Cate, near Ransom....---- 720 543°) Drift, mainly till, 285 feet; Coal Measures and | limestone (Trenton?) extending to St. Peter sandstone at 510 feet. S. Cleals, near Ransom--.---.-- 720 370 | Drift, mainly till, 270 feet; Coal Measures, 100 feet; limestone (Trenton?) near bottom. SecsdeDvols Rio Mises scenes 720 144 | Mainly till; sand at bottom. SeCroomlroleekuf on erase tree a= 700 130 | Enters rock near bottom. Ries G1 PBI, 13,6591) Goo seue aden 675 160 | Enters rock at 120 feet. PCS Ap Rosi its 6) 19s Bees eeeeoo 700 175 | Gas well from drift sand; water stands 6 feet below surface. Sec. 36, T. 31, R.4 E.; alsosecs. 700 160 | Several wells about 160 feet; none enter rock. 25 and 26. The following table includes the deepest well sections obtained in other parts of the county aside from the artesian wells discussed above:' Wells of Lasalle County outside the Marseilles moraine. = 4 : Altitude Owner or location. labovetidey| Depth. | Remarks. acre =| ass Es ; | Feet | Feet. Sec. 11, T. 36, R.5 E-..--..-..- 650 | 80 | Five wells enter first rock at about 20 feet and | St. Peter sandstone at 35 or 40 feet. Secale ee SG wv OMe eres eae at 650 20 | Black muck with wood and leaves below till at bottom. SOOO) WBS; 1853 10) eaeedoccases 700 180 | Boring for coal struck old soil at 35 to 40 feet and entered rock at 50 feet. Ses SPM ei} Ike) 10) sogese aeeeee 680 20 | Two flowing wells in Indian Creek Valley. T.36, Rs.2and3 H..-....-.--. 690) ese eae Thirty flowing wells 18 to 85 feet in depth from i sand below till. D. Knight, sec. 34, T. 36, R. 4 E- 675 | 80 | Enters rock at 63 feet; well half mile west enters | rock at 63 feet. | NW. part of T.36, R.1 E-----. 850 | 200 | Several wells 150 to 200 feet, with no rock. 14 miles north of Mendota-.-- 800 | 198 | Gas at 75 and 128 feet; old soil at 178 feet; water _ rises 90 feet from gravel at bottom. Mr. Miller, near Mendota. -- --- | 725 | 144 | Flowing well from gravel below till; a buried soil from 120 to 125 feet. 'For sections of several wells in the vicinity of Mendota the writer is indebted to Mr. L. R. Curtis of that city. MON XXxXVIII——41 THE ILLINOIS GLACIAL LOBE. Wells of Lasalle County outside the Marseilles moraine—Continued. Altitude. Owner or location. (above tide). Depth. | Remarks. | Feet. Feet. Porterfield’s gas wells near |700 to 725 176 | Five wells 120 to 176 feet; deepest reaches rock; Mendota. | black muck or soil with leached subsoil between till sheets at about 600 feet above tide; gas in sand above old soil. Blanchard’s gas well, near 750 218 | Yellow till, 10 feet; blue till, 56 feet; sand with Mendota. | gas, 96 feet; Trenton limestone, 56 feet. Sec.26;"b..go; kul kipate =~ alanine 610 46 | Trenton limestone at 46 feet. Mr. Finfsen, 6 miles S. from | 700 143 | Well enters Coal Measures shale below drift at 143 Mendota. | feet. Secio2n Dokl) By eee an ee ee | 650 40 | Gas from gravel below till. ! Sec. 26, T.35, R.2 BE. .--...---- 700 121 | Three wells of similar depth and structure: yellow till, 16 feet; blue till, 85 feet; gravel, 20 feet. Seca23 ee sbiihte ash eene se oeel 660 63 | Rock at bottom. Secns2eidow Re athe meee 675 54 | No rock; mainly till. Secrco wl wh ap ee eee 700 98 | Rock at bottom; mainly till. Two wells. Sec os lesa. Rae Maer server 675 76 | No rock; mainly blue till. ECHO woth hips e eee eee 700 80 | No rock; mainly blue till. Seco D ody Quien ese pesca 700 91 | Entirely till. J. Bowen, near Serena .--.---- 600 104 | Till, 40 feet; sand and gravel, 64 feet. H. Bowen, near Serena---.---- 600 75 | Enters sandstone at bottom. Serena and vicinity ---..----- 635 100 | Mainly blue till, 50 or 60 feet; sand and gravel, 15 or 20 feet; St. Peter sandstone at 75 or 100 feet. Sheridan Junction -.......---- | 641 40 | Mainly till; no rock. Sietidan-.cee-c sane wee: | 591 16 | St. Peter sandstone at 12 to 16 feet. Seckoqlyoouhn 2 picasa secre | 620 100 | No rock; mainly till. SECS CREAN BBE ip? ID songesossss 620 100 | No rock; mainly till. Seco whoo wou arce see 600 88 | Very hard red till near bottom under soft blue till. (Seyi TH SBR 1) 0) Boe Fe Ga 650 47 | No rock; mainly till. Sets AR, IS BBY IGP) 1D) Se cocea nose 625 50 | Rock at 50 feet. Mr. Kistler, 8. Ottawa-.--.----.- | 585 30 | Gravel, 30 feet; till at bottom. Ottawa waterworks ..---..--- 600 27 | Mainly gravel and sand; no rock. Grand Ridge Station ....-----. 663 153 | Till, 120 feet; sand and gravel to bottom. Secs2h, o2, Heo eee nnn ome 650 200 | Till, 140 feet; sand and gravel, 60 feet. HOP Ih) Soe Seo Sasa esooce 680 50 | Mainly sand; no rock. R. Williams, 9 miles north of | 650 140 | No rock; blue clay with some sand. Streator. | One mile from preceding ------ 650 187 | Water rises 87 feet. One mile from preceding. ----- 650 315 | St. Peter sandstone at bottom; water brackish. SO, Hy NS Pe Tio 1D} S ose oases | 675 150 | Till about 50 feet; sand about 100 feet; rock at | bottom. NOCrL Sele ol hve Pipeee staat ae 610 65 | Mainly sand and gravel; shale at bottom. Sec. 34, T. 31, R.4 BE .-....-.--- 660 100 | No rock; entirely till. WELLS OF KENDALL COUNTY, ILLINOIS. 643 KENDALL COUNTY. GENERAL STATEMENT. Kendall is a small county, with an area of but 330 square miles, sit- uated east of the northern part of Lasalle and the southern part of Dekalb County, with Yorkville as the county seat. Fox River crosses its north- western portion in a southwestward course, and nearly half the county is tributary to it. The remainder of the county drains southeastward directly to the Hlinois River through Aux Sable Creek and smaller streams. The Marseilles moraine traverses this county centrally from northeast to southwest, following the southeast border of Fox River Valley, or rather Fox River Valley follows the outer border of this moraine, the course of the stream being determined by the moraine. The remainder of the county has a plane surface, except the east border, which is occupied by the Minooka till ridge. he drift is of moderate thickness, averaging probably 100 feet. A small area in the southern part is very thinly coated and there are numerous rock outcrops along the Fox River Valley. The heaviest drift, apparently, is along the line of the Marseilles moraine, where, as shown in the table below, the thickness usually exceeds 150 feet. An extensive gravelly area occupies townships bordering Fox River. The gravel extends usually as deep as wells have penetrated, and may con- tinue to the underlying rock. ‘The remainder of the county outside the moraine apparently has much sand and gravel in the lower part of the drift. The Marseilles moraine and the plain to the southeast are characterized by a heavy sheet of till, though there are limited areas in which wells pene- trate a large amount of sand or gravel. The Minooka Ridge, also, is com- posed largely of till. Wells are ordinarily obtained in this county at depths of 25 to 35 feet. The deeper ones are largely found along the Marseilles and Minooka ridges. INDIVIDUAL WELLS. At Plano, in the northwest part of the county, several wells reach a depth of 45 feet without entering rock, and are mainly through sand and gravel. The public water supply is from a well.’ North of this village for 2 or 3 miles wells usually penetrate about 20 feet of till and then enter sand and gravel, in which they terminate at depths of 40 or 50 feet. One !Manual of American Waterworks, 1857. 644 THE ILLINOIS GLACIAL LOBE. well, however, in sec. 11, was sunk to a depth of 196 feet and entered rock at about 150 feet. Mr. Otis Latham made a well in Plano which struck an old soil containing grass leaves beneath till at a depth of about 25 feet. Southwest of Plano, in secs. 29 and 31, two wells 44 and 69 feet in depth are mainly through sand, and do not enter rock. At Oswego there is a very thin coating of gravelly drift on the rock, and wells are usually sunk into the limestone about to the level of Fox River, 30 or 40 feet. The public water supply is from drilled wells... For about 5 miles below Oswego there is a gravel plain on the east side of Fox River a mile or more in width, on which wells are obtained at depths of 10 to 30 feet without entering rock. At Yorkville the public water supply is obtained from springs in the Marseilles moraine which borders the town on the southeast. The private wells are obtained at depths of 15 to 30 feet and seldom enter the rock. At Millington flowing wells may be obtained from the St. Peter sand- stone at slight depth. Two at the residence of Dr. J. A. Freeman, 78 feet in depth, enter this sandstone 27 feet. The drift, with the exception of about 20 feet of gravel at surface, is mainly till. The wells are ordinarily obtained in this village at depths of 12 to 20 feet in the gravel of the Fox River Valley. In the vicinity of the village of Plattville on the plain east of the Marseilles moraine many flowing wells have been obtained. The majority have a depth of but 30 to 45 feet, but occasionally a depth of 70 feet or more is reached. The water is obtained in sand below till and the absorb- ing area is, in all probability, in the Marseilles moraine on the west. A deep well 2 miles north of Plattville at an altitude about 50 feet above the village, or 650 feet above tide, reached a depth of 550 feet and entered St. Peter sandstone at 511 feet. A large amount of water is obtained, but it does not overflow. Rock was entered at 143 feet and is mainly limestone down to the St. Peter sandstone. A well 1$ miles east of Plattville at about the same elevation (600 feet) entered rock at 40 feet and was drilled to a depth of 80 feet. In the vicinity of Lisbon, where the altitude is 625 to 640 feet, limestone is entered at a depth of 10 feet or less, and wells are obtained at depths of only 30 to 50 feet. For 4 or 5 miles northeast of Lisbon rock is usually 1 Manual of American Waterworks, 1897. WELLS OF KENDALL COUNTY, ILLINOIS. 645 entered at less than 50 feet, but occasionally a well reaches a depth of 90 feet without entering it. Three wells in secs. 11 and 12, 'T. 35, R. 7 E., are 48, 50, and 90 feet in depth without reaching rock, and the water has a head nearly level with the surface. The altitude is about 40 feet lower than at Lisbon, or 600 feet above tide. The following list of wells along the Marseilles moraine include the deepest of which records were obtained. Many shallower wells occur which obtain water at depths of 30 to 40 feet or less. The sections are taken in order, beginning at the northeast corner of the county and passing southwestward: Wells on the Marseilles moraine in Kendall County. | Altitude Owner or location. lransace tide).| Depth. | Remarks. | Feet. Hae heer. Sec. 24, 1.37, R.8 EH ........--. 700 | 200 | Enters rock at about 200 feet. Seci24, 1. 37)R.8 2255-226 750 | 152 | Yellow till, 18 feet; blue till, 108 feet; sand witb | | clay streaks, 24 feet; gravel at bottom. Mr. Miner, 4 miles southeast of 700 | 121 | No rock; till 100, sand, 21 feet. Oswego. Secs. 31 and 32, T. 37, R.8 E ... 700 | 100 | Several wells; mainly till; no rock. Secgbs ia sG iho) lnseer eaters <1 725 150 | Enters rock at about 100 feet. Secs. 22 and 28, T. 36, R.6 E .-.- 675 | 120 Several wells; mainly blue till; no rock. G. Whitfield, near Millbrook -. 650 | 60 | Sand below till. Mr. Darnell, 2 miles south of 700 | 190 | Mainly blue till, 160 feet; old soil with wood, 2 to Millbrook. |) 2 feet; blue sand to bottom. Newark village well ......-.-. 640 110 | No rock; mainly till. C. Sleezer, east of Newark --.-. 700. 141 | Mainly till; rock at bottom. F. Sleezer, east of Newark .... 700 | 140 | Entirely till. S. Sleezer, east of Newark..-.. 725 160 | No water or rock struck. I, Anderson, east of Newark -- 725 160 Soft till, 100 feet; hard till with wood near bottom, 60 feet; St. Peter sandstone at bottom. PSEC 2) Wt 8s), 1850.18) cosa seeeesod | 725 150 | Entirely in till. Ses 4h, WS Gh 1B 18) coos odancsos | 725 161 | Limestone at bottom. Holderman’s Grove ...-------. 700 50 | Mainly till; no rock. Bios Grovererhectiamsceek ccs coSaed DoDSEt Sond sana doaerS heemoNdoseosTeSade 61 Sil 2. S5ee See ses odsccobasoos banbed Saduodocsos sbdqouebdsss pbESCE Haas odsues bosooetecdes ceandode 4 BG) WU hee ss ces adseoend oneoce cadens Seo obo SSO tbe cones cobs Sd oeeo OdsObHUCsS Sdacse SeSeoDesdosS 76 ART Uheh these seEsoCcOnCoraE corp eocees seoodo doe obs coUaus dou Loe soUSSC SoU SEE Econ SM boos 161 In Vol. IV of the Geology of Illinois a coal shaft at Bloomington, one-half mile north of the Chicago and Alton Railway station, is reported to have penetrated 252 feet of drift, as follows: Section in coal shaft one-half mile north of preceding. Feet. WOW AN ERY Sonda5 Seb sse5 Bosose so dous copeSecososéusuaos Senses coosso coos nSdass Soceds bauSsabeSese 10 IDO OE; Gocuss BeSocdcocece Rese cond acebae SnBBod Bao EGS ne Sade od eoeo cacebd odbues SebsuecEsa teedonce 40° (Greil eh eM S635 S560 so Sooo sa seeeee So sase Soodes CgocoboSSac oncuse Coob SaSeos cease esse eoccs. 60 Blaclkamoldawithyplecesiofawo0 dissec. eee te eae eater eae ae eat eee 13 Hardpan and clay... ------- Sado Hodd Saeed Hoe EeSmenD EGoces code SeSmEs BdoHoe bodS oSabsN cose coeES 89 IIE TONG) cS abd ss etde Sao socsesbea SoSeeS aS osSe sSsoStstose s25nec penSssbecsSs pandorsods coptsese 6 WINS Oba? cocc oseise Se Sese. debs6s StoSes socdoS cabhod oSboSs ossasscSsads ssbteSasossciSosousssSosoeses 34 Sands butivan«tlidrabeawithefossiliishellseso. ss ssseseee cee se eee eee ee eee eee eee ote See ee eee 2 Morel babii 6 eM oon oo moO BSS aeIGeOS OER Goon Enoeoodb cada Sose bode anop nooo sHeS.cocoSdee 252 A well in the east part of Bloomington 140 feet in depth is reported by the driller to have penetrated a “blue rock” the lower 40 feet. It is WELLS OF McLEAN COUNTY, ILLINOIS. 695 possible, however, that the “blue rock” is only a hard till. A well at the Soldiers’ Orphans’ Home near Bloomington obtains water in gravel below till at 130 feet. At Leroy, on a plain south of the Bloomington morainic system, strong wells are obtained in sand at a depth of 20 or 30 feet. In the vicinity of the village wells pass through a black muck at 35 to 40 feet. The public water supply is from a well 110 feet in depth and 8 inches in diame- ter, which will yield at least 100 gallons a minute. Many wells on farms in the vicinity of Leroy are sunk to depths of 75 or 100 feet, and occa- sionally 200 feet, without entering rock, and the water rises to within 50 feet of the surface, and occasionally within 10 feet. A prospect boring for coal at Leroy, made some years ago, was abandoned at a depth of 200 feet without entering rock. At Saybrook, in the eastern part of the county, on the outer slope of the Bloomington morainic system, a prospect boring for coal reached rock at 247 feet. It was mainly through till for 388 feet, then mainly sand for 57 feet, beneath which was 100 feet of till, which was in turn underlain by 52 feet of sandy and gravelly drift. The village of Danvers, in the western part of the county, has recently put in a waterworks system which obtains its supply from a well about 200 feet in depth which does not enter rock. The creamery well at Danvers is also about 200 feet in depth without entering -rock. It is mainly through till, and struck an inflammable gas at about 170 feet. The village stands on the outer ridge of the Bloomington morainic system at an altitude slightly above S00 feet. In the vicinity of Shirley and Funk’s Grove the wells are reported by Mr. Lafayette Funk to have a general depth of only 30 or 40 feet, and rarely to exceed 80 feet. Water is obtained in gravel below till. The village well at Shirley has a depth of 40 feet, but a neighboring well at Mr. Douglas’s residence reached a depth of 75 feet. At Heyworth the general depth of wells is.30 to 40 feet, abundance of water being found in the gravel below the upper sheet of till. This village has sunk borings for gas which reach a depth of 155 to 300 feet. Gas is found in sand at 155 to 165 feet in a well about one-half mile south of the village, and at 214 feet ina well three-fourths of a mile south of the village. A well in the village 300 feet in depth obtained very little gas, though it is thought 696 THE ILLINOIS GLACIAL LOBE. to have reached the rock. The village is supplied with gas from a well southeast of it. This is reported by the owner, J. C. Wakefield, to have a pressure of 22 pounds to the square inch from a 2-inch pipe, and during the winter of 1896-97 it supplied fuel for 200 stoves. The gas may be derived in part from underlying Coal Measures shale, but muck beds inclosed in the drift afford a probable source. A section of the drift beds penetrated appears on page 215. The wells in the following table are the deepest of which records were obtained, and include but a small part of those which have been sunk in the county. There is probably not a township in the county which does not include several wells over 100 feet in depth. Wells of McLean County. Altitude Owner or location. |(above tide). Depth. | Remarks. Feet. Feet. Mr. Helderley, near Carlock -- 715 210° Three beds of black clay, probably soil, the lowest | at about 200 feet, separated by till, sand, and | gravel; upper 90 feet of well entirely till. Jacob Shad, 3 miles east of | 800 | 250 | Black clay, probably soil, at about 150 feet. Carlock. Sec. ol) 124 R25) Bi -22- ==. ==. 850 146 Inflammable gas from drift at bottom. Sec. 4, 17.24, R.4 BE ...--..----- | 175 | 140 | Yellow till, 15 feet; soft blue till, 11 feet; hard | blue till, 12 feet; sand and gravel, 6 feet; hard | blue till, 40 feet; soft blue till, 56 feet. Secs inode dab) eerste ae 7715 95 | Yellow till, 15 feet; soft blue till, 65 feet: hard sandy blue till, 15 feet. SPR ME TR) neeoooaace| 850 198 | Mainly till, 136 feet; sand and gravel with gas, 62 | | feet; shale at bottom. Sec. 36, T. 24,R.4E.....-..--- | 850 180 | Mainly sand; probably rock at bottom. Sec. 6, T.24,R.4 EB ..-.---.--.. 800 230 | Yellow till, 18 feet; blne till, 60 feet; white sand, 80 feet; blue sand, 50 feet; gravel, 7 feet; blue clay to bottom, 15 feet. Neca 9 abn d Ree reer iats ernie 125 | 256 | Loess and yellow till, 12 feet; blue clay with few pebbles, 244 feet; gas at 111 feet. Secs 290i 2ae Rel Waeeenes S605 ope SS SoROGbbaeco 2 Coal Measures and Devonian strata .-..-.------------------ +--+ -----+ -- 2-22 2222 22-22 222 >> 950 Hard gray limestone (probably Upper Silurian). ...------. ----------+---- -+---++----- +2200 ---- 51 Soft gray limestone with H2S gas ...--..---------+ +++ s22+ +225 2-22 202 e ee terete Ste aSe 10 Limestone, both dark and light colored. -.-.-------------------+---+ +--+ -++---+ +--+ ---- 0-07 ---- 160 Soft white limestone with H.S gas ...--.------------ -------- ------ +2225 22-22 ere rere eee 12 Limestone, both dark and light colored.....--------.-----------+++---+ 222-220-2225 s00r rr rrree 342 White sandstone (St. Peter?), and brackish water ..---.------------------ +--+ +--+ ++---+------ 35 Clay shale ....-.----..----------------- Joab posbds cac0 onos cond cone buna soMaEs SoUgisene Daases hace 110 Graryaliimestones ose. = os nm oe = ala alae al mle e ainda ol aoa miciei cla cI a 125 THlm® Imes KONG. codsad ssod Snob CoaSCh Coben ceed Sece cece S056 Shoe 6569 cooene cee eae copoee Bie picts 65 IMPOR O a5 coop. ceense ceonbc SocSee ase S00 CONSE Goss Gedo Ses 6600800009 5800 SEED ReaS OCS OSSSSOSaCe 57 IR@GL ROG Ks soso sone acos Osco USE oon GauO Bo6o Dens Goce Sercedbe cscs Beco Rost enen sea ase sobs Sem eos5cc 15 Tai GEN coco cobs cneH sees cou 500 Baad case Gas5 bedeo9 Boas HeEE EES S=O065 585559 CS COS0 aESRa 2, 008 700 THE ILLINOIS GLACIAL LOBE. A well near the waterworks in the Vermilion Valley penetrated to supposed Upper Silurian limestone, which it enters at a depth of 1,075 feet. The thickness of drift at the Danville Junction well much exceeds that of other wells in the neighborhood, and indicates that a preglacial _ valley was entered by the boring. At Fithian, in the western part of the county, wells are usually obtained from sand or gravel associated with the till at depths of 50 feet or less, but one well was found to have a depth of 90 feet, of which the lower 15 feet is in rock. At Fairmount rock is entered at slight depth, and wells usually are obtained at less than 50 feet. At Indianola wells are obtained from sand or gravel below till at a depth of about 30 feet, a strong supply of water being found at this depth. At the village of Ridge Farm the wells are usually obtained at a depth of 20 feet or less, in sand associated with till. The flowing wells near Potomac, in the north part of the county, referred to above, usually penetrate the following series of drift beds, the section being furnished by George Platt, a well driller who has sunk sev- eral of the wells: Generalized section of flowing wells near Potomac, Illinois. Feet. ellowpspebDbiiyiclaiyy GWaASCOMSIN)) jeter te ete tele le le ater ee alma el 10- 12 Blue clay, soft like putty, and containing few pebbles (Wisconsin) ..---. .--- ep sesecses ceooce 60- 70 Hardystouy clay, olmternn CinouSs GLUSt esses see ee ae eee ae ere ere eel ee iets ale ee ae 1- 3 Sandland praveljamithiartestamswiaiter= sea) ele ae eee et ete ae ela eee eee 6- 10 Hardy pantiallyacemented) Sam diya) a yp oe apse ey eee oe eae ete a 25- 30 Sand and gravel, with artesian water._.-.-.-------.-----)..-------- ---- +----- --------------- 5 Hard, partially cemented, sandy clay---.-----.--.-----.-..----.--.- rotaceheee ss Shcceae see aae 15— 20 Sandlandioraveluwathanteslangwabeness a= se = => seee se ee eee ee eee eee several feet Very few records of deep wells were obtained in this county outside the villages just discussed. The record of a farm well, made in see. 31, T. 23, R. 13 W., shows 240 feet of drift, mainly till of a blue color, at the bottom of which water was obtained in sand and gravel. A well in sec. 36, in the same township, penetrated drift a depth of 160 feet without reaching rock, and a well near Alvin a depth of 173 feet. WELLS OF CHAMPAIGN COUNTY, ILLINOIS. : 701 CHAMPAIGN COUNTY. GENERAL STATEMENT. Champaign County is situated west of Vermilion, and has an area of 1,000 square miles, with Urbana as the county seat. The eastern and northeastern portions are tributary to the Vermilion River. The southern portion contains the headwaters of the Embarras and Kaskaskia rivers, and the northwestern portion is crossed by the Sangamon River. Much of the surface is so level that artificial ditching has been necessary to give good drainage. There are, however, two morainic systems crossing the county. The outer belt of the Bloomington system crosses the northeast corner, while the Champaign morainic system traverses the gounty in a southeast course, a little to the south of the center. 'The latter system consists of three dis- tinct ridges in the southeast part of the county, which become united into a single ridge near Champaign, and continue united to southeastern McLean County, beyond which the morainic system is not traceable. The belt belonging to the Bloomington system has an average relief of about 50 feet above the plain bordering it on the southwest. ‘The Champaign morainic system has even less average relief above the bordering plains. In the portion of the county southeast from Urbana the drift has an average thickness of scarcely 100 feet, but throughout the remainder of the county its thickness is much greater. Records of 22 borings which did not reach rock show an average of 171 feet, and it is probable that the average for the county is not less than 200 feet. The drift to a depth of about 100 feet is, in the main, a soft blue till of Wisconsin age. On the moraines the depth is correspondingly greater. Prof. C. W. Rolfe, of the University of Illinois, reports that throughout much of the county wells are found to pass through a buried soil immediately below the blue till, and then to enter a harder till. The writer found exposures, of which description has already been given (p. 216), of a peaty muck or soil along the blutts of the Sangamon River in the western part of the county. Many wells have been sunk through the blue till into beds of sand or eravel associated with the underlying harder till, as shown in the discussion below. Throughout much of the county the wells have strong hydrostatic pressure, though they seldom overflow. 702 THE ILLINOIS GLACIAL LOBE. INDIVIDUAL WELLS. In the vicinity of Ludlow, in the north part of the county, at an altitude about 800 feet above tide, several wells have been sunk to a depth of 150 feet without reaching rock. They are largely through till. A well at F. Delaney’s near Dickerson, in the northwest part of the county, at an altitude about 750 feet above tide, reached a depth of 280 feet without encountering rock. In the vicinity of Rantoul the wells range from 80 to 200 feet im drift. The public water supply for this village is obtained from a well 135 feet in depth, mainly through blue till. A prospect boring for coal at this village, reported in the Geology of Illinois, 1 is said to have reached rock at a depth of 80 feet. The report, however, is based upon rather imperfectly sup- ported data, the results of the boring having been kept secret for about twelve years before they were communicated to the Survey.’ . Near Gifford, in the northeast part of the county, on the crest of the outer ridge of the Bloomington morainic system, a well is reported to have reached a depth of 260 feet and little or no rock was penetrated. No more definite record of the well was obtainable. In the vicinity of Mayview several wells have been obtamed m sand and gravel below till at depths of 80 to 100 feet. A well at the residence of T. Hissong in Mayview reached a depth of 118 feet. The cities of Champaign and Urbana have a common public water supply obtained from seven wells sunk to depths of 157 to 162 feet in the glacial drift. The combined daily capacity of the wells is nearly a million gallons. The wells range in diameter from 5 to 8 inches. Two coal bor- ings at Urbana show a difference of 165 feet in the distance to rock, one entering rock at 100 feet, the other at 265 feet. The drift section of the deeper one, furnished by Prof C. W. Rolfe, appears on page 235. At Champaign a deep boring prospecting for coal and gas, as indi- cated in the section on page 234, has penetrated a deposit of drift even thicker than in the deepest boring at Urbana, it being 300 feet, but the altitude is about 30 feet higher than at the Urbana boring, thus giving the rock surface nearly the same altitude at both places. At Sidney the dug wells are about 30 feet and bored wells 30 to 70 1 Geology of Illinois, Vol. LV, p. 274. WELLS OF PIATT COUNTY, ILLINOIS. 703 feet in depth, water being obtained in beds of sand and gravel associated with till, A prospect boring for coal at this village entered rock at 95 feet. The section of the drift penetrated appears on page 236. In the vicinity of Homer wells are usually obtained at about 30 feet, and rock is entered at 90 feet. South from Homer, near the southeast corner of the county, wells are usually obtained at 20 to 40 feet, but occa- sionally reach a depth of 100 feet without entering rock. At the village of Philo, which is situated on the crest of one of the ridges of the Champaign system, a well reached a depth of 171 feet with- out entering rock (see p. 235). Several wells in the vicinity of Philo reach a depth of 100 feet without entering rock. At Mahomet several wells obtain water at 45 to 50 feet. A well in this village at D. MeArthur’s has the following section: Section of McArthur well at Mahomet, Illinois. Feet (CHGS cada sébbeubean doce Soekou pos ane BORO CoEt A SAE abIE ans Saceneda sadn Gasode. au se sostonssemaoosds 7 Rel blelessicl a yates tee yey ate aia ee ere re eid are eee ree a ee er = ee eeu me are a aay ee 3 IBROAWORAT HOTA yeh le es rre pat pallens sel arstal ata a veie cs a eoe Re oye Oe ea eh eset a oO aE Nea ENE DUS OLE 32 IB VEVC MspT CGNs epee ee het eon tate rsjaeye lolol) state eceret ote ate Steen ochre rye er a lee Se Mpa SD) Yat pC 2 TFVaxr LECH ie oer se acts etta ie Sree a ae sin) ers aioe sine ecole ape oe enter slateiere ee release eee Seen Ag TROuA LG NEN aos Geos coSace mo oceR BEseSseruosbe poodos Sop aes conapEGocbE cbeccobesude sosckouses 100 A well at Jonas Lester’s, a half mile south of Mahomet, passes through a black soil below till at about 36 feet.. The section of an exposure in the Sangamon bluff south from Mr. Lester’s appears on page 216. A well at George Frankenburgher’s, 2 miles east of Mahomet, at an altitude 60 feet higher than the village, reached a depth of 200 feet with- out entering rock. About 4 miles southwest from Mahomet, on ground no higher than the village, records of three wells were obtained which penetrate over 200 feet of drift, mainly blue till, without entering rock (see pp. 219-220). PIATT COUNTY. GENERAL STATEMENT. Piatt County is situated in the east-central part of the State, immedi- ately west of Champaign County, and has an area of 440 square miles, with Monticello as the county seat. The Sangamon River leads southwest- ward through the central portion of the county, and is the only stream of 704 THE ILLINOIS GLACIAL LOBE. importance within its limits. Much of the county has a very level surface which requires artificial drainage. The few borings of which records were obtained indicate that the county is covered with a very thick sheet of drift, averaging probably more than 200 feet. The greater part of the drift appears to be blue till. Shal- low wells of moderate strength are often obtained at depths of 25 to 40 feet, but tubular wells are usually sunk to depths of 100 feet or more and obtain stronger supplies than at shallow depths. INDIVIDUAL WELLS. At Monticello the public water supply, as noted on page 220, is from two wells 212 and 316 feet in depth, neither of which enters rock. At Bement the public water supply is obtained from two wells, one 138 feet, in gravel below till, the other 225 feet, in rock the lower 3 feet. The shallower one obtains the larger supply of water. The Wabash Railway has a strong well at this village 152 feet in depth, from gravel below till. A well at the mill, 141 feet in depth, is also in gravel below till. Joseph Rodman sunk a well to a depth of 384 feet, which entered rock at 205 feet. A well at the Bement cemetery, 2 miles north of the village, at an altitude about 45 feet higher, reached a depth of 221 feet without entering rock, and a well one-half mile east of the cemetery, 222 feet in depth, did not reach rock. At Cerro Gordo several wells have been sunk to a depth of about 150 feet without reaching rock. They are mainly through blue till, and im some cases are rather weak. A well near Mansfield, on the farm of Mrs. R. Carson, as noted on page 234, reached a depth of 200 feet without entering rock, mainly through sand. DEWITT COUNTY. GENERAL STATEMENT. Dewitt County is situated in the central part of the State, west of the ’ northern portion of Piatt County, and south of McLean County. It has an area of 405 square miles, and Clinton is the county seat. Salt Creek, a tributary of the Sangamon River, leads westward through the central por- tion of the county, and is the main stream within its limits. The western WELLS OF DEWITT COUNTY, ILLINOIS. 705 part of the county is traversed by the outer moraine of the Wisconsin drift sheet, which here has a relief of nearly 100 feet above the plain to the west, but rises only a few feet above the plain to the east. The drift of this county, like that of the neighboring counties, Piatt and McLean, is very heavy, averaging probably more than 200 feet. The upper 100 feet is mainly a blue till, except on the plain outside the Wiscon- sin drift, where much sand and gravel occurs. The few deep wells sunk on the newer drift indicate that the sandy drift continues eastward under the Wisconsin drift sheet. In several places buried soils, or muck beds, have been found about the level of the base of the Wisconsin drift. There are also numerous instances of inflammable gas from beds of sand and gravel in the drift. INDIVIDUAL WELLS. But few records of wells have been obtained in this county, and these are of considerable depth. Wells are often obtained at moderate depths in sand or gravel associated with the blue till. At Farmer City the public water supply is from a well 176 feet in depth, which terminates in sand. The head is now a few feet below the surface, but when first made the well overflowed. A prospect boring for coal at this town entered rock at a depth of 189 feet. The upper half of the drift is mainly till, the lower half largely sand and gravel. (See section on page 216.) A well one mile north of Parnell, 200 feet in depth, did not enter the rock. At Clinton strong wells are obtained from sand and gravel below till at depths of 80 to 110 feet. The public water supply is obtained from several wells about 110 feet in depth. The following detailed record of the drift penetrated at Clinton, in a prospect boring for coal, made with a diamond drill, is taken from the Geology of Ilinois:! Drift beds in a prospect boring for coal at Clinton, Illinois. Feet Surfaceisoilsss. 208 4 ce fsee oo ateee WaDs cok aeee eae aa em Sane feted iy ob Se eS 5 Quick san deere pet oo oo anne ese alee tars eif oa ae pe a 2 eseosee 15 Sandawithroravelsandbowlders esa. 2 nsec misse eee Op ae eI see seis ee Ui Uae 17 Samal ame! Gly WveG6l oes abodes eros bond odease seSonasod Cnc codado EuOn ao SodeHe Sosn ocenoaeecoe 53 TR MGNEN oocas seneeHcecous Gs00 Bob SSy SOU EATbBasS basbo6 baguce sodden bRneHss coe sooo mS EBA unaoaae 12 Grave Were stapereictn cet SS hue alo) Sa teictarcicta= eta Olle Na meaner GEV IER Sy hie Ie it TE il IBERIA oo5cug 6o5009 So00 so58e0 Sob Sed oo gase SSE bn6 boone hasoL A eheden aodooes6 See bESe eanoesseSbase 4 ! Vol. VIII, p. 34. MON XXXVIII——45 706 THE ILLINOIS GLACIAL LOBE. Feet. Glay, and! sands 2252 - seelncee ae nee ein oS ole ale ile am a(o)niim em = SES nocaas aaa SoS 4 (Gholi Olin oac6 Qaetooscen aeeoeees cecese decced bros ones onSocd 26 Boos aces cos Sat 7 Hard pam <..- 222220. 5-2 2-0> one se eon = 2 nse ere te nn meme amie wie ee ina ene eee 3 Clay and sand.------- .--------~ -=-- <== == 2 22 ose ennn wn n e n 7 Clay and gravel .....--- ------ ----- + <2 2-20 = 22-22 fon = nnn no = nn en ns a nn nee 14 (NE Wesee omaele dere coses a eenees caseor ne code 53s0S0 6os06n.d5 Snes HOSS UI ROCnEE Raraon CSct caaas=So5sos< 4 ISU oe coon eee eee ee ese S= Seba eae a> Ses] 2ceSe> S09 e26 poses pececo Rea ares m ===) aens aes a borone 6 Clay and gravel .... .----- ----- +--+ --- 22-252 2-2 = con nn ne ne nnn note es aes 2a oa 8 Quiles Sos eae ae ww ne en a a ae eal ele ean alm lalm ole tal in) nl lle) ela ila 5 Sand and gravel. ......------ -- =< -2-= 2=5- 222-22 ene nn nnn nn a enn ean 2 @oarse gravel .--..----------- 922-52 oe ena ee enn a inne ane es ee ae a 2) Clavgeeee eee see SERB Een SooSee cseses caatas SnoGos, saesescosas Ge cEnUOSUE SY omar Cameos oHSnosSsS ones. 6 Gravelly hardpan ..---.---------- ------ +--+ -2--2- 22-222 +--+ 522+ 252222 ane ern ene 22-2 aoe 25 Quicksand p22 22 - sen eia- 2 eee eae) a el ecient einln aim laying ao 6 (EE SEE DooeD Rp aseso9 bbc 2too SaegreAcS 9G Osi 3 Sea aa 6 TNO GN, cncoasacdecssecoss Sa00Ss cago tesa 550 Joe sisassIgne Seas sos5 Sac 6a06 30b >. oo5 Sonor aSrGS anos 9 GRxionl Gkalth oo acon deco sass coun Gane das aaoeeese eaoe cake saps Sb soSSSeescos6cs cosc dono cries aa 42 Several prospect borings for the waterworks have been made along Richland Creek Valley, between Belleville and O'Fallon, which penetrate in some instances 80 feet of drift, mainly till, The amount of water is scarcely sufficient to furnish a supply for water works, hence the use of impounded water is continued. A well at the Star Brewery, in the northern part of Belleville, reached a depth of 503 feet and obtained a slightly saline water, with head 80 feet below the surface. The depth of the drift is 87 feet. Coal shafts near the Louisville and Nashville depot, in the north- ern part of Belleville, penetrate mainly blue till and enter rock at depths of 40 to 80 feet, the rock surface being somewhat uneven. A coal shaft just south of Belleville enters rock at 30 feet, and there are exposures of rock within the city limits. At the village of Lebanon, in the northeast part of the county, shallow wells obtain water from gravel below clay at a depth of 30 or 40 feet. Considerable wood is found in some of the wells. There are also several deep wells in the village obtaining water from limestone at 150 to 200 feet. On a drift ridge 2 miles north of the village a well made by D. Bitzer reached a depth of 86 feet without encountering rock. The lower 46 feet was a hard blue till containing fragments of wood. The upper 40 feet con- sisted of alternations of clay with gravel. The altitude at this well is fully 60 feet above the railway station at Lebanon. At Summerfield rock is entered at about 35 feet, but on the plain north of this village the wells usually penetrate 50 feet of drift before entering rock. 764 THE ILLINOIS GLACIAL LOBE. A coal shaft at Mascoutah is reported in the Geology of Illinois to penetrate the following beds of drift: Section of coal shaft at Mascoutah, Tllinois. Feet. Soiltandiclaysesorere tcccpeos occiss hee eee ae eee eno Se AR OOaE pa tecn Onno dye bad Sao aSHOHooos 20 RG Rance ace a ieee eRe RE Sera neta GecGae SoS Se OEE DanC CSO DOC o Moats saab s 6 Blue vera, ran Ose dec] vy set acre. =a =e ee eg eee eae tata eee 50 Coarseiisandiwith' woods: 2sc5- 320 saan cecee eee ee meee ene ee eels coe ee See ee eee 6 RotaWavitt)- 2. ses sages sense ooo SoobrcabbelnoSoDoactEeocandar deans deasEs 82 At Rentchler wells enter rock at about 40 feet, but on the drift ridges between that place and Wilderman two wells are reported to have reached a depth of 85 feet without entering rock. The following section of thick drift is reported in the Geology. of Illinois. The boring was made in sec. 20, T.15., R. 6 W.: Section of a boring in sec. 20, T. 1 8S., R. 6 W. Feet Soultandhyellowscl ayer cee emit ase ee oe ele elton 14 Reddishibrownlerayvelvandisand! 2 eee ctsee ace eee ee ree Een eee eee ea ee 28 ING) OEay pasuéoscse cdoseocecomade sedan csuscosseo sod Cone boos cdcens SaoDea dnason sadeduan used Seoo ct 83 Motalwarift,= ace seee teats ele oes cesta eee eee sBeneoaobEeodaaRas See SNe fatale eects eae 125 In the vicinity of Freeburg and Smithton rock is entered in the deeper wells at about 25 to 30 feet. The upper 5 or 10 feet is a loess or pebble- less silt, and the remainder is a brown clay containing few pebbles. There appears to be but little typical till in this locality or, for that matter, in any part of the county west and south from Belleville. At Lementon a coal boring reported in the Geology of Illinois has the following section of drift: Section of drift beds in a coal boring at Lementon, Illinois. Feet. Oe eee co oobSes No COuO pou SUR ogee ee corer EROS a eiosE ae aaesae bod-cdodod tansarscnces odoo eens cosode 3 Yellow clay -.-----. EEO Geode HORSE CUSSED E Seb SS aen aaa CSE bO cca Conson dsussy cuasadmseeeoascans 14 Sand and gravel. ..---- Jorsscod2s50 ceedeccsca sabe ofsese SESE oEddCas coadas Eeoe BARS eaEEMSaMesae Hoos 1 Be: Clays 2 ae tec ialo nies slo ate fe tae cine atin Se aS er ciate Saisie cle eas Se Se ee Oe Ee ene nee eer a eee 20 Claysnesemblin g (souls ae rans stesso seats sso ss yseeeaee ee e eee eee eee ren 1 Blinexandtyell onviy cl aye se pe cisions slo sats re seins Sa sla cieloe Se eee OCR ee ee ee 11 Rediandtyellow/sand icc sete cctec ai mcminaree Se erae a) 5 ate eR ee ee ee eee ee ere ee 1 Totalldrifty cos -nle== == 5 685 cited on classification of glacial deposits. : 185 Butler, I1., wells at -.------ 7A cited on distribution of Illinois moraines.....-.. 2,3 Byron, Ill., wells at ..---------------+----+25000- 77 606 cited on early Wisconsin drift sheet .--..------- 191 cited on elevation of abandoned channel of the (Ob Mississippi------.--------------+--------++-- 93 | cited on erosion of Lake Michigan .-----.------- 457 Cache River, effect of glaciation on. ----------------- 528 | cited on extent of Shelbyville drift sheet. -..---- 192 Cairo, Ill., preglacial drainage near. - 71 cited on Leaf River or Adeline esker. ----- 2 76 wells at .-------------------- 786 cited on loess deposition .----------------- . 177,178 Cairo, Iowa, wells near -------- 50 cited on Marengo Ridge moraine. - - 290 Caledonia, Il., wells at .--..--------------+--------77- 574 cited on names of glacial deposits..-------.----- 19, 20 Calhoun County, Il., altitude of. 11, 15 cited on preglacial basin of Lake Michigan -.--. 7 drift border in 35, 37 cited on Shelbyville moraine ---.---- eeescccoodes 192 wells in'-.---.--<2----c0c--cee nnn nooo n sence TA5-746 | cited on structure of Champaign morainic sys- Call, R. E.. fossils identified by --.------------------- 168 | tempera eepeeereeins “HEpeOMSTO AIO AOS 232 Calumet or second beach, character of-.--------- ~ 444-446 cited on structure of Shelbyville moraine. ------ 198 course Of .-...-----------------=-"99--=2--5-* 442-444 cited on topography of Marengo Ridge moraine- 291 Calumet River, drainage basin of...---- - 538-539 cited on Valparaiso morainic system-.---------- 339 sand deposits near --------------- 409-410 cited on Wisconsin clay beds-...----- 441 section of ridge near .----- 396 examination of Warsaw exposure... - 94-95 structure of drift along ------------------------- 393 glacial work of.....-.------------- 3-4 Calvin, S., aid by ---------------------+-----+7 7+ 147, 148, 187 on invasions of the ice fields ---------- 23 cited on the ice margin in Jobnson County, Iowa. 150 | on material in abandoned channel of the Mis- cited’ on the Iowan and Kansan sheet of north- | sissippi 93-94 eastern Iowa, McGee and ..-..----.---------- 139 | on topography of Kettle moraine ..-----.------- 303 cited on the limits of Iowan drift.-------------- 144 quoted on drift in Kankakee Basin. ------------- 317 discovery of glacial striw by -------------------- 85 quoted on sand areas in Kankakee Basin. ---.--- 328 reference tO ..----------- ---220- ees etre 44,46 reference tO -.-------------------------°- 421, 543, 547, 551 Cambridge, Ill., wells at.--------------- --- -- 624-625 | report on boring at Lake Koshkonong -.-.------ 484 Campbell Hill, Ill., wells at----------------- =e 779 work on beaches -.------------ B RGEE Ra HOS 427 Campbell, J. T., information furnished by- Sp 412 work on sand areaS-.--.-------------------------- 333 Camp Point, Ill, wells at .---------------- see 716 | Chamberlin, T.C.,and Salisbury, R. D., cited on the Campton Township, topography south of. --- 299-300 drift border in southern Wisconsin 43-44 Campus, IIl., wells at --- 667 | Champaign, IIl., sections at-.--------------- 234 Canton, Ill., wells at .-------------------++----++--7-- 687 | topography near ...-----------------+++--+++---- 227 Carbondale, Lll., wells at.-- 780 EI) Ohl oa saasonesdon ssadeoceseoanSepSodes COS sade 702 Carbon Hill, Tll., wells at-----------------+--------- 647 | Champaign County, IL, altitude of..---------------- 10 Carlinville, Ill., wells at-.-.---.--------------------- 743 general features of ...-.-------------+++--------- 701 Carlyle, Ill., wells at-- 760 limestone in..------.---------------------------- 232 Carmi, Ill., wells at.--------------------------- 717 | till plain in......-------------------------------- 239 Carroll County, Ill., altitude of -..-.----------- : 9 wells in -- 701-703 general features of ...-.----------- . 148,611 | Champaign morainic system, distribution of. 223-225 wells in.....---------------------- - 611-613 range in altitude of -.---.------------- 226 Carroll Creek, gorge near ----- 495 INOPO)’ sosaaeccesdoston boo Sap eaceae = 655002005 225-226 Carrollton, Ill., wells at-.-.-------- 745, topography Of ..-----------------------++-++----- 227-231 Carthage, Ill., filled valley near-.---.--------------- 57 | Chapin, Ill., wells at--------- 723 wells at -.---------- 4 682 | Charles Mound, altitude of..------------------------ 8, 16 Cary, Ill., wells near-.-.----------+------++-2+077777 578 | Charleston, Ill., wells at--- 201, 735 Casey, Ill., wells at ----.--. ----------------2--270-7° 734 | Chatsworth-Cayuga Ridge, topography near.------- 259-260 Cass County, Ill., altitude Olnse asin eeecenan- === 10 | Chatsworth, Ill., wells at ---------------------------- 666-667 general features Of.-.-------------------+--01--> 710 | Chebanse, Ill., wells near. --.------------------------ 657 wells iM -.---+-------------------- 22-99" no" 710-711 | Chemung, IIl., wells near---.---------------- 576 Centralia, Il]l., wells at..--.---------------- 760 | Chenoa, Ill., wells at------------------------- 693 Cedarville, IIL, belt of gravelly drift near -- 81 | Chesterton, Ind., analysis of clay at--- 411 gorge at.----..-------------2 2222-777: 495 section of well near ..------------------- 3 396 soil analysis at..----------------- --e- 161 | Chicago, altitude of plain west and south of. 404 Cerro Gordo, Ill., drift at .-- ---- 220-221 structure of drift at Fullerton avenue in. .------ 409 wells at..------------------------ 704 structure of drift at Hyde Park Township in-.- 409 Cerro Gordo moraine, character of the outwash of... 221-222 striw on Stony Island in ---.-------------------- 415-416 distribution of -.-.------- 218 thickness of drift in..---------------+------+---- 406 structure of the drift in- 219-221 | Chicago Drainage Canal, bowlders along ------------ 426 topography of-...-----------+-----+---72 02700777 218-219 structure of the drift along --------------------- 407 Chadwick, Ill., wells at -----------------+++--+++---- 613 | Chicago Heights, Ill., wells at ..--------------------- 591 MON XXXVIII——51 802 INDEX. Page. Page. Chicago Outlet, maps of 420-421 | Cook County, Ill., wells in.....----...----.---.----- 581-591 meaning of name. =0 420 | Coon Creek, well near. : 574 WidthiOf--o--sceesseee eee 5 424 | Cooper, Ill., wells at..----.--- 692 Chicago River, beacn on west side of. --..--.---.---- 430 | Copperas Creek, watershed of ..----.--- Se 516 drainage basin of 538 | Coppock, Iowa, old channel of the Mississippi River Chillicothe*terracelat sses-255- == =e eee see 275-276 Bt SSN a ae cS 92,93 Christian County, Ill., altitude of-.-.-....----------- 10) | Cordilleran ice field, extent of..-....--.. 22... 2.222. 22 analysis of soil from ....-.-------.---.---------- 1615 Cornell Ll wellstateee-sem-ceaee ence tan eee eee 666 gencrul features of ..-.....--..5--.-.---.--------- 725-726 | Cortland, topography near .-----....-..--..--------- 248 WOLIS iM poset ece oe ae co Oocinia scl eerste eee ealerete 725-727 | Cottonwood, Ill., wells near -............-.----.----. 784 Cigsnaseanikealllbawellint==s-eee coos e eee aa GG Coulterville williiwellsyatcess=- essere =e eee eee 769 Cisne, lil., wells near ..-..--- 5 775 | Covel Creek, watershed of. - - 510-511 Clark County, Ill., altitude of. - - 10 | Covel Ridge, description of. .- 288-289 general features of -.------ - 733-734 | Covert, wells near..--...--- - 400401 wells in 733-734 | Covert Ridge, altitude of... 391 Clay County. Ill., altitude of....-.-.---.------------- 11 beach near.-.--..-- 0 433 general features of ----.------------- == 757-758 WO AGT Nass ese5 decsesaosroseceosecsstas sossos 393-394 TROIS Soest oko ssoseshonSatcesebssaseessssoses 757-758 (OUTS) QP RRS R eee bmcoconedeas ecnoobesseandsae 388-389 Cla; ton, Ill., drift sheets in the vicinity of ..-.-..--. 142 San derid 2 GON sae see ee ae eee 433 GWEN sno cosa ocrese eeSsonroseSe 660-661, 705-706, 716 | SOctiOMO fie. ese see eee eee scare ee eee 394 Clinton, Ill., section of gas well at -..---.---.-------- 205 topography, 0ffe- += eeea eee nace mene e eee ae 382-390 thickness\of.driftiat. 22.2222 <2 2 ee 205 | WAVE) ACION Ahysss ania eee eee 436 Clinton, Iowa, glacial deposits at ....-..---.--------- 147-148 wells and borings on..--.-- 400, 401, 402, 403 preglacial course of the Mississippi River below. 466-467 | Cowden, IIl., wells at...-.-.----.---. 739 Clinton County, IIL., altitude of-.......-------------- 11 | Crab Orchard Creek, watershed of -- 527 general features of 760 | Crawfish Flats, Ill., wells at....-.--- 776 table of wells in -.--..- 761 | Crawford County, Il., altitude of 11 TGWSVIN e kososre ooombabdedasgses sbastadenskcadon 760-761 generalifeatures) Of een as-ejasees eee eee eiaaeee els 755 Clinton County, Iowa, belt of drift in--...---.--.---. 144-145 WOLISKIN A ee ets saiatceisoeie nine ice site oe n 755-756 Clinton Township IIl., section of knoll in .....-.--. 28lo|uCrescentwlltswellsmeanosecse-eee ete tease ee eeeeee 659 Clyde Township, sandy belt in....----.---------.--- 149 | Crescent City, drift sheets at........-..-.----------- 142 CoaliOity Ul wi clishatiee sees ee seeeeeca= see G47 Crestonwllntwellstateeeecs see eener se eeer tee eee 608 Coal Creek, gravel along ...-..--.--.---------------- 239 | Crooked Creek, watershed of...........-...--.-----. 520 Coal Measures district, altitude and drainage of .--. 17 | Cropsey Ridge, topography near ..-..-----.---.-.--. 253-259 Coatsburg, Il., composition of ridge leading from... 61-62 | Crossville, I1l., wells near TT section in a boring for coal east of Crystal Lake, Ill., wells at - . 577-578 VAN MO hoctacocsacsoceases seccdosenceeu Cullom, Ill., wells at...-..--.-.------ 667 Coles County, II1., altitude of. = Cumberland County, D1., altitude of. 10 meneral LeaturesiOfic ee cecewece cess eiaaeee | exposures of Sangamon soil in-..--.. --- 127 TIE HY ee ice ase crgnocHEcHbeaooneSbeusssse | general features of .----..-.---.---.------ 736-737 Coleman, A. P., cited on Toronto formation...--..--- 189 SOUsAN ALY S18 pees seceer eee ee ert ee 162 ColfaxalllSnwellsiatresss sees ecie eee erin 694 | Wwellsyin sac eee eae ee sce 2 a eee 736-737 Collett, John, reference to.--..--- by fatter pattie 88 | Cumming, Thomas, information furnished by. ------ 647 Colomah Michi awelliatie= sno sesatse mercies teenie 3695 i CorranwOlleewell siatiemestect em araals semis a ala a 725 100,101,102 | Curtis, G. C., and J. B. Woodworth cited on Nan- Columbia, Ill., exposures at. -- 65 tucket as a morainal island.........----- cece 272 WOUMEIH Acbostisessssecesseee -- 755-766 | Curtis, L. R., acknowledgments to.------.--.------- 641 Columbia Station, Mich., section near. -- 365, Columbus City. Iowa, well at-.-.-....-........------ 50 1D Columbus Junction, Iowa, abandoned channel near. 90, 91,93 | Dakota, Stephenson County, transported rock ledges NVGLIS IS ipreenneeereaice esc aas toe scot eee eet 34,50 TOs Se emer anne SAO SSOORe SATE DOS SE RO ESBS SOS 83 Conaro, James, well section of...--.---.-.------.---- 55 | Dall, W.H., examination of fossils by .------------- 115 Concord, Ill., wells.at--------.--.------. ene 17 fossils identified by--.....---.---.------.-------- 169-170 Cooley, L. E., cited on the Chicago outlet...-...--.-- 419,425 | Dallas, Ill., wellsat..-....-.- 682 cited on variation in the bed of the upper Illi- Dalton, Ill., wells at .--..-- 730 MOS IGN Ohne Sas cod sooae sou see Ou Dee Eee ESS 502 | Dalton City, wells at.-- 217 cited on the watershed of Des Plaines Itiver-.-- 503 | Danforth, Tl., wells at... -- 657-658 the drainage area of the Illinois River estimated | Danvers, Il., wells at-. 695 by-- AQT | Danwilleyellle pyrG ll sits eee se eee eee ae ees 699 filling, estimated by.-----------------.---------- 424 | Danville Junction, Ill., well at.....--.-------2---+-- 699 information furnished by ----------------------- 384,422 | Darling, G. W., statement by. .-.....-----.-----.---- 671 study of the movement of water in Lake Michi- | Davenport, Iowa, fossils found at-.---.-.-----.----- 168, 173 [AN ios cbbecotessosSsoSa57 20 coseteoesceads 455-456 | section in railway cutting near. ...-.-.-.---.--.- 128 Cool Spring post-office, ridge near------.------.----. 72 | section of drift at -------------------.-----.----5 45 Cook County, I1., altitude of. 9 | Daviess County, IIl., drift border in 69 situation and general features of--.---.--------- 581-583 | Davis, W.M., cited on the Chicago Outlet .......... 420 INDEX. 803 Page. Page. Davis Junction, Ill., wells at ............--.-.-....-. 607 | Drift, previous investigations of.....-..--..--..----- 1-2 Dawson, George M., cited on centers of ice dispersion. 22 sections of the Illinoian ---- 33-34 cited on Cordilleran ice field .-.....-.--......--- 22 structureso fe cesses= = sao ene eee as soncce cena aae 27-28 Dean, George, acknowledgments to...-...........--. 627 thickn essjofeeresee sien ee ene ee eee 8-9, 27 Deans Corners, Ill., wellat-...........-.-.---.---.--- 581 topopraphiy Of es-- = eat sese= eminence seam ence 26-27 Decatur, Ill., sections of drift at......-...-..-.-.-.-- 203-204 | Drift border, character of east of the Illinois River. . 64 TGHE Giga ccnsanqeoacdsedSouecaEaaaEbouneSce=oc05 729 determination of the......2......--.........-.-. 37-38 Decorra,Tll., wells near --.....----.-..-.--.--------- 680 distributionyofsthes meee eeenenae eee enee ene 34-38 Deer Creek, gravel deposits in = 274 structure of,in southern Wisconsin. - 43-44 Deerfield, till ridge near ---.... 381 structure of, in southeastern Iowa. - - 40-63 Deerfield post-office, Il., well at - .-- 602 topographic character of the---.-.--...--.------ 38-40 Deep River, exposures of clay near. 5 410 | Driftless area, features of..-..-.-. 34, 144, 152, 153, 154, 185, 188 Deep River Basin, old bay near... -- 20 - 431 | Drift surface, Illinois, table of altitudes of .......-. 9-11 Dekalb; UT awell gator iscitnte sic -'=niiciese Sees wee ween 602-603 Michigan, Indiana, and Iowa, average altitude of- 12 Dekalb County, Ill., altitude of............-..--.---- 9°)" Drumlinssocourrenceof-s-os- sete a eieeae eee eee 73, 135 bowldersainses se serene eee aes ae eee 268 | Dubois County, Ind., drift border in ..-..--..-..---. 35, 69 buried soil in.-.-..- AbeaboOSoC00 See ee eee ntoeeoats 264 changes in drainage in ........-..-----.--.------ 98, 102 general features of .......--.-..-----.----- - 599-600 | Dubuque, Iowa, analyses of soil at ..-.---...-..---. 160, 164 structure of drift from Bloomington to........-. 267-268 | Dudley, Ill., wells at..........-..--..--.--------.--- 733 VOLS sh Ml eta ata ere A See rae ore are . 599-604 | Duncanville, I1]., wells near- - . 756 Delavan, Dl wellsiat 22-25-22. -ss---- 691 | Dundas, Dl., wells at.--. 757 Denmark, Iowa, section in wells near. bd bon Dundee, wl lenwellstatuscteceeace ee eae ata eee 595 Densmore, J. E., wells of. 63;\64" || Dunlap, wells mear)-2--~ = 2-2 e eo ae owe 207-208, 674 Deselm post-office, T1l., wells at 654 | Dunning, Ll., well near. .........--.-.--...----.----- 588 Des Moines County, Iowa, wells in 50 | Dupage County, Ill., altitude of..-........-..--..--- 9 Des Plaines River, beach on west side of .--..-.-.--- 430 area and general features of.--.-...---------.--- 591 depositsialoneenaasen sees eee ae on 376-377 WARN boaboeposssicossosodsstcbcabsesdcecacstos 591-594 erosion in valley of.-.-- Joochbooséabossocsudsesso 422-423 | Dupage River, deposits on......-.--.--..--..--..--. 376 strisyinivalleysOfscea-lm\smaciatal-inaistee seem clnjercinin —i=!> 415 Watershed: Ofee mesma eee ete SOSEEDAOSS 505 (HEARS GilicSbescosganednosdodescssencenucocnopes 821-322) | Duquoin, Tll., wells near.....--..--..--..----------- 771 till ridge near ----- 6 380 | Dustin post-office, Il., wells at. 601 topography along ... 384 | Dwight, D1., wells at.--. 665 topography near... 5 345 | Dyer, Ind., beach near .-- 2 431 watershed of the .......--- - 503-505 section of beach'at ........-.-..--...---.---..--- 439 Des Plaines Village, Ill., wells at - : 587 re Detroit, Ll; wellsinear)---..-..---2-.--- 32. .......--- 720 < “Devil’s Backbone,” description of ....-.-..--..--.- 286-287 | Eagle Lake, wells near.......--......-..-------.---- 364 Meyonianis haleseecseee: ysesees sae selsecisasciecine saieistee 14 | Harlville; Til., wells near---..------ +... -- 2.0... 22. 636 Dewey, F. W., information furnished by.----.-----.- 649 | Early Wisconsin drift........--.-------------------- 20 Dewitt County, Il., altitude of -.....--.--....------. 10 | East Carondelet, Ill., wells at.......--.-----..--..--. 762 general features of ..........-..----------------- East Crow Creek, watershed of..-.-.......------.--. 513 WOllstinimene come sse eee cewsceaccccae cc cinesa East Dubuque, Iowa, soil analyses at - 161 Dickey, Ill., wells at...........-.--.-..-------- WOW iS ses ncBRseccooctosechSsasses 565 Dickerson, Ill., well near. - East Lynn, Ill., wells at ..--.....---.----- 699 Miona wl wellsatiecscesmcca cee erence se East St. Louis, Il]., analyses of gumbo at 163 Displacement of the Mississippi, temporary -- drittibeloweemcscaceeseeee Ho eee eer semenaeree 65 Dixon, I1l., exposures of Iowan tillin --..----.-.--. 138 CGS Piiececocecaddand cegttoooseoatasosesoodsSoso 762 WE Oingoesedeeacdsnbagacsenusccabssouceenecesoe 609 | Eden Station, Ill., wells near ...--.--..-...-..---.-.. 769 Dowagiac River, course of ....-..--..--------------- 540 | Edgar County, I11., altitude of...............----.--. 10 Downers Grove, Ill., wells near..-.--...------------ 593 general features of -.......-.---.---.------.---.- 732 Donovan, IIl., drift sheets at -..........-...-...----- 143 outwashtinmorthermessce ss oeree nese ean ea ee 238 YOR UE IGE ne cononodecbancoscnesHeSdoassOSHRSOU SSS 659 WOllSiiMise 2a tone oan sac e tne acca eeeces 217, 732-733 Dooley, P. T., information furnished by --------.---- 580 | Edgewood, Ill., wells near............-..------------ 754 Douglas County, IIl., altitude of.........--..----.--- 10 | Edwards County, U1., altitude of- - abe general features of ...-..----- a 731 general features of ..-...-. 775 WIGUIE IN cecscceosnsSsonSadbESsndcesocesss --- 236, 731 wells in . 715-7176 Drainage, changes in southwestern Indiana in....-. 97-104 | Edwards River, description of course of- . 478-479 from the ice sheet in the Mississippi Valley ---. 71 Wellin ea ieemeseee ett aa meme nate sone acne eee 622 influence of the drift upon....------------------ 460-461 | Edwardsville, Ill., wells at.............----..----2-. 749 Drenthe, wells at 403 | Kel River, strie along -......-..--.-...-........--.. 414-415 Drift, altitude of 9-11 | Effingham, Dl., wells near-......-...--..----..-...--- 754 average thickness of .-........------------------ 544-546 | Effingham County, Il., altitude of -..-.........-.... 11 changes in central Illinois in -.---.---..--.------ 28 general features of.........-------....------.... 753 methods of estimating thickness of....-..--..--- 543 wellstineesacesecet . 753-754 relation of the Ilinoian to the Iowan .-..-.----- 24-25 | Eldorado, Ill., wells at-. 782 outline of andintervals between sheets of ....-- PXeaT |) Got. INL ei ea aaa ee soko shescecausscocenoescee 572-573 804 INDEX. Page. Page. Elgin, O1L., wells at and near 585, 595-596 | Forreston, I1l., classification of pebbles near 78 olichartwlllesr ell sia tse eerste tie seein tem aia 709 WOlLS 2 bye ce etre ape eersacte = aieie te ees 605 Elkhart Mound, description of.-.--...-..-.-.------- 75 | Fort Branch, Ind., ridged belt near. -.....---.--..--- 67-68 Tikhorn.Creekibasini--ac--sses. ==-==--------- 18, 79, 182,155 | Fort Madison, Iowa, drift thickness near ------ 52, 56, 71, 156 UMevalloslll naw OSA tesa eos eee ae cee eae ee N80uHossils, distributionofese--s+- aaseeoe eee ee eneeeae 165 Hillery, ule wy Gls Meaneseew sense = =< asec -==aeeennln 775 names in Pilsbry and Johnson's check list.----- 168-171 Elmhurst, Tl., wells at .-.-.-.......----------------- 592 Jistiof loess Ossi lS es see ease ee eee 168-174 Elmwood, Ill., wells near-......---.-------- eee sessS 675") eRosterburg, Dill wellsiat)-222-2-2s5-----seseeneeeniea= 749 Elpaso, Ill., wells at..---- 671 | Fountain Bluff, I1., deflection of Mississippi River at 474 Eivaston, Ill., wells at-.-....- 682 | Fountain County, Ind., wells in - 237 Elwood, Iowa, drift border near ---.---.- A 145} Fowler, Dl., wells at--:-...-...2---...2- 715 Embarras River, course and watershed of---.-------- 534-535 | Fowler and Liberty, Il., drift between . 60-61 outwash in valley of ...---....-------------- 209-210, 238 section in well between ---.--.----- 61 PIV GLIS} 21 OM) ee els aint alas miata ele tate oe 755 | Wox River, altitude east of .--....--.------.---+----- 305-306 Bimden ll welll ttes—s-r\ecs scenes ee eewe meee eis 708 altitude: westiofire 2 - 202-5 s2 on. sono ce = oe oe ee 297-298 English, J. G., well section reported by-.-.-..--.------ 699 beltofirravelialonpyeesssses=e eee eee ees 313 English Prairie post-office, wells at---------.-------- 577 character of drainage of.........-.-..--.-------. 498 Eolian loess dposits.--.-.-..----.-------------------- 183-184 | correlations of the morainic belt west of -...---- 302-304 erie, Tis; wellsinean --. esse cienceeeneenne meena 617-618 | morainic beltieast) Obes s.-sesce cease noes ee see 304-305 Esker, Hazelburst-.-..------ 78 outwash on 375-376 Garden Plain -.----.--.-- 79-80 | strie along 415 Leaf River or Adeline oo 76-78 | structure of drift east of-- 306-307 Esker ridges of northwestern Illinois - 76-82 | structure of drift west of - 300-302 Esker system, Pecatonica .....--.-..-- 80-81 thickness of drift along. -- 283 Eubanks, Ill., drift border near.-...-.......--------- 58 | thickness/of drift'east of=-2---~----2--eeseneeiee 306 Eugene, Ind., section of well near ........----------- 236 topography west of. 2.2... 298-299) Eureka, Dl., wells at-..---..-.---.--...------- 71 pra Lershed Of sen ene setae se ae alate eee eee 509-510 Evanston, Ill., sections of beach at ......---..--.---- 450,451 | Francisco, Ind., col near---...- a et en ae 101-102 shells found on beach at....-.-.---.-.--.-------- 451 eerankliny ly wellstate.---~e-con-4--s2- sae eeeeeaeee 724 structure of the bar near.....-.....--.----.--.-. 445 | Franklin County, Il., altitude of .......-..--.---.--- 11 pA casudetsondocbsens cde osdenosdseacesecnds 587-588 oneralteaturesiOle- sass asain eieseee 778 Kr TOG 52 3-55 os meeteaeeseesoshrmsaanscassscsosis 778 2 Franklin Grove, Il., wells at.- 609 Fairbury, Il., wells at - 666 | Freeburg, IIL, wells near....-- 764 Fairfield, Ll., wells at. --- 775 | Freeport, Ill., fossils found at - - 169-170 Fairgrange, Ill., wells at .--....-..----...--..-....-. 735 POTS e Mea essences ate =s=aeaae ae 494 MairsHavenv ll siwwellatioccasaceceecmeaecerimatee seis 613 section showing ‘‘Silveria formation”’ near . 112 Fairmount, Il., wells at ..........---..--.--..-...... 700 | “Silveria formation”’ near ...-...-.--.---------- 113 Farm Creek, gravel deposits on ..-.-..-.------------ 212,274 | NRO) et files ere es saint te te State 568 MALOLSHEC Ofna wen oe = ome ea eee 514 | Friendsville, Tl., wells at -..---.....-..-..:----.---- 776 Farmer City, Ill., section in boring for coal at ---.--- 215-216 | Fullersburg, Tll., wells at...-.....-.........--------- 592 WGI EN ypc sonShedsbéo sh sescnesdedonhesseectnce 705 Fulton, Il., deflection of the Mississippi River at--- 462 Farmington, Il., wells at and near .......--..---. 686-687, 736 RGR sartieete tener teeter eae cole steele ene meter 615 Farm Ridge, topography near ----. -. 260-261 | Fulton County, Il., drift ridge of- 76 Fayette County, D1., altitude of --- 11 general features of -- : 686 general features of 752 | WOU MRE es sco ssecceeaeaspecesos - 686-688 OLSHNiweee=nieasn 752-753 | Fultz, F. M., discovery of glacial strie by - 2 85 Fennville, Mich., wells at 403. Funk, Lafayette, information furnished by- - é 695 erdinnnain ds COMMGAT ee oe eae lae antares 101-102 Hunks GrovewUlewellsiateses=seemee eee cee ae 695 Ferruginous conglomerate. ---..--.-.---.----------- 107,109 Furse Creek, deflection by glacial boundary -.-....- 102 Bidelity, Dl) wells’at---- ~~ =~ eee 747 CG Hieldonwll welltatienes esses = aeeise- ew oneal s TAT ss Findlay, Ill., wells at 740 | Gallatin County, DL, general features of -.--..-..-- 783 Fisher, A.J., information furnished by -...--..----- 629 WwellSiniesesaasleasssa—= 783-784 Fithian, Dl., wells at.....-.-.--.--.-- 700 | Galesburg, Ill, wells at- - 676-677 Flint River, course of .- 479 | Galena, Ill., wells at -.-- 565 Flora, Tl., wells at --- 758 | Galewood, Ill., well near --.------ 588 Florentia jormation - - 167 Galien River, drainage basin of ------.-.------------ 539 Foggy, Andrew, well section of - = 53) Galvandll Sexposure\atiese scene ee ee eee 130 Ford County, Ill., altitude of ...---...---.----------- 10 WENA ip cencassockoe sockeseosacssa 624 general features of..-...------------..-----.---. 662 | Gannett, Henry, cited on magnetic variation. -..---- 412 table of deep wells in .-.....----------.---.----- 663-664 | cited on mean elevation of Illinois -........-.... va LODUBIAD Divs Ole men = eens ete eee ele ien 254-255 | Garden City, Ind., analysis of clay at -----.-------- 411 EME on See Re cease tt cetec ot Scnecnostusseao= 662-664 | Garden Plain esker. ---.-..------------- - 79-80 ores Gills awellsiaticcs ce sche cocoate eee eee aa 666 | Garden Plain, L1., wells at-- . 615-616 Forester, John, information furnished by ......----- Wie |eGardneraulleywellS|a Give seme ne este dete wetter 7 INDEX. ; 805 Page. Page. Gas wells in Illinois .........---.--.-.--------------- 537 | Greenleaf, J. L., cited on the area of the watersheds Geikie, James, cited on naming of glacial deposits. - 19 of the Illinois River..-..---.---------------- 496-497 Geneseo, Ill., well at ....---..----------------+------- 623-624 estimate of discharge through Rock River Val- Geneva, Ill., wells at-........------------------- -- 597-598 1G Viemaatencnmaaetascnnn mam = == Sein mnie a 489 Genoa, Il]., wells at...--.--------- 6 601 | Green River, age of the channel of.-..-..-----.----- 493 Gibson wl leewellstatj.so-es--enasesemees === 5 663 COULSClOhessene sae iseen = Spee oo Borate acceaOne 492-493 Gibson County, Ind., change of drainage in oe 97,98 | Green River Basin, erosion in...--.-.-.------------- 492 drift border in---.-...-...----.-2.------- =... 35, 39, 40 gravel plain at head of ....------.--.--------- 277 Gifford, Ill., wells near. .-...-.---.------------------- 702 loess ise ee eee einen see eewcen eee 793 Gilbert, G. K., cited on uplift of Niagara outlet ---.- 453 sand deposits near ....- : 277 reference tO ...--.--.------e een - oe =- 20 eens 84 | Greenup, IIl., wells at.....---------- : 737 Gilman, Ill., drift sheets at ...-.---.----------------- 142 | Green Valley Village, Ill., wells at -- > 692 WwellSlatines meet teecesasccnee ess BeSbebesacto0s7085 658 | Greenville, Ill., soil analysis at------ Pe 162 Gilmer, IIL, well at 581 MAICIELS Seas Sadnacspoddesocasbe dlegesrs 751 Girard, Il., wells at 743 | Griggsville, Ill., wells at and near...---.--..-.------ 63, 720 Glacialiboundaryen-snc\sseccsj= eee =e ede oT 44n) Griswold dlls Glisiitessme ta esee tessa eae alae a == 667 Glacial deposits, Chamberlin on names of 19,20 | Grundy County, Ill., altitude of ........-..---.------ 10 geographic names applied to -.---- 19-20 general features of. ---..-.--------------s------- 645-646 in St. Louis County, Mo ....--.---.------------- 64-65 RUE ET IN oa dee ee ncencooesccons Sea de RRS oN 645-648 near Plummer’s Creek .----------------+-------- 69-70 | Gumbo, extent of. -.-..-..--------. ==... ee 28-33 Glacial history, outline of......-...----------------- 20-21 (nN Wc ccechosseeasooccengsecoo angsoSeaSsigSs 29-30 Glacialistrimeecceceecssene cee ee eee 84-88, 105, 140-141 timeirelationsi0 hie seme see eee eee eee eae 30 Glacial waters, extent on the borders of the Missis- sippi River-..--..---------------------++----- 181 Hi. Gladstone, Il., soil analysis at a5 16] | Hainesville, Il., wells at 581 Glasgow, Ill., wells near...---..--------------------- 722,766 | Hallsville, Ill., wells at-.- 706 Glavin, —, elevations determined by as 433 | Hamilton, I1l., drift above. -- 58 measureménts of erosion of Lake Michigan fur- section in well south of...-....-..------.--.---- 57 nished by .--------------+-------2--220000 07° 458 OED CEN eo ces cassia seoaoscsacs cseaceonecseH 105 Gleenwood Beach, description of-- ~--- 428-442 MUSE RS See RR ne Si ths Un Aas mh ci Sr 683 Glenwood, Ill., wells near ..----- 590 | Hamilton County, IIl., altitude of ..........--.------ 11 Gobles, Mich., altitude near.-....-------------------- 350 meneral features Oft.-ma-s-= er -=ee- arenes 177-178 moraine near, description of.-------------------- 350 WELL SU Meee eee sete seein a eae ee eeaee a eee 777-778 SWOlliMeCAT eee eae ence siesta ales inna =n nlmmmin 366 | Hammond, Ind., thickness of drift at. 392 Godfrey, Ill., wells at-.--.-.------------------------- 749 | Hampshire, Ill., wells near .-...-- 594 Golconda, Ill., wells at ..-.-------------------------- 787 | Hancock County, IIL., altitude of - % 10 Golden Gate Station, Il., wells near --.--..--------- 775 general features of. - . 681-682 Good Hope, Ill., well at .----------------»----------- 686 table of wells in -- ~ 683-684 Gooding, William, report upon the survey of the wellsin.-- 681-684 Tllinois River, mentioned 418 | Hansel, Charles, information furnished by---.------- 204 Goose Lake Channel ......-.------------------------ 145 | Hardin County, I1., altitude of.--.----..---..------- ll Gordon, C. H., cited on preglacial channel of the Harman, J. H., information furnished by--.-...-.---. 675 Mississippi River. ..-...---.---------------- 469 | Harrington, Mark W., cited on the currents of Lake cited on the bowlder bed at Keokuk ------------ 95 WHO EPI S65 Ais aotaopensaccsssens Jas0806 455 cited on ‘‘ Yellow banks”’ section --------------- 94 | Harrison Harlan’s, well at ....-..----.-------------- 208 Gossert, S. D., information furnished by. ------------ 616 | Harristown, Ill., wells near....-..-...--------------- 728 Grand Detour, Ill., wells at. ...---.------.----------- 606 | Hartsburg, I1., well at ..-.--- 708 Grand Fork, Il., wells at-..---.--------------------- 750 | Harvard, Ll, well at..-.--- 2 576 Grand Junction, Mich., altitude of rock surface Harvey, Ill., well at .-. 590 PGE ade eace benooooboooae Ss HoSSenoerESeessSns 350 | Haubstadt, wells near... 67 moraine nears---------1ss-cne0~s-- == <= = 349 | Havana, Ill., wells at..... 3 689 TG Ed peo docoeeesooSsocScoce SaosEE: BASS eSOaSOoS 364 | Hazelhurst, Dll., wells at.-....----..----------------- 605-606 Grand Ridge, topography near...---. 260-261 | Hazelhurst esker, description of..-..-..-...-------- 78 Grand Tower, Ill., barrier ridge near - -- 14 ELE bp street teeta slo am en lnm 79 Grayville, Ill., wells at.--.------------ 777 Ten pU RITES 5= sso SacosScOb poe aceee= a awasecOos605 79 Great Bear Lake, topography near- 348 | Hecker, Ill., wells near ...----.---------------------- 766 wells near.-.------------------------------------- 365 | Henderson County, IIl., altitude of .----.------------ 10 Greene County, Ill., altitude of---------------------- 11 general features of .--..--.------------- 679 change of drainage in...-..--------------------- 102, 103 VUE Son Se seeopsae sone -oascsnasaese 79-681 general features of-..--.------------------------- 744 | Henderson River, course of. 479 wells inv eects Dee CRIES AO CORB CHD ROoBOE 744-755 | Hennepin, Ill., well at--. 634 Greene County, Ind., drift border in. --.----.-------- 36 | Henry, Ill., wells at ..------ ae 669 Eihubaibl ooouosbesbedosaducbodsbeesacHoneroacooscc 87 | Henry County, Ill., altitude of......-.-----.--------- 9 Greenfield, I11., wells at 745 general features of ..-... ------------------------ 623 Greenleaf, J. L., cited on descent in the lower rapids taploloLewellshitl=e=sssseeeee ss ae eee ae ee aa 625 of the Mississippi River .--..------.-------- 470 WHEAT 6 Seep hard cosnaasooS -SoRSeoDosE Ss o> 623-625 806 INDEX. Page. Page. Hershey, Oscar H., aid by-.--....----.---..------ 147-148, 567 | Illinois, gravelly soils in.............-.----.--.----- 792-793 cited on basin-like expansion of the valley of knolls in the vicinity of drift border in southern. 39 Pecatonica River. -.-se cose ee eee eee 676 | Lee County, Ill., altitude of ..-..---.-.............-- views in cuttings along Santa Fe Railway in Won V MN ee ca cS conemsntessecosocdecseictossess eastern 126 buried soilin..--.. wells in 676-678 general features of Knoxville, Tll., wells at ...-.............---..-...-.- 677 table of deep wells in eastern and southern L WANG RenendacesaonScaoS pace saSeeseceseedeas , 2 hee|CountyLoway ari{tinjes- 4-9. sees see ee eee Labradorian ice field, limits of - - 23 old channel of the Mississippi Riverin..---..... Macon wlllnwellsiatinesccore=-teceacienne ae seteae eee 669 red jaspery in 2 Lagrange, Ill., gravel pit between Salt Creek and... 438) plea staionyewelliatencs = -\---n--~-~n- === 265 Marcy, Oliver, section of beach taken by- - 3 450 general features of .--..------------------------- 692-693 shells collected by --------------- - 451 ridgein. ..-.-----.----- +--+ + --2 2-2-0 eee eee eee 244 Marengo, Il., wells at.--.----------- sei 577 table of wells in..-----.--------- Ha 696 Marengo Ridge, gravel plain on inner border Ofeniea 295 WellS\im\-----2--- 20222 wenn - 214-215, 692-697 Marengo Ridge moraine, correlations of-.-----.----- 295-296 | McLeansboro, IIl., wells at 778 distribution of...---.--.-------------+---+---+-- 290-291 | McWendle, William, information furnished by. 386 relief of 291 | Mead, Daniel W., information furnished by -- 572 structure of the drift in.-.---------------------- 293-294 well records from report of--..--------.---.------ 556 thickness of the drift in ---.-------------------- 292-293 | Medora, Ill., coal boring at..-.-..------------------- 743 810 INDEX. 2 Page. | Page. Menard County, Il.. altitude of ....-.-...-.--..----- 10 | Monroe County, Ill., altitude of.............-....--- 16 general features of --.--...-- | general features Of.-------nno cnn enn 765 wells in . eee | Wellsiin |. 2-2-9. -coe cee een eee sae oe eee 765-766 Mendon, Il., wells at... Mont Clare, artesian well at.....-....------ 56 Mendota, Il., wells at.- | Monroe County, Ind., changes in drainage in. - 104 Mephiticus mephitica.--.---..---- odes | driftsbord ern ss= seme se eens = 36,170 Mercer County, I1., altitude of. --..-...-...---.----- 9 | Montgomery County, Il., altitude of - 5 11 general features\of. -- 92-3. een ne 622 | general features of ...........-. - 740-741 WOlleyinito serie tear ante on sarees conse emans 622-623 | ICI Dp BRE SE SAS socbc: eSaebeceuaTecdacesreccoe 740-742 Meriam, Tl., wells near-.--.---.-.<..-..-...-<..----- 775 | Montgomery County, Ind., wells in..-............-. 237 Metamoraylllswellsjabsees--)2--2--- =n serene 672 | Monticello, Il., section of well at.....-..-.-..------ 220 Metropolis City, Ill., wells near -----..--..---------- 785 | oe 704 Michigan, drift in southwestern. ---..---- 353 | Morgan County, I1., altitude of 11 Michigan City, Ind., analysis of clay at -- 411) general features Of----.----<----.-n2--- enn -- 722 depth of gravel at... - 439 | WEES MonSsencsheao ssssosk so4=4 722-724 section of boring at. - 397 | Morgan County, Ind., drift border in- 23 70 section of well at--- 398 | Morgan Park, Ill., well at .--...-.. - 589-590 thickness of drift at..-.-----..------------------ 392 | Morris, Ill., wells at =>. --- 647 Milan, Ill., fossils found near...-........------.----- 174 | Morris Basin, deposits at the 423 WMA 2 Sete cated Saeccarossosasseciod Sasscnaseso 621 tHisplainimear the n-- 2s seas a 315 ME) ocr ul sew ells iat eeeects sangeet eee ane 580 | Morrison, I1., exposure of till at 5 140 MAIOS LON an LUE U8 aa alse a ow on nae 146 NOGSS atseoset cent Scene eee eee aera eee 149 Milford, Il., drift sheets at.-.............-....--..-- 143 Te GIRS NEE a peo peta Spee sense mon acncogeeeenaene 134, 150 OWES: sh = Son SsacntobasbscossnsecnosSsoseaees 660 | WHC Pb ton ase sdopecBenesdobacoseesacceessecS 617 Mill Creek, fossils|\found'at:----..-----.-2---2 ==. <-- 745 | eMorrisonvillowlllnwellsiate noses eee ese cee 727 Milledgeville, Ill , well at----. G1sn| Morton wills wellsjati--\se---- oe eee esas meee 214, 583, 691 Miller, Jacob, information furnished by -- 6287) |p Moweaquarldletwelliatocess--se seen ee eee 738 Millington, Ill., wells at .-....-..--..-- 644 | Moultrie County, IIl., altitude of. : 10 Millstadt, I1]., wells at --- 762 general features of. .--.---. - 729-730 Milton hls wellsmeanssc- 2-2 see eem eee ee sere seers 720 WOlS dines eee - 729-730 Milwaukee, Wis., profile across Lake Michigan at-.. 13 | Mound Station, Ill., wells at .-......- = 713 Minonk, I11., wells at 670-671 | Mount, J. D., information furnished by- - 206, 207 Minooka, Ill., wells at-.-- 647); MounteAtuburn, alliwellsiat---.-----+s-sscecn ese eee 726 Minooka till ridge, distribution of ....---.-...--.--- 319 | Mount Carmel, Ill., wells at ......-.....-.-.---- 611-612, 776 probable line of continuation of.......---------- 319-320 | Mount Carroll, Ill., exposures at ..--.....-...------- 129-130 Biro evureomariib Oem eect oe saeco eae 321 | Mount Morris, Ill., wells at.-----.-.-....-.--...--2- 605 thickness of drift near - -- 320-821 Mount Pleasant, Ind., drift border near ..-.-...-...- 36, 69 topography near 320 Mount Pulaski, Ill., wells at.......--..-..--.--..--. 709 Mississippi bluff, section at Muscatine, Iowa-.-...-.- 47-48 | Mount Sterling, Il., wells at - 5 713 Mississippi River, altitude of rock bottom and pres- Moweaqua, I1., soil analysis at--- 5 162 Qn binivere ses asese ate cees asec neeetaae 474-476 | Muck, buried, at Belleville, Il - 3 763 composition of ridge between Illinois River and. 60-61 | at Bethany, Ill ......-.... = 730 deflection at Leclaire..-...--.-......-.....------ 463-464 © at Dalton City, Ill.--. — 217 deflections of, south of glacial boundary ....---- 474 | at Delavan wll yeeecereeeete eee nee cen ae 206-207, 691 determination of the date of excavation of lower at Hopedale lili sespeceeee asc cs seae eee seer 214, 692 WA Bpscoreansbeosocsesadcacnesensacosdsocos 470-473 GUNN A 0S ne eh cabboss Sascepcossencece ae eacae 695 elevation of the abandoned channel of the .-....- 93 | at Mahomet shllteemes seme aee oe ae ae ees 703 limestone belt along ---..-.-.---.- ......--.---- 14 atuMetamoraye ll teemetsesneseseseeesaa se eee 672 material in the abandoned channel of the .-.---- 93-94 at) Mount! Carroll eens eccn oe sore onan eeete 129-130 preglacial course of, below Clinton ---...-- 466-467 atpbanayiloaeaseeemen samen anaes eee ee 726 reestablishment of, below the lower rapids - 473-474 | at Rocks sland eller ses e ocean sae eee 114 temporary displacement of the.-.-.-.-.-.. 89-97 | at Windsor, Ill.--..... 202, 739-740 Mississippi Valley, artesian wells in the.-..- 56 | in Christian County, Ill. == 725 drainage for the ice sheet in the 7 in Dewitt County, Ill - 3 705 relative sizes of the present and preglacial...--- 468-469 inkWordi County lll eeeae ese see eee ee eee 663 Wellgting 768 Ravinia, Il., section at ...-.------------ a 386 | Rushville, Ill., wells at .---------------+-------5007 712 wolliat .22---------0--- = 45 581 | Russell, I. C., cited on Leaf River or Adeline esker- a7 Read, W. T. B., referred to ---. 584 | Rynear, knolls near.---------------+---+++50700077-7" 230 Red Bud, I1., wells at ..----- 768 = Rentchler, Ill., wells at. --- 764 =e Richardson, II1., wells near. --- 597 | Saginaw lobe, extent of... --------------+------77---- 341 Richland County, 1l., altitude Of nee nee eee eerie 11 | St. Anne, Ill., wells at .--------------------------*+"- 654 general features of .-------------+------+7720777> 756-757 | St. Charles, Ill, wells near. ----- a 597 wellsin! ---c< 588 wWelllatwess neon eee 400 Riverside, Il., wells at ---------------------------77- 589 | St. Joseph River, drainage basimiOtsssess= == =a 540 Robinson, Il., wells at---------------------+------ 755 gravelly plain on..----------------+---25000777 7" 434-495 Rochelle, Ill., wells at -.----------------- . 607- 608 moraine near .----------------------""----7-" 342, 352-353 Rock Creek, belt of loess in ------------- 2 150 structure of drift along.--.----------------------- 399-400 Rockfalls, T1., wells at ------------ _ 616-617 | St. Louis, Mo., deposits near - 64,71 Rock floor, table of altitudes of .-------------------- 9-11 drift border near 35, 37, 39 Rockford, Il., analyses of sand near ---------------- 163 limestone belt near-.--------+------------------- 14, 15 gorge near 492 | St. Louis County, Mo., glacial deposits in------------ 64-65 pwelleatiececcncicszocce see -e eee anic === nme 572 | St. Marie, Ill., well at ---------------------- 755 Rock gorges, measurements of, in northwestern St. Mary’s, Ill., wells at.------------------- 656 Mino Sos sae ese eo eae eee 494 | St. Mary’s, Ind., duittatess ses 201 Rock Island, Il., analyses of loess at---.------------ 161 silt near. ..--------------------- 208 exposures of silt near .------------------+-2-777> 114 | Salem, I1., coal boring at 2 759 section of well at..------------------- 114 | Saline County, Ill., general features of. ---.---------- 181 782 Rock Island County, Il, altitude of -.-.- : 9 well§in: -----+-c-2-e-s===05c5-5 "== o ean nan 781-782 general features of-.------------- . 619-620 | Saline River, course of- - 527-528 table of wells in ..-------------------------7-7--- 620-621 | Salisbury, R. D., cited on drift in southeastern Illinois wells in ---.---.--------- eo onGuSose 619-621 and southwestern Indiana ------------------ 109 Rockport, Ind., loess near -.----------------"---+777- 156 cited on glaciation of limestone ridges ..----+--- 15 Rock River, course of. --.------------------------ 485, 486-487 cited on mineralogical constitution and size of descent of the lower portion of------------------ 492 Towan loess .------------------------- - 158-159 drainage basin of .------------------------5777>> 483493 cited on the drift border 37 excavation along, near Pine Creek..-..--------- 489 fossils collected by-------------- 168 gravel plain in valley of. .-..--------------++---- 490-491 glacial work of.--.------ 3 preglacial valley of .------------------ - 483-484 reference to---.------------- 43, 160, 166, 543, 547, 714, 745 rock excavation in the new course of. --------- 487 | Salisbury, R. D., and Chamberlin, T. C., cited on the ‘table of well sections east of, in Winnebago drift border in southern Wisconsin. --.----- 43-44 County, Ill.--..---------- 570-572 | Salt Creek, course of ...------------------------++--- 504 time of deflection of 491-492 gravel pit between Lagrange ANG\-=-2cee=es=- 438 Rock surface, Michigan, Indiana, and Iowa, average old bay in basin of --------------+-------+---+--- 431-432 altitude 0f.-.--+--------«--------===0------=- 12 outwash in valley of.---------------------------- 211 Rockville, drift near :-...-----+----+----+-------777- 200 topography near B45 Rolfe, C. W., aid by.----------------++--22-20 5000777 7 | Sandoval, Ill., wells at.----------------- 759 cited on altitudes in Ilinois---.---.------------- 7,12 | Sandwich, Ill., wells at ----------------- 604 maps of Chicago Outlet by, mentioned. --.---.-- 421 | Sandy Creek, watershed of -- 513 records of wells collected by------------- =o 223 | Sanford, Ill., section of drift at--------- 201 referred to .--.-----------+------------°--- . 375,701 | Sangamon, analyses of bowlder clays at------------- 163 sections of boring reported by -------------»-- 235, 236 width of the Illinois Valley near. --------------- 499 Rome, Iowa, abandoned channel of the Mississippi Sangamon County, Tl., altitude of-.----..---------- 10 River near -.---.---------------7-- 922 90, 92, 93 general features of ..---------------------------- 724 Roodhouse, Ill., wells at ------------++--+------+777> 745 wells ill= co cceecedenoet eeew shen — nance 724-725 Rosebud, Il., wells near .-------------------+7-7+7>- 787 | Sangamon River, exposures near Mahomet, on-. 216 Roselle, Tl., wells near -------------------+----+777> 592 drift in the valley of see 214 Rossville, Ml., bowlders at---.---------------------- 269 outwash in valley of .--.------------ - 210-211 wells at 699 topography near ---------------------- : 227 Round Grove, Ml., exposure of till at--------------- 140 watershed of --------------- --- 517-520 ridge at ....----------------2=<-------=- 135 | San Jose, Ill., wells at .----------------------------+- 689 section of well at 139 | Saunemin, Il., wells at .----------------------------- 667 814 INDEX. Page Page. Savanna, II1L., fossils found at.....-..--.-...-----.--- 166,168 | Siebenthal, C. E., cited on drift in Owen County. --. 70 AWOL 8 fete eters oelalen tea eee crise ete tae 611 cited on the glacial boundary.........--.-...--.. 36-37 Sawyer, Mich:,section at---------------------s-<---- 399 Teference tO sean see ane e eee e 38, 88, 104 well at 439) | Silt, buried, at Atlanta, Ill----.-..-.2-- 2222-2. 22a ae 206 Sawyer Station, Mich, thickness of drift at - 392 lav Monticello lle e artes tae eee 220 Saybrook, Tll., wells at ------.--.-..--..--...- 695 at Muscatine slower ose ee ne eee eae 47 Schererville, depth of sand at-- 439 at Stratford, Il] .....-- 138, 606 Schermerville, Il., wells near ......-....- 587 in Adams County, Il ....- 61, 62 Schlemming, J., information furnished by-.--------- 613 in Muscatine County, Lowa .. - 40 Scotland; Ind=) tillat ic < oo - oo e w cee ene 69 in northwestern Illinois --- - 111-118 Scottville, Ill, wells at .-..-..----------..-----.-.--- 743 in Rock Island County, Ill .-----.--.-... e 621 Scovell, J. T., on striw in Wabash Valley.-----.-.--- 87 | on east bluff of Mississippi River.....-. 115 Schuyler County, Ill., altitude of.-----.----- aancesne 10 | MeaTyICGO ku kyo OW satan ne ne ee ene ee 94 general features of.......--...-..--..-----.----- 711-712 | mear Mahomet, lllieec sesso sese see eee 237 WOLSpNwseaa eee eee 711-712 MesarAviaAshin' eg LON elles see cee ee eee 32 Scott County, I11., altitude of. 11 mearwarmouth Lowaeeeenesess eee ene eee 51 general features of ....- -. 721-722 | Silver Creek, watershed of . - 525-526 TGR itetcene aE cmanpauoo burton hoSaSocseas 721-722 | Silveria formation ... 112-118 Scott County, Iowa, exposures in.-..--..--..---- 46 | Simpson, C. T., fossils identified by.. 115, 168, 169, 170-171, 451 Senachwine Creek, watershed of....--...:...-.----- 513 | Skunk River, interglacial course of ..-..-.. - 122-123 Seneca; Dliwellsyats22cse~ scenceses = Soe eee eae ee 638 | Sloat, William, well section of.......- 2 51 Shannon, Il., wells near. --- 613 Smith; }.well/section of: --5-:---------+-+s-4--- 51 Shaw, James, cited on Leaf River or Adeline esker- - 76 | Smithboro, Il., coal boring at mol cited on well at Princeton, Ill.--..-..-.---.---.. 628 | Snyder, J. F., fossils collected and identified by -...- 171 information furnished by ...-...-.--..-----.---- 612 information furnished by.-..-.....-.------------ 711 Shawnee Township, Ind., outwash in - 239 | quoted on section at Virginia, I]..-...-..-...--. 108 Shawneetown, IL, boring at-- 65-66 Soil, buried, at and near Coatsburg, Ill. .-...-.--- 62, 109, 716 wellsvatic=s cess peseese ence 784 at and near Davenport, Iowa .......------------ 45, 128 Shelby County, I11., altitude of ---..- ae 10 at and near Keokuk, Iowa....-..-........-.... 94, 95, 96 general features of-..----......... -- 137-738 | at Arlington Heights.---. 587 WMOLI Ass Se Se ae ee OE Cee era 737-740 at Ash Grove, Ill.....--. 8 661 Shelbywilleull silt mearteses eee ee en aeseacer eee ee = 198-199 at Atlanta, Il] .-- 206, 708 Wwellsiateascouesscmem mem ciite cats meine aera eieerae 739 atiClaytontsbllyssi nas cne cane Alcs ae ates ceeeeee 660 Shelbyville drift sheet, extent of -.-......--..-...--. 192 at Dalton, Ill 730 Shelbyville moraine, character and extent of....-.-- 192-213 at Decatur, Il 204 character of the outwash from.........-.--..--. 208 | at Elkhart) iss astees se ahs 58 ole Sa ee 709 distribution of ....-..-.---...--- - 193-194 ati Galva sssoen erie stocese acs nee cee es sees 130, 624 range in altitude of .- - 194-195 EUR OR ION) ocoeeesboboreceescencabeccoaseces 659 MEO EO bersoos sacndesccsdebecadeacesca Be 194 LG EECA S 215 300) eaters mantener 217 structure and thickness of the drift of. -- -- 197-208 Bip Mice) lee sooo sotoseosoabesbensesonsssece 293 table of stria within limit of.......-- -- 412-414 at Muscatine, Iowa 47 tonoerap hyiO faassen see eee eee 195-197 at Pana, Ill......- 107 topography of the inner-border tract.--...-..--. 213 at Plano, Ill ---- 644 Shelbyville till sheet, thickness of the inner-border atiRoclovillep lll eeeemeemees ese oe aoe eee 200 URE ironosensasoce stobsoscsheanbbadansassags 213 atyRoundenovey el lameness ieee ae eee eee 139 Sheldon, Il., analyses of bowlder clays at-..-.....-- 163 abi Sta Charles yell areas sera telat alae 597 Te GER Seen esos oncaosanesasoscortasice <5c055 659-660 ati Salem Wllleeeee senses amas eee eee ee eee 759 Sherburnville, Ill., wells at. 654 at/Shavetail) Slough. 2. . <2. scence se eee sens 661 Shiloh Hill, D1., wells at-...-..---.-... 769 atiUrbanaw llc cece ss sone anaes Senne meeene 235 Shimek, B., cited on distribution of fossils. 165 at Virginia, I] .-- - 108, 711 citedionwbimnea essa e sneer beeen aS 172 at Woodstock, Ill -......-... ocepticeticctoedess 577 list of fossils revised by .-...-...---.--.- . 168-169 between Dudley and Kansas, I1..--. 733 notes on fossils. --..----- Dnotnoabosasodsebshscasan 171-176 between Oregon and Mount Morris, Il. 32 606 quoted on loess fossils..........---...-----.----- 175-176 depth of, in Illinois. ........-.-...---- - 263-266 Shirley lll srw ella ya Gee eee et ee eee 695 elevation where it occurs...-..-.....-.----.---- 29 Shoal Creek, watershed of.--------.---.------+--..-- 524-525 exposures of, near Henton, Il...-..........----- 59 welldnhyalleyloteen esse smeaeee ee metas eet 751 in Adams County, Dl. ------.~-..-- 2-2-8. 61 Shovetail Slough, Ill., wells at.......-.-....-..------ 661 Ho): AUG TO oso eat coose sisscoccsbeosaesiosss 576 Shufeldt, George A., jr., referred to- - 584 in'Bureaw County, USS 2s sscesmee === 2s - eee= 264, 627 Sidney, M11., section in boring at ---. - 236 in Champaign County, Ill...-..-.. --...-..-.--- 240, 701 wells at 702-703 in Clark County, Ill .....-- ae 733 Siebenthal, C. E., cited on deflections in Cook County, Tl. -- 583, 586 TR te Pci ssoeeHeceebic oNee cums seeiag¢obersddssos 533 in Dekalb County, D1 264 cited on deflections of small streams by glacial intDenmark slow aseeee see eee eee eee 55 IDOUN MALY seecten epee acide Seae ee on eee reece 102-103 in Dewitt County, Ill ...-....-..--..-.. 2 705 cited on drift in Morgan County .....--..--..--. 70 in’ Mord County; Woes esamescsececin csr seeieeee 664 INDEX. Page. Soil, buried, in Hancock and Adams counties, Ill .--. 105, 106 in Iroquois County, Ill ....-----.------------ 141, 265, 657 in Kane County, Ill ..-...---.-- 263-264, 301, 597, 598 in Kankakee County, Ill .---- ---- 325, 654 in Kendall County, Ill.....-.....-.------.---+--- 645 in Lasalle County, I11- ..- 264, 641, 642 in Lee County, Ill---- 264 in Lee County, Iowa .........------------++----- 40, 52 in McLean County, Ill-....--.....---------- 265, 693, 696 in Ogle County, Ill .......------------++--------- 607 in Parke County, Ind........-------------++----- 200 in southeastern lowa..-..----------.-- - 120-121 in Vermilion County, Ill..--..-.---------- 698 in Will County, Ill..-...-..------.--- 651 on east bluff of the Mississippi River. . 115 near Baylis, Ill.-.--..--..-.--.--------- 720 near Belvidere, Il. 139 near Clinton, Il-.-. 205 mean Orescent,ellluemejasceceinenteisns same seinen === 659 near Denmark, Iowa ...-..--.-------------------- 54 near Elgin, Ill......-.--.------------------------ 585, 596 near Greenup, Ill.-.----..----------------------- 127 near Hamilton, Il...-....------------ 57 near Lily Lake, Ill .....-------------- : 294 near Mahomet, Ill.---. 30 216 near Marshall, Ill ---- 129 near Milton, Ill -.--- 720 near Mount Carroll) Ill.--.-.-.--...-.--.-------- 612 near Mount Pulaski, Il.-.--.---.----.----------- 709 near Newton, Ill....--.---.-.------------+------- 717 near ‘Thawville, Ill ...-...-..-------------------- 661 near Wapoella, Ill......--------------+----------- 706-707 near Washington, Ill ....----.-------------+----- 32 near West Point, lowa.-..--.--.------------ 53, 70 Somonauk Creek, knolls along ---.---.---------- - 287-288 Sorento, Ill., wells near. ------- 751 South Fork, watershed of .-----.------- 5 519 South Haven, Mich., section of boring in 401 thickness of drift at .....--..------------------- 392 South Kishwaukee River, sand and gravel deposits OM lcciciciclecceccc cau cecceesecner-~\-sese=5 5055 = topography near South Riley, Ill., wells at..-.-.--..--.---------------- 578 Sparta, Il., section of Pleistocene beds near..--.---- 117 WellS) Abie eect e ean tceinln = ni-=-n == saaenadpaodese 769 Spaulding Station, Il., well near....---.------------ 585 Spencer, J. W., cited on uplift of Niagara outlet....- 453 Spoon River, watershed of ------.--- --- 516-517 gravel deposits near valley of.------------------ 276-277 Springfield, Il., generalized section of wells north- west of 125 wells at ..----.--- 725 Spring Hill, Ill.,exposures near ...----------------- 133, 140 paha near ...-.--------------------+----+---- 22+ 135 wollsimealee----cls- coer eceerees erie n= =n nm 618 Spring Lake, depth of...---.------------------------ 441 Stark, Ill., wells near. .-.-----------------------+----- 672 Stark County, IIL, altitude of -- 10 general features of ...-- o¢ 672 wells in ..-..------- 2 672 Staunton, Dl., wells at.-...-------------------------- 743-744 Steeleville, Ill., wells at 5 769 Stephenson County, II1., altitude of 9 MRE O? scosecepecuoopopSceancasocoss eppsansossccs 567 silt deposit in --...-.-..--.------+------00+------ 113 table of well sections in.....-..---.-------- ---- 568-569 815 Page. Stephenson County, Il., transported rock ledges near Dakota....-------2---------2-+++-=2----- 83 567-569 616-617 146 606 51 Stilter, William, well section of ..------------ 42 Stockton, wells in preglacial valley-north of - 566 Strata, altitude of, in Illinois ..-..---.------ 553-554 Stratford, exposure of fossiliferous silt at ..---.----- 138 wells at 606 Strawn, Il., wells at..-------------------+--+-------- 667 Streator, Ill., wells at---..-----.-----------------+--- 639 Striw, glacial.....--...-.------2+ e22-- eee eee re eee 84-88 at Burlington .....-------.----------- +222 2222 e+ 85-86 near Hamilton, Ill....--.------------------++ 105 outside the Shelbyville moraine (table) -.--- 88 Stronghurst, Ill., wells at ..--..-..-------------- 680 Structure of drift border in southeastern Iowa. . 40-43 Sugar Creek, belt of gravel on .--..--.-------- . 272-273 COULSOlOfis are nam oleae ii 536 gravel terraces in valley of. 239 watershed of ....-.---.-.--------+----+----------- 519, 536 Sugar Grove Township, Lil vellsin= assesses. <---—- 599 | Sullivan, Ill., depth of drift at-.-..----------------- 217 SIG ERH Ge onoecosbencoggncensossHSHoeQesRIOSce509 730 Summerfield Ill., wells at ----.---------------- 763 Summit, Ill., wells at .....--.---.------------ 5 589 Sumner, Ill., wells near .--..--.---- 756 Swanwick, Ill)., wells at.....--.------- 771 Sweet, T, O., information furnished by. - ss 371 Sweetwater, II1., wells at- 710 Sycamore, Ill., wells at.---.-------------------+----- 603 Sykes, J., well section of .-- 60 fq0G Taylor, F. B., cited on the beaches of Lake Michigan - 420 suggestion by ..---------------------+++re+ 222+ 356 Taylorville, Ml., wells near. ..------------------ 726 Tazewell County, II1., altitude of - c 10 general features of---...- -- 689-690 thickness of drift in - = 265 wells in Soo 689-692 Terre Haute, Ind., analyses of loess near..---------- 164 Texas City, Ill., wells at...------------------------- 782 Thawville, Il., wells at ..--------.------------------ 661 Thebes, Il., deflection of the Mississippi River at-. - 474 SENG So etbeod bos bocossase scbeeeoes ease aeeRseoS 786 Thomasville, Ill., wells at ....---------------- 741 Time, I1., exposures and wells at ..---------- 63 AES EMR coasting paccspsaseeeses 721 Timpe, F., well section of. --. ---- c 53 Tippecanoe River, altitude near- . 331-332 sand ridge along ---.-------- 329 Todd, J. E., cited on drift deposits - 37 cited on striw at Alton, Ill..-------.------------- 86 Toledo, Ill., wells at -....--..-----.------------+----- 737 Tolleston beach, altitude of. ..--.-------------------- 452 composition of, in linois ----.------------------ 450 composition of, in Indiana.------- 2 450 course Of ..-.-.------------------- - 447-450 Tolono, drift at. .-.-------- 233 Toluca, Il., wells at....--.-------------------------- 669 Toronto formation ...--.--------------------- 20, 185, 189-199 Totemeir, Anton, information furnished by. --..----- 51 816 INDEX. Page. Page. Monlon will spell sistem ee eteatnste sietoae wala arcinta rate 672 | Vermilion River, course and watershed of the Wa- Mower wellsyateseeeetebedessie ks eee eae 739 LA Nerwesoteses is TR We We a a pea Solas eee eee 536-537 Townships, method of numbering....--------------- 4-6 | Vermilion River, drift structure along..-.....--..-- 283, Trail Creek, drainage basin of..-----..-..--.-------- 539 AO HER CINE Macias Se cbocoSpnceenpconoosoososnS 279 old bay in valley of.--.-.---.------ 432 sand ridge near . - 330 Troy ell spat OlLS 2 Gece iaeee liao aie sini 750 topography near - 311 True, F. W., cited on bones found in peat = 42 watershed of .-.---. 511 examination of animal remains by- -- 124 | Vermilionville, Ill., well at.--....-.--.------..-...-. 639 Turkey Creek, ridge along ---...-------------------- Sotelp MeXMONt LL1., wells) ate ssee ste se eee eee eae 688 Turner Junction, Ill., wells at....-..--.------------- 5OSR VOLO a D1]. wellsiatemeas=ses ae ee riy cent ees 647 Turner Park, Ill., wells near ..--.-.---.-..---------- DSB) iVersailles; Jl! wellsyateo=--\--- 2-2 25ss eee nee 713 Tuscola, Ill., wells at and near .--.---.-.--------------- 222,731 | Vicksburg, Miss., analysis of loess at....-...--.---. 164 Tyrrell, J. B., cited on separation of Albertan and Vienna, Ll: swellsjatss-sss225-— ace ceeineee eee 786 sub-Aftonian drift sheets .-----...--.--.---- 2 almivarden, wellsat=-s--2- ese ee eco ceeeeee aS 743 U Virginia, Ill., analysis of bluff loess at. -..- -- 160,161 5 fossils found at........----..---- 171 Udden, J. A., aid by--- oes - 114, 147, 148, 187 section at ..-- : 108 analysis of loess by ----------------------------- 159 WWE fitiscosodbos choose consebsancotionsancbnadedcse 127, 711 cited on loess deposition -.. 177, 179 cited on old lake bed in Muscatine County, Ww . MOV Gls Seanocssedctosadccodassn occoesetosssaes 96 cited on the rock constituents of the drifts of Wabash County, Ill., altitude of........-...--------- 11 Muscatine County -..-.----------------------- 44 general features of .-.---.-------------- =. .-2 8 775 cited on wells in Rock Island County ---.-.------ 621 WAIST oon sree Saseostocososqcadcssosacoborconte 775-776 fossils collected by-.--..--.------ 415, 168, 170-171, 173-174 | Wabash River, deflections of. - Ss 530 information furnished by...-------------.----- 412, drainage basin of -.....----. -- 528-529 616, 618, 620, 624, 625, 630, 634 gravel terraces in valley of -- a 238 investigation of the preglacial course of the knolls east of.--.------------ - 228-229 IMISBISSID Dieses eean eee eee eae seen 463, 465, 466 outwash in valley of - - 208-209 trip with 145-146 preglacial valley of------.-.--..---.-.....----.-- 529-530 well record obtained by 615 BETIS MeV All| ysO feetaelataia olotalararal a alae ol talatmel lel aietatta 87 Udden, J. A., Calvin, Samuel, and Bain, H. Foster, Wallace,'S. Ji, reference to /.---.-.------.2-.--.----- 95 WOLEPOM LILES foment nineteen 44-45 | Wapella, Ill., wells at..-...-.-.--.-..--.----.-..----- 215, 706 Udden, J. A.,and McGee, W J, cited on the displace- Warren, G. K., cited on preglacial channel of the ment of the Mississippi. --.-.-----.--------- 90 Mississippi River .-..--.--.--.---.------.--- 469 Underground waters, classification of--.------..--.- 550-55 | Warren, altitude of. --.-- 566 UM OFF OSS 11S ees re tee ere telat ee ae a 167 wells near------------.-.-... 566 Union County, Ll., altitnde of-. 11 | Warren County, DL., altitude of . 10 Union Grove, Ill., wells near .-. 616 general features of ---.-.-. Ss 678 Union Hill, Ill., wells at---.-... 654 wells in Pace eecean -. 678-679 Urbana, I., section of boring at . 235 | Warrick County, Ind., changes of drainage in --.--- 98 Wl] Stati osee sence ena secin 702 | Warsaw, Ill., analysis of soil at-..-.-.----------.--- 163 Wsticksllletwellsin Gar sees arte ee se seeae niet eerie 615 OXPOSULCS Aber anes e eee nents =e aaleee 94-95 WAN ON LN Uy oA ae Se ee cola ceecocsonens 638 WOL]S] aliens else see ee et leaner 683 yr Washbvrns Mound -. 299 r Washington, Ill., section of a cutting near .--....-.- 32 Valleys, preglacial -------- 2.2... eee 17,18 WG) LS Veltysee et eee rete tet ieteleleteta - 690-691 Valvaraiso morainic system, altitude of, range in-.. 343-344 | Washington County, I11., altitude of... 11 CIShrIDUGLON Oly sem male ae alee eee ee 339-340 general features of 770 drainage of the.- - 379 wells in 770 drift, thickness of - . 353-355 | Washington Heights, IIl., well at. 589 eastern border of -- 27340-3410 ||) iWraterloo; Lllenwellsiatesss-se-2seeeaeeee aes eseeeee 766 topography of. 345-348 | Waterloo quartzite, movement of -----.------.------ 110-111 Van Buren County, Mich., thickness of drift in---.- 355 | Water supply, sources of, for towns in Illinois..-.. 558-564 WOLISt eso eee beee emittance 366, 347, 368, 370, 371,372 | Watseka, Ill., wells at -...----.-------..----.------- 659 Vandalia, Tl; wells near ----------.-----...----.---. 752-753 | Waucond, Ill., wells near........-.......-.-.--..... 580 Vanderburg County, Ind., change of drainage in ... 97 | Waukegan, Ill., beach near....---..-.------.------- 429 rifiiibord erin sees sieeteeesctente see eee 35 SWS Ain ceescotebetsedoasoc : 580 Wells}in! /22-- 2-2-2. acesinademactwansnocscmeccones 67 | Wanpecan Creek, watershed of. - 508-509 Van Tuy], S., well section of. 54 | Waverly, Ill, wells at.-.....- 724 Velpen, Ind., col near.-.-...-..-- 100 | Wayne, Ill., wells near...---.-- 592 Vermilion County, 111., altitude of- 10 | Wayne County, IIl., altitude of - 11 drift structure in -..-.-.-.-- 267 general features of ...---.--.---.----------.----- 774 general features of. - --- 697-698 Wi UE TN cen sctcicpoonedp-enteeseorcacecost cece 774-175 inUlT OEM pI sHpeac anon sos so aesdoSeceseneSosean5 239-240 | Waynesville, Il., wells at...-.-.-.-----------++-+--- 706 Ye ET i sri pe OSH ROC I COSCO CIS HI SSSOOSS 697-700 | Wellington, Ill., wells at........-...-.-.-.-.-------- 660 INDEX. Page. Wells, artesian, conditions for...........-...-.-.--- 555-556 | NWienona whl werlsiat: «—so-o-0)- = oe eet 669 West Point, Iowa, exposure of Sangamon soil at. 129 SCCHONSMeAL Seine one e see eee see os a eee 53, 70 West Salem, Ill., wells near..............-....-.---- 776 AWiheaton will wellsiat=a-esscse eee ~ =o see ceases 593 Wheeler, H. A., cited on drift deposits : 37 Wheeler, Ind., section of ridge north of. 396 White, C. A., cited on animal remaius at Darennene Towa Bet veieic\e siesta oye ne nie sietereiee\s ciate wale tin aieneterete 127, 128 cited on peat bed at; Davenport, Iowa. . n 128 TREY KEINE) U0) Sp asggoemn Sena coe SpOSHOaeIaS 88 White County, Ill., altitude of ..........--.-.--..--. 11 general features of ......-.--...-..-------.sae--- 776-177 WAM II ausdscodescees AconbEeseosasbaosoooadesoe 776-177 Wihitehail, Tll., wells at----.-...--.:--.-.-...------- 745 Wihiterbakes dep thiofes= can - ema te ee eee eee le 441 White River, course and watershed of..-...--------. 532-534 preglacial and present course. --..---.-.--- 104 preglacial valley of..-...-..-....-...----- 36 534 Whitney, Milton, analyses of loess by- - 159, 160 quoted on analyses of white clay... 796 quoted on bluff loess........----------- =o 794 quoted on bowlder-clay soils of Tlinois.-......-. 792 (QUO TEC Onis O19 tem ete eeseeee = een neti ctatarei= = 789-790 | Whiteside County, Il, altitude of........-.--..-.--- 11 general features of...-...-..---.-.---.------ 148, 614-615 TG ERIS GIG) No iTNG Bone Roc ck eg he Saco aessSoeopUabSdde 154 fablelotawellspicmestetes= senses eecemm selina 617 WON ocosbgEbsaes tedods coae nada cusnoebondccEaE 614-619 Will County, Tl., altitude of...-.-..-..--.--..------- 10 general features of 648-649 table of wells on Valparaiso morainic system in. 650-651 | table of wells outside the Valparaiso morainic system wells in Page. Wanvetkuplllsrittmear-------.-. acne nneenceeeen 385 till ridge near... - 381-382 welliatigesse=sseee 587 IWHSCOnsinvaltitud Oto sess eee ee 7 | Wisconsin and Iowan drift sheets, soil ratiil peat be- UNCLE coos senootéoc aca nsacesensn ise eeaee 185-186 Wisconsin drift, character/ot.--.-----..--2---:----0 141-143 beached loess beneath the.-..........-...----... 187-188 limite of: Sosorees aaesete wnsciaccine sete sane see eis 262-263 Wisconsin drift sheets, extent of early 19). Wisconsin, structure of drift border in sonthern.... 43-44 Witter, F. M., fossils identified by...-..-.........--. 168-169 cited on mammalian remains in loess - - 166, 167 cited on wells in Louisa County, Iowa - 49 Woburnlllenwellstates ees eee eee eee 752 . Woodford County, Ill, altitude of....-- 10 eneralifeatures(O fesse mien eee eet ateease 670 CERT i asemepassmasqaacunosaseeao-ssemoauad 264, 670-672 Woodstock ltwellstatiosss-—-meae ates eee emer 577 Woodworth, J. B., cited on Nantucket as a morainal island SC. Curtisiand=ssse-.ces-es- seers 272, Woolridge, C. W., cited on the deep channels along east shore of Lake Michigan-..--..-...--...- 441 Wooster, L. C., geologic work of . 3, 339 Worth, Ill., bowlders near.---- 426 wells a Bbossoeesaoobedanes Soe 590 Worthen, A. H., cited on drift de noite cebobSdoscede 37 cited on drift phenomena of northwestern Ili- NOIS Hoa a sos seeaces See eapececenteseecet eee esis 76 cited on changes in drift structure at Clinton-- 205 cited on mammalian remains in loess ......--..- 166 cited on Niagara limestone areas..-...-.-..----- 16 cited on section at Virginia, Ill.--.............- 108 cited on section of well at Pana, Ill .. 107 cited on the interval of deglaciation - 125 TOLL GN CONLO aaa eee ees elec 2, 157, 526, 714, 726 Wright, G. F., cited on drift deposits. 37 cited on strive in Williamson and Jackson coun- eS LM O1S =e eee ee ee ee 87 Wyoming, I11., analysis of soil at 162 WAS GP 65555 Sons onaseecerosenaesbesaoscS s5an5 672 > Exes SNEni A pl ssuw Cll Syaiteecene eae aantalalre eee eee 758 SEC Yarmouth, Iowa, bones found in peat near........-. 42 Secuions Of wellsmeaL. a=. sac eaises sea =e eeees 42,51 Yarmouth soil near Denmark, Iowa 54 aia tesulllen wellsiate--s2ser sec ecae se se/ce .. 677-678 “Vellow banks” section near Keokuk, lowa ES 94 Yellow River, watershed of the.-...-...........-..-- 507 Wavorlcvaille ls wellovatereccecer cuss cinterceseeineerees G44. Z. Zeeland Ridge, altitude of.....-.......-.....-..----- 391 COUTHE Of. oo nn cnc ce cceee sane anns 390-391 Williams, L., wells drilled by Willliamstield, I1., wells at.-.---------.-.---.------- 677 Williamson County, II1., altitude of-...-..-.-------- 1 general features of .....------- _ SOs Sees eee 780-781 Walmette ll welliat) 2-22 ----25 2 oe 587 Wilmington, Ill., wells at ..--.------.----------.--- 650 Wilson, James H., report upon the survey of the Tllinois River mentioned --.- 418 | Winchell, Alexander, cited on bowlders in Van Buren County. -----.-- 358 cited on deep channels along east shore of Lake | Michigan ...-------------.------.----------- 441 Winchester, Ill., wells near ..-...-------.---------- Q 722 Aan dSOrspll pepe State sortase siete etn = -aial iar 202,739 SWan eve PUL ew Olli aise eee satete eitel ae alain llelte ma 769 Winfield, Iowa, abandoned valley near....------ 90, 91, 92, 93 Winnebago County, altitude of..----..-------------- 9 | gravel knolls in = eie e186) situation and areaiof -------.-- 252-322. =. -- 569-570 table of well sections in - - 570-572 till ridges in.-..-- 135 MGHIE DN, Sons sooddoa sosaoo sosocSnSSsaschoopososece 569-573 MON XXXVIII——52 ADVERTISH MEN 2. {Monograph XXXVIII.] The statute approved March 3, 1879, establishing the United States Geological Survey, contains the following provisions: “The publications of the Geological Survey shall consist of the annual report of operations, geo- logical and economic maps illustrating the resources and classification of the lands, and reports upon general and economic geology and paleontology. ‘The annual report of operations of the Geological Survey shall accompany the annual report of the Secretary of the Interior. All special memoirs and reports of said Survey shall be issued in uniform quarto series if deemed necessary by the Director, but otherwise in ordinary octavos. Three thousand copies of each shall he published for scientific exchanges and for sale at the price of publication; and all literary and cartographic materials received in exchange shall be the property of the United States and form a part of the library of the organization: And the money resulting froin the sale of such publications shall be covered into the Treasury of the United States.” Except in those cases in which an extra number ot any special memoir or report has been sup- plied to the Survey by special resolution of Congress or has been ordered by the Secretary of the Interior, this office has no copies for gratuitous distribution. ANNUAL REPORTS. I. First Annual Report of the United States Geological Survey, by Clarence King. 1880. 8°. 79 pp. 1map.—A preliminary report describing plan of organization and publications. II. Second Annual Report of the United States Geological Survey, 1880~81, by J. W. Powell. 1882. 8°. ly, 588 pp. 62 pl. 1 map. Ill. Third Annual Report of the United States Geological Survey, 1881-’82, by J. W. Powell. 1883. 8°. xviii, 564 pp. 67 pl. and maps. IV. Fourth Annual Report of the United States Geological Survey, 188283, by J. W. Powell. 1884. 8°. xxxii,473 pp. 85 pl. and maps. VY. Fifth Annual Report of the United States Geological Survey, 1883~84, by J. W. Powell. 1885. 8°. xxxvi,469 pp. 58 pl. and maps. VI. Sixth Annual Report of the United States Geological Survey, 188485, by J. W. Powell. 1885. 8°. xxix, 570 pp. 65 pl. and maps. VII. Seventh Annual Report of the United States Geological Survey, 1885-86, by J. W. Powell. 1888. 8°. xx,656pp. 71 pl..and maps. 3 VII. Eighth Annual Report of the United States Geological Survey, 1886—87, by J. W. Powell. 1889. 8°. 2pt. xix, 474, xii pp., 53 pl. and maps; 1 prel. leaf, 475-1063 pp., 54-76 pl. and maps. TX. Ninth Annual Report of the United States Geological Survey, 1887~88, by J. W. Powell. 1889. 8°. xiii,717 pp. 88 pl. and maps. X. Tenth Annual Report of the United States Geological Survey, 188889, by J. W. Powell. 1890. 8°. 2 pt. xv,774 pp., 98 pl. and maps; viii, 123 pp. XI. Eleventh Annual Report of the United States Geological Survey, 1889-90, by J. W. Powell. 1891. 8°. 2pt. xv, 757 pp., 66 pl. and maps; ix, 351 pp., 30 pl. and maps. XII. Twelfth Annual Report of the United States Geological Survey, 1890-91, by J. W. Powell. 1891. 8°. 2pt., xiii, 675 pp., 53 pl. and maps; xviii, 576 pp., 146 pl. and maps. XIII. Thirteenth Annual Report of the United States Geological Survey, 1891-92, by J. W. Powell. 1893. 8°. 3 pt. vii, 240 pp., 2 maps; x, 372 pp., 105 pl. and maps; xi, 486 pp., 77 pl. and maps. : E XIV. Fourteenth Annual Report of the United States Geological Survey, 189293, by J. W. Powell. 1893. 8°. 2pt. vi, 321 pp., 1 pl.; xx, 597 pp., 74 pl. and maps. XV. Fifteenth Annual Report of the United States Geological Survey, 1893~94, by J. W. Powell. 1895. 8°. xiv, 755 pp., 48 pl. and maps. XVI. Sixteenth Annual Report of the United States Geological Survey, 1894~95, Charles D. Walcott, Director. 1895. (Part I, 1896.) 8°. 4 pt. xxii, 910 pp., 117 pl. and maps; xix, 598 pp.. 43, pl. and maps; xv, 646 pp., 23 pl.; xix, 735 pp., 6 pl. XVII. Seventeenth Annual Report of the United States Geological Survey, 1895~96, Charles D. Waleott, Director. 1896. 8°. 3 pt. in 4 vol. xxii, 1076 pp., 67 pl. and maps; xxv, 864 pp., 113 pl. and maps; xxiii, 542 pp., 8 pl. and maps; iil, 543-1058 pp., 9-13 pl. XVIII. Eighteenth Annual Report of the United States Geological Survey, 1896-’97, Charles D. Walcott, Director. 1897. (Parts II and III, 1898.) 8°. 5pt.in6vol. 1-440 pp.,4 pl. and maps; i-y, ut II ADVERTISEMENT. 1-653 pp., 105 pl. and maps; i-v, 1-861 pp., 11S pl. and maps; i-x, 1-756 pp., 102 pl. and maps; i-xii, 1-612 pp., 1 pl.; 645-1400 pp. XIX. Nineteenth Annual Report of the United States Geological Survey, 1897—98, Charles D. Walcott, Director. 1898. 8°. 6 pt. in 7 vol. MONOGRAPHS. I. Lake Bonneville, by Grove Karl Gilbert. 1890, 4°. xx,438 pp. 51pl. Lmap. Price $1.50, Il. Tertiary History of the Grand Canon District, with Atlas, by Clarence E. Dutton, Capt., U.S. A. 1882. 4°. xiv, 264 pp. 42 pl. and atlas of 24 sheets folio. Price $10.00. III. Geology of the Comstock Lode and the Washoe District, with Atlas, by George F. Becker. 1882. 4°. xv, 422 pp. 7pl. and atlas of 21 sheets folio. Price $11.00. LV. Comstock Mining and Miners, by Eliot Lord. 1883. 4°. xiv, 451 pp. 3 pl. Price $1.50. V. The Copper-Bearing Rocks of Lake Superior, by Roland Duer Irving. 1883. 4°. xvi, 464 pp. 15]. 29 pl. and maps. Price $1.85. VI. Contributions to the Knowledge of the Older Mesozoic Flora of Virginia, by William Morris Fontaine. ee 4°, xi, 144 pp. d4]. 54 pl. Price $1.05. VII. yer-Lead Deposits of Eureka, Noun, by Joseph Story Curtis. 1884. 4°. xiii, 200 pp. 16 pl. Price $1.20. VIII. Paleontology of the Eureka District, by Charles Doolittle Walcott. 1884. 4°. xiii, 298 pp. 241]. 24 pl. Price $1.10. IX. Brachiopoda and Lamellibranchiata of the Raritan Clays and Greensand Marls of New Jersey, by Robert P. Whitfield. 1885. 4°. xx,338 pp. 35 pl. Ilmap. Price $1.15. X. Dinocerata. A Monograph of an Extinet Order of Gigantic Mammals, by Othniel Charles Marsh. 1886. 4°. xviii, 243 pp. 561. 56 pl. Price $2.70. XI. Geological History of Lake Lahontan, a Quaternary Lake of Northwestern Nevada, by Israel Cook Russell. 1885. 4°. xiy, 288 pp. 46 pl. and maps. Price $1.75. XII. 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A Bibliographic Index of North American Carboniferous Invertebrates, by Stuart Weller. 1898. 8°. 653 pp. Price 35 cents. 154. A Gazetteer of Kansas, by Henry Gannett. 1898. 8°. 246 pp. 6 pl. Price 20 cents. 155. Earthquakes in California in 1896 and 1897, by Charles D. Perrine, Assistant Astronomer in Charge of Earthquake Observations at the Lick Observatory. 189% 8°. 47 pp. Price 5 cents. 156. Bibliography and Index of North American Geology, Paleontology, Petroloyy. and Miner- alogy for the Year 1897, by Fred Boughton Weeks. 1898. 8°. 130 pp. Price 15 cents. 160. A Dictionary of Altitudes in the United States (Third Edition), compiled by Henry Gannett. 1899. 8°. 775 pp. Price 40 cents. 161. Earthquakes in California in 1898, by Charles D. Perrine, Assistant Astronomer in Charge of Earthquake Observations at the Lick Observatory. 1899. 8°. 3lpp. Ipl. Price 5 cents. In preparation: “ 157, The Gneisses, Gabbro-Schists, and Associated Rocks of Southeastern Minnesota, by C. W. Hail. 158. The Moraines of southeastern South Dakota and their Attendant Deposits, by J. E. Todd. 159. The Geology of Eastern Berkshire County, Massachusetts, by B. K. Emerson. WATER-SUPPLY AND IRRIGATION PAPERS. By act of Congress approved June 11, 1896, the following provision was made: “Provided, That hereafter the reports of the Geolo: ical Survey in relation to the gauging of streams and to the methods of utilizing the water resources may be prin ed in octavo form, not to exceed one hundred paves in length and five thousand copies in number; one thousand copies of which shall be for the official use of the Geological Survey, one thousand five hundred copies shall he deliv- ered to the Senate, and two thousand five hundred copies shall be delivered to the House of Repre- sentatives, for distribution.” Under this law the following papers have been issued: 1. Pumping Water for Irrigation, by Herbert M. \\ ilson. 1896. 8°. 57 pp. 9 pl. 2. Irrigation near Pheenix, Arizona, by Arthur P. Davis. 1897. 8°. 97 pp. 31 pl. 3. Sewage Irrigation, by George W. Rafter. 1897. 8°. 100 pp. 4 pl. 4. A Reconnoissance in Southeastern Washington, by Israel Cook Russell. 1897. 8°. 96pp. Tpl. 5. Irrigation Practice on the Great Plains, by Elias Branson Cowgill. 1897. 8°. 39 pp. 12 pl. 6. Underground Waters of Southwestern Kansas, by Erasmus Haworth. 1897, 8°. 65pp. 12pl. 7. Seepage Waters of Northern Utah, by Samuel Fortier. 1897. 8°. 50 pp. 3pl. 8. Windmills for Irrigation, by Edward Charles Murphy. 1897. 8°. 49 pp. 8 pl. 9. Irrigation near Greeley, Colorado, by David Boyd. 1897. 8°. 90 pp. 21 pl. 10. Irrigation in Mesilla Valley, New Mexico, by F. C. Barker. 1898. 8°. 5lpp. 11 pl. 11. River Heights for 1896, by Arthur P. Davis. i897. 89°. 100 pp. 12. Water Resources of Southeastern Nebraska, by Nelson H. Darton. 1898. 8°. 55 pp. 21 pl. 13. Irrigation Systems in Texas, by William Ferguson Hutson. 1898. 8°. 67 pp. 10 pl. 14. New Tests of Certain Pumps and Water-Lifts used in Irrigation, by Ozni P. Hood. 1889. 8°. Si ppree Lap: 15. Operations at River Stations, 1897, Part I. 1898. 8°. 100 pp. 16. Operations at River Stations, 1897, Part II. 1898. 8°. 101-200 pp. 17. Irrigation near Bakersfield, California, by C. E. Grunsky. 1898. 8°. 96 pp. 16 pl. 18. Irrigation near Fresno, California, by C. E, Grunsky. 1898. 8°. 94pp. 14 pl. 19. Irrigation near Merced, California, by C. i. Grunsky. 1899. 8°. 59 pp. 11 pl. 20. Experiments with Windmills, by T. O. Perry. 1899. 8°. 97 pp. 12 pl. Vill ADVERTISEMENT. 21. Wells of Northern Indiana, by Frank Leverett. 1899. 8°. 82pp. 2pl. 22. Sewage Irrigation, Part II, by George W. Raiter. 1899. 8°. 100 pp. 7 pl. 23. Water-Right Problems of Bighorn Mountains, by Elwood Mead. 1899. 8°. 62pp. 7 pl. 24. Water Resources of the State of New York, Part I, by George W. Rafter. 1899. 8°, 99 pp. 13 pl. 25. Water Resources of the State of New York, Part II, by George W. Rafter. 1899. 8°, 101-200 pp. 12 pl. 26. Wells of Southern Indiana (Continuation of No. 21), by Frank Leverett. 1899. 8°. 64 pp. 27. Operations at River Stations, 1898, Part I, 1899. 8°. 100 pp. 28. Operations at River Stations, 1898, Part II. 1899. 8°. 101-200 pp. In preparation: 29. Wells and Windmills in Nebraska, by Edwin H. Barbour. 30. Water Resources of the Lower Peninsula of Michigan, by Alfred C. Lane. TOPOGRAPHIC MAP OF THE UNITED STATES. When, in 1882, the Geological Survey was directed by law to make a geologic map of the United States there was in existence no suitable topographic map to serve as a base for the geologic map. The preparation of such a topographic map was therefore immediately begun. About one-fifth of the area of the country, excluding Alaska, has now been thus mapped. The map is published in atlas sheets, each sheet representing a small quadrangular district, as explained under the next head- ing. The separate sheets are sold at 5 cents each when fewer than 100 copies are purchased, but when they are ordered in lots of 100 or more copies, whether of the same sheet or of different sheets, the price is 2 cents each. The mapped areas are widely scattered, nearly every State being-represented. About 900 sheets have been engraved and printed; they are tabulated by States in the Survey’s ‘List of Publications,” a pamphlet which may be had on application, The map sheets represent a great variety of topographic features, and with the aid of descriptive text they can be used to illustrate topographic forms, This has led to the projection ot an educational series of topographic folios, for use wherever geography is taught in high schools, academies, and colleges. Of this series the first folio has been issued, viz: 1. Physiographic types, by Henry Gannett, 1898, folio, consisting of the following sheets and 4 pages of descriptive text: Fargo (N. Dak.-Minn.), a region in youth; Charleston (W.Va.),a region in maturity ; Caldwell (Kans.), aregion in old age; Palmyra (Va.), a rejuvenated region; Mount Shasta, (Cal.), a young voleanic mountain; Eagle (Wis.), moraines; Sun Prairie (Wis.), drumlins; Donald- sonville (La.), river flood plains; Boothbay (Me.), a fiord coast; Atlantic City (N.J.), a barrier-beach coast. GEOLOGIC ATLAS OF THE UNITED STATES. The Geologic Atlas of the United States is the final form of publication of the topographic and geologicmaps. The atlas is issued in parts, progressively as the surveys are extended, and is designed ultimately to cover the entire country. Under the plan adopted the entire area of the country is divided into small rectangular districts (designated quadrangles), bounded by certain meridians and parallels. The unit of survey is also the unit of publication, and the maps and descriptions of each rectangular district are issued as a folio of » the Geologic Atlas. Each folio contains topographic, geologic, economic, and structural maps, together with textual descriptions and explanations, and is designated by the name of a principal town or of a prominent natural feature within the district. Two forms of issue have been adopted, a ‘‘library edition” and a “field edition.” In both the sheets are bound between heavy paper covers, but the library copies are permanently bound, while the sheets and covers of the field copies are only temporarily wired together. Under the law a copy of each folio is sent to certain public libraries and educational institu- tions. The remainder are sold at 25 cents each, except such as contain an unusual amount of matter, which are priced accordingly. Prepaymentis obligatory. The folios ready for distribution are listed below. O | | | | | Area, in |Price, No. Name of sheet. State. Limiting meridians. Limiting parallels. | square in | | miles. j|cents. } 1 | TGV SUON ee eae mint atotal top etetete | Montana. .-- 110°-111° 459-469 | 3, 354 | 25 ON Ring oldies canes een ees peer cess 85°-85° 30/ 34° 30/359 980 | 25 Placerville: --=2-2- 22... --| California. -- 120° 30/-121° 38° 30/-399 932 | 25 | Xingston\-- — 2-2. BI Tennessee 84° 30/-85° 35° 30/-36° | 969 25 51 Saovamenton eae ..| California... 1219-1219 30! 38° 30!-39- | 932 | 25 6 | Chattanooga..---...-..-- -.| Tennessee ------ 85°-85° 30/ 359-359 30! | 975 | 25 7 | Pikes Peak (out of stock) ..-.--| Colorado.-.-.-.-. 105°-105° 30/ 38° 30/-39° 932 | 25 8} Sewanee. ----------- 8. --| Tennessee 85° 30/869 359-352 30! | 975 | 25 9 | Anthraéite-Crested Butte ..... | Colorado. - 106° 45’-1079° 15’ 38° 45/-39° | 465 | 50 |( Virginia - - 35 \ 10 | Harpers Ferry:....--.----.---- {ives Virginia -. 77° 30'-789 392-399 30’ | 925 | 25 |(Maryland..-...- J | | ADVERTISEMENT. Ix Area, in |Price, No. Name of sheet. State. Limiting meridians. Limiting parallels. square in miles, cents. Tit ||) (BONER Sas6Sacanoncoossosepons California. ...-.- 120° 30/-1219° 38°-38° 30/ 938 25 Virginia .. E ° 1) oR ANE) Sec eaes pacocobossosbe {Rrentucky: } 82° 30/-83° 36° 30/379 957 | 25 Tennessee 5 saan {Maryland. > mi 1 9 9 13 | Fredericksburg. .....----.----- (Virginia “| 772-779 30 387-389 30/ 938| 25 y irginia 2150 ; - ‘ fay ES tatmntont sees. sor se see sec (west Wanginiane \ 792-792 30 380-389 30/ 938 | 25 15 | Lassen Peak. ..---..--...-..-.. California. ee 1219-1229 409-419 3, 634 25 HGH kiemoxvillonse-eae--/ ae -e- 2! renner Sealy 830 30/840 35° 30/-360 925 | 25 Us| Marysville:.-.-----.--.-------- California. .----- 121° 30'-122° 39°-39° 30/ 925 25 18 | Smartsville.....-...-. secossadd California. 4 1219-1219 30’ 39°-89° 30! 925 | 25 Alabama. . a | 19:| Stevenson’..-...-...-------.--- |Geonsin.: : 85° 30'-86° 34° 30/-35° 980 | 25 ‘Tennessee E 20 Cleveland/cess= m= == i--cis -m-- =n Tennessee - 5 84° 30/-85° 35°-35° 30/ 975 25 21 | Pikeville -.- Tennessee - 4 85°-85° 30/ 35° 30/-36° 969 25 22 | McMinnville Tennessee - 5 85° 30/-86° 35° 30'-36° 969 25 RONEN omininee ees seen) eae cat 76° 30'-77° 389-380 30! 938 | 25 24 | Three Forks. - Montana. 3 . 1119-112° 459-469 3, 354 | 50 25 | Loudon....-.-. -| Tennessee - 849-819 30/ 35° 30/-36° 969 25 Virginia ........ = 5 1 | 26 | Pocahontas ........--.--.2+---- {weet Vanilla. \ 819-81° 30 370-372 30/ 951 | 25 27 | Morristown. .-.--..-.-.----..-.. Tennessee 83°-83° 30/ 36°-36° 30/ 963 | 25 ‘ Virginia -. 9 | 28) |) Piedmont, ---.--...-...:------- | arytand: eee 79°-79° 30’ 39°-39° 30! 925 25 West Virginia... | Nevada City - 121° 00! 25//-121° 03/ 45// | 39° 13’ 50//-39° 17’ 16” 11. 65 29 | Nevada City-. {eras Valley: California ....-- {rae Ol! 35//-121° 05’ 04/' | 39° 10! 22//-39° 13/ 50” 12.09 } 50 Banner Hill - 120° 57’ 05/-121° 00/ 25 | 39° 13/ 50/-39° 17’ 16” 11. 65 5 Gallatin -- | \;Yellowstone Na- ]Canyon..-- Se a = 30 \ tioral Park. Shoshone Wyoming .----- 1109-1119 449-459 3, 412 75 ake ..-.- ] | 31 | Pyramid Peak ...........--.... California ....-- 120°-120° 30/ 38° 30/-39° 932 25 32 | Franklin VNB csooocdhl 790-799 30! 38° 30/-399 932| 25 ti | amuse critics ~~ |\West Virginia --|/ = 33 | Briceville..-.- -| Tennessee -.-.-- 849-849 30/ 36°-36° 30! 963 25 34 | Buckhannon.. -| West Virginia .. 80°-80° 30/ 38° 30/-39° 932 25 35 | Gadsden ---- -| Alabama-......-. 86°-86° 30/ 349-349 30/ 986 | 25 36 | Pueblo..---- -| Colorado. J 104° 30’-105° 389-389 30! 938 | 50 37 | Downieville -- California 120° 30/-121° 39° 30/-40° 919 25 38 | Butte Special. Montana. - 112° 29 80/-112° 36/ 42/7 | 45° 59/ 28//-46° 02! 54” 22.80 50 39 | Truckee ..-...- -| California 120°-120° 30/ 39°-39° 30/ 925 | 25 40 | Wartburg -- -| Tennessee - 84° 30/-85° 36°-36° 30/ 963 | 25 41 | Sonora. ..-.- California - 120°-120° 30/ 37° 30/-38° 944 25 42 | Nueces ......- al peexaseene 100°-100° 30/ 29° 30/-30° 1, 085 25 43 | Bidwell Bar ...-.....- OBS DERCNE California 121°-121° 30! 39° 30/409 918 25 44 | Tazewell 81° 30/-82° 379-379 30! 950 25 45 | Boise 4 aie 116°-116° 30! 43° 30/440 864 25 46 | Richmond = soSoe 849-84° 30/ 37° 30/-38° 944 25 47 | London -| Kentucky - - §49-84° 30/ 37°-37° 30/ 950 25 48 | Tenmile District Special. -| Colorado. 360 106° 8/-106° 16’ | 39° 22! 30-399 30’ 30 55 3) 49] Roseburg...-..------.- -| Oregon ........- 123°-123° 30/ 43°-43° 30/ 871 25 re {Massachusetts - Fifi) || TRAKTOR: secianceocdodsocosoueds NGereesHoat eeu 72° 30/730 420-499 30! 885 25 STATISTICAL PAPERS. Mineral Resources of the United States [1882], by Albert Williams, jr. 1883. 8°. xvii, 813 pp. Price 50 cents. Mineral Resources of the United States, 1883 and 1884, by Albert Williams, jr. 1885. 8°. xiv, 1016 pp. Price 60 cents. Mineral Resources of the United States, 1885. Division of Mining Statistics and Technology. 1886. 8°. vii,576 pp. Price 40 cents. Mineral Resources of the United States, 1886, by David T. Day. 1887. 8°. viii,813 pp. Price 60 cents. Mineral Resources of the United States, 1887, by David T. Day. 1888. 8°. vii,832 pp. Price 50 cents. Mineral Resources of the United States, 1888, by David T. Day. 1890. 8°. vii,652 pp. Price 50 cents. 5 Mineral Resources of the United States, 1889 and 1890, by David T. Day. 1892. 8°. viii, 671 pp. Price 50 cents. : Mineral Resources of the United States, 1891, by David T. Day. 1898. 8°. vii, 680 pp. Price 50 cents. x ADVERTISEMENT. Mineral Resources of the United States, 1892, by David T. Day. 1893. 8°. vii, 850 pp. Price 50 cents. : Mineral Resources of the United States, 1893, by David T. Day. 1894. 8%. viii, 810 pp. Price 50 cents. On March 2, 1895, the following provision was included in an act of Congress: “Provided, That hereafter the report of the mineral resources of the United States shall be issued as a part of the report of the Director of the Geological Survey.” In compliance with this legislation the following reports have been published : Mineral Resources of the United States, 1894, David T. Day, Chief of Division. 1895. 8°. xy, 646 pp., 23 pl.; xix, 735 pp., 6 pl. Being Parts III and IV of the Sixteenth Annual Report. Mineral Resources of the United States, 1895, David T. Day, Chief of Division. 1896. 89. xxiii, 542 pp., 8 pl. and maps; iii, 543-1058 pp., 9-13 pl. Being Part III (in 2 vols.) of the Seventeenth Annual Report. Mineral Resources of the United States, 1896, David T. Day, Chief of Division. 1897. 8°. xii, 642 pp.,1 pl.; 643-1400 pp. Being Part V (in 2 vols.) of the Nineteenth Annual Report. Mineral Resources of the United States, 1897, David T. Day, Chief of Division. 1898. 8». viii, 651 pp., 11 pl.; viii, 706 pp. Being Part VI (in 2 vols.) of the Nineteenth Annual Report. The money received from the sale of the Survey publications is deposited in the Treasury, and the Secretary of that Department declines to receive bank checks, drafts, or postage stamps; all remit- tances, therefore, must be by MONEY ORDER, made payable to the Director of the United States Geological Survey, or in CURRENCY—the exact amount. Correspondence relating to the publications of the Survey should he addressed to THe DirecToR, UNITED STATES GEOLOGICAL SURVEY, WASHINGTON, D. C., June, 1899, WASHINGTON, D. C. Series. Author. Subject. [Take this leat out and paste the separated titles upon three of your cata- logue cards. The first and second titles need no addition; over the third write that subject under which you would place the book in your library.) LIBRARY CATALOGUE SLIPS. United States. Department of the interior. (U.S. geological survey.) Department of the interior | — | Monographs | of the | United States geological survey | Volume XXXVIII | [Seal of the depart- ment] | Washington | government printing office | 1899 Second title: United States geological survey | Charles D. Walcott, director |— | The | Illinois glacial lobe | by | Frank Leverett | [Vignette] | Washington | government printing oftice | 1899 4°, xxi, 817 pp. 24 pl. Leverett (Frank). United States geological survey | Charles D. Walcott, di- rector | — | The | Illinois glacial lobe | by | Frank Leverett | [Vignette] | Washington | government printing office | 1899 4°. xxi,817 pp. 24 pl. [UnIreD STATES. Department of the interior. (U. S: geological survey.) Monograph XX XVIII. ] United States geological survey | Charles D. Walcott, di- rector | — | The | Illinois glacial lobe | by | Frank Leverett | [Vignette] | Washington | government printing office | 1899 4°, xxi,817pp. 24 pl. (Unrrep Srares. Department of the interior. (U. 8. geological survey.) Monograph XXXVIII.} ee le eh i ti at ee