Edited by James E. Palmer and Russell R. Dutcher - University of ...

ThicknessIm)lft)Sandstone; thin and irregularly 27,4 1bedded; channel fill (?)Interval of b!ack shale containingsiderite nodules, underlain by thintomedium-irregularly beddedsandstoneIFigure IL-29. lllinois Route I east of Harrisburg, Illinois,looking east. Flat area in the foreground isunderlain by silt and clay deposits ofPleistocene Lake Saline. The tree-coveredhills in the background were islands in LakeSaline and are composed of bedrock overlainhy wind-blown loess deposits.coal is about one foot (0.3 m) thick and is known locallyas the "Pe K~ven rider." No detailed studies ofthis coal are available, but it may be correlative withthe Seelyville Coal Member (I l I) of east-central lllinoisand Indiana.The Davis and De Koven Coals are located about100 feet (30 m) below the upper boundary of theSpoon Formation and about 750 feet (230 m) abovethe base of the Pennsylvanian System. Coals of theunderlying Abbott and Caseyville Formations are generallythin and lenticular and rarely contain marinelimestones. These lower coals apparently were depositedin an alluvial plain or upper delta plain environment.The first clearly recognizable development ofregionally extensive marine limestones occurred withthe deposition of the Curlew Limestone Memberabout175 feet (53 m) below the Davis Coal-which iswidespread in southern lllinois and western Kentucky.The Curlew Limestone has been correlated with theSeville Limestone Member of northern Illinois, theLower Mercer Limestone of Ohio and Pennsylvania,and the Verne Shaly Limestone Member of Michigan(Wanless, 1957).With the development of regionally extensivemarine and coastal plain environments, the verticalsuccession of strata became much more uniform. TheDe Koven Coal, for example, lies from 15 to 30 feet(4.5 to 9 m) above the Davis Coal and is uniformlypresent above it for a lateral distance of more than 100miles (161 km).Above the Davis and De Koven Coals, the verticalsuccession of strata becomes even more uniform, andsome limestones and coals of the Kewanee Group(middle Pennsylvanian) extend, with certain variationsand interruptions, essentially the full extent of the IllinoisBasin. The unusually orderly sequence of strata,Black shale containing large (1 ft)' 8'31concretionsI'De Koven rider" CoalInterval of sandstone overlain bydark gray shale: generally halfsandstone and half shale; sandstollocally occupies entire interval; tcis soft medium-gray underclay,extensively rootedDe Koven CoalFine-grained sandstone and sandyunderclay; underclay rootedDark-gray shale; gradationalupper contactDark bluish-gray to black shale;large (1 to 2 ft-0.3 to 0.6 m)concretions at base; discontinuous1-2 in (2.5 to 5 cm) thick clay nodulelayer 2.5 ft (0.75 m) from baseDavis Coal at base of sectionFigure IL-30.ISGS 1979Columnar section of highwall at Will ScarletMine. Rider coal, near middle part of highwall,may be correlative with the SeelyvilleCoal of east-central Illinois and Indiana.given the name "cyclothem" by Wanless and Weller(1932), was first recognized in western Illinois in rocksof the Kewanee Group.11.0 Leave Will Scarlet Mine and proceed northeaston U.S. 45.14.5 Enter Carrier Mills.14.9 lntersection with County Road 9. Turn left(north). Follow County Road 9 through CarrierMills.15.0 Cross railroad tracks and turn left (west).Proceed one block to stop sign and turn right(north).17.0 Stripping on right is in Davis and De KovenCoals.18.9 lntersection with lllinois Route 13. Turn left(west). Omit alternate mileage No. 2 and turnto mileage 75.1.ALTERNATE MILEAGE NO. 269.5 lntersection at stop light with U.S. 45. Continuestraight (west) on lllinois Route 13.72.9 Mine subsidence has occurred on both sidesand under road. Mine No. 16, Sahara CoalCompany, removed Harrisburg (No. 5) Coal at