Pg. 8 (fig. 1), 26 (fig. 4), 27, 38-39, 50, pl. 1, geol. sections (p. 70+). Bond formation of McLeansboro group. Proposed for strata extending from base of Shoal Creek limestone member to top of Millersville limestone member. Characterized in area of typical development by thick limestones. Thickness in type area nearly 300 feet; east of LaSalle anticline 75 feet or less. Overlies Modesto formation and underlies Mattoon formation (both new). Age is Pennsylvanian. Report presents new rock-stratigraphic classification of Pennsylvanian strata in Illinois. Cyclical classification retained but is entirely independent of rock-stratigraphic classification; includes rocks also assigned to (alphabetical): Bunje, Flannigan, Flat Creek, Hall (part), LaSalle (part), Shoal Creek (part), Sorento, and Witt cyclothems.
Members, central and southwestem Illinois (ascending): Shoal Creek limestone, McWain sandstone, Sorento limestone (new), Bunje limestone (new), Flat Creek coal (new), Witt coal (new), Coffeen limestone (new), and Millersville limestone.
Members, southeastern and eastern Illinois (ascending): Shoal Creek limestone, Mount Carmel sandstone, Flannigan coal, Reel limestone, Livingston limestone, and Millersville limestone.
Members, northern Illinois (ascending): Hall limestone and LaSalle limestone.
Type section (composite): seven exposures (geologic sections 8A-G) in Hillsboro, Mt. Olive, New Douglas, Nokomis, and Pana quadrangles, Bond, Christian, and Montgomery Cos., central western IL. Named from Bond Co., central western IL.
Reference section (subsurface): core from Peabody Coal Company drillhole 59, in NW/4 NE/4 NW/4 sec. 33, T. 11 N., R. 1 E., Pana quadrangle, Christian Co., central western IL.

Source: Publication; US geologic names lexicon (USGS Bull. 1200, p. 424).

Paleobotanic and palynologic data from the Bristol Hill Coal Member of the Bond Formation in IL show that tree-fern species were the most dominant flora in coal swamps represented by this unit. The Bristol Hill Coal Member is 0.5 meters thick and underlies the Millersville Limestone Member or Livingston Limestone Member of the Bond Formation. The Bristol Hill is of Late Pennsylvanian (Missourian) age.

Source: GNU records (USGS DDS-6; Reston GNULEX).

Bond Formation of McLeansboro Group is the bedrock unit most commonly present at the bedrock surface in the study area. Regionally it is characterized by about 300 ft of claystone, shale, limestone, and sandstone. Thickness reaches 165 ft on the east side of the Martinsville site, but unit is absent on the west side. Formal members in eastern IL include (ascending) Carthage Limestone, Mt. Carmel Sandstone, Flannigan Coal, Reel Limestone, and Livingston/Millersville Limestone Members, however, the upper and lower limestone members are not present in the study area. Most common lithology at the surface is sandstone. Overlies the Macoupin Limestone or Inglefield Sandstone Members of the Modesto Formation and unconformably underlies glacial deposits. Age is Late Pennsylvanian.

Source: GNU records (USGS DDS-6; Reston GNULEX).

Pg. 2 (fig. 1), 18-20, pl. 1. Bond formation of McLeansboro group. Extends from base of Carthage (Shoal Creek) Limestone Member to top of Livingston (Millersville) Limestone Member. Age is Late Pennsylvanian (Missourian).
[Tri-State Comm. rejects Kosanke and others’ (1960) composite type section of 7 localities; considers these reference sections. States it does not meet NACSN 1983 nomenclatural guidelines, several units are repeated, and about 100 feet of the Bond is missing. The U.S. Geologic Names Committee retains Kosanke and others’ (1960) composite type section, based on: (1) it was designated in accordance with CSN 1933 nomenclatural guidelines, in place at time of publication; (2) the inadequacies (repetition of units, missing intervals) were addressed in Kosanke and others' published description; (3) the upper and lower boundaries of the Bond are well represented; and (4) several reference sections may constitute a composite type section.]

Source: Publication.

See also Kolata and Nimz, eds., 2010, Geol. Illinois, p. 188 (fig. 10-1), 200-201. Bond Formation of McLeansboro Group. In northern Illinois includes (descending) LaSalle Limestone Member, Hall Limestone Member, and Carthage Limestone Member; thickness 0 to 65 feet. In southern Illinois includes (descending) Millersville Limestone Member, Flannigan Coal Member, Mt. Carmel Sandstone Member, and Carthage Limestone Member; thickness 0 to 350 feet. Lies below Mattoon Formation and above Shelburn Formation; all of McLeansboro Group. Age is Late Pennsylvanian (Kasimovian; Stephanian A-B; Missourian).

Source: Publication.