Pg. 110-111, 112, 236. Kings Lake Formation of Decorah subgroup [informal] of Galena Group. Present in western Missouri and eastern Illinois. Differentiated by Herbert (1949, unpub. thesis), as member of Decorah Formation, the Kings Lake is classified here as formation overlying the Spechts Ferry and underlying the Guttenberg (both of Decorah subgroup). Subdivided into Mincke and Tyson Members (both new). Commonly 5 to 10 feet thick; maximum thickness 15 feet; thins to northeast in subsurface. Age is Middle Ordovician (Champlainian).
Type section: exposure at top of Mississippi River bluff, 1.6 mi north of Foley, Lincoln Co., MO, about 500 feet north of road junction at Kings Lake, in SE/4 SE/4 NE/4 sec. 26, T. 50 N., R. 2 E., Hardin quadrangle [Foley 7.5-min quadrangle], Lincoln Co., MO.
["Subgroup" not recognized as a formal stratigraphic rank term (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). Considered informal and should not be capitalized.]

Source: US geologic names lexicon (USGS Bull. 1350, p. 394); supplemental information from GNU records (USGS DDS-6; Reston GNULEX).

Pg. 74 (fig. O-22), 75-76. Kings Lake Formation of Decorah subgroup [informal] of Galena Group. Exposed in Illinois only near West Point Landing, Calhoun County. Largely an argillaceous, very silty, dolomitic limestone with a few thin beds of shale, calcarenite, and bentonite. Thickness commonly 5 to 10 feet. Includes (ascending) Mincke and Tyson Members. Overlies Spechts Ferry Formation and underlies Guttenberg Formation. Many of the characteristics of the Kings Lake are transitional from those of the Spechts Ferry to those of the Guttenberg, but the Kings Lake is more silty and sandy than either of them. Lithologically similar to lower part of Logana Formation of Kentucky, and Hermitage Formation of Tennessee. Carries a mixture of Spechts Ferry and Guttenberg fossils, most abundant being PIONODEMA SUBAEQUATA, ZYGOSPIRA RECURVIROSTRIS, and locally SOWERBYELLA CURDSVILLENSIS. [Age is late Middle Ordovician (Trentonian).] Report includes geologic maps, cross sections, correlation charts.
["Subgroup" not recognized as a formal stratigraphic rank term (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). Considered informal and should not be capitalized.]

Source: Publication.

Kings Lake Formation included in Middle Ordovician (Mohawkian) Decorah Group in IL and MO in St. Louis area. A thin, unnamed bentonite bed is correlated with K-5 bentonite in TN by Templeton and Willman (1963). [Author follows usage of Thompson (1991).]

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