Historical:Berry Clay Member
H. B. Willman and John C. Frye
The Berry Clay Member of the Glasford Formation is named for Berry, Sangamon County.
In earlier reports it was generally called "Illinoian gumbotil" (Leighton and MacClintock, 1930, 1962).
The type section is a roadcut exposure, the Rochester Section (table 6) 3 miles west of Berry, NW SE NW Sec. 34, T. 15 N., R. 4 W. The composition and origin of the deposit have been intensively studied at the type section and throughout central Illinois (Frye, Willman, and Glass, 1960; Frye and Willman, 1963b; Willman, Glass, and Frye, 1966). Other notable exposures of the Berry Clay Member are described in the Coleta, Effingham, Funkhouser East, Hipple School, Panama-A, and Rapids City B Sections (table 7).
As the deposit is an accreted soil, the Berry Clay Member is included as part of the Sangamon Soil. The Berry Clay Member may overlie the Sterling, Radnor, Hulick, Vandalia, or other members of the Glasford Formation, and is overlain by Roxana Silt, Robein Silt, Peoria Loess, or the Wedron Formation.
Extent and thickness
The Berry Clay Member is commonly 2 to 5 feet thick.
The member consists of gray accretion-gley of clay, silt, and sparse small pebbles. It rests on till and is overlain by loess.
Age and correlation
The time span of the member, although largely Sangamonian, may range from late Illinoian to early Wisconsinan.
FRYE, J. C., and H. B. WILLMAN, 1963b, Loess stratigraphy, Wisconsinan classification and accretion-gleys in central western Illinois: Midwestern Sec. Friends of the Pleistocene, 14th Annual Meeting, Illinois State Geological Survey Guidebook Ser. 5, 37 p.
FRYE, J. C., H. B. WILLMAN, and H. D. GLASS, 1960, Gumbotil, accretion-gley, and the weathering profile: Illinois State Geological Survey Circular 295, 39 p.
LEIGHTON, M. M., and PAUL MacCLINTOCK, 1930, Weathered zones of the drift-sheets of Illinois: Journal of Geology, v. 38, no. 1, p. 28-53.
LEIGHTON, M. M., and PAUL MacCLINTOCK, 1962, The weathered mantle of glacial tills beneath original surfaces in north-central United States: Journal of Geology, v. 70, no. 3, p.
WILLMAN, H. B., H. D. GLASS, and J. C. FRYE, 1966, Mineralogy of glacial tills and their weathering profiles in Illinois. Part II—Weathering profiles: Illinois State Geological Survey Circular 400, 76 p.
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