Historical:Esmond Till Member
H. B. Willman and John C. Frye
The Esmond Till Member of the Wedron Formation was informally named the Esmond till (Frye et al., 1969, p. 26) from the village of Esmond, De Kalb County.
The type section is in roadcuts, NW SW NW Sec. 27, T. 43 N., R. 2 E., Winnebago County, 10 miles north of Esmond, but the till has been studied in detail in the Greenway School cores near Esmond (Frye et al., 1969). The type section exposes about 10 feet of brownish gray, calcareous, clayey till of the Esmond Member overlain by 2 feet of Richland Loess. The underlying pink sandy till of the Winnebago Formation is exposed down the hill 100 yards to the north. The Esmond is also well exposed in the Dixon Northwest and the Grand Detour Sections (table 7).
The upper boundary of the member is the pink-tan Tiskilwa Member or equivalent deposits, and the lower boundary is on Morton Loess or deposits of the Robein Silt or Winnebago Formation.
Extent and thickness
It is a thin drift, generally not more than 20 to 30 feet thick. Its geographic distribution is shown in figure 6.
The Esmond Till has two phases, an upper silty phase and a lower silty clay phase, both of which are characterized by a high illite content (tables 2 and 3). It is gray and contains relatively few cobbles and pebbles.
Age and correlation
The Esmond Till is in the early part of the Woodfordian Substage of the Wisconsinan Stage. It was deposited by the Dixon Sublobe of the Lake Michigan Lobe.
FRYE, J. C. (et al.), H. D. GLASS, J. P. KEMPTON, and H. B. WILLMAN, 1969, Glacial tills of northwestern Illinois: Illinois State Geological Survey Circular 437, 47 p.
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