Informally named the Winslow till for Winslow, Stephenson Co, IL (Frye and others, 1969, p. 25). Is formally named a member of Glasford Formation (new). Type section in roadcuts west of Winslow, SW SE SW sec 21, T29N, R6E, where 12 ft of dark-gray clayey till, the upper 3 ft of which is leached, is exposed. Geographic extent shown in fig 6 (southern part of Wisconsin arch). Typical composition summarized in table 2. Till is distinguished from till of Ogle Member that partly surrounds it by its much higher clay content and gray color. Is generally less than 20 ft thick. Stratigraphic relations are not adequately known; is assigned to Glasford Formation on basis of Sangamon Soil that occurs above it. May be a lithologic variant of Ogle Till Member, or may be stratigraphic equivalent of Sterling Till Member. Is commonly bounded at base by bedrock or by a residual soil developed in bedrock. Age is not firmly established, but it is judged to be in either the Monican or Jubileean Substages of the Illinoian Stage.

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