Radnor Till Member

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Lithostratigraphy: Glasford Formation >>Radnor Till Member
Chronostratigraphy: Cenozoic Erathem >>Quaternary System >>Pleistocene Series

Primary source

Willman, H. B., and John C. Frye, 1970, Pleistocene Stratigraphy of Illinois: Illinois State Geological Survey Bulletin 94, 204 p.

Contributing author(s)

H. B. Willman and John C. Frye


Original description

Radnor Till Member, Glasford Formation (William and Frye 1970).


The Radnor Till Member of the Glasford Formation is named for Radnor Township, Peoria County.

Other names


Type section

Type location

The Radnor Till is described from roadcut exposures in the Jubilee College Section (table 6), SW SW SW Sec. 7, T. 10 N., R. 7 E. It is also described in the Farm Creek, Tindall School, and Toulon Sections (table 6).

Table 6 -- Stratigraphic Sections (partial)
The following 21 stratigraphic sections describe exposures in Illinois and illustrate many of the aspects of Pleistocene stratigraphy. These sections contain the type localities for 21 rock-stratigraphic units, 4 soil-stratigraphic units, and 3 time-stratigraphic units and include paratypes for several other units. The sample numbers preceded by "P" are the numbers used in the Illinois State Geological Survey collections. Analytical data on many of these samples are on file at the Survey. The sections are arrange alphabetically by name.

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

In the type section the Radnor Till is bounded at the top by the top of the Sangamon Soil. It is overlain by Roxana Silt and it rests on the Toulon Member. The Radnor Till Member may be a stratigraphic equivalent of the Sterling Till Member of northern Illinois but is geographically separated from it by the Green River Lobe.

Extent and thickness

Its geographic distribution is shown in figure 6 and its spatial relations are shown diagrammatically in figure 7.


The Radnor Till is gray, compact, silty, and high in illite content. Its matrix grain size and composition of clay minerals are given in tables 2 and 5, and its heavy mineral analyses are summarized in table 4.




Well log characteristics


Age and correlation

It is in the Jubileean Substage of the Illinoian Stage and was deposited by the Lake Michigan Lobe.

Environments of deposition

Economic importance



ISGS Codes

Stratigraphic Code Geo Unit Designation