Historical:Elmhurst Sandstone Member
T. C. Buschbach
The Elmhurst Sandstone Member of the Eau Claire Formation (Buschbach, 1964, p. 32), the basal member, is named for Elmhurst, Du Page County.
The type section of the Elmhurst Sandstone Member is located a half mile west of Elmhurst, Du Page County, at a depth of 1640-1759 feet in a boring (Wander Co. No. 11, SE NW NE 10, 39N-11E) (sample set 15,336).
Extent and Thickness
The Elmhurst Member is widely distributed in the northern half of Illinois and is 10-200 feet thick.
Most of the Elmhurst is fine- to medium-grained, fossiliferous, gray sandstone that contains various amounts of interbedded gray shale. The basal part contains the sooty zone.
BUSCHBACH, T. C., 1964, Cambrian and Ordovician strata of northeastern Illinois: Illinois State Geological Survey Report of Investigations 218, 90 p.
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