<p>Glacially striated limestone pebble from the Vandalia Till member of the Glasford Formation exposed in the Athens North Quarry, Menard County, Illinois. Scalecube is 1 centimeter square.
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Follmer, L. R. and others, 1979, Wisconsinan, Sangamonian, and Illinoian stratigraphy in central Illinois. Illinois Geological Survey Guidebook no. 13: Urbana, Illinois
Paul Heinrich
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>