The Thornton Reef is exposed in quarries owned by the Material Service Corporation and in roadcuts along 1-80 and 1-294, about 4.8mi(8km) west of the Illinois-Indiana boundary (Figs. 1 and 2), in the W¼,Sec.27,N¼Sec.33,T.36N.,R.13E,Harvey and Calumet City 7¼-minute Quadrangles, Thornton, Cook County, Illinois.
Figures & Tables
North-Central Section of the Geological Society of America
One hundred field guides, with area maps, to locations in Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Nebraska, Ohio, and Wisconsin.