Preglacial Erosion Surfaces in Illinois

摘要: A generalized map of buried erosion surfaces in Illinois, compiled from detailed maps the bedrock topography, provides regional perspective for recognition and correlation within state. Lancaster peneplain northwestern Calhoun western Ozark northern Illinois is suggested; an independent lower surface which developed on weak rocks basin described named "Central peneplain"; possible straths along major preglacial valleys are recognized "Havana strath."