A gap or interruption in the continuity of the geologic record either because the record was never formed or because it was destroyed by erosion. It represents the time interval spanned by an unconformity
Iowa State University, College of Liberal Arts and Sciences, Department of Geological and Atmospheric Sciences, Glossary of Geologic Terms (based on the glossary in Earth: An Introduction to Geologic Change, by S. Judson and S.M. Richardson, Englewood Cliffs, NJ, Prentice Hall, 1995), Iowa, USA 2004. http://www.ge-at.iastate.edu/courses/Geol_100/old_ files/glossary.v2.html, (ND/ Geol - Amer) {111}