An unconformable contact between two geological units in which the older, underlying
rocks dip at an angle different from the younger, overlying strata, usually in which
younger sediments rest upon the eroded surface of tilted or folded older rocks.
Neuendorf, K.K.E, Mehl, J.P. & Jackson, J.A. (eds), 2005. Glossary of geology, 5th
Edition. American Geological Institute, Alexandria, 779 p.