An unconformable contact between two geological units in which the bedding of the
older, underlying unit is parallel to the bedding of the younger, overlying unit,
in which the contact between the two units is planar, and may be coincident with a
Neuendorf, K.K.E, Mehl, J.P. & Jackson, J.A. (eds), 2005. Glossary of geology, 5th
Edition. American Geological Institute, Alexandria, 779 p.