1) Nonconformity 1) Unconformity 
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a surface that represents missing rock strata but beds above and below that surface are parallel to one another.
• (n.) Want of conformity or correspondence; inconsistency; disagreement.
An unconformity between parallel layers of sedimentary rocks which represents a period of erosion or non-deposition.
An unconformity marked by a distinct erosion-produced, irregular, uneven surface of appreciable relief between parallel strata below and above the break; sometimes represents a considerable interval of nondeposition.
Dis`con·form'i·ty noun Want of conformity or correspondence; inconsistency; disagreement. « Those . . . in some disconformity to ourselves.» Milton. « Disagreement and disconformity betwixt the speech and the conception of the mind.» Hakewill. 
An unconformity in which beds above and below are parallel.
An unconformity in which the beds above the unconformity are parallel to the beds below the unconformity.
the surface of a division between parallel rock strata, indicating interruption of sedimentation: a type of unconformity. · nonconformity.