دگرشیبی

thumb|''Hutton's Unconformity'' at [[Jedburgh, Scotland, illustrated by John Clerk in 1787 and photographed in 2003.]] An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record. The significance of angular unconformity (see below) was shown by James Hutton, who found examples of Hutton'