disconformity (dis-con-form'-i-ty). An unconformity in which the bedding planes above and below the break are essentially parallel, indicating a significant interruption in the orderly sequence of sedimentary rocks, generally by a considerable interval of erosion (or sometimes of nondeposition), and usually marked by a visible and irregular or uneven erosion surface of appreciable relief; e.g. an unconformity in which the older rocks remained essentially horizontal during erosion or during simple vertical rising and sinking of the crust (without tilting or faulting). The tendency is to apply the term to breaks represented elsewhere by rock units of at least formation rank (Stokes and Varnes, 1955, p.157). The term formerly included what is now known as paraconformity. Syn: parallel unconformity; erosional unconformity; nonangular unconformity.