Many cases could be given of the lower beds of a formation having been upraised, denuded, submerged, and then re-covered by the upper beds of the same formation-facts, showing what wide, yet easily overlooked, intervals have occurred in its accumulation.
Beste kasu asko aipa daitezke, formazio baten behe geruzak azaleratu, higatu, urperatu eta gero formazio beraren goragoko geruzak estalirik geratu direla erakusten dutenak, egitateok argi uzten dutelarik zein tarte luzeak, baina ohartzeke erraz pasa daitezkeenak, iragan diren haiek metatzeko.