1947 F. A. Melton in Bull. Amer. Assoc. Petroleum Geologists 31 1869 The writer proposes that the simpler name marine-onlap, which has already been used by various authors, be substituted for the more cumbersome term used by Grabau. Marine-onlap is thus used to describe the regular progressive pinching-out of marine strata above an unconformity..in such a way that the younger beds extend farther landward than do the older beds which lie beneath... The term terrestrial-onlap can be used in connection with terrestrial formations.

1955 Sci. Amer. Mar. 84/2 When the sea advanced, under the simplest conditions the new deposits overlapped the older in a shoreward direction—a process called onlap.

1982 N.Z. Jrnl. Geol. & Geophysics 25 149 Sedimentation is typified by a greatly condensed mudstone succession with local unconformities and onlaps which disappear basinwards.

2002 Geomorphol. 42 131 The two most viable tectonic models for our study area..include (i) sediment onlap with seismic folding and (ii) flexural slip faulting.

1959 F. E. Lozo et al. Symp. Edwards Limestone Central Texas (Univ. Texas) 105/2 This distribution suggests that the formation thins from the bottom and that it onlaps the unconformable surface at the top of the Edwards limestone.

1977 Offshore Engineer May 38/1 Seismic evidence suggests thick deeply buried deposits onlapping old ridges which may form hydrocarbon traps.

2002 Tectonophysics 344 175 Basin fills formed in a thermal subsidence period onlapped the fault basin margins and were deposited in a broad downwarped lacustrine depression.