What is an extension of geological beds above and beyond others, as in a conformable series of beds, when the upper beds extend over a wider space than the lower, either in one or in all directions called?

overlap — (Geol.) An extension of geological beds above and beyond others, as in a conformable series of beds, when the upper beds extend over a wider space than the lower, either in one or in all directions. (Webster's 1913.)

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