James Hutton was a geologist whose explanations of Earth's changing surface connected the decay of existing rocks with the formation and elevation of new land. His arguments helped establish deep time by showing that visible geological relationships could require a long sequence of distinct processes, even without a numerical date.[ref]
At Jedburgh he described nearly vertical older geological strata beneath comparatively horizontal younger geological strata. Their junction posed a test: had the older geological strata been tilted before the younger sedimentary deposits accumulated? The truncated older beds and intervening fragments supported a sequence of formation, hardening into rock, deformation, erosion and renewed accumulation of sediment. Such an unconformity records missing geological history rather than a continuously deposited stack. Hutton's reasoning illustrates how stratigraphy can establish a relative sequence before assigning absolute ages.[ref]
Theory of the Earth by James Hutton (1795). Volume I, chapter VI, section II: Jedburgh, vertical strata, their truncated upper surface and the overlying conglomerate
Portrait of James Hutton
. Henry Raeburn (painting); National Galleries of Scotland / Google Art Project reproduction. Public domain (historical painting and faithful reproduction, as declared on Commons). Source and usage information on the linked Wikimedia file page. Source.
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