A canal surveyor's map of rock layers founded an entire science

William Smith, working on English canals, noticed the same sequence of rock strata appeared across the country in the same order, each layer holding its own distinctive fossils. His 1815 map, the first geological map of an entire nation, let him predict what rock lay underground before anyone dug, and is now credited with founding modern stratigraphy, though gentleman geologists initially froze out the tradesman who made it.

— William Smith, A Delineation of the Strata of England and Wales, with Part of Scotland — 1815