March 23, 1769 (a Thursday)

William Smith’s “A Geological Map of England and Wales and Part of Scotland” (1815)

On this date, the English engineer and geologist William Smith was born. Smith was instrumental in extending the science of stratigraphy. His early work was as a miner and an engineer, for a canal-digging company. From this experience he observed the difference in rock layers. He also recognized that the same succession of fossil groups from older to younger rocks could be found in many parts of England, which he called the principle of faunal succession. He traveled the entire country to verify that relationships between the strata and their characteristics were consistent everywhere. Thus Smith created a profile of the entire country of England. His great geologic map of England and Wales (1815) set the standard for modern geologic maps. Many of the colorful names he gave to the strata are still in use today.