William Smith (geologist) - Life's Work

Life's Work

Smith worked at one of the estate's older mines, the Mearns Pit at High Littleton, part of the Somerset coalfield and the Somerset Coal Canal. As he observed the rock layers (or strata) at the pit, he realised that they were arranged in a predictable pattern and that the various strata could always be found in the same relative positions. Additionally, each particular stratum could be identified by the fossils it contained, and the same succession of fossil groups from older to younger rocks could be found in many parts of England. Furthermore, he noticed an easterly dip of the beds of rock- small near the surface (about three degrees) then bigger after the Triassic rocks. This gave Smith a testable hypothesis, which he termed The Principle of Faunal Succession, and he began his search to determine if the relationships between the strata and their characteristics were consistent throughout the country. During subsequent travels, first as a surveyor (appointed by noted engineer John Rennie) for the canal company until 1799 when he was dismissed, and later, he was continually taking samples and mapping the locations of the various strata, and displaying the vertical extent of the strata, and drawing cross-sections and tables of what he saw. This would earn him the name "Strata Smith". As a natural consequence, Smith amassed a large and valuable collection of fossils of the strata he had examined himself from exposures in canals, road and railway cuttings, quarries and escarpments across the country. He also developed methods for the identification of deposits of Fuller's earth to the south of Bath.

He published his findings with many pictures from his fossil collection, enabling others to investigate their distribution and test his theories. His collection is especially good on Jurassic fossils he collected from the Cornbrash, Kimmeridge clay, Oxford clay, Oolitic limestone and other horizons in the sequence. They included many types of brachiopods, ammonites and molluscs characteristic of the shallow seas in which they were deposited. Some of the names he coined (like Cornbrash) are still used today for this formation.