For many of us the name William Smith does not mean anything, a common name as befits the humble origins of the man. But in 1815, some 200 years ago, Smith published the first geological map of an entire country. His methods so clarified the understanding of how the Earth’s rocks and soils are organized that they ushered in a new era of scientific exploration of mineral resources, precisely at a time when they were needed most.
In the late eighteenth and early nineteenth centuries, the Industrial Revolution was redesigning the world. Steam power was replacing manual labor and machines began to fill the factories. To feed the voracious boilers and the new economic growth, firewood gave way to coal. Although some scholars such as the Scottish geologist James Hutton had elevated geology to the category of science, and fossils were being used decorate the libraries of aristocrats, the fact is that knowledge of the subsoil was not yet being put to practical use. When the time came to search for coal, the engineers were still playing it by ear.
William Smith did not seemed destined to win a chair of honor in the history of science. Born in 1769 in the small town of Churchill (Oxfordshire, UK), he was the son of a blacksmith with farming roots. Fatherless from the age of eight, life did not provide him with a polished education and by age 18 he was making his living as an assistant land surveyor and appraiser. While he was gaining experience as a civil engineer for the mining industry and a canal surveyor, he observed that in widely-separated places one could find matching strata that not only corresponded by rock composition, but also the type of fossils, which were different from those of other layers. In the words of Smith himself, “each stratum contained organized fossils peculiar to itself, and might, in cases otherwise doubtful, be recognized and discriminated from others like it, but in a different part of the series, by examination of them.”
Smith deduced that each rock strata could be individually identified by its fossils, and this idea was crystallized in his law of faunal succession, the seed of modern biostratigraphy and one of the foundations in the development of the theory of biological evolution. After an extensive and systematic collection of data and samples across the country, in 1815 he released his greatest work: the first large-scale geological map covering England, Wales and parts of Scotland. The work of the engineer, which earned him the nickname of Strata Smith, detailed the outcrops and the overlapping of layers across large regions, colouring each rock with a tone close to real one. “However, the real innovation was the astute (albeit expensive) use of a darker watercolour tone to indicate the base of each stratum, becoming lighter toward the top of the layer to give an impression of three dimensions,” wrote geologist Tom Sharpe of the University of Cardiff (UK) recently in Science magazine.
“Two hundred years on, Smith’s map has become an icon of Earth science, and the basic principles he developed and applied are still used in interpreting rock sequences and making geological maps,” notes Sharpe. But beyond its purely scientific interest, the work of Smith had huge practical applications, as it corresponds to the focus of a veteran prospector. “It was to be a practical tool for mineral exploration, land drainage and agriculture,” says Sharpe. Before the existence of Smith’s map, coal diggers were guided by the presence of dark shale, sedimentary rocks rich in organic matter. But often this indication failed because it corresponded to similar layers of different ages. While the composition of two layers may be the same, what never deceives is the order of fossils; Smith’s method reliably predicted where to look for coal.
Although other geologists on the European continent came to the same conclusions, none of them applied them on such a grand scale as Smith. However, his lack of scientific training and connections in academic circles prevented his scientific advances from being appreciated by scholars of the newly founded Geological Society of London, who did not believe in the method of this unknown land surveyor. However, when the Society undertook its own project, it ended up using the principles of Smith, while he was plunged into financial ruin and forced to sell his extensive fossil collection to the British Museum. In 1819, his debts led him to prison. His recognition did not come until 1831, eight years before his death.
Despite the fact that new technologies now offer sophisticated methods of scanning and digital mapping, all prospecting requires a geological map. According to Sharpe, from the search for rare earths in Greenland to the pinpointing of hydrocarbons pockets, the principles of Smith are still valid, and even the global geologic map of Mars completed in 2014 reminds us of those maps that he drew and coloure.