The first large scale, detailed scientific geological map of any country: "A major cartographic and scientific achievement" (Eyles, DSB). Smith's triumph in executing this, his subsequent fall and then final recognition is the stuff of scientific legend: "he was imprisoned for debt, turned out of his home, his work was plagiarised, his wife went insane and the scientific establishment shunned him" (Winchester). However, Smith's overwhelming contribution to the science of geology was his recognition, as outlined in the Memoir, "that each stratum is also possessed of properties peculiar to itself, has the same exterior characters and chemical properties, and the same extraneous or organised fossils throughout its course". It was this theory, developed as early as 1796, that enabled Smith to "accurately predict, and therefore map, the geological composition of Britain" (Challinor). The connection between strata and their fossils was noted by the Danish scientist Nicolas Steno in his 1669 work 'De Solido', but it was Smith who first understood that the principles of stratigraphy could be applied on a national scale. His development of the mechanisms of superposition (the theory that geological strata are formed in order), placed palaeontology as a fundamental part of geology and lent credence to the theory of deep time, leading to a better understanding of the age of the earth. His great map is astoundingly accurate, and modern versions have made only relatively minor modifications to his work.

Five states of Smith's work have been identified: an early unnumbered state (known in only a few copies); a series numbered 1-100, which Smith signed between 2 November and 17 December 1815; a series numbered a1-100 (the present example is of this series), signed between 17 December 1815 and 23 January 1816; a series numbered b1-100, signed after 23 January 1816; and an unnumbered series probably issued in 1823 or later (watermarks are dated 1823).

"The map was supplied either in sheets [usually bound as an atlas], or mounted on canvas and rollers, or fitted in a case for travelling [as in the present example]" (Eyles, Bibliography). Most probably no more than 320-350 copies of the map were published, of which perhaps 130 survive today.

The present example corresponds to Eyles' second issue, series III map: "a65", was examined and signed by Smith on 13 January 1816. It was one of a batch of 15, which had been coloured by Morse, signed that day and numbered.

Scale: 5 miles to one inch.