John Morton provides detailed foot-by-foot descriptions of a number of Jurassic sequences which he describes from quarries and pits across the county. On his map, Smith notes the presence of the Barnack Rag and the Collyweston slate, both of which were previously described by Morton. Although Smith’s County Geological Map of Northamptonshire was never published, the manuscript version is almost complete. The rocks of Northamptonshire would have been of particular interest to Smith as they are entirely Jurassic, ranging in age from Lower Liassic to Oxford Clay and Kellaways. John Morton Natural History of Northamptonshire (1712) Smith would probably have viewed these books essentially as data sources, drawing from them description of fossils and locations of various strata rather than being influenced by outlandish theories as to the origin of the fossils and minerals, particularly those put forward by Plot and Woodward. Phillips notes in particular Plot’s Oxfordshire, Morton’s Northamptonshire and Woodward’s Catalogue of Fossils. It is not known if William Smith ever read this article or corresponded with Player at a later date, but we do know of other instances where Smith was familiar with older literature.Īccording to John Phillips in his Memoirs of William Smith, Smith turned to a number of previously written texts in order to reinforce and strengthen his general view. Player clearly illustrated that, in 1763, he already had a clear understanding of how regularly stratified the rocks in this area were and how this could be a guide to future coal seeking (Torrens 2003). He then describes the progressively older strata encountered to the north and northwest. The author, identified by Hugh Torrens (2003) as John Player (1725- 1808), states that wherever there is Bath or freestone on the surface coal is not to be expected to the South or South-East. This short article (see the reprint in the Gentlemen’s Magazine, 1764) outlines how the presence of coal in south Gloucestershire might be inferred. Also, this may well have influenced him at a later date when he started to construct his own geologic cross-sections.Ĭross-section (reversed to fit map) from John Strachley: Observation of the different strata of earths and minerals (1727) shown on the reconstructed Smith Somerset MapĪnother possible forerunner of Smith made a contribution to the Museum Rusticum using the pseudonym Ruricola Glocestris. It is known that Smith possessed a copy of Strachey’s cross-section and was bound to have been influenced by Strachey’s work of some 80 years previously. Smith was involved in a number of underground surveys for Lady Elizabeth Jones at her estates at Stowey, which were adjacent to John Strachey’s family home at Sutton Court. From this it is apparent that Strachey appreciated the different geometries of dip and strike sections.
Interestingly, Strachey also shows another section at right angles to the first section where the drift of the coal seams appears horizontal. In the cross-section illustrated below he shows the coal seams below the Red Earth. Strachey made some very accurate observations of the sequence and attitude of coal beds and associated strata in coal fields at Stowey and High Littleton. These would have included John Strachey’s Observations on the Different Strata of Earths and Minerals, more particularly of such as are found in the Coal Mines of Great Britain (1727). It is certain that he would have been influenced by the work of others. It would be incorrect to assume that William Smith invented stratigraphy in England and Wales. Previous work and possible influences on Smith
Smith never used the term “stratigraphy” but he applied its principles in his 1815 map of England and Wales and his later geological cross-sections which he made across the country. The first practical application of stratigraphy was made by William Smith. There are two main elements of stratigraphy lithostratigraphy, which is related to rock units and biostratigraphy, which is based on the fossils within strata. Nicolas Steno (1638-1686) is generally credited with defining some of the principles of stratigraphy, specifically the law of superposition which, put simply states that in undisturbed strata the youngest layer is on the top and the oldest layer is on the bottom. Stratigraphy is a part of geology concerned primarily with layering in sedimentary rocks (and to a limited extent in some volcanic rocks).
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