Professor J. W. Judd—Wm. Smith's MS. Majjs. 445 



to have been greatly struck by an exposure of the Chalk in a road- 

 cutting at Henley. In 1787, when 18 years of age, he was 

 apprenticed to Edward Webb, and, as he himself says, " was 

 employed in the survey of estates and the inclosure of extensive 

 commons and open fields in the counties of Oxford, Warwick, 

 Worcester, Gloucester, Wilts, Hants, and Somerset, which embraced 

 all the strata, from the red marl at Inkborough and Rugby, near 

 Alcester, to the sand and gravel over chalk at Dibden, between the 

 New Forest and Southampton." 



When Smith settled in Somersetshire in 1791, he was familiar 

 with •' the surface of the country from London to Bath, and from 

 Warwick to Southampton " ; and during his surveys at Stowey and 

 the High Littleton Collieries (1791-2) he not only found fresh 

 evidence of his views about the superposition and continuity of the 

 several strata, but detected the unconformity between the Secondary 

 strata and the underlying Carboniferous rocks. In 1793, while 

 taking levels for the Somersetshire Coal Canal, he "proved the red 

 marl, lias, blue marl, and inferior oolite on the tops of the highest 

 hills to be generally inclined towards the east ; and this notion of 

 a general declination appeared to hold through all the varieties of 

 strata in the considerable extent of country before noticed ; and 

 other levels down two parallel valleys in the same strata seemed 

 further to confirm the same notion." In 1794 Smith made a post- 

 chaise journey of 900 miles — from Bath to Newcastle-on-Tyne by 

 one route, and back again by another — and was able to satisfy 

 himself that the order of succession which he had made out in the 

 south-west of England could be applied to the whole of the country. 

 During the period that Smith was resident engineer to the Somerset- 

 shire Coal Canal (1793-9), he not only worked out the minute 

 details of the order of succession of the Jurassic rocks in the district, 

 but finding difficulty in identifying the several Jurassic strata — owing 

 to the resemblances between the several clays and oolitic limestones 

 on different geological horizons — he was led to the great discovery 

 with which his name will ever be associated. In Smith's own 

 M'ords : " Doubts wei'e at length removed by a more particular 

 attention to the site of the organized fossils, which I had long 

 collected. This discovery of a mode of identifying the strata by 

 the organized fossils respectively imbedded therein — the sharpness 

 of those in their primitive sites, contrasted with the same fossils 

 rounded and water- worn in gi'avel — led to the most important dis- 

 tinctions, which at once seemed to clear away the rubbish and 

 common stumbling-blocks in geology." 



It will thus be seen that at the date when Stnith prepared the 

 manuscript geological map of England, he had minutely surveyed 

 the Jurassic strata and Carboniferous rocks of Somersetshire, and 

 gained a wide but much more general knowledge of all the strata, 

 from the Chalk to the Coal-measures inclusive, over an area 

 extending from Warwickshire and the Bristol Channel on the west 

 to London and Southampton on the east. Outside this area. Smith's 

 knowledge of the country was derived from his post-chaise journey 



