444 Professor J. W. Judd—Wm. Smith's MS. Maj^s. 



preserved by the Geological Society. It bears the inscription in 

 Smith's handwriting : 



"Presented to the Geological Society, Feb. 18fch, 1831. 



Wm. Smith. 

 Coloured Geologically in 1799." 



The basis of this geological map is of circular form and 15 inches 

 in diameter. It is entitled : " A Map of Five Miles round the City 

 of Bath, on a scale of one inch and a half to a mile, from an Actual 

 Survey, including all the New Eoads, with Alterations and Im- 

 provements to the present time, 1799." *' Printed for and sold 

 by A. Taylor and W. Moyler, Booksellers, Bath." 



Although this map includes only a very small area, it presents 

 many features of great interest. In the first place, it shows that 

 William Smith was aware of the importance of representing upon 

 maps the actual limits between the outcrops of different strata. 

 Though no lines are drawn, Smith's well-known method of colouring 

 the base of a formation with a deep tint, and shading this upwards 

 towards the outcrop of the next overlying stratum, enables us to 

 see how carefully he had mapped all the geological lines around 

 Bath. There are only three colours employed on the map and no 

 index ; but it is evident that the yellow tint represents the Bath 

 Oolite, the base of the freestones being very accurately mapped, so 

 that even the smallest outliers can be made out agreeing most 

 closely with the map of the Geological Survey ; a blue tint is drawn 

 at the base of the Lias, and a red one at the base of the Trias, the 

 inliers of Carboniferous being left blank. How far William Smith 

 was in advance of his contemporaries, is shown by a comparison of 

 this map of William Smith, showing carefully indicated lines of 

 outcrop, with the excellent map of the Environs of Paris by Cuvier 

 and Brongniart (1809), in which colour is spread over the areas 

 occupied by the several formations, without any clear and definite 

 indications of the actual limits of the outcrops. The colours used 

 by Smith in this map were the same as those employed by him in 

 the later maps of 1801 and 1815, and thus we have in it the first 

 indication of a scheme of colour now very generally adopted by 

 geologists. 



The third and most important of these documents is a copy of 

 Carey's Index to the Map of England, coloured geologically. The 

 map is eleven inches high by nine inches in breadth, and has the 

 manuscript title, " General Map of Strata found in England and 

 Wales, by Wm. Smith, Surveyor, 1801." On the side of the map 

 is written, " Wm. Smith, Milford, near Bath," and at the bottom, 

 " Presented to the Geological Society by Wm. Smith, Feb. 21, 1831," 

 all the inscriptions being in Smith's own handwriting. 



Before considering the geological information which is furnished 

 by this map, it will be interesting to recall the opportunities which 

 Smith really had of making himself acquainted with the positions 

 of the outcrops of the English strata. When between 12 and 13 

 years of age (in. 1781)^ Smith paid a visit to London, and appears 



