First edition of William Smith's geological map of Kent, one in a series of county maps produced by Smith, each separately issued, which were the first detailed geological maps of specific areas. Smith's individual maps are extremely rare on the market.

Smith produced the first geological map of England and Wales in 1815, which contained "an amazing amount of correct detail" (D.S.B.) and was the basis for all the geological maps that followed. In 1819 he began the publication of a geological atlas of England and Wales. Published in parts over five years, it remained unfinished, containing twenty-one maps of various English counties.

"All the county maps published contain much more information than was shown on Smith's large map of 1815, and indicate that during the intervening years he had done much to increase his knowledge. The maps are based on Cary's county maps, and are headed 'By W. Smith, Mineral Surveyor.' Each map measures 21 ½ inches by 19 1/4 inches [across the ruled border]; the scale varies slightly but averages 3 miles to an inch."–Sheppard, William Smith: His Maps and his Memoirs (1920), p. 155.

In his major work 'A Delineation of the Strata of England and Wales with part of Scotland' of 1815, Smith ordered the strata through a colour key, whereas here he identifies them by name and number with coloured boxes, and places them around the boundary adjacent to their outcrop.

Smith's map of Kent was first published by Cary in 1819, in Part I of 'A New Geological Atlas of England and Wales' with Sussex, Norfolk and Wiltshire. It is a reissue of Cary's map of 1801, with the addition of the geological information.

Stratigraphy

1. London Clay, forming the detached hills in the Environs of London. In this Stratum the Septarium is found, from which Parker's Roman Cement is made. The highest Strata in the County.
2, 3 and 4. Brick  Earth and Sand, with pebbly Gravel and Crag occasionally.
5. Chalk, the upper beds of which are soft enough to mark with, abounding with flinty Nodules. The under beds are much harder, and without Flints.
6. Green Sand, which immediately lies under the Chalk. 7. Golt Brick Earth, at the foot of the Chalk Hills represented by the lighter blue shade.
8, 9, 10. Sand and Sandstone, in which the Portland Rock is found, which is marked by the blue patches. In this County it is called Kentish Rag.
11. Oaktree Clay, part Slaty, and highly Bituminous, as at Kimmeridge.
13. Sand and Sandstone.