372 University of California Publications in Agricultural Sciences [Vol. 3 



But it was not until 1743 that Packe executed a map of Kent, showing 

 the occurrence of minerals by symbols. Apparently the next advance 

 was by the Germans, when Fiichsel, 1773, and Gioser, 1775, first used 

 colors to show granite, limestone, etc. This work constituted the first 

 real geologic map in the modern sense. There was not much activity 

 in this line of geologic work until 1870 or later. Such activity as there 

 was showed a lack of emphasis on soils in the agricultural sense of 

 the term. 



The work on the geologic drifts of northern Europe, and studies of 

 the more recent lowland formations and soils of Germany led to soil 

 mapping. The first real soil map, according to Blanck, was prepared 

 by Benningsten-Forder of Halle, in 1864-67 ; while Carnot 4 states 

 that in 1863 M. Scipion Gras used superposable maps of the Depart- 

 ment of Isere, showing (1) geology, (2) agricultural soils, (3) alti- 

 tudes of agricultural regions, and (4) culture. The first true geologic- 

 agronomic map published by the Preussischegeologische Landesan- 

 stalt appeared in 1878. 



The school of soil classification and mapping just mentioned, using 

 the geologic maps and methods as a point of departure have evolved 

 numerous though similar S3 r stems of recording the agrogeologic data 

 on the map. The geologic formation is shown by the color, and the 

 soil textures by symbols, while one or more of the following groups 

 of data appear and may be shown : topography by contours, subter- 

 ranean water by blue figures, location of borings in red with figures 

 referring to tables, amount of plant food elements or substances by 

 figures or hatchings, varying directions, color, or nature of lines, etc. 

 The nature and amount of the data shown and the manner of repre- 

 senting them vary a great deal. Some soilists, to use a term proposed 

 by Coffey, 5 advocate and use superposable maps to show one or more 

 groups of data, thus avoiding unnecessary confusion on the main map. 



Hazard 6 proposed a scheme of classification which is quite as 

 directly connected with the economic factors controlling the crops 

 grown, and with the assessable valuation of the land, as with the 

 actual or potential fertility of the soil itself. There are several classi- 

 fications of this type, involving the assessable values of the land. 



4 Eapport sur les cartes agronomiques, Bull. Min. Agr. France, 1893, no. 8, 

 pp. 956-73. 



s Jour. Amer. Soc. Agron., vol. 8 (1916), p. 239. 

 6Landw. Jahrb., vol. 29 (1900), pp. 805-911. 



Gregoire, A., and Halet, F., Bull. Inst. Chem. et Bact. Gembloux, 1906, no. 75, 

 pp. 1-43. 



