1919] Pendleton: A Study of Soil Types 371 



and the results of the scheme of mapping. It was thought that pos-' 

 sibly some of the many questions could be answered through a labora- 

 tory study of some typical soils. This paper is a description of cer- 

 tain parts of the work done in this connection. 



THE NEED OP A CLASSIFICATION OF SOILS 



Since soils consist of a number of more or less distinct groups they 

 are fitting subjects for classification. In fact, it is nry belief that it 

 is as necessary to have a classification for soils as for any other group 

 of natural objects in order that "the various and complex relations 

 may be shown as far as practicable," 1 and that there be a definite 

 basis for systematic and thorough investigations. 2 The advantages of 

 a classification of soils are apparent. But because soils grade gradu- 

 ally into one another, rather than exist as discrete individuals which 

 can be more easily considered and treated from a systematic stand- 

 point, the problem of evolving a satisfactory classification has been 

 particularly difficult. The many and diverse classifications proposed, 

 and the difficulty of applying many of these classifications under con- 

 ditions other than those for which they were evolved, testify to the 

 difficulty of the task in question. 



The mapping of soils without a classification is impossible, and 

 so a brief summary of the development of soil mapping will bear a 

 close relation to the development of soil classification. 



HISTORICAL DEVELOPMENT OF THE CLASSIFICATION 



OF SOILS 



The early history of the making of soil maps is that of geologic 

 maps as well, when soils, from the agricultural standpoint, and the 

 less distinct geological formations as such, were not sharply distin- 

 guished. Blanck 3 has an excellent treatment of the development of 

 soil mapping and of the modern continental European conceptions of 

 the nature and significance of soil maps. According to Blanck the 

 earliest record of a proposal to make a map to show something of the 

 nature of the actual material composing the surface of the earth is 

 that of Lister's proposal, in 1683, to the Royal Society of London. 



i Coffey, G. N., Proc. Amer. Soe. Agron., vol. 1 (1909), p. 175. 

 2 Cameron, F. K., Eighth Internal Cong. Chem., vol. 26 (1912), sees. via-Xlb; 

 app. pp. 699-706. 



sFuhling, Landw. Ztg., vol. 60 (1911), pp. 121-45. 



