SCIENCE AND SOIL 



as a sample to show the amounts of plant foods in the material actually used as 

 a fertilizer. The potash content is not high for a greensand marl, but the 

 phosphoric -acid content is unusually high. The subsoil analysis (by acid 

 digestion) reveals the fact that the lime, potash, and phosphoric acid of the 

 original material have been extensively dissolved and removed, though fair 

 amounts still remain. " (Report for 1901, page 139.) 



Unless otherwise stated, the above quotations from the soil 

 survey field men and from Bureau of Soils Bulletin 54 refer specifi- 

 cally to the areas in which the samples analyzed (Table 22) were 

 collected. 



In general, there is very distinct correlation between the compo- 

 sition of these extensive soil types and their natural productive- 

 ness as recorded by the soil surveyors themselves some years be- 

 fore the chemical analyses were made. It should be kept in mind 

 that the data reported in Table 22 are for amounts in 2 million 

 pounds of ignited soil, and are thus somewhat higher than, and not 

 strictly comparable with, the results of analyses of the ordinary 

 dry soil. It is important, also, to know that most of the 27 type 

 soils described are found not only in the state and area in which 

 these analyzed samples were taken, but are widely distributed 

 throughout the respective formations, as the Coastal Plains, glacial 

 areas, Piedmont, or other regions. Thus the 1903 Report of Field 

 Operations of the Bureau of Soils mentions that Norfolk sand was 

 found that year in New York, Delaware, Maryland, Virginia, North 

 Carolina, Georgia, Florida, and Alabama; and Marshall black clay 

 loam has been reported for Ohio, Indiana, Michigan, Wisconsin, 

 Illinois, Iowa, Minnesota, South Dakota, and North Dakota. 



The Bureau of Soils includes in the one soil type (Marshall silt 

 loam) the common brown silt loams of the Middle and Upper 

 Illinoisan glaciations, of the Pre-Iowan, lowan, and Early Wiscon- 

 sin glaciations, in Illinois, as well as soil in the Janes ville and 

 Viroqua areas of Wisconsin, in the Grand Island and Staunton 

 areas of Nebraska, and in the Jamestown area of North Dakota, 

 with other areas in Colorado, Minnesota, Kansas, Missouri, Iowa, 

 Indiana, and Louisiana; but it is apparent that the ultimate 

 chemical composition of the soil is not considered among the 

 characteristics required by the Bureau for a soil type. Thus the 

 Marshall silt loam (brown silt loam) of the Middle Illinoisan glacia- 



