1919] SOILS FERTILIZERS. 511 



mineral soils of Sweden which contain either little or no humus, on the basis 

 of consistency. The grouping and classification is as follows : 



Gi'oup I. — Plastic clays and clay soils containing litt^le or no humus. 



Class 1. Highly plastic clay in which the degi-ee of stickiness lies 



between the flowing limit and the rolling-out limit. 

 Class 2. Dry plastic clay and clay loam. 



Subclass A. Loamy clay of dry plasticity, low flow limit and high 



firmness. 

 Subclass B. Loamy clay of dry plasticity, high flow limit, and low 



firmness. 

 Subclass C. Poor clay of low consistency and plasticity. 

 Class 3. Siliceous and sandy clays. 

 Group II. — Loams of low plasticity which have a relatively high binding 

 power. 

 Class 1. Heavy clay loam, hard and firm when dry and loose and 



easily worked when moist. 

 Class 2. Lighter loams of low firmness. 

 Subclass A. Fine sandy loam. 



Subclass B. Poor weathered clay loam of sedimentary origin. 

 Class 3. Siliceous and coarse sandy loam. 

 Group III. — Sandy soils of loose texture, very low firmness, and practically 

 no consistency. 

 Class 1. Fine sands. 

 Class 2. Coarse sands. 

 Class 3. Siliceous sands. 

 The classification of the mineral soils of high, humus content of Sweden, 

 A. Atterberg and S. Johansson {Intermit. Mitt. Bodenk., 6 (1916), No. 1, pp. 

 38-59, figs. 3). — ^Studies of the mineral soils of Sweden, of high humus content, 

 with reference to determining their proper classification, are reported. The 

 results obtained indicate that these soils should be classified into the four 

 following main groups : 



(I). Nonplastic soils containing from 3 to 6 per cent humus. 

 (II). Nonplastic black soils containing over 6 per cent humus. 



Subclass 1. Soils with low flow limit containing from 8 to 9 



per cent humus. 

 Subclass 2. Soils with high flow limit containing from 10 to 22 

 per cent humus. 

 (III). Kieselguhr black soils containing from 12 to 21 per cent humus and 

 characterized by the high content of diatomaceous residues and 

 high flow limit. 

 (IV). Clays rich in humus of high plasticity. 

 Subclass 1. Soils of low consistency. 

 Subclass 2. Soils of medium consistency. 

 Subclass 3. Soils of high consistency. 

 On the basis of these results it is concluded that mechanical analyses are 

 superfluous for these soils, and that volume weight and flow limit determina- 

 tions are suflicient for their classification. 



Soil survey of the Los Angeles area, Cal., J. W. Nelson, C. J. Zinn, A. T. 

 Strahorn, E. B. Watson, and J. E. Dunn (U. S. Dept. Agr., Adv. Sheets Field 

 Oper. Bur. Soils, 1916, pp. 78, i)ls. 3, fig. 1, map 1). — This report, prepared in 

 cooperation with the California University Experiment Station, deals with 

 the soils of an area of 360,320 acres in southern California which topograph- 

 ically consists of a fringe of low hills and a low alluvial plain. The area is 



