GEOLOGICAL CLASSIFICATION OF SOILS 49 

 Table VII 



CHEMICAL ANALYSES OF TWO ALLUVIAL SURFACE SOILS AND THE 



RESPECTIVE SURFACE SOILS FROM WHICH 



THEY WERE DERIVED. 1 



Delta soils, where they occur in any acreage, are very im- 

 portant. The deltas of the Mississippi, Ganges, Po, Tigris, 

 and Euphrates rivers are striking examples. Egypt, for 

 centuries the granary of Rome, bespeaks the fertility of such 

 land. Flood plain soils are found to a certain extent along 

 every stream, the greatest development in the United States 

 occurring along the Mississippi. This area varies from forty 

 to sixty miles in width and has a length from Cairo to the 

 Gulf of over 600 miles. Such soils are very rich but, if 

 they are first bottoms, they require drainage and protection 

 from overflow. Alluvial fan soils are found over wide areas 

 in arid and semi-arid regions and when irrigated and prop- 

 erly handled have proven very productive. They often occur 

 in large enough areas in humid regions to be of considerable 



1 Williams, C. B., et al., Report on the Piedmont Soils ; Bui. N. C. 

 Dept. Agr., Vol. 36, No. 2, Feb., 1915. 



1. Average of 8 analyses of Piedmont alluvial soils, Congaree 

 series, to a large extent a wash from the Cecil. 



2. Average of 71 analyses of Cecil series soils, the typical upland 

 soil of the North Carolina Piedmont. 



Williams, C. B., et al., Report on the Coastal Plain Soils; Bui. N. C. 

 Dept. Agr., Vol. 39, No. 5, May, 1918. 



3. Average of 8 analyses of coastal plain alluvial soils, Johnston 

 and Kalmia series. 



4. Average of 165 analyses of Norfolk series soils, the typical 

 upland coastal plain soil of North Carolina. 



