576 Journal of Agricultural Research voi. v.no. 13 



for the first 6^ inches, which is considerably higher than the average 

 for the soils of the State. Field experiments which have been conducted 

 on this series for the past five years indicate that phosphorus is in no 

 way the hmiting element in crop production. 



The Granville soils, which are found in limited areas in the Piedmont 

 Plateau, are formed from sandstone and shale. These soils are unusually 

 high carriers of potassium, which is supplied mainly as microcline and 

 orthoclase. While some biotite and muscovite are encountered, very 

 little of the potassium rtiust come from this source. It would be inter- 

 esting to have field data on the requirements of the soils of this series 

 for potassium, for comparison with those of the Mountain province, 

 in which mica predominates. 



The Georgeville soils represent those formed from Carolina slate, and 

 the minerals other than quartz are mainly the potash feldspars and those 

 of a highly refractory character. Many of the particles carry an infil- 

 tration of iron oxid, which makes identification quite difficult. Much of 

 the orthoclase and biotite is badly altered, while other particles of these 

 minerals are found in an unusually fresh condition, which indicates that 

 an admixture of the material which enters into the formation of this soil 

 has taken place. 



The soils of the Atlantic Coastal Plain are characterized by their low 

 content of other minerals than quartz. The Norfolk and Portsmouth 

 series are by far the prevailing soils of this province, and, with few 

 exceptions, no particular mineral other than quartz predominates. 

 It might be said in passing that a few instances occur in which the other 

 minerals than quartz will run higher, but this is unusual. 



The average among the sand particles for the Norfolk series will not 

 exceed 5 per cent of minerals other than quartz, of which none pre- 

 dominate. Among the particles the size of silt will be found orthoclase 

 residues, microcline predominating. The less abundant minerals are 

 composed mainly of a heterogeneous mixture of the more refractory 

 minerals found in the provinces of higher topography. A point of interest 

 is the scarcity of the micas in the series ; they are encountered often, but 

 the quantity found is usually so small that they can be of little value 

 in maintaining the potash content of the soil solution. Apatite and the 

 plagioclase feldspars are rarely found, as they have passed out of existence 

 during the formation of this soil. 



The Portsmouth soils are quite similar to the Norfolk, the only dis- 

 tinctive difference being in the amount of organic matter found in the 

 former. On account of their location, which is usually in submerged 

 or recently drained areas, an accumulation of vegetable matter is en- 

 countered. The average content of minerals other than quartz in this 

 series is even lower than that of the Norfolk, being 3 per cent. The 

 persistence of sponge spicules or Rhizopoda casts in this series is rather 



