^•jo Journal of Agricultural Research voi. v, no. 13 



and granites. The sandy loams, sands, and most of the loams are prod- 

 ucts of the gneiss and granites; the heavier loams, clay loams, and clays 

 have been derived, for the most part, from schists. 



With few exceptions, the soils of the Piedmont Plateau are residual. 

 The rocks of this section are varied and complex, being composed of (i) 

 such igneous material as diorite, diabase, gabbro, and granites; (2) such 

 metamorphosed igneous material as gneiss, schists, and slate, and (3) 

 such young sedimentary rocks as Triassic sandstone and shale. 



None of the soils of the Atlantic Coastal Plain are residual. They all 

 belong to the broad division known as "transported" and are composed 

 of unconsolidated material laid down from the provinces of higher 

 topography. Because of the abrasive and leaching forces which have 

 entered into their formation, the least resistant minerals have been 

 removed, quartz composing mainly the entire soil mass. 



In the mineralogical composition of the soils series here reported, 

 the average analyses of five samples of each series were taken. These 

 samples were selected from widely separated areas in order that the 

 series might be as nearly representative as possible. It was recognized 

 at the outset that it would have been better to show the composition of 

 the various types of a series, but space would not permit such procedure. 

 However, it may be said as a general rule that there are no appreciable 

 differences in the occurrence of the minerals in the various types of a 

 series. There are wide variations in the preponderance of different 

 minerals in the types, but usually each series carries the same minerals 

 in all of its types. 



To obtain these results, a separation by mechanical analyses of the sand, 

 silt, and clay of each sample was necessary, and the mineral composi- 

 tion of the sand and coarse silt was determined. The clay particles were 

 discarded as being too small for identification. The results are given in 

 Table I, and include the estimation of all the minerals except quartz — 

 the more abundant or characteristic minerals and the less abundant or 

 secondary in quantity present. 



A careful study of Table I will show some rather interesting data con- 

 cerning the mineral component of the sand and silt particles of these 

 soils. One of the most striking points is the wide difference in mineral 

 complexity between soils of the Appalachian Mountains and those of 

 the Piedmont Plateau and the Atlantic Coastal Plain. The soils of the 

 Porters series are the predominating soils of the former province. The 

 Toxaway soils, which are found in the valleys, are of alluvial origin 

 modified by colluvial wash. In these soils there is a more decided occur- 

 rence of the original minerals of the parent rock than is found elsewhere. 



