10 The Bulletin 



lying rocks. The only exception is the small area of alluvial soils found 

 along the streams, and here the soils are composed of fine material 

 which has been washed down from adjoining uplands or mountain sec- 

 tions, carried and deposited along the streams at times of normal rain- 

 fall and freshets. 



The rocks of the Piedmont region are varied and complex, including 

 old igneous rocks, such as diorite, diabase, gabbro and granite; the 

 metamorphosed igneous and sedimentary rocks, such as gneiss, schist 

 and slate ; and the young sedimentary rocks, such as Triassic sandstone 

 and shales. The older rocks have been tilted and warped out of all 

 semblance to their original position, this tilting and folding being 

 noticeable in road cuts in many localities. 



At one time there was no soil over the present Piedmont region, but 

 the surface was composed of hard bed rocks, and the waves and tides 

 of the waters of the Atlantic Ocean lashed the rocks along the eastern 

 edge of this region. The disintegration and weathering of the rocks by 

 the slow but constant action for centuries of nature's agencies of de- 

 composition and decay, such as rain, sunshine, freezing, thawing, vege- 

 tation and the like, has gradually broken down these rocks into very 

 small particles, which mixed with organic and vegetable matter, forms 

 the present soils. In many places on the slopes erosion has kept such a 

 close pace with disintegration that the rotten rock or bed rock is ex- 

 posed. As a general rule, however, these rocks have weathered to a con- 

 siderable depth as seen in railroad cuts and in digging wells. 



The varied rocks of this region differ materially in their physical 

 and chemical composition and their disintegration and subsequent proc- 

 esses of weathering have gi^ en rise to apparent differences in the result- 

 ant soils. These differences have justified the grouping of the soils 

 into series based principally on the origin or character of rock from 

 which derived, color, structure, and crop adaptation. There is gener- 

 ally a close relation between soil series and certain rock formations. 

 The Alamance and Georgeville series are confined exclusively to the 

 Carolina slate belt; the Iredell and Mecklenburg series to an area un- 

 derlain by diorite, gabbro-diorite, and mica-diorite ; the Granville and 

 Penn series to the Triassic basin, where sandstone and shales occur. 

 The largest and most important series in the Piedmont region is the 

 Cecil. This series and the Durham series owe their origin mainly to 

 granites and gneisses. 



Tlie names given to the series and types, such as Cecil, Durham, Ire- 

 dell, Granville, Mecklenburg, etc., are usually the names of counties or 

 towns where the types were first mapped and are used for purposes of 

 identification, as being more distinctive and easier to remember than 

 numbers. 



CECIL SERIES. 



The Cecil Series includes the most important and widely distributed 

 soils of the Piedmont Plateau, being the dominant soils in every county, 

 except in a few counties in the slate belt. The heavier members are 

 knoAvn as "red-clay land," while the sandy surface areas are called 

 "gray lands." A characteiistic of the subsoil is the content of sharp 

 quartz sand, and the frequent occurrence of veins of quartz. Mica 



