GEOLOGY OF CHAPEL HILL AND VICINITY 



An Outline 



BY JOHN E. SMITH 



The circular area having a radius of about five miles with 

 Chapel Hill near its center is located chiefly on the eastern mar- 

 gin of the Piedmont Belt, but includes a small portion of the 

 arm of the Coastal Plain that extends northward beyond Oxford 

 and whose western border is less than two miles east of the vil- 

 lage. 



TOPOGRAPHY 



The area is traversed by New Hope Creek in its northern 

 part, by Bolin's Creek near the middle, and by Morgan's Creek 

 on the south. Its drainage is therefore excellent. These streams 

 flow eastward to the plain where they join and flow south- 

 ward until they reach the waters of the Cape Fear. The 

 general elevation of the upland is 500 to 540 feet and that of 

 the creek bottoms and the plain is about 200 to 250 feet lower. 

 This gives the area the rugged topography typical of the eastern 

 margin of the Piedmont Plateau. 



Into this plateau the streams have cut their valleys by erosion ; 

 this work is still in progress and can be observed in every stage 

 of advancement in each of the larger streams of the area, from 

 the smallest gulley to the broad mature valley. The small deep, 

 steep sided valleys show youthful stages of development. As 

 one proceeds down stream, a point is reached where the current 

 is checked to such an extent that the cutting is confined to one 

 level; here the valley begins to grow in width, a floodplain 

 forms, and from this place down the valley, the various stages 

 of maturity, increasing in age with the distance, are illustrated. 

 This side cutting or lateral planation proceeds very slowly on 

 the outer curve of a meander where it touches the valley wall, 

 and in time, by crossing from one valley wall to the other, de- 

 velops a broad floodplain. The region as a whole is one of ma- 



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