ELISHA MITCHELL SCIENTIFIC SOCIETY. 75 



where the supply is abunda-nt directly into and across the 

 Coastal Plain region. 



Plank Roads. — As suggested above, in deep sandy regions 

 where timber is abundant the plank road may prove the 

 most economical good road that can be built for temporary 

 use, and some of them last six to ten years. But the great- 

 est objection to them lies in the fact that when the timbers 

 decay, whether this be at the end of four or ten years, the 

 road is orone; and the entire cost in labor and monev must 

 be repeated. 



Ix THE MiDLAXD AXD PiEDMOXT CouxTiES. — Throughout 

 the midland and Piedmont counties of the State, w^est of 

 the Coastal Plain region, rocks suitable for road purposes 

 are abundant and widely distributed, so that no one can 

 claim as an excuse for bad roads that the materials are not 

 at hand for good roads. It will serve our present purpose 

 to discuss these in the order of their geographic distribu- 

 tion, with but little regard to their geologic relations. 



Trap Rock in the Sandstone Areas. — As stated above, 

 sandstones possess very little value as road material, espe- 

 cially when broken into fragments, as is necessary in making 

 Macadam and Telford roads, but fortunately in this respect 

 the sandstones of North Carolina are quite limited in their 

 distribution. The larger of the two areas begins near 

 Oxford, in Granville county, and extends south-westward, 

 passing into South Carolina below Wadesboro. It has its 

 maximum width of about sixteen miles between Chapel 

 Hill and Cary, and its average width is less than ten miles. 

 It occupies the southern portion of Granville county, the 

 southern half of Durham, the western border of Wake, the 

 south-eastern border of Chatham, and portions of Moore, 

 Montgomery, x\nson and Richmond counties. The other 

 sandstone area is much more limited in extent.- It lies 

 mainly in Stokes and Rockingham counties, along the Dan 

 River, between Germantown and the Virginia line, a 



