STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 33 



ties where the coal is very thick. Several observers have urged 

 that the varying interval between the coal and the granite floor is 

 likewise a result of disturbance. This suggestion may, perhaps, 

 prove good for some localities but to the writer it seems unnecessary 

 to resort to that hypothesis ; Rogers's suggestion is far better, that 

 the deposits were made on an irregular surface. This accords with 

 the conditions observed in North Carolina as well as in Virginia. 



Two Triassic areas are in North Carolina ; the Dan River, at the 

 northwest, is without coal in Virginia but has some irregular de- 

 posits in North Carolina ; the Deep River, at the southeast, begins 

 near the Virginia line and extends as a narrow strip southwest- 

 wardly into South Carolina.*^ 



Emmons's section in the Deep River area shows a triple struc- 

 ture : Upper red sandstones and marls ; Coal measures, slates, shales 

 and drab sandstones ; Lower red sandstone with conglomerate at 

 base. The red rocks, wanting in the Cumberland and Richmond 

 areas of Virginia, reappear here on the southeasterly border. The 

 middle group, about 1,200 feet thick, has fine-grained sandstones 

 which frequently are rippled ; the coal seams are few and very ir- 

 regular but some of them have been opened. Russell states that at 

 Egypt a shaft reached, at 422 feet from the surface, a coal seam 

 showing (i) black shale; (2) coal, 2 feet; (3) black band, i foot, 4 

 inches; (4) coal, i foot, i inch; (5) slate, 6 inches; (6) coal, 7 

 inches. Another seam, 25 feet lower, has black band roof and floor 

 and is one foot thick ; the upper seam has black shale roof and floor. 

 Both are irregular in thickness and Russell asserts that there is no 

 reason to suppose that they are continuous in any considerable area. 



The coals are indefinite within the Dan River area. Emmons 

 reports that, near Leakesville in northern part of the area, a coal 

 seam shows: (i) coal, semibituminous, 2 to 3 feet; (2) micaceous 

 shale, 2 feet; (3) coal, shaly, i foot, 6 inches. This is very near 

 the base of the coal group. The lowest rock at the southern extrem- 



-5 E. Emmons, " Geological Report of the Midland Counties of North 

 Carolina," 1856, pp. 228, 230, 235, 256, 257; I. C. Russell, Bull. 85, p. 41; W. 

 C. Kerr, " Report of the Geological Survey of North Carolina," Vol. I., 1875, 

 p. 143 ; R. W. Stone, " Coal on Dan River, North Carolina," Bull. 471-B, 1812, 

 pp. 5, 6, 16. 



PROC. AMF.R. PHIL. SOC, VOL. LVII, C, JANUARY 30, I918. 



