478 STEVENSON— THE FORMATION OF COAL BEDS. [Nov. i, 



.in that after a niaxinuim area was reached, the conditions ceased 

 to be general, became more or less localized and the deposits were 

 jsolated, at times widely separated. 



The earliest appearance of the Pennsylvanian reds is in the New 

 River of northwestern Georgia, where two beds, ii and 35 feet, were 

 found, with 103 feet of variegated shale intervening.'"''' No reds are 

 reported from the Pottsville of the anthracite region and they are rare 

 in the Allegheny, occurring only in the lower part of that formation. 

 A bed, 32 feet thick, was found near Drifton in the Eastern Middle 

 at 30 feet below the Buck Mountain coal bed and, near Harleigh. a 

 thin bed underlies that coal. In the northern part of the field, a soft 

 red sandstone is at a few feet below the Mammoth and near Har- 

 leigh a thin bed of red sandstone overlies the Buck Mountain ; at a 

 few miles west, in the Western Middle, some thin streaks of red 

 shale exist between the Buck Mountain and the Mammoth. These 

 are all within a narrow north and south space and must have been 

 brought down from the Alleghania slope. 



Red shale first appears in the bituminous region during the latter 

 part of the Allegheny. The most southerly locality is in Boyd county 

 of Kentucky, where 18 feet of green and red shale were seen near 

 the top of the formation. The deposit is altogether local, for meas- 

 ured sections and well records in adjoining counties of Ohio and 

 West Virginia show no trace of red at this horizon. The nearest 

 notable deposit is more than 80 miles distant toward the northeast in 

 Washington county of Ohio, where 64 feet of red shale begins at 

 503 feet below the assumed place of the Pittsburgh coal bed and so 

 extends downward to the middle of the Allegheny. There, one has 

 reached what may be termed the Central area, in which red shales 

 are a striking feature from the middle of the Allegheny to the close 

 of the Pennsylvanian. This area embraces contiguous portions of 

 Washington county of Ohio, Wood, Ritchie, Wirt, Calhoun, Roane. 

 Jackson, Gilmer and Clay counties of West Mrginia, in all not far 

 from 3.500 square, miles. Red shale in the Allegheny is reported 

 here and there from other counties but in each case the deposit is 

 insignificant. 



"'J.' W. Spencer, "The Palaeozoic Group." Geol. Surv. Georgia, 1893. 

 p. 139- 



