130 J. J. STEVENSON — CARBONIFEROUS OF APPALACHIAN BASIN 



third and fourth conglomerates are equivalent to the Rockcastle and 

 Corbin is very great, the more so because midway between the Bonair 

 and the third there is a great and persistent sandstone holding a rela- 

 tive place very like that of the persistent sandstone above the Sewanee 

 coal bed in the Tennessee sections. But in the absence of beds above 

 the Bonair conglomerate almost everywhere south from the Etna mines, 

 in Tennessee, to Blount county stratigraphy is helpless, and the final 

 determination must be made by means of paleobotany. Happily the 

 material is within easy reach, for plant-bearing beds are present at sev- 

 eral horizons up to within 200 feet of the fourth conglomerate. More 

 than twenty-five years ago Leo Lesquereux, after studying the plant re- 

 mains, referred the formation to the Pottsville * Mr Gibson's section 

 shows twenty-six coal beds above the Etna conglomerate, most of which 

 attain workable thickness in some portion of the area. Three beds are 

 persistent between the Bonair and Etna, the middle one being the 

 Cashie. The coal beds in the Lower Measures are insignificant.f 



The Raccoon Mountain area may be regarded as extending only to 

 the southern line of Blount county, where Sequatchie-Browns valley 

 terminates and Raccoon becomes continuous with the Great Warrior 

 coal field, covering a large area west from Browns valley and tapering 

 southward to Tuscaloosa. At the west and south the Coal Measures 

 pass under the cretaceous beds. Messrs Gibson and McCalley have 

 studied the formation in Blount county. The work of the latter was 

 merely reconnaissance, but he traced the Bonair on both sides of Rac- 

 coon and found the Etna coal bed at a few localities, nowhere more than 

 1 foot thick. Whether or not more than one coal bed are present be- 

 tween the conglomerates was not ascertained.! 



Mr Gibson's section of Berry mountain, a high fragment remaining in 

 the southern part of Blount county, contrasts strangely with the sec- 

 tion on Blount mountain on Blackburns fork, about 6 miles toward the 

 southeast. The measures below the Etna are but 30 to 40 feet thick. 

 The Bonair and Etna conglomerates are each 50 to 60 feet and are sepa- 

 rated by 25 to 30 feet of flaggy sandstone with clay. Seven hundred 

 feet of measures remain above the Bonair, with coal beds at 150-200, 

 250-300, 375-425, 455-500, 475-520, and 495-535 feet above that con- 

 glomerate. One can not determine the equivalents of these beds in the 

 general section of Blount mountain. Plant-bearing shales are present 

 near the top of the section.§ 



* E. A. Smith in letter to writer. 



t A. M. Gibson : Geol. Survey of Alabama, Coal Measures of Blount Mountain, 1893, pp. 17, 18, 21 

 22, 23, 32, 33, 36, 38, 42, 47, 49. 

 % H. McCalley : Op. cit., pp. 132-134. 

 §A. M. Gibson: Coal Measures of Plateau Region, pp. 192, 193. 



