COAL. 365 



considerably split by partings. These areas are not delineated, bul from 

 observation in the mines open al the time of examination it was inferred 

 thai the northwestern half of the syncline would prove the more important. 

 Here the Nos. 3 and 1 seams locally approach within an inch of each other, 

 and over a considerable area are sufficiently close to be mined together. 

 Where separated the No. .'! was more commonly mined, although No. 4 

 might also be workable both al the same point and at others. The sections 

 A and B, PI. XIX. and V to I., inclusive, PI. XX, afford a general view 

 of the character and relations of the several beds. 



The hollow of the Louisville syncline is apparently broad and gently 

 rolling, with local faults of light throw, encountered in mining. In the 



northwestern half there is a gentle rise of the strata toward the rim, 



increasing from 1 or 2 to 10 or L5 . The rise to the southeasl is much 



sharper, l.V to 20 . increasing locally to 25 , 30 . or even Hi . The 

 heavier coal scams an- quite free from dirt ami the smaller layers of sand 

 or clay, the only impurities of this nature being the partings of slate or 

 bone from 1 to <; inches or a foot thick, prevalent throughout the district. 



The coal is in the main bright, black, ami sipiare-joinfed. Its texture is 



homogeneous, laminated, or fibrous, the last character being due to 

 maintenance- of the original wood structure in certain of the layers, it 

 mines either in dicy blocks or with a conchoidal fracture in irregular 

 lumps. The hardness varies, being perhaps the greater in the lower 

 portions of the seams. With the exception of a single slope on the 



Southeast outcrop of the coal, the >eains are all worked from shafts. 



I in i M il I l II DI81 RICT. 



This district includes the half of the Coal ('reek syncline east of the 



Louisville fault. The precise limits are as yet undefined. To the northeast 



it is possibly continuous with the Mitchell area. On the northwest the- line 

 of demarcation is probably a little lielow the crest on the northwestern 



slope of die ridge separating Sand Gulch from Coal Creek, until the 



Louisville fault is reached, when this becomes its limit. To the southwest 



and south it probably continues beyond the rim of die syncline, although 

 interruption may occur in this direction by the possible prolongation of 



the 15a ker fault from east of Coal ('reek. On the easl the Coal ('reck 



