326 TRANS. ST. I.OUIS ACAD. SCIENCE. 



where the hthifaction is perfect, appears to be at least in part cal- 

 careous. This sandstone is overlaid, and appears also to be 

 underlaid, by arenaceous shale. Only one of the coal-workings 

 was carefully examined. The coal (which is quite uniform) 

 averages 4 feet 5 inches in thickness, and was found to be under- 

 laid by dark shale or clay and covered commonly by arenaceous 

 shale, sometimes lithified, but occasionally by argillaceous shale. 

 The seam is sensibly horizontal, and lies perhaps 50 feet below 

 the railroad grade. It is sometimes affected by '^ difficulties," 

 comprising both "rolls" and "horsebacks"; and more rarely it is 

 interrupted by clay -partings, which are usually slickensided. 

 Consistent and unquestionably reliable information, derived from 

 different individuals at this point, indicates that at Summit and 

 elsewhere there is a thin (about 15-inch) coal- seam some 25 or 

 28 feet above the heavy seam, and that a few feet below the lat- 

 ter a notable ledge of limestone occurs. The various data fall 

 into the following relation : 



14. Re^ler Section. 



Feet. 



1. Drift, variable, but in one case 20 



2. Hiatus, say 5 



3. Coal li 



4. Hiatus, say 7 



5. Arenaceous shale, sometimes lithified, not less than 20 



6. Argillaceous or argillo-arinaceous shale i 



7. Coal 4h 



8. Under-clay, etc., about 5 



9. Compact limestone, say 5 



6SJ 

 T/ic Borijig ill Macon. — The prospect bore is located in the 

 southeastern part of the city in a ravine some 30 feet deep, where 

 the drift was found to be 36 feet in thickness. An ordinary 

 plunge drill was used. The diameter of the bore is 13 inches in 

 the drift and 8 inches in the rock to 320 feet from the surface, 

 where a strong flow of water was encountered and the diameter 

 was reduced to 5 inches. Samples were taken by means of the 

 "sand pump" at frequent intervals, particularly when change in 

 character of material was indicated by the behavior of the drill ; 

 and special care was exercised in taking samples and in deter- 

 mining thicknesses of strata when the boiings indicated the prox- 



