CARBONIFEROUS AGE. 



317 



to give sulphur fumes to the gases from the burning coal, and sometimes enough to 

 make the coal valueless in metallurgical operations. Some thin layers are occasionally 

 full of concretionary pyrite. 



Sulphur also occurs, in some coal-beds, as a constituent of a resinous substance; and 

 Wormley has shown that part of the sulphur in the Ohio coals is in some analogous 

 state, there being not iron enough present to take the whole into combination. 



Wormley gives the following analyses (besides others) of the ash of two coals, one 

 from the Youghiogheny, in Western Pennsylvania, and the second from Pigeon Creek, 

 Jackson County, Ohio: Silica 49-10, 37*40, alumina 38-60, 40-77, sesquioxyd of iron 

 3-68, 9-73, magnesia 0-16, 1-60, lime 4-53,6-27, potash and soda 1-10, 1-29, phosphoric 

 acid 2-23, 0-51, sulphuric acid 0-07, 1-99, sulphur (combined) 0*14, 0-08, chlorine trace = 

 99*61, 99*64. The fact that there is too much sulphur in the Ohio coals for combination 

 with the iron present, is shown in the following table, containing some of his results: — 



Sulphur in the coals .... 0*57 1*18 2-00 0-91 0-86 



Iron in the coals 0-075 0-742 0*425 0-122 0*052 



Sulphur required by the iron 0*086 0-848 0-486 0-139 0*06 



The average amount of ash, in eighty-eight coals from the southern half of Ohio, ac- 

 cording to Wormley, is 4*718 per cent. ; in sixty-six coals from the northern half , 5*120; 

 in all, from both regions, 4*891; or, omitting ten, having more than ten per cent, of 

 ash, the average is 4*28. In eleven Ohio cannels, the average amount of ash was 

 12-827. 



In rare cases, an occasional bowlder or rounded stone has been found in a coal-bed, 

 as well as in other layers of the. Coal-measures. E. B. Andrews describes one of 

 quartzyte, lying half buried in the top of the Nelsonville coal-bed, at Zaleski, Ohio, 

 which was twelve and seventeen inches in its two diameters. F. H. Bradley reports 

 one, also of quartzyte, about four by six inches, found in the middle of the coal-bed 

 mined at Coal Creek, East Tennessee. These may have been dropped from the roots of 

 floating trees, as are the masses of basaltic rocks occasionally found upon the coral 

 atolls of the Pacific. 



4. Vegetable Remains in the Coal. — In many places, there are 

 vegetable remains in the coal itself, such as impressions of the trunks 



Figs. 615-616. 

 615a 



Fig. 615 a, b, e t Vegetable tissues in anthracite ; 616, Spores and part of a Sporangium, in bitumi- 

 nous coal of Ohio (X 70). 



or stems of trees, or of leaves, or charcoal-like fragments, which in 

 texture resemble charcoal from modern wood ; but which have been 

 found to be carbonized stems, leaves, or tissues ot plants. 



