510 STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 



horizon being the Barro Branco. Southwardly, the coal measures 

 pass under cover not far south from Minas and come again to the 

 surface near Sao Jeronymo in Rio Grande do Sul, where the Tre- 

 viso is represented by shale, the Irapua by shale and coal, but the 

 Barro Branco or Sao Jeronymo is important. At Serro Partido 

 near Rio Candiota, where Plant obtained his section, the section as 

 measured by White is, thicknesses being given in meters, (i) shale, 

 sandstone and concealed, 19.28; (2) coaly shale, 0.91 ; (3) shale with 

 plants, 2.29; (4) coal and shale, 0.305; (5) clay, 1.52; (6) shales, 

 dark and yellow, plants in latter, 1.04; (7) Sao Jeronymo. Coal, 

 4.78, consisting of (a) slaty coal, with Sigillar'm in roof, 1.22, (&) 

 blue clay, 0.51, (c) carbonaceous shale, some coal, 1.22, {d) impure 

 coal, 1.83; (8) clay and shale, 6.59; (9) interval in shaft, reported, 

 12.19; (10) Irapua Coal, 0.20 to 0.36. It is evident that the earher 

 observer mistook dark shale for coal. 



The one persistent coal horizon is the Barro Branco-Sao Je- 

 ronymo, but it varies greatly. It is usually triple in the Minas 

 region, though more divided at times, the thickness varies from 0.93 

 to 2.20 meters, and the coal is described as " good " to *' fairly good " 

 and " slaty." In Rio Grande do Sul, it has, at one place, 2.68 thick- 

 ness with a parting of clay, only 10 centimeters, but at other places 

 this parting is from 3 to 5.30 meters. The other seams are traceable 

 in the two southern states, but for the most part they are thin. The 

 roof at most places is a leaf-bearing shale and the floor is clay or 

 clay shale. One can hardly recognize faux-mur or faux-toit owing 

 to character of the coal. 



The coal is always high in ash and usually in sulphur. Analyses 

 of that from the one important horizon show : 



Barro Branco. Sao Jeronymo. 



Moisture i.oi to 1.21 3-43 to 6.05 



Volatile 7.64 to 26.00 22.98 to 29.09 



Fixed Carbon 35.34 to 54-63 37-52 to 44.20 



Ash 24.88 to 28.38 23.04 to 31.17 



Sulphur 1.58 to 11.42 0.60 to 12.96 



The sulphur is present as pyrite and it, as well as a great part of 

 the ash, can be removed by washing. Briquettes, made from 

 washed coal, have from 8 to 14 per cent, of ash and 0.64 to 1.31 of 



