English: This profile was photographed in Rwanda, Africa. The soil is formed in shale on an 8 percent slope. The site is vegetated by grasses but previously cultivated by shifting cultivation. The soil contains more than 12 kg/m2 organic carbon to a depth of 100 cm thus the placement in the suborder Humults. Clay content in the A horizon (0-30 cm) is 37 percent. The Kandic (Bt) horizon extends from 30 cm to the bottom of the pit has a clay content of 57 percent, an apparent CEC7 of 4.6 cmols kg-1 clay and a CEC8.2 base saturation of 25 percent. Well drained Ultisols with a high content of organic carbon in the surface horizons (Humults) are most common in areas that may have been subjected to occasional dusting with volcanic ash. The decomposition of the ash may be responsible for coating and preserving the organic carbon. (Tape is marked in 5 cm squares)