These are medium-aged soils that usually form under deciduous forests. Names end in alf . Ultisol - ult from Latin ultimus. These soils are essentially acidic counterparts of alfisols. They have argillic horizons and low base saturation.
Name ends in ult .
Oxisol - ox from oxide. These have an oxic horizon, no argillic horizon. Oxisols are the most highly weathered soils, and are usually found in tropical regions. Oxisols are often bright red-orange. Name ends in ox .