The degree of soil horizon development can be used as a proxy for this process. The ashy soil horizon had prehistoric artifacts associated with them. The upper soil horizon of a rendzina therefore contains considerable amounts of humus. A soil horizon "sensu stricto" is a result of soil-forming processes (pedogenesis). Varying horizontal bands of colour in the soil often identify a specific soil horizon. A soil horizon formed due to eluviation is an eluvial zone or eluvial horizon. Landsat ETM+, to develop the soil horizon and therefore aid its classification. The bleached soil horizon goes over into a red or red-brown horizon (so-called Podzolic B).