Identical designations may be appropriate for two or more horizons or layers separated by at least one horizon or layer of a more different kind in the same pedon. The sequence A-E-Bt-E-Btx-C is an example - the soil has two E horizons. To make communication easier, a prime is used with the master horizon symbol of the lower of two horizons having identical letter designations: A-E-Bt-EÆ-Btx-C. The prime is applied to the capital letter designation, and any lower case symbol follows it: BÆt. The prime is not used unless all letters of the designations of two different layers are identical. Prime can be used for both minerals and organic soils.