In southern Alberta, a buried Ah horizon is frequently present beneath Mazama tephra (ca. 6600 years BP). Drainage conditions during the formation of such buried Ah horizons may determine the quality of the aliphatic carboxylic acids in the soil organic matter. The spectrum of aliphatic acids extracted from a number of buried Ah horizons indeed suggests either well drained or poorly drained conditions during soil formation regardless of the mode of deposition of materials before or after the soil-forming interval. The climate required for development of the well drained paleosols was inferred to be similar to the climate under which surficial Black Chernozemic Ah horizons were formed.