La Fontaine de la Demoiselle site (Dordogne, France) is an open-air dwelling of the late Neolithic age. Micromorphology and physico-chemical analysis of samples collected in archaeological layers and in a pit-filling show that different types of pedogenesis took place simultaneously in the two deposits. In the first, a brown acid soil has developed; the second is characterized by the presence of numerous black micro-particles, laminated argillans and a high percentage of exchangeable calcium. The pit materials have been brought there by humans. Such analyses help the archaeologists to determine the pit function. (See also <b>AATA</b> <i>20-32</i>) -- AATA