While karst environments present methodological and interpretive challenges to archaeologists, they also provide some unique opportunities. One of these opportunities is the ability to date field walls by measuring divergent rates of bedrock dissolution underneath and adjacent to ancient walls. Field walls are traditionally difficult to date, either by using morphological typologies or through the association of diagnostic or chronometric materials. The method presented here, therefore, represents a valuable tool for archaeologists working in karst landscapes. The methodology is described along with a discussion of potential problems, drawing in particular upon evidence from the karstic terrain of the Burren in western Ireland. The methodology is then applied to a group of field walls on the Burren, which are shown to date to the Chalcolithic - Early Bronze Age. (C) 2015 Wiley Periodicals, Inc.