Are your lower strata compacting as they become older? Are you losing your organic matter with age? When you're in the pits is sterility really at the bottom of it all? Questions such as these come to all archaeologists, sooner or later. In my own case it was the excavations in Cathedral Cave, a sandstone rockshelter in southeast central Queensland (Beaton 1977), which prompted these questions and led ultimately to the development of a simple device for estimating the bulk-density (compactness), moisture, and organic content of the shelter sediments. Other archaeologists, especially those working in any of the numerous sandstone rockshelters in Australia, may find it to their advantage to be able to collect constant-volume samples from their stratigraphic profiles as an aid to understanding aspects of deposit formation processes.