This monograph presents a study of Indigenous economies in traditional Larrakia country, the Darwin coastal region of northern Australia, during the Late Holocene period. Subsistence and settlement patterns of this period are revealed through archaeological investigation of shell mounds, which dominate the study area and have long been a topic of scholarly interest both internationally and in Australia. Addressed are cultural, environmental and taphonomic aspects of mound formation and the implications of inter and intra-midden variability for interpretations of chronological change in hunter-gatherer economic systems, particularly with regard to theories of Holocene intensification in the Australian literature. In this work, therefore, the author explores the question of why people built mounds of shell and why they then stopped this practice that had continued for millennia.