The expansion of large-scale excavation in Britain and parts of Continental Europe, funded by major development projects, has generated extensive new datasets. But what might we be losing when surfaces are routinely stripped by machines? Investigation by hand of ploughsoils and buried soils in the Fenlands of eastern England reveals high densities of artefacts and features that would often be destroyed or overlooked. These investigations throw new light on the concept of site sequences where features cut into underlying ground may give only a limited and misleading indication of the pattern and timing of prehistoric occupation. The consequential loss of data has a particular impact on estimates of settlement density and population numbers, which may have been much higher than many current estimates envisage.