Here we quantify the three-dimensional geometry of a bedrock hollow that is mantled with a thick colluvial fill on a hillslope near Clear Lake, California. The site was selected because of a recent and thorough study of radiocarbon-dated pollen cores in Clear Lake by Adam et al. (1981). We found well-defined pollen changes in the wedge that, when correlated with Adam et al.' s pollen stratigraphy, provide an approximate age of the oldest colluvium in the hollow. In conjunction with documentation of the volume of colluvium in the hollow, we have obtained unique data on local rates oflandscape lowering.