The title of the series comes from the boulders, deposits from the glacial periods of the Pleistocene, which are scattered along the edge of the seawall of Stanley Park in Vancouver, BC, Canada.

The shoreline is a locale where changes take place continuously at various time scales: the sea rises and falls twice in a lunar day; animals and humans come and go daily and as the seasons change; peoples and communities of living organisms migrate across the water over the centuries; land is eroded and remade across the geological ages, while species evolve as they move from water to land, with some returning to water. In this myriad of changes, pieces of driftwood, temporary visitors of the shore, remind us that the present we occupy is but a point in the continuum of time: many generations of biological species have come before us, and many more generations will come after us, if we fulfill our duty as custodians of the Earth.