Grain, other seeds, other parts of plants, and also small animals, such as insects, may become incorporated in pottery, bricks, daub or other clay materials. On firing, or as a result of decomposition over time, the organic material itself is lost, but the outline remains as an impression within the clay. Casts of these impressions are taken using latex rubber, and the original plant or animal may be identified.
The Macmillan dictionary of archaeology, Ruth D. Whitehouse, 1983Copied