A fosse is a long narrow depression that lies between the front of a moraine and its outwash plain. Nantucket, an island of singular beauty off the coast of Massachusetts, is the easternmost point reached by the great glacial land transformers of millennia past, and strikingly exhibits the varied work of the ice sheet. All the topographical phenomena that result from the morainal margin are clearly present—kame hills, fosse, contact slope, and an apron plain. Widening and shrinking, rising and sinking, at times to near sea level, this particular fosse winds though almost the entire length of the twelve-mile island. Nantucket Town lies in the fosse.