Cape Cod is composed almost entirely of rock debris deposited by Ice Age glaciers more than 18,000 years ago. Most of this debris, called glacial till, consists of clay, sand, and pebbles, but the Ice Age also deposited larger stones. Doane Rock, also called Enos Rock, is one of the largest ice-carried boulders in southeastern New England. It stands 18 feet high, extends an estimated 12 feet below ground, and is 45 feet long. Between 18,000 and 25,000 years ago, a giant ice sheet crept over this region, plucked the rock up in the Massachusetts Bay area, and carried it to Cape Cod. The grinding action of the glacier rounded its contours. The ice sheet gathered up rocks and transported them many miles, depositing them as glacial till where the ice melted. Other glacial boulders can be seen along the nearby beach, where winds and waves have dislodged them from the glacial till of the eroding sea cliffs.