By ice, County Down

Boulder clay (moraine): a mixture of clay, pebbles and large rocks left by a glacier

Around 10,000 years ago, the ice sheet that covered much of N. Ireland during the last “Ice Age” began to melt rapidly as global climate became warmer and sea levels began to rise.

As the ice melted, it left behind irregular mounds of rock material or moraine. These mounds, known as drumlins, cover much of the lowlands of County Down, but are most clearly seen in Strangford Lough where they formed attractive islands as sea level rose and flooded the area.

Strangford Lough is a Special Area of Conservation (SAC), renowned for the marine and bird life that inhabits its waters and surroundings. The National Trust operates a Wildlife and Conservation Centre at Castle Ward Estate.