When the ice melts from around the meltwater tunnels, the beds of sand and gravel are deposited on the Earth's surface as long twisting ridges known as eskers . When glaciers are rapidly retreating , numerous blocks of ice can become detached from the main body of the glacier. If glacial drift is then placed around the ice, a depression on the surface called a kettle hole can be created when the ice melts . Kettle holes are commonly found on moraine and outwash plain deposits. Large kettle holes that reach below the water table can form into lakes.
Some kettle holes develop into wetlands such as bogs, swamps, and marshes.
Kettle Lakes, Northwest Territory, Canada. Glacial retreat also creates hill shaped deposits of till known as a drumlins . Drumlins often occur in large congregations across areas of New York and Wisconsin, USA and Ontario, Canada. The streamline shape of these glacial features resembles a protracted teaspoon laying bowl down. The narrow end of the drumlin points to the general direction of glacial retreat.