Origin of devil´s churns.

The potholes were created about 10 000 years ago as a result of erosion by the powerful meltwater stream that occurred in marginal zone of the retreating continental ice sheet. The water rushing through the meltwater tunnels in the bottom of the glacier carried boulders and rock with it. These meltwater streams removed all the loose material from the slope of the rocky hills of Sukulanvaara, from example. The powerful whirls that were created in the meltwater tunnel as a result set the boulders in the water in a spinning motion, so that they drilled their way into the broken rock beneath them, giving rise to these round potholes known as devil´s churns. Most of rock transported by the meltwater was deposited in the form of an esker running parallel to the tunnel. In fact, potholes always occur in esker chains deposited by meltwater.