Kummakivi Erratic Boulder


  • Kummakiventie 58 56310 Ruokolahti Navigate

Why not take a nice, safe & easy forest hike to go see a bizarre effect of the last Ice Age? Kummakivi ["Strange boulder" in English] is a big erratic boulder which was glacially transported to rest on top of flat rock. The boulder is special because only 0.5m2 of it is in contact with the rock below and the dimensions of the boulder itself - approx. 7 x 4 x 5 m. Both the erratic boulder and the rock below are mixed granite-cordierite-mica-gneiss typical of the area, and the grooves are signs of glacial erosion. The area emerged from under the continental ice sheet around 11500 years ago. The environment around Kummakivi at that time differed drastically from that of today: instead of nestling in the shade of the forest, the boulder was perched on the shore of an ancient ice lake. Near Kummakivi erratic there is a moss bridge ["sammalsilta” in Finnish] across Pitkäjärvi lake. The bridge was built by the Kaukas company in the 1930s and its original purpose was to shorten the distance of forest workers traveling from one side of Lake Pitkäjärvi ["Long lake in English] to another. Today, the bridge serves Kummakivi erratic passers-by and other nature enthusiasts. The circular path is 2,2 km long and easygoing and while there, you can enjoy typical South Finnish coniferous forest & lake ecosystems. There is a Saimaa Geopark sign at Kummakivi Parking area and another next to Kummakivi itself. Kummakivi is protected as a natural monument outlined in the Nature Conservation Act.