The geological-landscape nature reserve set up in 1972 lies south from Lake Hańcza in the Czarna Hańcza Valley in Suwałki Landscape Park. It is estimated that on the area of 1ha there are about 10 thousand boulders of various size ( from 0,5 to 8,7 m in perimeter). The boulders are naturally arranged on 4 terraces: in the Czarna Hańcza channel, on the bottom of the valley, on the terrace (about 10 m above the river level), on the surface of the outwash (about 25 m above the river level). It was brought here by a Scandinavian glacier together with a huge amount of clay which was washed away of all the fine-grained fractions and moved down the river. The boulders, being the heaviest and the most difficult to move, stayed. On its surface many species of lichen have been found, among them many occurring mainly in the mountains. Out of green plants the most interesting ones are adder's-tongue, greater meadow-rue, viburnum and various species of orchids.