When the ice sheet formed about 8,000 years B.C. started to melt, the water level rose. The Littorina stones were cut and rounded by the friction of the waves moving underwater. Today they cover a large area. The size of the stones varies. In some places they are small and polished, probably where the sea edge used to be, and the further you go, the larger and more uneven the stones become, probably due to greater depth.
The stone field is at Hornåsen, west of Hästhagssjön on Hornslandet in Västervik