sentences:  Other vicinity landmarks are the ancient royal game reserve (now a nature reserve) at Ottenby, found at the southern tip of the island about 30 kilometers to the south and the Eketorp fortress, a restored Iron Age ringfort, lying 21 kilometers south.Bedrock layers are primarily Ordovician limestone that dates to at least 600 million years ago.Most of the limited supply of topsoil was created from glacial grinding of the limestone bedrock, which action created the nearly flat alvar formation.